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[Question]
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I'm working on a setting where one of the large continents is similar to North America before the arrival of humans, including a biome containing the three large grazing ungulate species: [aurochs](https://en.wikipedia.org/wiki/Aurochs), bison, horses. I'm trying to figure out exactly what their ranges will be, and in particular, how they relate to each other.
All three are stereotypically animals of the prairies, but bison at least seemed to actually be able to live in quite forested regions. There is an account here of what seems to have been quite a substantial population of bison in Louisiana, which is nowhere near the prairies, and at first glance, entirely forested: <https://heartoflouisiana.com/last-buffalo-in-louisiana/>
I'm not quite sure how it is possible for a grazer to live in a forest, but there is a variety of bison called the wood bison <https://en.wikipedia.org/wiki/Wood_bison> confirming it is possible. Perhaps primordial forests are patchier, possessed of more meadows or at least margins of grass, than one might think?
Is this also true of aurochs and horses? Or put another way, if you make your way from forest toward prairie, would you be equally likely to encounter all three species at any given time? Or would you have a scenario where you could encounter bison in the forest, but would need to travel another few hundred miles up the Mississippi, say, before reaching prairies and encountering horses?
[Answer]
Here is a proposal.
1. [**Aurochs are wetland specialists.**](http://bioweb.uwlax.edu/bio203/s2014/hoefgen_laur/habitat.htm#:%7E:text=The%20exact%20habitat%20of%20the,lives%20in%20a%20river%20valley.) Your auroch herds will be along rivers and in wetlands / flooded areas. You can pattern them on the existing niche for water buffalo. In temperate areas they might make seasonal migrations.
2. **Bison are browser / grazers.** They are versatile and subpopulations might specialize in one ecosystem type or another. Large herds will roam the grasslands as the American bison did. Smaller groups would live in open forest or edge ecosystems as European bison did in historic times. There are places where the bison and auroch overlap and even interbreed.
3. **Horse groups are everywhere.** Horses can get by in more marginal territories but will exist in rich territories also. They live from the desert all the way to subalpine areas with regional adaptations for these subpopulations or even subspecies. Small groups of horses or small stallion herds can be found at higher altitudes than the bovids, and in drier places where browse would not support herds of bovids. Occasionally horses will join mixed herds with bison as one can see with zebra / wildebeest mixed herds in Africa - the bison benefit from the keener senses of the horses and the horses benefit from the offensive capabilities of the bison.
4. **Yaks**. Did you mention yaks? I guess I dreamed that. Can you have yaks too please?
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Jellyfish also called sea jellies or pain-blobs (my favorite name) are unusual animals to say the least. Members of the subphylum Medusozoa, a major part of the phylum Cnidaria, jellyfish have no organs to speak of. No central nervous system, no pulmonary system instead they get their oxygen entirely through diffusion. About 95% water, these blobs are the last animal you’d expect to be fast. Although don’t get me wrong they are efficient.
[](https://i.stack.imgur.com/FJELI.jpg)
The bell shape scyphozoans are so famous for creates vortices that push them up or forward... these animals don’t really have directions. This is so good it has remained unchanged for over 500 million years. Though some species diverge from this shape.
**My goal is to design a jellyfish capable of great bursts of speed.**
The box jellyfish actively hunts its prey (small fish), rather than drifting as do true jellyfish. They are capable of achieving speeds of up to 1.5 to 2 metres per second. It’s also good to get away from hungry sea turtles. What I’m having trouble with is making this already perfect anatomy faster.
My first instinct was to stack jellyfish bells together to get more thrust. Another idea was to have tubes passing through the jellyfish to squirt water.
Creative solutions are welcome.
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I feel an unaccustomed humility, thinking of how to improve the jellyfish. The jellyfish! Oldest of us, how can my little schemings improve on 500 million years of your trials, your survival of the fittest?
**Let us consider the squid.**
[](https://i.stack.imgur.com/1TDzS.jpg)
<https://www.researchgate.net/figure/Conceptual-diagram-of-underwater-jet-locomotion-for-both-a-squid-and-b-jellyfish_fig3_224329313>
The squid is conceptually similar to the jellyfish but it has a difference. The output of its contracting mantle is funnelled through a small orifice, and so speeds up as it does. Squids are fast.
Why would a jellyfish not have evolved something similar? Are they structurally not equal to the pressures created? Squids are tough. Would jellyfish burst?
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now getting hypothetical. Consider the human heart. The atrium provides a kick and then the ventricle even more. Could a chambered jellyfish do something similar? Let us consider a 10 chambered jellyfish in which each chamber passes to the next via a peristaltic wave.
In each successive chamber the water is moving faster - and so by Bernoulli's principle exerts less force on the walls of the chamber - the faster the flow the lower the pressure.
Thus each chamber can add its pressure to the flowing fluid. The additive end result is a very fast fluid flow, but at no point did the jellyfish have to exert (and withstand) massive pressure to achieve that jet. It was accelerated incrementally.
Such a jellyish would be long to accomodate its 10 linear chambers. Maybe it would have an outer mantle to collect the water then an inner to focus and propel the jet.
Oh this is a squid again. Yeah, squids got jet propulsion pretty much figured out.
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If a snake-person, which we'll say is a human with a snake's face and senses, could not smell (the vomeronasal organ doesn't work), what technologies could be made to replace this sense's usual functions? Able-bodied snake-people use their sense of smell to detect obstacles and identity others, as their sense of sight is poor. They are also deaf. The world has roughly medieval european technology
[Answer]
**Cane, hat, service animal.**
<http://www.bl.uk/catalogues/illuminatedmanuscripts/ILLUMIN.ASP?Size=mid&IllID=32758>
[](https://i.stack.imgur.com/HH0DS.jpg)
found linked from <http://www.larsdatter.com/blind.htm>
Your anosmic snake person is the equivalent of a blind person. The snake person will dress or be marked in such a way that other persons with normal senses understand the disability and extend extra consideration. If you know a person is blind you will not assume she will get out of your way or recognize you from a distance. You might extend your assistance to the person if appropriate.
A service animal can be helpful. Your anosmic snake people could associate with service animals to help them navigate their worlds.
Tactile sensation can substitute for visual and perhaps olfactory senses. This medieval blind person carries a cane as some blind people do today. A broad brimmed hat makes sense as impediments situated to hit the face might not be felt by the cane, but could be intercepted by the brim of the hat. If a snake person has no hands to hold a cane the hat could serve double duty with an extra big brim, and look styling as well. Illustrations very welcome!
[Answer]
Snake’s eyesight isn’t the best by any means since their world is made of smells, but you still could give them glasses or enhancement lenses so that they can rely on a different sensorial sphere to navigate life. Second option, a ‘smelling service dog’, or another animal that can be trained to alert the owner of different smells, for example making the presence of a friend or prey known to them.
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The state of [Bihar](https://en.wikipedia.org/wiki/Demographics_of_Bihar), in India, has an estimated population density of 1,307 humans per square kilometer even though 89% of the population lives in rural areas. How much more people could inhabit a rural region if every piece of land was used in land-efficient agriculture with modern or near future technology?
The land in question is extremely fertile, much more than even the [chernozem](https://en.wikipedia.org/wiki/Chernozem) in Ukraine, and the population has access to more than enough modern fertilizers and irrigation. Furthermore, due to cultural reasons, the vast majority of the population works in agriculture, meaning they can use labour intensive systems such as [polyculture](https://en.wikipedia.org/wiki/Polyculture) and [integrated aquaculture](https://en.wikipedia.org/wiki/Integrated_multi-trophic_aquaculture).
[Answer]
Generally speaking, any self-sufficient inhabited region will have a concentrated population area (from a village up to a fortress or city) surrounded by lightly populated agricultural areas. If I remember correctly, each person on average requires between half an acre of productive land (for a purely vegetarian diet) to up to two and a half acres of land (for a meat-heavy diet). That amount of good land in a decent climate that will produce the approximately 2000 calories per day that a human needs. If the soil is poor or the climate is cold, that would have to be increased; poorer soil and colder climates produce fewer calories per acre, and colder climates increase calorie consumption.
This implies that the maximal density for rural, agricultural region would be something on the order of a sparse suburban neighborhood: each family of four needing two to ten acres of land in agricultural production to meet their own basic needs, without much left over. And note that this isn't accounting for farm animals like horses or oxen, which have their own separate calorie requirements. Of course, this density could be compacted some by calorie-dense foods (like rice or maize), or by some sci-fi genetic engineering that increased the sunlight-to-calorie conversion capacities of plants. And as a rule large industrial/commercial farms produce calories more efficiently than small family farms, but you get the drift...
[Answer]
**Rural isn't a definition so much as it's an idea**
*A quick joke: A farmer wants the most efficient sheep pen possible. It must hold the most sheep for the least amount of fencing. The engineer says it's a rectangle because sheep are rectanglularish and so the most sheep can be put into the pen. The physicist says it's a circle because that maximizes area with the least circumference, minimizing fence cost. The mathematician, on the other hand, steps up, quietly draws a circle around his feet and proudly proclaims, "I declare everything outside this circle to be the pen." Why is the joke important? because this is the kind of answer you're about to get.*
The [U.S. Census Bureau](https://mtgis-portal.geo.census.gov/arcgis/apps/MapSeries/index.html?appid=49cd4bc9c8eb444ab51218c1d5001ef6) has a remarkably practical definition of "Rural."
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> For the average American, rural is an abstract concept of rolling hills and farmland rather than a concrete definition. Thus, it can be a difficult task trying to define the term "rural" and an even harder task trying to explain it.The Census Bureau defines rural as any population, housing, or territory **NOT** in an urban area.
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OK, so what's "Urban?"
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> Today, "urban areas" consist of two types of geographies:• "Urbanized Areas" have a population of 50,000 or more.
> • "Urban Clusters" have a population of at least 2,500 and less than 50,000.
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The problem with defining words like "urban" and "rural" by population density is that population density is variable. Really variable. In one square kilometer you might have 20 people. In a second, you might have 2,000 people. A square kilometer is a really big chunk of realestate, so both can be considered rural.
What the U.S. Census (and, by extension, the U.S. government, as many if not all departments use the Census' definition) did was define the *smallest geometry.* In other words, what's everything that's NOT rural, because "rural" is going to define the vast, vast, vast majority of land everywhere other than on [Trantor](https://www.google.com/search?client=firefox-b-1-d&q=definition+of+rural).
This is important for you, too, because the vast, vast, vast majority of your land is rural (or wilderness). So, the real question is, "What's urban?"
If you define (in your world) "urban" as any small location filled with people and buildings containing merchants and more than a couple of families, then you've won — because everything *else* is rural.
[Answer]
For the US anything less than 1000 people per square mile can be rural, down to 1 person per square mile, lower than that it is considered wilderness.
BUT a place with 500 people per square mile can also be urban, it is also based on the total number of people, a settlement with less than 2500 individuals is considered rural regardless of density.
**<https://www.census.gov/newsroom/press-releases/2016/cb16-210.html>**
Keep in mind this can vary quite a lot from country to country.
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I am working on a speculative evolution project, which takes place in a reducing atmosphere consisting mainly of methane, nitrogen gas, hydrogen gas and carbon dioxide, along with liquid ammonia as the solvent. This is a pretty reducing atmosphere, thus i dont know what will organisms consume and create energy from. I have recieved couple suggestions like:
* Using acetylene as fuel and hydrogenate it.
* Methanogenesis
* Hydrazine (as fuel) from ammonia and hydrogen gas
* Diborane and Ammonia to create borazine
* People on reddit also suggested reacting hydrides and water (and also reduction to silanes)
etc
I have not rejected all of them, but i would like to receive some more ideas (and speculate upon them)!
What i am looking for is a fairly rough picture of how these creatures consume and get energy to run their bodies. Photosynthetic and heterotrophic suggestions are both fine. My requirements are as follows:
Follows something like (for photosynthesis as heterotrophy would just run the reverse, with different intermediaries)
$CH4 + (NH3) + x --> y + jH2$ *where () denotes optional*
i.e: uses methane (and optionally, ammonia) and other stuff to create j number of Hydrogen molecules and a sugar analogue that could power the body by hydrogenating it (and release methane along with other compounds used). This sugar analogue would be needed to release fairly enough (at least 1/6th of energy released by earthlings) energy to power organisms. This sugar analogue should be able to be utilised as a solid
Thanks for reading!
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You propose acetylene as a glucose substitute. That has been mooted elsewhere on this stack. Yes yes, well and good.
But what about **cyanide?**
<https://en.wikipedia.org/wiki/Hydrogen_cyanide>
CH4 + NH3 → HCN + 3H2
[Cyanides exist on Titan](https://www.asbmb.org/asbmb-today/science/100117/the-cyanides-of-titan) and presumably other planets with reducing atmospheres like yours, and like the early Earth. The formation of CN is endothermic.
[The standard enthalpies of formation of HCN(g) and P(CN)3(g) at 298.15 K were determined by ab initio molecular orbital calculation as 137 ± 10 and 493 ± 15 kJ mol−1](https://www.sciencedirect.com/science/article/abs/pii/004060319285249U)
and abiogenic cyanide is formed via sparks (lightning), ultraviolet radiation and the like.
On your world, biology harnesses energy sources and captures the energy as cyanide. Energy can then be released by hydrogenation of cyanide back to methane and ammonia.
Cyanide is not an intrinsically better energy storage molecule than acetylene. But cyanide is cooler, because nitrogen chemistry is the stuff of life. Vinyl cyanide can do some of the things phospholipids do for us.
And from another idea on this stack that captured my imagination -
[Augmenting melanins with Prussian blue?](https://worldbuilding.stackexchange.com/questions/196871/augmenting-melanins-with-prussian-blue)
[](https://i.stack.imgur.com/MJmDL.png)
Thats, right. The sweet blue symmetry that is Prussian Blue. A cyanide based lifeform could store its cyanides as Prussian blue. But more than that - prussian blue composites with subsituted metals (nickel, cobalt) is electrochemically active. The chloroplast equivalent of your creatures is a blue organelle based on metal nucleated cyanide which transfers environmental electrochemical energy into chemical reactions.
[](https://i.stack.imgur.com/yBivc.jpg)
[Prussian blue, its analogues and their derived materials for electrochemical energy storage and conversion](https://www.sciencedirect.com/science/article/abs/pii/S240582971930978X)
[Answer]
You can use $H\_2S$, as it is used by [anaerobic bacteria](https://en.wikipedia.org/wiki/Hydrogen_sulfide#Microbial:_The_sulfur_cycle) on Earth
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Basically, in my world, there is a continent bigger than the whole of Eurasia, it is extremely flat (a 50 meter hill would be considered an important landmark), and its whole surface is a flood plain. I don't know if that's even possible, but I would like to know how it *could be made* possible, whether with a single giant river or a metric ton of smaller rivers all across the continent (if impossible, I would like to know how **big** could a floodplain be. The flooding should be either yearly or every other year, and it must be predictable. The flooding, if possible, shouldn't be too extreme, but should elevate enough to flood the vast majority of the continent.
Thank you for your time and attention.
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**Tides.**
[](https://i.stack.imgur.com/Y1C1P.jpg)
[](https://i.stack.imgur.com/oXhgw.png)
<https://scijinks.gov/tides/>
High tide is flood phase for your continent. Low tide is dry land. On Earth, tides are caused by the moon. You want tides once a year and I could imagine this might work if your world were a Ganymede-like moon of a gas giant. The giant causes tides on your moon which rotates slowly. The year is caused by progress of your moon world and its parent planet around the sun. The tides (and floods) are caused by the orientation of your slowly turning planet surface as it relates to the gas giant.
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You could only have a tidal floodplain; a river floodplain can never cover more than a small minority of the continent.
The area of [Eurasia](https://en.wikipedia.org/wiki/Eurasia), combined, is roughly 55 million km^2. Whereas the largest single floodplain on Earth, [the Pantanal](https://www.britannica.com/place/Pantanal), is only around 200,000 km^2. So it would take over 200 rivers the size of the Amazon (each) to flood the whole continent.
Except ... even that wouldn't work. [The Amazon's](https://en.wikipedia.org/wiki/Amazon_River) drainage basin is over 7 million km^2. Even if we assume that the total area flooded is triple the size of the Pantanal, we're still looking at only 10% of the total drainage basin area being floodplain. Figures for the Nile and Mississippi are similar. This is inevitable because the water has to come from somewhere, and floodplains happen because of water draining from somewhere else.
So, even if your entire continent were covered in meandering river basins, you still couldn't reasonably have more than around 6 million km^2 as floodplain ... the rest might be soggy, but it wouldn't be flooded.
So making the entire continent *river* floodplain just isn't possible. Tides may be your only choice.
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My world is that of a humongous cliff and pretty much nothing else. I was unable to be a [flatlander](https://medium.com/universe-factory/you-are-a-flat-earther-or-how-i-learned-to-stop-worrying-and-model-less-b1daae928cca) so I justified it by making a humongous alien artifact and jabbing it into a polar region of a gas giant with a density of Saturn.
[](https://i.stack.imgur.com/ZELvx.png)
[](https://i.stack.imgur.com/WhrXj.png)
(Yeah, I suppose the star wouldn't be able to be so high above the cloudline... Perhaps it's an orbital mirror.)
It is positioned above the ambient density of the gas giant, and it is dotted with "emitters", that spew out air and moisture, keping the air pressure leveled out and breathable for a wider band of the structure than it would otherwise been (I needed hundreds of kilometers wide band of habitability, but naturally it would be more like just a few kms before the atmosphere becomes too thin to breathe.)
I was thinking about how the atmosphere might work on the structure like this, and came to this setup:
[](https://i.stack.imgur.com/Dx8qx.png)
There are several bands of air zones:
Zone A is where the temperature and the pressure of the air drops too low for life to exist.
Zone B is where the oxygen levels and the pressure optimal to be roughly earth-like.
Zone C is where all the air and stuff from above begins to be compressed by the gas giant's own atmosphere, it is unpleasant, hot, and dark down there.
Band 1 is close to the surface that breaks down the air flow, and it is a quite turbulent zone with relatively unpredictable winds.
Band 2 is the transitional zone, where the air currents are relatively uniform and calm, flowing outwards, pushed away by the air generated by the emitters.
finally, there's band 3, where the air generated by the structure begins to mix with the unbreathable atmosphere of the gas giant, and due to it being more dense than it, falling down into the abyss, forming a rather strong downdraft that drags everything caught there down with it and forming a wall of clouds on the outer side in a sort of reverse eye of the storm fashion.
So if you go too high, you'll freeze, if you descent too deep you'll be crushed, and if you'll stray too far from the surface you'll be caught up in a downdraft and dragged below, where you'll be crushed. This should nicely box the inhabitants of the slope close to the surface, by limiting where the airships can relatively safely travel (The green area), preventing them from straying too far from the surface and realize that it is not in fact a flat wall (Up close enough it's uneven structure should be hiding the curvature rather nicely).
I imagine that bands 1 and 2 would be rather thin, extending outwards from the surface of the structure to no more than a few kilometers.
So, does this makes sense? The game I'm doing this for isn't intended to be hard science fiction (it's a steampunk platformer (Justified by the setting to be a platformer!) with "magic"), so if it isn't entirely lines up with equations, that should be fine by me.
[Answer]
# Yes, with a bit of hand waving
Based on your comments stating that it pulls gas out from the planet, this eliminates the whole "needs a lot of air to do that" part. Considering oxygen and nitrogen and other gases they will want to move down. The hand wavy part begins with when you realize the other gas (and therefore clouds) will want to move upwards, which means you need some weird windy stuff pushing down from above as well and your outer cloud layer might not be as smooth as pictured in the drawings. Other than all that this setup seems pretty good and really interesting for a story.
[Answer]
**Not without a counter-balancing air consumer** or force field. Your entire idea is premised on being able to displace the atmosphere of the gas giant by essentially blowing a lot of air around the mountain. The issue is that is a LOT of air. A lot. You are displacing a huge amount of the planet's atmosphere all the time, and it will want to keep mixing with your atmosphere. Therefore, the ambient gas giant atmospheric pressure has to be lower than the pressure at your breathable zone, and the breathable air has to be constantly pushing the gas giant's air away.
In order for this to be possible, either you need to consume the air at the edges, presumably filter out the bad stuff that happened at the interface (the mixing) and recycle it, or something, and refresh it, OR you need a force field to keep the bad atmosphere out. With a force field then the mixing zone never happens, so it looks like you're going to need to consume it.
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An old NASA news article I came across states that a solar flare observed in 2002 produced around a half-kilo of antimatter:
<https://www.nasa.gov/vision/universe/solarsystem/rhessi_antimatter.html>
How realistic would it be to harvest the antimatter from a solar flare? Presumably, a mission to obtain the antimatter (with the intention of using it to power an interstellar spacecraft) would need to overcome some of the following obstacles:
1. Survival: the spacecraft and harvesting apparatus would need to be able to withstand violent, high-temperature conditions.
2. Prediction: the spacecraft would need to be located in a region where a solar flare is likely to happen, before it happens (presumably near a sunspot), and then to stand idly by for a period of months (or even years) waiting for a flare.
3. Collection: the harvesting apparatus would need to somehow isolate the stream of antiparticles released in the solar flare (perhaps using very strong magnets), collect them into storage and then deliver them to a spacecraft.
Assuming cost is not an issue, how realistic would it be for this mission to take place within, say, the next 50 years? Which of the obstacles I outlined is the most difficult for modern human civilization to overcome? Are there other problems I haven't thought of that would make this idea impossible?
[Answer]
### It will probably be cheaper and faster to make it in a lab.
Cost to produce 1g of Antimatter in a lab:
* 1999 [62.5 trillion USD](https://en.wikipedia.org/wiki/Antimatter)
* 2006 [25 billion USD](https://en.wikipedia.org/wiki/Antimatter)
* In 7 years, The cost per gram has gone down by 1:2500.
* I can find no more recent cost estimates, as we haven't attempted mass production, we're more interested in using CERN to figure out physics than mass produce antimatter. Lets assume that no technological advances have occurred between 2006 and 2020 for sake of simplicity.
Resuming antimatter production research in 2020, and extrapolating that rate of improvement;
* 2020: 25 billion USD
* 2027: 10 million USD per gram.
* 2034: 4 thousand USD per gram. $2million / kg.
I'm stopping the extrapolating here (otherwise by 2050 antimatter is cheaper than bananas, and that seems silly), however assuming technology makes 2 similar leaps between now and 2050 that it did between 1999 and 2006, and we're looking at $1 million to make in a lab what you'd capture from a solar flare.
Just to play it safe, lets allow an extra 16 years for those innovations to occur (2050 is a nice round number). We've got economies of scale working in our favour, as well as being able to replace phd physicists with minimum wage technicians.
This crazy cost extrapolation is not without precedent: Transistor costs dropped [12 orders of magnitude in 40 years](http://www.singularity.com/charts/page62.html), and [21 orders of magnitude in 90 years if you include vacuum tubes](https://www.quora.com/Where-can-I-get-a-list-of-vacuum-tube-prices-in-1920-1950-I-mean-the-price-of-vacuum-tubes-in-that-period-not-the-current-prices-for-historical-tubes)
The parker solar probe cost 1.5 billion USD. Assuming your anti-matter collector is as expensive as that (which is very generous), the startup costs of the collector would be better spent creating 750kg of antimatter in a lab.
Even if we only get 1 leap in tech in the next 30 years, the cost of the spacecraft to capture flares would pay for 150 grams of antimatter. Enough for whatever engine you can imagine.
With [solar flare frequency](https://en.wikipedia.org/wiki/Solar_flare#:%7E:text=The%20frequency%20of%20occurrence%20of,less%20frequent%20than%20smaller%20ones.) varying from several per day to 2-per-month over its 11 year cycle, 750kg of antimatter would take several years to collect naturally even if you could capture every single flare and every single gram - which is pretty unrealistic to expect from orbital mechanics. You may be able to capture 1 in 10 using orbital manoeuvring, you're looking several decades to make similar quantities.
[Answer]
**Good Question** - because it solved another problem, how to control solar flares.
**Plasma** is composed atomic nuclei, (atoms stripped of some or all their electrons), so it has a positive charge.
A plasma stream generates and reacts to magnetic fields.
A collection of plasma streams could be generated from a space craft in a solar orbit using solar power to power the magnetic fields controlling the Plasma.
These plasma control streams, PC-Streams for short, can control the solar flare plasma, from a safe distance.
Directed toward the flare PC-Streams could be used to direct some or most of the positive particles from the flare for sorting at a anti-matter collection and processing plant, A-Matter generator for short, in another orbital volume and also away from space habitats ,settlements (including Earth) or space lanes.
**Orbital Solar Power Station**
A side point.
At an orbit half way from Earth to the Sun pushes about 5 kilo Joules (Kj) of energy per square meter per second.
In 52 days over an area of 4 square kilometers the total energy is over 9 times 10 power 13 Kj
A half kilogram of anti-matter combined with an equal amount of normal matter generates slightly less than 9 times 10 power 13 Kj
# Bottom Line - costs.
As the mechanism can be used to protect humans and property, it is in the words of Douglas Adams
[Somebody else's problem](https://en.wikipedia.org/wiki/Somebody_else%27s_problem) and the insurance people will get it done.
The A-Matter Generator, could also produce A-Matter Directly using the energy from the Sun.
Nice Job.
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What would their techniques be like, what weapons would they use(if at all), to what real martial art those would be comparable to and how would their strategies change depending on the opponent(Say, an elf and an orc)
I've already thought of 2 styles that could exist in my world, let's call them "goblin-fu" and "kung-gnome".
Goblin-Fu is meant to make its user a hazard in battle. To skirmish and cause the most harm possible and escape *or* die in suicidal attacks. No concept of honor or discipline.
Kung-Gnome on the other hand is focused on avoiding being hit and taking advantage of the user's size to hop around unharmed, with an extra emphasis on not being hit. It is not designed to harm, but has a few maneuvers to trip and harass the opponent. It's often mixed with illusion magic.
I'd like to have some insight in how these would(n't) work.
[Answer]
**Whenever you have the option, use weapons**
Weapons are force multipliers and equalizers. An elementary schooler has almost no chance in an unarmed fight with an adult. With swords or knives they're going to still almost certainly lose, but there's a chance of them doing some real damage and possibly getting in a lucky stab that decides the fight, and a child with a knife can probably be areal danger to an unarmed adult. With guns it's even more fo a toss-up. Child soldiers with AKs are a thing, and a bullet doesn't really care who shot it.
**For flailing around, use flails**
A goblin suicide trooper would paradoxically work best as not a throwaway unit but one heavily invested into. Put it in plate armour, put blades and/or spikes on the outside to make it hard to grab and hold down and attack chains with spiked balls on them to its gauntlets. Chain weapons are relatively powerful without needing to put in much power, they're very hard to block or parry and they're a danger to everyone including the wielder when employed without caution. Maybe also put a dagger-like spike for close-range stabbing on the gauntlets. What you get is a unit that can't really march or do anything but fight, they need to be suited up directly before battle, possibly drugged up and sent out screaming and flailing around, ideally from close distance. Supplement with poison, firebombs and explosives as available.
The reasoning here is that a martial art which makes you a hazard in battle also makes you a hazard to your companions. As such, you can't really fight in close formation but would fill a more shock-trooper-like role. Such fighters would be useful to disrupt enemy ranks and delay their advance, possibly also to erode morale. In a field battle they'd be best used as a distraction to set up a bigger plan, funnel the enemy into a trap or make them more vulnerable to ranged attacks.
As a martial art there'd be very little to it. The more random and unpredictable the better. The most important ability besides pain tolerance and endurance in general would be balance: these fighters need to be able to stay on their feet as long as possible. Expect lots of lower body conditioning, body hardening, running and jumping and possibly some acrobatics and chain weapon training for those who survive long enough. You could supplement this with jump tackles and grappling for single-target assassination with the dagger-spikes. Footwork should focus on stability with rooted, deep stances that allow for jumps and forceful rotations, not unlike how Shotokan Karate looks (even if Karate is actually much more grappling-based than modern interpretations would have us believe).
Against orcs this would probably work semi-well, especially if you use poisoned weapons, because you'll definitely get cut fighting those things. But they're pretty helpless against a solid shield wall and/or spears. When massed, they might be able to jump, slide and climb over, under and around defences, but they're more useful as ambushers. However, against a single orc or just a few, this would take one goblin from a small annoyance to an actual danger.
With elves they'd be pretty helpless. Elves tend to have excellent senses and thus are hard to surprise. Since they tend to focus on ranged weapons, they'd probably just kite them until they drop dead.
All in all it's not a very practical style. More so if you consider that what I just lined out relies on expensive and somewhat high-tech (for the time) equipment which generally wouldn't be used on suicide squads. But then again, goblins aren't really supposed to be very good at stuff, are they?
**I'm here! Now I'm over there! Now you're gone!**
For your gnomes you want to focus on evasive movement. That's a good start for a small and weak fighter and the first style that comes to mind here is Baguazhang. Circling an opponent is, if you're quick enough to pull it off, a good tactic to not let them bring their superior strength to bear. Smaller creatures are often thought to have faster perception, so this might just work.
Ignoring for a moment that Bagua is actually intended as a supplementary style for already accomplished martial artists, its focus on stand-up grappling isn't a good fit for gnomes. You'd want strikes that have as long a range as you can muster and target weak points so you don't need much strength. An armed Outboxer, basically. Thrusting weapons like spears or rapiers would work best, as might quick ranged weapons like slingshots or pistols (gnomes are tinkers, yes?). Low kicks and sweeps to destabilize the opponent are also useful. If you insist on nonlethal options, try whips and bolas.
What you end up with is a martial art that relies on being more skilled than your opponent. That's probably the expected outcome when you're weaker and smaller.
Against an orc your main tactic is to keep distance and hope that your attacks are strong enough to disable. Against an elf, use your magic to catch them off guard and hope for the best. Elves have basically the same strengths as gnomes, only they're also stronger, so that's often not really a fair comparison. If elves in your world have specific discernable weaknesses, this answer might change.
[Answer]
Regarding warfare, the essential parts is about team work and coordination.
I suggest to use both Spear-Fu and Shield-Fu in regards to warfare scenario for both races, at least it's cheap, which probably what goblins can afford. If the goblins can afford better, I suggest Montante-Fu or Zweihander-Fu for the goblins which is more fitting for your scenario. Both weapons at least give reach for their short stature, not much compare to longer person using the same thing but it's still better than not, it can be use in reckless charge like by using a Scandinavian boar snout or wedge formation for Spear-Fu users, outside of the typical/usual norm in Spear-Fu and Shield-Fu formation, or to brute swing in wide arc to swipe an opposing Spear-Fu or Pike-Fu aside to disturb the enemy formation and to give opening to the reserve Spear-Fu user to stabbity stab stab and poke a hole to the enemy for Montante-Fu or Zweihander-Fu user. Or just simply choppity chop to enemy if there's no Spear-Fu user to reinforce with, the Shield-Fu can protect yourself from elf-Fu range attack; not so much for montante-Fu or zweihander-Fu user which is a two handed weapon so they either depend on the Spear-Fu and Shield-Fu, or just deal with it, which can still be done if in an ambush scenario. It's up to you for the goblin to wear plate armor or not in order to encompass their recklessness, but at least don't forget to wear Helmet-Fu.
In self defense, specifically for gnomes, I suggest Quarterstaffu or [Whip-Fu](https://en.wikipedia.org/wiki/Chain_whip) which can be use to harass and trip your opponent and depend on where it hit, you can deliver fatal strike or dislocate their opponent's bones or break their non fatal bones, and I agree with @Pahlavan for gnomes to use Baguazhang style.
[Answer]
**Swift, Hard to hit, Coordinated**
They're small and fragile, so they definitely don't want to be hit. And they don't have to. They move quickly and their bodies are a small target.
A small group of lionesses can bring down a much bigger elephant, the same as a big enough swarm of bees or even ants can kill or seriously annoy and halt a orc general.
So I imagine your goblings fighting as an organism, doing multiple hit-and-run rounds, until their target drops down.
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Ultimately, this scenario will depend on whether or not this alternate Earth would orbit one G-type star or two, and whether dawn would still be in the east, like back home, or in the west, like in Venus. But for now, let's assume that this alternate Earth orbits one G-type star at a distance of 93 million miles. The one difference is this--the axial tilt varies between 19.7 and 26.9 degrees over a cycle of 122,000 years. Here is the map:
[](https://i.stack.imgur.com/5QKcu.jpg)
It's not much, so here is how it looks in comparison to our map, out of respect for how climate changes with latitude:
[](https://i.stack.imgur.com/5gItf.jpg)
It still does not say much, I know, so I have sealed the deal with a mountain ranges map:
[](https://i.stack.imgur.com/aC1IS.jpg)
The ranges vary in height above sea level from 5,885 to 8,848 meters. The arrows indicate the directions in which the mountains are rising, therefore the landmasses are colliding with each other. It's reasonable to believe that behind each plateau comparable to Tibet.
In the event that one of you would be asking about atmosphere, since it does play a part in climate, too, oxygen makes up one-third of the atmosphere and there are 4500 parts per million of carbon dioxide.
So with all the information listed above, what would the climate of this alternate Earth be like?
*(I'm not looking for all the Koppen complexities, just something more basic.)*
[Answer]
Your planet would be hot. Quite hot.
With 30% O$\_2$ and 4500 ppm CO$\_2$ you've essentially married the conditions of the [Cretaceous Thermal Maximum](https://en.wikipedia.org/wiki/Cretaceous_Thermal_Maximum), one of the warmest periods of our planet's history when global temperatures averaged up to 35°C and the poles were ice-free cool temperate regions, and the Cambrian greenhouse period, when CO$\_2$ levels were around 4000 ppm and global temperatures averaged 22°C (with high latitude seas exceeding 20°), much warmer than today's average of about 15°C.
[This study into the paleoclimate](https://www.sciencedirect.com/science/article/abs/pii/S0037073817302427) abstracted the Late Cretaceous climate as follows:
[](https://i.stack.imgur.com/ZJyJt.jpg)
Using [Artifexian's guide to climates on hot planets](https://www.youtube.com/watch?v=cnKUbcVrZVg) I've estimated your climate to the following:
[](https://i.stack.imgur.com/aE2dy.png)
Some notes:
* I've averaged your axial tilt to 23.3°, which is barely distinguishable from Earth's. You may want to watch the above video for the impact tilt can have on deserts at perihelion and take that into account.
* Wind and ocean currents are generalized.
* Your equatorial mountain range devastates the tropical belt.
* The net effect of the two parallel mountain ranges is rainshadows feeding rainshadows; that northern desert isn't going to see rain for centuries.
* I may be overgenerous with the extent of the southern humid continental region, it would probably be a narrow, patchy strip along the coast, moreso at the western extent than the southern or eastern.
* Likewise I've used the onshore prevailing wind of the northern Ferrel cell to justify the more southern extent of the northern humid continental region, as it would bring moist, humid air inland.
[Answer]
Here are an approximation of your prevailing winds from orbital motion:
[](https://i.stack.imgur.com/pDIS8.png)
I've basically taken the diagram from [Wikipedia's prevailing winds](https://en.wikipedia.org/wiki/Prevailing_winds), the red lines match the lines on the globe diagram.
From this prevailing winds diagram, you can follow the same process I did on [What climates can I expect on my fictional continent?](https://worldbuilding.stackexchange.com/questions/184276/what-climates-can-i-expect-on-my-fictional-continent/184531#184531)
The affect of the tilt of basically 28 degrees is gone into here [How to Determine Planetary Extremes of Temperature from Average Global Temperature?](https://worldbuilding.stackexchange.com/questions/185703/how-to-determine-planetary-extremes-of-temperature-from-average-global-temperatu/185728#185728), you're going to get very cold winters and very hot summers, and most of that top detailed coastline will not see much sun for months.
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[Question]
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If there is a magical weapon that can 'teleport away' a spherical volume of air/some fluid, basically creating a spherical volume of vacuum in that region, what kind would the resulting implosion be? (As the surrounding fluid rushes in). Will it be affected by whether the fluid formerly in the volume is 'pushed' to the side rather than teleported? Please give the case of air and water.
By 'what kind of implosion', I mean that how much energy would it release and, much more importantly (it is a weapon, after all), how much damage would it do to people/structures, both very close and a bit far away.
Also, assume that the initial teleportation/pushing is the only 'magical' part of the weapon; I want to analyse the results using hard(er) science.
To help in calculations, maybe this can be connected to real world phenomena in some way: In the case of water at least, this is sorta related to the phenomenon of cavitation, but I can find no analogue for air (sonic boom?)
**EDIT-** Adding in some specifics:
The general use case for this weapon is *at* a distance of a few metres and *having* a vacuum-sphere radius of a few millimetres at most. This is what the user can typically handle, and the energy cost scales with distance and size both (and other, irrelevant-here factors). And though Ash's answer helps with the extreme use case, what I specifically want is:
Will the general use case (as mentioned above) be enough to do severe damage to soft tissue, when vacuuming air from inside the body? Damage to structures (wood, stone, rarely metals; note that vacuum is only formed on one side of something as solid as a building material i.e. 'bubble' cannot be on two sides of a wall at once )? And how does doing this in water perform vs air?
[Answer]
### Precisely controlling this power could be devastating:
A nice intro to "what happens if a vacuum appears randomly" is [What if the glass is really half empty?](https://what-if.xkcd.com/6/).
[](https://i.stack.imgur.com/Osm6x.png)
The glass on the right makes a loud shockwave, the glass on the left launches upwards, shatters when the water hits the glass, and sprays broken glass everywhere.
This little thought experiment should show that the size of the vacuum isn't as important as the ability to control where it goes. A precisely placed vacuum can wreck havoc.
This will spray broken glass to the left:
[](https://i.stack.imgur.com/w4Rqz.png)
You could remove a sphere of water from one side of a water tower to knock the tower over. You could burst a dam by removing a chunk of water next to it.
### If you crank it up, this is very overpowered
So, a few issues we may have to deal with. Cherry picking your comment. "any size", "time doesn't matter"; this weapon could kill an entire town by suffocation. Just remove all the air for the entire village for 10 minutes. This isn't quite what you're after I'm guessing, so I'm going with "near-0 holding time" from here.
Removing the air around a person who is holding their breath will damage their lungs severely, probably fatally. Removing the air around a person who isn't holding their breath will give them ~6 seconds of useful consciousness before they pass out.
The air will rush back in at the speed of sound. So if you teleport out the air in a sphere of radius ~2km around someone, and release immediately (ie hold for 0 seconds), it will take about 6 seconds for the air to return. They'll be passing out when hit by the sonic boom. That doesn't sound pleasant.
A sphere of radius 80km will kill the average person even with immediate first aid after the air returns - it will take about 4 minutes for oxygen to become available.
### This can be a very effective area weapon
To the best of my knowledge, the sonic boom will be [about 200db](https://en.wikibooks.org/wiki/Acoustics/Sonic_Boom), and will hold 100 megawatts per square meter. This will cause permanent hearing damage.
The returning air will travel fast enough to knock anyone over, even if braced. It will be impossible to walk against the shock-wave. It will destroy most structures, but will not be fast enough to destroy reinforced concrete.
No matter how much water you remove, you [will not be able to make massive waves which flatten cities](https://apps.dtic.mil/dtic/tr/fulltext/u2/a304244.pdf). That report is about using nukes to vaporise parts of ocean but the physics is the same as if you teleported it to the edges or pushed it out. Vaporising a chunk of ocean near the surface makes waves which break very early. Vaporising a chunk down deep creates a massive (like 1km) bubble of steam which expands and shrinks 3 or 4 times.
Of course, your character needs to be out of the way of the area weapon. The [best ear protection I could find](https://www.3m.com.au/3M/en_AU/company-au/all-3m-products/%7E/3M-E-A-R-Swerve-Banded-Hearing-Protector-322-2000/?N=5002385+8720745+3294756878&preselect=8709322+8711405+8720539+8720546+3293786499&rt=rud) lower the noise by ~30db, ie to 170db. 130db is a jet taking off, repeated exposure to 90db can cause hearing loss. Your character needs to create the sphere a long way away from them, as nothing will protect their ears from the repeat exposure.
### Teleport or push the fluid?
The resulting effect wont matter whether the air was pushed to the edges or teleported to it - it's still fluid returning to a vacuum. The surprise of the teleportation is a plus, but if you're able to suck the air out of your sphere at the same rate it flows back, then you've got a weapon twice as strong, eg two sonic booms, knocks people over twice. That may be a win too. A slow charge up will probably look cooler if this is going to a visual medium.
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[Question]
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I want to ensure that my burial tomb is guarded by a pit of snakes for all the ages, similar to that featured in Indiana Jones (Raiders of the Lost Ark). Initially, I thought I could have an ecosystem of snakes where larger species ate smaller species, but there would reach a point where the food supply would truncate and the species upstream on the food chain would be affected.
## Question
Working backwards, if I want a pit that is perpetually filled with snakes, what starting ingredients do I need to include at time of burial?
**Further clarifications**
* Time frame: needs to be viable for thousands of years
* Closed off, it's a sealed, self-contained pit (possibly with tiny vents for oxygen)
[Answer]
**Let the snakes pick.**
Find a cave that is already full of year round snakes. Then get buried in there. If the snakes are not ever leaving, the food will have to come to them. A good option is bats, which are tasty and which come and go from caves. So you could use
*THE CAVE OF THE HANGING SNAKES!*
[](https://i.stack.imgur.com/WOMdq.jpg)
<https://www.atlasobscura.com/places/cave-of-the-hanging-snakes>
>
> In addition to the swarms of bats and dangling serpents, there is also
> a flooded portion of the cave that houses blind albino crustaceans.
> It’s possible that this is the creepiest cave in the world. Or at
> least the one that most resembles a Dungeons and Dragons setting.
>
>
>
Many bats, and the snakes that eat them actually living in the ceiling. Probably some wind up on the floor too. I suspect the bat biomass also supplies the albino crustaceans. Would it be excessive to have a giant [Olm](https://en.wikipedia.org/wiki/Olm) be the apex predator? No, I think that would be very appropriate.
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[
Related:
[What are the scientific issues with this method of dragons breathing fire?](https://worldbuilding.stackexchange.com/questions/106926/what-are-the-scientific-issues-with-this-method-of-dragons-breathing-fire)
[Could dragons theoretically breathe alcohol based fire?](https://worldbuilding.stackexchange.com/questions/41762/could-dragons-theoretically-breathe-alcohol-based-fire)
[Can a dragon's fire breath be liquid based?](https://worldbuilding.stackexchange.com/questions/38038/can-a-dragons-fire-breath-be-liquid-based)
[Recreating dragon fire](https://worldbuilding.stackexchange.com/questions/162480/recreating-dragon-fire)
I, like many others, am trying to find a way to science-ify dragonfire. I have settled on liquid hypergolic chemical reactions for the methodology, as hydrogen, methane or ethyl just don't have enough 'oomph' to them, and most of those kinds of solutions require the dragon to eat masses of plant matter. But the problem with most extant hypergolic reactions mentioned in the other questions is that they invariably require something so weird and niche (dragons eating coal, dragons eating phosphene-containing rocks, dragons eating limestone, etc) that the geographical range of dragons would be extremely narrow. Considering just how much meat a predator the size of a dragon would need, it's infeasible to have them all huddled together in one cave so they can drink phthalic acid from some natural oil well.
Bombardier beetles, for comparison, have an enormous territorial/climate range and manage to produce the two chemicals necessary for a reaction via normal organic processes from their diet of other bugs. If they produced giant gouts of flame, I'd stop right at hydrogen peroxide and hydroquinone.
So! My question. Are there any combinations of chemicals that form a flaming hypergolic reaction that:
1. Can be found or synthesized inside an animal body in a wide range of biomes/climates without major alteration of the terrain.
AND
2. Can be procured via a non-obligate (ideally, obligate) carnivorous diet?
[Answer]
**Unsaturated fats can spontaneously burst into flame.**
This is why you need to be careful about leaving oily rags crammed in a bucket.
Some oils and fats spontaneously oxidize. That propensity to oxidize is dependent on [iodine value](https://en.wikipedia.org/wiki/Iodine_value) which measures how many unsaturated double bonds are in the oil. Higher iodine value = more iodine can get soaked up by those double bonds. The double bonds also soak up oxygen.
Linseed oil is an example of a high iodine value oil. It is one of the oils which can cause fabrics to burst into flame on their own, especially if there is a [metal catalyst](https://www.sciencedirect.com/science/article/pii/S1540748910001677). Fish oils are unsaturated oils of animal origin and are ["notorious for their self-heating properties"](https://www.mfs.sa.gov.au/site/community_safety/home_fire_and_life_safety_fact_sheets/self_heating_and_spontaneous_combustion.jsp)
Your dragon makes unsaturated high iodine value oil in its body and stores it in an internal reservoir. It must get it ready to use it as a breath weapon. When fire breathing is needed, it heats the oil by bringing to bear metal catalysts (cobalt, iron, manganese; all available as biomolecules) and oxidants (oxygen or biologically generated peroxide). Perhaps there is a durable organ made of cartilage which it can push into the oil reservoir, increasing the surface area for reaction and bringing in reactants.
This oil heats up as it oxidizes inside the dragon. When it is very hot it will burst into flame on its own if given access to oxygen. When the dragon spews fire this is what happens - a spray of hot oil meets oxygen in the air and energetically burns. As opposed to a hot gas, hot oil would be a good breath weapon. The very liquid unsaturated oil might contain within it larger biomolecules and waxes which do not auto-oxidize but will ignite with the main mass once it is out in the air. These greasy waxes have even more fuel value, and are also sticky if the breath is used offensively.
---
This has some ramifications.
1: One is that fire breath for a dragon has a limited number of shots after which it must regenerate its oil reserve.
2: Two is that once a dragon heats up its internal oil, if it does not get rid of it as a breath weapon it must somehow get rid of the excess heat. It might need to drink a lot of water or eat snow or swim.
3: Oil has a lot of caloric value and is energetically expensive to make. Use of this breath weapon for predation means that whatever you kill has to be at least worth the caloric cost of the oil you used to kill it. Use of this breath weapon to ward off predators would mean you need advance notice that you are intended prey which predators do not like to give.
Use of the breath weapon as a flashy and expensive display of fitness makes a lot of sense. A dragon able to waste calories as fire is a healthy strong dragon and a good potential mate. Fire is visible and flashy and there is no faking it. A dragon lek would have many dragons at height in the dark, blowing giant clouds of fire.
[Answer]
It’s certainly possible for hypergolic components to evolve as in the case of the Bombardier beetle. Many other hypergolic combinations are known and there a probably a multitude waiting to be discovered for example diethylenetriamine and hydrogen peroxide
<https://www.sciencedirect.com/science/article/abs/pii/S0094576517300267>
Hydrogen peroxide is already produced by the Bombardier beetle. Diethylenetriamine is not generated in nature as far as I know, however it is a simple organic compound and given sufficient evolutionary pressure it might well evolve. Nature has found ways to push reactions “uphill” as in photosynthesis and ATP.
Many powerful oxidizing agent and powerful reducing agent combinations are hypergolic especially where a catalyst or high temperatures are involved. I have no doubt that if forced nature could well generate such hypergolic combinations as the scope of organic chemistry coupled to evolution are vast beyond measure.
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So the mass of air around the earth has doubled. How it doubled isn't part of the question, but for the curious let's say a space station floating around earth processed all the nitrogen, oxygen, carbon, etc from some comets and pumped it down to sea-level. The process took a week to complete and the new gas temperature was at 15C(the earth-average). By the end, there was twice as much air(by mass) around the earth.
What I'm wondering is how this actually affects the earth. How much would the pressure increase(if any) and would the ground-level composition of the atmosphere change?
Any information helps, but I'm most interested in how the change would affect pressure and the balance of the atmosphere on the macro scale.
Thanks for your help!
[Answer]
**1 + 1 = 700(ish)**
Assumptions and approximations:
1. [Earth](https://en.wikipedia.org/wiki/Earth) has a mean radius of 6371 km. The [Kármán line](https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line) for the existing, unmodified Earth atmosphere is 100 km up. Even if doubling the mass of the atmosphere doubled this to 200 km (it would not), the effective atmospheric surface area that can radiate energy back into space would change by a trivial amount and will be disregarded.
2. The solar radiation intercepted by Earth remains at current levels.
3. Human attempts to stop the additional atmosphere being added or do anything of relevance subsequently can be disregarded in the face of technology this overwhelming.
4. Any short term effects of the additional atmosphere being added such as temperature fluctuations, hypersonic shockwaves scouring the surface etc are trivial on the macro level.
**Energy budget:** Earth has a radiation budget (nicely illustrated in a NASA poster [here](https://science-edu.larc.nasa.gov/energy_budget/)). In order to maintain a constant temperature at the planetary level, the same amount of energy from solar radiation that Earth intercepts must be radiated or reflected back into space. If Earth changes its characteristics so that it is no longer radiating or reflecting the same amount of energy back into space then its temperature will change until a new equilibrium is reached.
Imagine that you are lying down trying to sleep in a summer weight sleeping bag in freezing conditions - you simply cannot get warm. Now imagine that you are in a sleeping bag twice as thick designed for those conditions - now you are warm. Your body is still generating the same amount of heat and over a long timescale the sleeping bag is still radiating the same amount of heat to the freezing conditions outside but a comfortable temperature can be maintained inside the sleeping bag.
Doubling the mass of the Earth's atmosphere would have the same effect as getting into a thicker sleeping bag, except that the conditions on Earth would go from "normal" to "lethally hot". Earth would suddenly stop radiating as much net energy to space while still intercepting the same amount, which means that the temperature goes up. The increase in temperature just as a result of adding more atmosphere would compound with:
* melting polar icecaps, which would decrease the amount of surface reflection and increase surface absorption; and
* increased [greenhouse effect](https://en.wikipedia.org/wiki/Greenhouse_effect) as more water vapor is added to the atmosphere.
Given the drastic changes being modelled by climate scientists based on relatively tiny changes to Earth's atmosphere as a result of human activities, it is highly likely that adding an entire extra atmosphere worth of gas would trigger a runaway greenhouse effect, with surface and atmospheric temperatures rising above the boiling point of water. This would then turn Earth's [hydrosphere](https://en.wikipedia.org/wiki/Hydrosphere) of an estimated 1.4 x 10^21 kg into part of the atmosphere, meaning that the atmosphere that originally had a mass of 5 x 10^18 kg would not mass twice as much as it did originally but around *700 times* as much, with water vapor being the large majority initially. (Chemical reactions will start occurring in the high temperature environment to change at least some of the water into other compounds, but that is a whole separate question.) The nearest point of comparison would be the atmosphere of [Venus](https://en.wikipedia.org/wiki/Venus) but the massively changed Earth atmosphere would have even higher pressure at ground level.
**Timeframes:** Wild guesses here, but conservatively assuming that adding a second atmosphere to Earth will result in an average 1% net absorption of sunlight per year for a couple of centuries at least:
* It will somewhere between a few decades to a century to raise the atmospheric temperature to 100C (depending on how effectively the crust acts as a heat sink). During this period the mass of the atmosphere will only increase gradually (as the water vapor mass increases) but the temperature will be increasing constantly. Looking how this corresponds to the [ideal gas law](https://en.wikipedia.org/wiki/Ideal_gas_law), the "sea level" pressure will only increase very gradually above the starting pressure of 2 atm, but the "bubble" of atmosphere around the Earth will expand.
* Once the atmosphere reaches the boiling point of water then it would take about another century or so to boil the hydrosphere completely. During this period the atmospheric temperature would remain relatively constant at around 100C but the pressure at the former sea level would increase continually as the mass of the atmosphere increases.
* After the hydrosphere has finished boiling, the pressure at the former sea level will remain constant while the atmospheric temperature will continue to increase until an equilibrium is reached. Given that Earth is further from the sun than Venus, the equilibrium temperature is likely to be lower than Venus' 462C. During this period the atmosphere will expand outwards again as the temperature increases.
What weather systems will exist at each stage along this progression are outside my area of expertise. However, given that the increased energy absorption will be uneven across the Earth's surface and will change over time (eg as icecaps melt and eventually the oceans boil), I would confidently predict an increase in high energy events. On the bright side, after the first few decades there will be few lifeforms left on Earth to be inconvenienced by them and within a century they will bother no one.
[Answer]
The pressure would increase by a lot.
From the [ideal gas equation](https://www.chemguide.co.uk/physical/kt/idealgases.html) (nRT=PV) doubling the quantity of gas (n = number of molecules \* a constant) would double the pressure assuming a constant volume. It is unlikely that the volume of the atmosphere would remain constant, so I suspect the increase would be much less than double, but the pressure increase would be between 1-2 atmospheres and probably much closer to 2 than to 1.
The composition of the atmosphere would be roughly the same with twice as much carbon dioxide to trap heat at least initially. But it would trap a lot more heat increasing temperature which would allow more water vapour to enter the atmosphere. As water vapour is a greenhouse gas this would increase temperatures further still and could easily cause a runaway greenhouse effect with average global temperatures soaring possibly by many tens of degrees or more.
As a side note adding all of that atmosphere within one week would require some fairly fancy process to say the least. The volume of air required could easily create hypersonic shock waves and increase temperatures by hundreds of degrees unless very well managed (no doubt you have that in hand…)
[Answer]
Potentially huge weather effects, depends on how you're adding atmosphere, etc, etc.
One effect, would be that any low-orbiting satellites would like start experiencing friction and would have to be raised in orbit, the remainder would start crashing. You would ground all human space flights until spacecraft are redesigned; they would need (probably) more than double their current thrust capacity (longer time to get thru more atmosphere carrying more fuel - 90%+ of all fuel is used to move the fuel needed to the height and speed at which it needs to get used).
You might also be stranding (or killing them on re-entry) all orbiting astronauts, as re-entry now has twice as much air to get thru (and perhaps frictional heating lasts a lot longer?).
Mass of the Earth 5.972x10^24 kg
Mass of the Atmosphere 5.1480×10^18 kg
Mass of the Earth after 5.97200515 × 10^24 kg (negligible increase)
Would have an insignificant impact on gravity, as barely nudges the overall mass.
Depending on what you're adding (ozone?), and if you add it all at sealevel, could result in a higher percentage of things which are more stratified in the upper atmosphere (currently). These are trace amounts of the bulk of the atmosphere, but would probably be considered pollutants. This would take some detailed science to figure out. As a single example, the current ozone is stretched so thin that we have an ozone hole, if you double the atmosphere, the amount you need to cover the sphere at that density more than doubles. So you would end up vastly increasing the ozone hole - even if you were injecting the ozone at the appropriate layer of the atmosphere. If you inject it all at sealevel, at an average temperature, it will take time, and have temperature changes to get where it needs to go - however the need for it to be where it needs to be will be immediate. And, AFAIK ozone is not available in Oort-cloud material, so is your space-station manufacturing this?
Also, this is a *huge* space station to process so much material, so quickly. I'm assuming it has antigrav, as it would have to be well out of a LEO yet needs some means to transport its product?
There are a lot of potential answers, which all depend on the choices you make with how you're adding the gases and particulates.
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My augmented society of humans have managed to engineer their power-hungry cyborg components to run on a hydrogen fusion reactor. Whilst they have so far managed to fuel it by drinking lots of water, they would rather a solution which would make their lives more convienient. Would they be able to add either hydrogen (at appropriate pressure) replacing the nitrogen, or even just a couple percent of hydrogen that would stay at ground level for them to breathe?
Other criteria:
They don't care about the hydrogen staying over geological time and can replenish it, but would like the planet to be at least inhabitable if their technology stopped maintaining it. (It has an ecosystem like Earth)
They have handwavium nanotech clouds that would help with fire supression, but would like to avoid any situations where a spark would blow up the planet anyway
So, is this possible?
[Answer]
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> They have handwavium nanotech clouds that would help with fire supression
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You have essentially handwaved away the main issue with mixing oxygen and hydrogen, which has an obvious outcome otherwise.
What remains then are secondary concerns:
**Will there be enough?**
The oceans weight around 200 times more than the atmosphere on Earth, so only a small portions of them would have to be converted in order to supply some percentage of hydrogen in the air.
**Will the hydrogen go away in other ways than burning?**
Over geological timescales, Earth looses hydrogen and even some heavier gasses to space. But this is not a large drain, and over a much longer timescale than the one you care about.
**The planet to be at least inhabitable if their technology stopped maintaining it?**
When you fire suppression systems stop working, things will essentially go back to status quo, with the hydrogen going back into water. There are two things to consider for the cyborg here:
* The hydrogen percentage can't be so high that it swipes away all the oxygen in case of a collapse, ideally 90% or more of the oxygen should remain in the air.
* The nanobots should fail *slowly*, letting the hydrogen leak as water form the atmosphere over an extended period of time. A single flash would cause significant damage to all life that's not located underground.
One has to wonder how these miraculous nanobots are easier to construct than conventional pipelines, supply stations and containers...
[Answer]
I am neither a chemist nor physicist, I cannot calculate the speed of the reaction, but what I can tell is that mixing gas oxygen and gas hydrogen isn't the best idea.
If there is any source of ignition, the reaction will be locally instant and on a planetary scale fast. I doubt any anti-fire system will be fast enough to handle this before it gets out of any control. Actually, it will probably get out of control within a fraction of a second. Once started, the reaction will continue as you have all you need for it (fuel, oxygen and ignition).
The initial ignition can be anything highly energetic. Since you want this to be part of your planet atmosphere you will actually have to keep more or less similar atmosphere everywhere, meaning for instance that if you have ignition anywhere in the entire planet. Now as long as you have any clouds, you will have storms and lightnings. It means a very powerful source of ignition, occurring on a very regular basis. On Earth, there is a number of storms running in parallel all the time with lots of lightning hitting every second round the clock. Shortly speaking, as soon as you manage to create the conditions you describe (which in itself is unplausible), one spark (ekhem, lightning) is going to blow everything up, should you have the nanoclouds ready or not.
To give you the idea, have a look at this [video](https://www.youtube.com/watch?v=RL7acBSFUAQ)
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Let's assume a world where humanity managed to stabilize the climate again and maybe even reversed the effects of the current climate change. (So that we can ignore the current global warming in this question.)
In this world humanity grows further and builds more machines and electronic devices for an ever increasing standard of living.
All of them are extremely optimized to have minimal energy consumption and such but no matter what we do each device (and each living being) produces some waste heat even if it is not much.
How realistic is it that in this world the waste heat will ever contribute significantly to the temperature of earths atmosphere?
[Answer]
Waste heat (on planetary scale) is not an issue today, and likely not going to be an issue for the next 100 years and even more. But as the civilization approaches a full [Kardashev I](https://en.wikipedia.org/wiki/Kardashev_scale) level, it inevitably should deal with waste heat. Either through decreasing planetary albedo (for effective energy capture), or by building space collectors, beaming energy to the surface, or via other, non-solar sources like fusion, energy balance of the planet will be shifted.
An obvious answer here is moving all energy-intensive operations to space. Over there, we can spread our infrastructure as thin as we like, eliminating the heat issue.
One logical consequence of this approach is that planet-bound civilization can never truly achieve Kardashev I level. We can get close to capturing all solar energy reaching Earth, but some percentage of it would inevitably go to waste heat, so we should be careful with maintaining Earth's albedo.
Are there any ways to cool a Kardashev I planet? Yes, it is possible to build radiant "planetary air conditioners". However I can not estimate their net effect on a planet and can not tell if they would be practically feasible.
[Answer]
The simple way to avoid problems with waste heat on Earth is to gradually move the most energy intensive aspects of human civilization off world. As more and more energy using and waste heat producing activities go off world, a larger and larger percentage of the human population will live in space close to energy using activities, and a smaller and smaller percentage of the human population will live on Earth, until eventually all humans might live in space habitats and Earth might be maintained as a nature preserve.
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For context, I'm working on a music style generator for an online tool that procedurally generates fantasy cultures.
I want each culture to have a distinct musical style. I have very little idea of what attributes a style might have (the generator's "knobs to turn," essentially).
My initial thoughts are pace, instrument types in use, presence or absence of vocals, presence or absence of atonality, and dissonance. I know there should be much more, but I'm not well-versed enough in musical theory or anthropology to come up with any.
What, for example, would differentiate Pakistani folk music from French folk music?
[Answer]
The big one you're missing is the concept of a scale; a regular progressive sequence of tones that is the foundation of melody and chord structure within the culture's music. Even within what we consider the "Western" system of music theory, the proliferation of scale definitions and qualities allow for myriad variations to evoke different regional cultural music styles in your mind when you hear them.
Most English speakers are intuitively familiar with the sound of two basic scales, which we call the "major" and "minor" scales. Major scales sound "happy", minor scales sound "sad". But this is just the tip of the iceberg of Western music theory. Using the same relative progression of pitches, but changing which note you use as the tonal "root" of your melody, you can change the sound of your melody and invoke other human cultures for which those melodic progressions are stereotypically common. Dorian mode, for instance, is based on what would be the second note of a major scale, and gives you a juxtaposition of both major and minor scale qualities. This mode is commonly associated with old European sacred styles like plainchant and early polyphony, and in a more alien context can be used to elicit a sense of age and gravity to a race. Start one scale degree higher, on what would be the third note of a major scale, and you have Phrygian. This scale sounds vaguely Middle-Eastern, though variations of it are also common in Spanish flamenco (understandable given the Moorish influence on Spanish culture, imported from across the Gibraltar), and it's been appropriated for many styles of metal for its more dissonant-sounding early note intervals. You might use it to evoke a similar "exotic" vibe for a race or planet, or in the metal sense to create an unsettled, dissonant atmosphere of ordered chaos.
This is all really just the tip of the iceberg of human music. From this foundation of heptatonic modal music systems, you get into:
* sparser pentatonic scales (stereotypically Asian sounding, though also used in American folk styles like blues),
* non-modal variations (Harmonic Minor, Byzantine, Hungarian Minor, Phrygian Dominant etc do not follow the typical Western progression of note modifications commonly referred to as the "Circle of Fifths", and commonly include unintuitive three- and four-semitone intervals between "adjacent" notes),
* more chromatic scales that include multiple adjacent semitones (a rule called Myhill's Property discourages this in Western theory, but the most commonly taught "blues scale" is a hexatonic scale that includes the tritone in an otherwise minor pentatonic scale, producing three adjacent scale degrees a semitone apart from each other), and even into
* microtonal scales, with intervals of less than a semitone (the "minimum resolution" of Western theory) that are more accurate translations of Arabic *maqam* tonal systems and similar Turkish, Persian and Hindi microtonal scale systems.
Cultural styles are also commonly defined by:
* the level of tonality (the importance of a "root note" to the structure of melody and harmony; most cultural genres are very tonal, to the extent of employing sustained "drones" on or closely related to the tonal center), but atonality is notable in jazz and classical styles),
* tuning centers (the importance of the notes played being within close tolerances to defined pitch centers based on a tuning standard; Western ears expect glissandos and pitch bends only in certain places in music, while African and East Asian styles have looser rules),
* consonance (the importance of multiple different pitches intuitively "fitting together" both within a chord and through a progression of notes and chords; what's "intuitive" is very culturally-dependent) and
* rhythm structure (most cultural styles have a defined beat system, often based on a layered recurring structure of sequences of beats and notes; not all music requires one though).
All of this is also dependent on time period; Western music styles, unarguably, have progressed and regressed in many ways over the period of recorded history, and many styles and genres progress more or less in parallel. Classical music has long pushed the boundaries of what we consider "consonant" or "dissonant", and while we can very easily identify very unpleasantly-dissonant arrangements of notes, there's an in-between of pitches and chord structures that "conflict" in frequency interval and are thus "dissonant", but aren't nearly as jarring to listen to as open dissonance, and these often lend a more ethereal quality to a music style, especially at slower tempos with more sustained, slower-attack/release note qualities. The human voice excels at these styles, and can, quite ironically, create some very unearthly-sounding music.
Switch up these basic variables, and you can create "music systems" playable by human instruments that sound very alien. Bring in instruments not commonly heard by Western ears (or at least not recognizable as being from any specific human culture) and you can further increase the "this is not human music" angle as you choose. Or, you can play something instantly recognizable as big-band funk, with Huttese lyrics. Your choice.
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I have a ship that begins the equation traveling at 50 percent the speed of light, but decelerating constantly to finally land on a certain planet (towards which it is moving the entire time). It begins its journey 7.5 light years away from the planet, with which it is exchanging messages as rapidly as possible. I am wondering if there is a formula I can use to calculate how many messages they can send, and at what times/distances each will be sent (and received) by the time they arrive. Does this make sense? Is it even a sensible question?
[Answer]
The first thing you need to keep in mind is that when two observers are moving relative to each other in a system, each one will perceive the other as experiencing dilated time. That means from your point of view, it will seem that whomever you are communicating with is experimenting slowed down time - but from their point of view, it is you who are experiencing slow time. You can find more [at the wikipedia article for time dilation, under "reciprocity"](https://en.wikipedia.org/wiki/Time_dilation#Reciprocity). While you keep at different velocities, you may disagree on the timespan between events.
That said, I think the formulas you are looking for is this. For the span of time at the other end of communication:
$$\Delta t = \frac{1}{\sqrt{1 - \frac{v^2}{c^2}}}$$
Where $v$ is their speed relative to you.
If your signals are traveling at the speed of light, they will clear the space between you and the other guy in time $t = \frac{d}{c}$, where $d$ is the distance between you both. Otherwise you will need to calculate compressed space. Its formula is the opposite of the first one. Compressed space is calculated as:
$$s = \sqrt{1 - {v^2 \over c^2}}$$
That's the length the signal has to traverse if it is at subluminal speeds, then you can calculate the time it takes to arrive (as measured from its frame of reference) by using the old $s = vt$ formula. Notice that its own measure time may be different from the time measured by sender and recipient.
[Answer]
You do not need relativistic formula if you do not change the reference frame.
From POV of a planet this comunication process is straightforward: first message from the ship travels 20y, when planet recieves it ship is at 20 - 0,5\*20 +(1/160)\*20^2 / 2 = 11,25ly distance. Reply would take +7,5y (27,5y from start) to reach the ship and so on.
From POV of ship it's a little harder since starting conditions differ (its only 17,2ly from a planet) and start point will "move" (it is "move" without move - like universe expanding) to 20 ly while this ship deaccelearates with all other points. This leads to "strange" fact - speed of light in non-inertial frame is not **c**. It even is not constant in time (and, for rotating frames, in space). But we can make a shortcut - take numbers from planet POV and transform them with Lorenz formula using speed of the ship at the event points as a parameter. Since accelearation is very small - 1/160 g (it easy to get using suprising coinsedence - 1ly/y^2 is a little less then 1g) we can neglet acceleration time dilation, using only speed time dilation. But we can't do this directly - we need to integrate to calculate "accumulated" dilation. So time in planet frame transform to time in ship frame like this:
$$ t\_{ship} = \int\_{0}^{t\_{planet}}\sqrt{1 - (0.5 - t/160)^2}dt$$
So from POV a ship first signal will reach the planet in about 18y, reply will arrive in about 25y from start
(total deacceleration time for the ship is about 76.5y)
BUT if you want a constant acceleration in ship frame - it would be different and a harder calculations.
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Let's say we have a species of plant, that, for whatever reason, only wants to be pollenated by female pollinators. Maybe this gives some advantage to the plant and/or pollinator.
Why would a plant only want to be pollenated by a specific *sex*? How would it tell the difference?
Bonus question: How would the plant defend against *non-female* would-be pollinators?
Feel free to make up evolutionary traits, but if you can tie it to real-world examples that would be even better!
[Answer]
Ultimately, the answer you seek lies in [Enzymes](https://www.livescience.com/45145-how-do-enzymes-work.html). These are essentially biological catalysts that greatly increase the rate of specific biochemical reactions in the body.
Tie this to a hormone, like [Estrogen](https://en.wikipedia.org/wiki/Estrogen) (which is found in greater levels in females) and you have a biological catalyst that may only occur in female pollinators.
The mechanism would be that the male pollen would be either toxic or infertile to the female plant in its raw state; it needs to be activated via an enzymatic process that relies on estrogen, progesterone or some other hormone that is found in greater quantities in a female. So, male pollinators can disperse the pollen, but not activate it.
I couldn't find any examples of this working in real life; Bees for instance have a distinct difference in how they operate between the genders and while male bees seek nectar directly from flowers, they lack the pollen sacs on their legs that the females have to collect (and disperse) the pollen. So, they operate in completely different ways and therefore are not helpful as an analogue of this process.
The other important thing to note is that evolutionarily speaking, the plant is creating a rod for its own back and is highly unlikely to form this kind of symbiosis with a specific gender of pollinator for the simple reason that if for any reason that gender doesn't drop by, the pollination cannot be successful. Ultimately, a plant is better off having the pollen in a ready-to-use form, so that *anything*, including wind, can fertilise nearby flowers. This kind of evolution creates an environmental niche that can easily go wrong with a simple change of environment so I would not expect such a plant to evolve naturally, or if it did, not to last across eons of evolution.
But, the idea that a female hormone acts as an enzyme on pollen to activate it is not all that far-fetched from a biological engineering perspective at the very least.
[Answer]
**Females might get around more.**
In general, females of any species invest more energy in offspring than males. Eggs require more resource investment than sperm. This is true for pollinators too.
If a female needs more energy, it must go get it. Assuming pollinators are visiting flowers for food, a female might visit more flowers than a male: it needs more food.
Pollen is a resource as well. It makes sense to bestow it on the pollinators who will spread it most widely. If the females are visiting more flowers they will spread the pollen more widely. In that case it makes sense to give all your pollen to females.
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As regards how to make that happen it is much tricker. "Pollinators" can include a wide range of animals with very size and body habitus. Some flowers exclude certain pollinators with flower shape; for example those that want only hummingbirds have long deep nectaries that only a hummingbird can reach. Some flowers have a flap that only robust pollinators like bees can lift. If you are offering nectar and you have a specific pollinator type with sexual dimorphism then you can use that dimorphism to allow the females and bar the males.
The other way I can think of is to select for females by mimicking the attraction they use to find an egg laying site. For example still water with algae will attract female mosquitoes to lay eggs but not males. If your attraction is a cheat (smells like good laying food plant substrate but actually is not) this is not a long term evolutionary strategy - the females you fool will waste their eggs and you will select for those you cannot fool. But if you actually provide a good egg laying environment (and a flower could definitely harbor water and algae for mosquito larvae) then it is a good long term strategy. This would only work for females that distribute eggs at more than one site.
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Rust Monsters are one the few original monsters in D&D that didn't fade into obscurity. Probably because of their ability to turn James' favourite metal items into dust.
[](https://i.stack.imgur.com/MQGau.jpg)
Rust monsters are basically large bugs with two equally large antennae. The Rust Monster, with the antennae, rubs an unspecified chemical on the metal that degrades it and turns most of the item into dust.
* Rust Monsters affect iron and iron-based alloys.
* It's not neccessary for the item to start to turn into dust immediately, but it should lose structural integrity at a rapid pace, so as to prevent the adventurer (James) from smacking the poor critter in the head with that sword before it ceases to be one.
* Since, along with Mordenkainen's Disjunction, these creatures were invented for the sole purpose of striking fear in the hearts of adventurers, they don't (have to) follow the conventions of evolution.
**How could Rust Monsters effectively erode iron-based metals?**
[Answer]
Ok, so here’s the thing, in order to rust metal that quickly, you’re going to make it burst into flames. However, since we’re trying to strike fear into the hearts of daring adventurers, this is a big bonus!
As for how to do it, its actually fairly easy to explain. See, contrary to its name, oxygen is not the best oxidization agent we have. Enter fluorine, which oxidizes so strongly that it can cause water to burst into flames. So, your rust bug obtains some fluorine, and since we’re talking about D&D you can use a little handwavium to explain how they get pure fluorine and keep it from burning them alive, and they store it in a viscous, gel-like substance in special organs at the base of each antenna. On command, the gel is pumped through the antennae and out special pores. The gel sticks to whatever it hits and rapidly begins to evaporate, exposing the deadly fluorine within. The gel, and whatever it has touched, bursts into flames as the fluorine begins oxidizing everything around it. By the time the flames die down the adventurer has dropped his weapon/stripped off his armor and ran away screaming. When they come back later to retrieve their items, all they find is a pile of rust.
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As landlubbers, we often let ourselves think that if salty seawater is undrinkable for us, it could be even worse for plants. However, certain types of angiosperms have found ways to not only thrive on marine environments but specialize on them. These are the mangroves and four families of alismataleans collectively called "seagrasses".
But what about the other major groups of plants--the conifers, the ginkgoes, the ferns, the cycads, the liverworts, the mosses, the clubmosses? In an alternate Earth, could any of them have what it takes to adapt for saltwater life and grow into marine forests as complex if not more so than the kelp forests of back home?
[Answer]
There's no rule against it. Salinity is not a barrier for plants, as seen by sea grasses and mangroves. If it evolved once it would evolve again.
Growing underwater has certain mechanical considerations because water currents are a lot harsher than air currents. Your new seaplants would probably start to resemble the current seaplants, because the mechanical considerations of not having stuff break off would lead to similar solutions evolving. ([MESA link](http://www.mesa.edu.au/seagrass/seagrass02.asp))
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> Seagrasses have evolved adaptations to survive in marine environments including salt tolerance and resistance to the energy of waves (rhizomes and roots firmly anchor seagrasses to the sediments and flexible blades offer little resistance to water movement.
>
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If you have a clubmoss underwater, I'm not sure how much resistance those spikes are going to give, but it will likely develop a lower structure similar to current seagrasses, because it'll be trying to collect sunlight from all the way at the bottom of the water.
As far as pulling a mangrove and growing in shallower brackish water, go nuts. There's less water to deal with forces, and the shallower water means that most plants can actually get their leaves above water so they can have the typical shape.
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inspired by this question [Wearing vs Growing Clothes](https://worldbuilding.stackexchange.com/questions/157382/wearing-vs-growing-clothes)
and this link [medical news today](https://www.medicalnewstoday.com/articles/174852.php)
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> Chemical peels
>
>
> A chemical peel involves applying a chemical solution to wrinkly
> areas, causing the dead skin to shed and eventually peel off. The
> regenerated skin tends to be smoother and less wrinkled than the old
> skin.
>
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> Some types of chemical peels can be bought and used without a medical
> license, but it is advisable to consult a medical health care
> professional for the treatment.
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>
i want to know if a creature like elf (either made of plantbase or just organic animal)
can shed their skin or layers like snake or onions that have multiple layers, will it protect from forming a wrinkle on their skin or make them not look like an elder? i know [human can shed or peel their skin](https://en.wikipedia.org/wiki/Desquamation) but it mostly because of skin damage like burn or sunburn,skin disease,etc.
does it have different effect between the creature skin if it made/form from organic animal and plantbase such as wood/bark?
[Answer]
If they shed their skin deeply enough, sure. However, wrinkles are not just a surface effect and deals with the collagen that, essentially, glues the skin to the underlying muscle and bone.
Another problem is that as things break down with aging, what keeps the mechanism for creating new skin from breaking down. Maybe each new skin actually looks worse than the previous due to the breakdown of the new skin making organ. I would only see this as a viable evolutionary strategy if they could not easily repair/heal their existing skin. Then, if the damage builds up enough to go through the trauma, they "use up" one of their sheddings to replace the old, damaged, skin.
Also, even if they look young, this will not have any effect on the wear and tear on the rest of the body. So, while they may look young, they will still get weaker and die of old age (unless you tinker with more of their biology).
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I'm currently designing the armory for my far-future hard-scifi setting. Technology is quite advanced and for the purpose of this question assume that liquid metallic hydrogen (LMH from now on) is actually metastable, and diamonoid material tanks capable of holding it are a thing. The technology was developed for spacecraft propulsion as LMH is the best chemical rocket fuel (actually uncertain about how to call it, since no chemical reaction is used, just a phase change; any clarification would be appreciated). All technological problems concerning the LMH part of the question are to be considered already solved.
The actual design would work as follows.
* a diamonoid material shell containing the LMH is inserted into the barrel; it is near the edge of the pressure it can hold
* it is propelled down the barrel, currently I'm thinking that pressurised hydrogen gas would serve me best
* a laser in the back of the barrel is fired to heat the shell so the pressure inside it increases and the diamonoid material is weakend; the bullet is now armed and while it will still survive travelling though air, a direct impact will break it
* the impact on the target breaks the bullet, the rupturing of a high pressure pressure vessel, the highly energetic phase change to H2 gas (I read once that the rocket exhaust of LMH would be at 7000K) and a number of chemical reactions initiated by the hot, reactive hydrogen will wreak havoc on the target; I'm uncertain about what exactly would happen on impact, if someone would explain the process which is likely to occur in detail, it would be nice
I'm aware that this isn't really a real plasma weapon in the spirit of star wars, but a ludicrous grande launcher. Yet considering the nature of the explosion some plasma might be involved. Whatever the case, the marketing department decided to call it a plasma weapon, so it is a plasma weapon. Furthermore I'm not trying to make a practical infanterie weapon here. I'm aware that enemy snipers would make it a sport to shoot your ammo supply. However this weapon will be great if my protagonist has to show of his manliness on a monster infested jungle-world. Or if you are not in the mood to dispose of the body and don't mind major scorch marks. Additionally the gun, or lets be real here, the portable light atelery piece, should have a feature prohibiting it to be shot at a point less than 20m from the user.
**Is the design plausable? Could I improve it somehow? Will it be as effective as I think?**
[Answer]
[](https://i.stack.imgur.com/JBh2U.jpg)
**It is totally impractical and so perfect for your purpose.**
<https://www.sportsmansoutdoorsuperstore.com/products2.cfm/ID/132134/de44tgts/magnum-research-desert-eagle-.44-mag-mark-xix-titanium-gold-with-tiger-stripes>
You poked the obvious holes in your crazy scheme yourself. Lean into them! You know exactly the man who must have a weapon which is such an ostentatious cadenza of high technology in the service of violence. A man oblivious to cost but very conscious of appearances. Probably he has several capable hirelings with more practical weapons nearby, in case his attempts to bring down Xenotyrannosaurus with his modified rocket tech do not go well.
[Answer]
The temperature of 7000K is pretty much a plasma by definition, so heat and various EMP effects will be felt by the target. I would suggest the mechanism you describe for launch is probably both too complex and unlikely to work well in practice; the most likely result is you will also be caught in the fireball (since the round is likely going to drom on the ground after exiting the barrel).
Something more on the lines of a mass driver would make sense, especially since the LMH core would react to and interact with the moving magnetic fields of the weapon, you could accelerate the round without over stressing the casing, but give it enough kinetic energy that the casing will fracture on impact. This might actually cause a few other issues - the round will pass through soft targets without detonating, while failure due to manufacturing flaws, mishandling by the troops and so on will cause the round to prematurely detonate in the barrel.
The fireball and EMP will be very short lived effects (milliseconds), while the high velocity of the plasma will mean any flame front from the Hydrogen reacting with Oxygen will take place at a great distance from the initial explosion once the Hydrogen has cooled enough to chemically react with the Oxygen in the air (or any other reactive materials). This will be a very minor issue since it will be so diffused and moving so rapidly, the eye might get a flicker as the flame front ignites and then dissipates in a tiny fraction of a second. Most of the damage will actually be caused by the shockwave as the hydrogen plasma expands at hypersonic speeds through the air.
This seems like an extremely elaborate and specialized weapon, and it is difficult to see what advantages it would have over a much cheaper chemical explosive round or grenade. Indeed, even the ability to launch at massive velocities using a mass driver is not unique to the use of LMH, a simple tungsten bar would act as a kinetic energy round and an explosive round would have very flat trajectory and the possibility of penetrating into targets using a delay fuse.
Perhaps you should think about other elements in the setting to understand why such an elaborate weapon would make sense (i.e. what are the targets, what sort of effects would you want to achieve and what sort of economic and logistical capacity does the user have to make and supply the ammunition?) Once you answer that, then everything else will fall into place.
[Answer]
As @Thucydides said, your design is far too complex and dangerous for a rifle-like implementation, it would make much more sense as an artillery-style weapon or like an RPG.
### Artillery Style:
If you've watched Clone Wars, you would know about the droid tanks in S1E14 with the biomatter destroying weapon, which was attached to the tank, kind of like a suppressor on a rifle. And for propulsion, mix cesium into the metallic hydrogen and fire it like a railgun (cesium is affected by magnets). This piece of the weapon would be placed on specialized versions of the tanks. The metallic hydrogen would be stored in the aforementioned diamondoid tanks/shells laced with cesium or some other metal, which would be loaded into the tanks. This also solves the problem of safety as the tank would have a magnetic field, shielding it from metal projectiles and the plasma. This solution would also propel the projectile much further and at greater speeds. With your design, if the enemy were to concentrate their fire on the opening of the weapon's muzzle, the diamondoid material would shatter, vaporizing the shooter.
### RPG Application:
In this case, the diamondoid tank would be loaded into an RPG/Missile launcher, with the barrel of the weapon containing a powerful magnetic field, the head of the rocket is also attached to an SRB, which will assist in the arming process. Here is a picture that should make it more intuitive:
[](https://i.stack.imgur.com/RnnOE.jpg)
The LIDAR sensor helps guide the rocket and the SRB is laced with cesium. First, the arming apparatus is attached to the head, then the head is attached to the SRB with the help of the arming apparatus. Then a code is inputted to the arming apparatus by twisting the head, like a safe. The arming apparatus scans the SRB, and will only continue if the SRB is accepted, then, the apparatus energizes the cesium, preparing it for launch. Then the rocker is loaded into the launcher where the targeting system connects to the user's HUD and will only launch if the target is more than 30m away from the target - this can be overridden in dire situations with a special code that can ***only*** be inputted remotely. The head also has a magnetic field that will prevent from being hit and exploding before it reaches the target. (P.S. the HUD part is optional if you don't have that in your world).
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[Question]
[
In this world, there are reptilean demi-humans (like lizardmen and lamia) which are appearance wise half-human half-reptile, they live in coexistence with humans and other types of demi-humans. These reptileans are poikilothermics (cold-blooded), so in theory they would be vulnerable to cold temperatures and usually seek warm places if possible.
Knowing that these half-human half-reptiles monsters (essentially humans with reptile traces and characteristcs), how could some characteristcs of the reptiles, like being cold-blooded, translate to daily life?
For example: would a reptilean demi-human student have distance education during winters for example? Or maybe heaters being used with more frequency?
How could cold climates affect them in general? Could it be lethal or dangerous to be in cold weather? Or maybe just affect their reflexes and/or disposition? Generate a tendency to hibernate (or brumate)?
[Answer]
**Clothes.**
[](https://i.stack.imgur.com/GdLgq.jpg)
Lizardmen are usually depicted strutting around in the buff, or with some kind of scanty loincloth. There is definitely a place for that. But cold lizardmen would want clothes, and thick ones. It would be even more important for them than for us mammal types. Warm clothes would let them retain the metabolic heat they make with muscles. These warmly-clad lizardfolk would also keep moving; flexing, squatting, posturing, shimmying side to side; doing whatever they needed to do to generate that heat from their muscles.
[Answer]
Many real world reptiles and amphibians slow down in colder weather, hence why they develop special ways to absorb heat from the suns rays. Some species, for instance, can hibernate under frozen rivers in mud, or straight up freeze themselves too. You can read some here, [its called cryptobiosis](https://en.wikipedia.org/wiki/Cryptobiosis). Because of different types of reptiles and amphibians, the affect of cold weather (and how harsh it becomes) severely depends on how you will build your species. If cold winters are common, it would be natural for the demi-humans to have some sort of biological tactic to deal with the temperature drops.
As for education, perhaps your reptilian demi-humans have a winter break rather than a summer break (if conditions are not extreme). Winter would likely slow them down if they cannot control their inner temperature, thus impacting education.
[Answer]
There your reptiles might have evolved to survive the cold to some degree or not even have a problem with it like some amphibious animals. The temperature should impact them regardless because the reaction speed of chemical processes will go slower in the cold. That’s like when we humans have not enough sugar , or oxygen in the blood what slows us down in speed, power in the muscles or process speed in the brain. But just as with us humans proper clothing and controlled activity can circumvent such problems.
Intelligent reptiles however would need extra heat sources to take with them while a human takes the energy in through food and produce the heat themselves, that is also why species like humans eat more in comparison.
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[Question]
[
I've read several sites and even questions on here where the sky would appear almost white or light blue if it orbited an orange dwarf star. However, that is if the planet has the same atmosphere as ours. But what if it didn't?
From what I read, different amounts of gases in the atmosphere might make the sky appear to be different.
Given these facts, what if the atmosphere of this planet was 75.09% nitrogen, 21.95% oxygen, 1.40% argon, 0.14% carbon dioxide, 0.29% neon, and small amounts of other gases.
For comparison, the levels of argon and neon in our atmosphere are 0.93% argon and 0.001818% neon.
However, this is just an example. My figures might be off and the levels are either too high or too low.
Also, there are probably other factors that are necessary for the sky to appear orange while the planet orbits an orange dwarf star.
My question boils down to this: what levels of Argon and Neon, along with any necessary other factors, are needed for this planet to have an orange/reddish-orange sky while orbiting an orange dwarf star and still be sustainable for life?
Sustainable for life I mean for anything that breathes oxygen! Or in this scenario, a species that evolves on the planet and breathes oxygen.
[Answer]
1. Human vision is very sophisticated at filtering out colored illumination – basically, whether the sun is very red or very blue, our eyes and brains define the color of sunlight to be "white" and shift our perception of other colors accordingly. Even under sodium street lamps, we see trees as green and so on, despite the fact that a photo will show that everything in the scene has the exact same yellow hue. (This phenomenon is what "white balance" in photography corrects for).
The significance of this is that, for the *sky* to appear orange, it must be orange-hued *relative to the source of light*. Which means that you would *not* get an orange sky by making the sun orange (either by lowering the star's emission temperature or by adding an orange "filter" in the atmosphere).
2. For the sky to *reflect* orange light, it would need reflective particles, which would mostly just reduce the amount of light. That is, if you try to make the air look orange by spraying orange paint around, the light will get dimmer much faster than it changes in hue.
3. The scattering that makes our sky blue can also make it orange, depending where you're standing. The sun is constantly firing bullets of light in all directions, and the bluer bullets are more likely to ricochet off an air molecule along the way (without affecting the overall amount of energy / illumination).
So, if you're looking at the sky with the sun off to one side, the bullets from the sun don't hit your eyes directly, but you *do* see the bullets that get scattered as they're flying over your head – you see the scattered blue light, which is why the sky looks blue.
But if you are facing toward the sun, the sky in that area looks more orange because a greater proportion of the blue bullets have been deflected before they hit you, so it's the redder light that is left over. For various reasons, we don't tend to notice this at midday, but it is very noticeable in sunsets, where you do indeed get orange skies.
The physics of this aren't really negotiable – scattering makes light redder from the front and bluer from the side, period. But you could certainly contrive a way to have a sunset that lasts all day.
4. If the sky is otherwise dark – because the sun is dim, or at night – then you can have gases in the atmosphere *emit* light by corona discharge, i.e. an aurora. The color is determined by the gases involved, and the intensity is determined by the strength of the ionizing radiation hitting the atmosphere. However, the physics determining light color are quite complicated – Earth auroras are mostly green and red, with both colors being due to atomic oxygen (O•) at different altitudes. High concentrations of neon probably would give you red auroras, but the problem is that neon, like helium, is so light that it would boil off into space. Another problem is that if you want auroras over the whole planet, it implies there is a lot of cosmic radiation and no magnetic field, which makes it questionable whether you would even have an atmosphere or be able to support life.
If you wave away that concern, you could have a red aurora covering the entire sky, produced solely by atomic oxygen at high altitude. In order to get rid of the green light, you could say that the atmosphere has no nitrogen at all (since molecular nitrogen is required for the process whereby oxygen emits green light). You could replace the nitrogen with more oxygen, though you'd have a very flammable planet, and humans can't breathe such a rich mix at Earth-normal pressure. Or, you could replace the nitrogen with argon, except I think that would anaesthetize humans at high concentrations. Or you could just assume that there is a workable mixture somewhere between the two.
[Answer]
Color of a sky is due to [Rayleigh scattering](https://en.wikipedia.org/wiki/Rayleigh_scattering). It means it doesn't depend much on atmosphere composition (only small tints). Yes, even on Mars sky is blue, unless for dust storm. And thats how you can "paint" your atmosphere - use some aerosol. Say planet is covered with dence mono-species forest wich constnatly emmits lots of orange pollen or smth like that.
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[Question]
[
In a near-future sci-fi world, I described a disease with the following characteristics:
* Affects human female children (not necessarily exclusively).
* Is a neurodegenerative or similar disorder, leading to progressively reduced mobility.
* Can occur as the result of a chance mutation in the genes of an afflicted person in the early embryonic stage.
* Could lead to a girl of age 5 to occasionally (or more frequently) require a wheelchair for mobility.
* Is not curable or able to be mitigated significantly as of the present day.
* Can leave the afflicted person's cognitive functions relatively unimpaired, at least until after the age of 5.
* Leads to a greatly reduced lifespan, and can be expected to result in death between the ages of 10 and 30.
Does this describe any real-world disease? If so, which best fits this description?
# EDIT:
The setting is a Shadowrun RPG game, set in 2075. The girl in question was 5 years old when her illness led her parents - who were top researchers in the field of cybernetics - to subject her to an experimental invasive treatment where her brain was removed from her body and enclosed in a life-support shell while nanites read the state of each neuron, created an artificial duplicate and removed the original, effectively remaking her into an inorganic consciousness. Very Ghost-in-the-shell like.
When it became apparent that a megacorporation perceived by her parents to be hostile was about to stage a hostile takeover of the parents' smaller corporation, her parents had her mind-shell placed in a simulation run at 100 times normal speed, allowing her to mature (the neuroreplacement technology allows this, it wasn't possible for earlier versions) to adulthood in 2 months, so that when the megacorp takes over, she is no longer a child, but an adult, her mind-shell placed into a cybernetic body powerful enough to allow her to defend herself.
The nature of this question is effectively, "What disease would be sufficiently terrible that loving parents would do this to their daughter rather than use some far less invasive method of treatment?".
I thought of some sort of neurodegenerative disease, on the justification that even replacing the entire body but leaving the brain untouched would likely be seen as an incomplete cure by her perfectionist parents. They don't just want to mitigate the disease that's killing their daughter by inches, they want to eradicate it so that she can become completely independent.
It may be that the disease occurred as a mutation in the girl, or that her parents are carriers. Either would work.
A very important point is that the girl must not be significantly mentally impaired at the age of 5. Later mental impairment is allowable, since it would give a good reason to replace her neurons... but it is not strictly necessary, as her parents may have been considering the accelerated maturation as being worth the additional risks.
Finally, to address the potential duplicate... The disease affecting the girl in my description may be a variety of cancer. My main criterion is actually the absence of mental impairment as of age 5.
[Answer]
**Osteogenesis imperfecta type III.**
[](https://i.stack.imgur.com/UcALw.jpg)
<https://globalgenes.org/2012/07/11/sweet-bella-is-battling-osteogenesis-imperfecta-and-has-survived-over-40-broken-bones-since-birth/>
<https://rarediseases.info.nih.gov/diseases/8695/osteogenesis-imperfecta-type-iii>
>
> Osteogenesis imperfecta type III (OI type III) is a form of
> osteogenesis imperfecta, a group of genetic conditions that primarily
> affect the bones. In OI type III, specifically, a diagnosis can often
> be made shortly after birth as fractures (broken bones) during the
> newborn period simply from handling the infant are common. Other signs
> and symptoms vary significantly from person to person but may include
> severe bone fragility, bone malformations, short stature, dental
> problems (dentinogenesis imperfect), macrocephaly (unusually large
> head), hearing loss, and blue sclerae (whites of the eyes). Most
> affected people are unable to walk without assistance.[1](https://i.stack.imgur.com/c3RUW.png) OI type
> III is caused by changes (mutations) in the COL1A1 or COL1A2 genes and
> is inherited in an autosomal dominant manner.[1](https://i.stack.imgur.com/UcALw.jpg)[3] Treatment is based
> on the signs and symptoms present in each person...
>
>
>
[Life expectancy in osteogenesis imperfecta](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2350292/?page=1)
[](https://i.stack.imgur.com/c3RUW.png)
>
> Of 26 deaths, 19 occurred before the age of 10. Patients surviving
> beyond this age seem to have a better outlook.
>
>
>
OA type 3 meets your criteria except there is no propensity for females. It is not neurodegenerative: the bones are the issue. It cannot be cured but can be managed. The published survival curves look to me like in that group at least, the girls did not do as well as the boys. It is genetic and can happen sporadically. The kids are very fragile but their brains work fine. They need wheelchairs. I put the picture of Bella here because she looks a little different but she is not disfigured. I could imagine Bella at age 8 being the protagonist of your story.
I have not thought about this from a scifi perspective until now. Near future scifi could be super helpful to a person with osteogenesis imperfecta - I am thinking bone augmentations and wearable smart prostheses.
[Answer]
>
> Does this describe any real-world disease?
>
>
>
Mmmaybe? It doesn't *precisely* describe any that I'm aware of, but I'm not an expert, so I could easily have missed things.
I'd suggest inventing your own based on a real one, because that way there's no danger of you being wrong about any aspect of it.
>
> Is a neurodegenerative or similar disorder, leading to progressively reduced mobility.
>
>
>
As it happens, the first thing I thought of was a [muscular dystrophy](https://en.wikipedia.org/wiki/Muscular_dystrophy), because those generally don't seriously affect the brain but do cause significant movement issues and can be fatal within the sort of timespan you're looking at.
One example would be [Fukuyama muscular dystrophy](https://en.wikipedia.org/wiki/Fukuyama_congenital_muscular_dystrophy). This isn't sex-linked (unlike other forms of muscular dystrophy which affect men more often than women) and it is generally fatal by the age of 20, but its affects tend to be noticable from birth rather than having a delayed onset. It does have some mental impairment unlike other kinds of muscular dystrophy.
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[Question]
[
I've just come here for some help drawing a map for this **fictional planet** where two roughly similar planets have been smushed into kind of pear shape like this:
[](https://i.stack.imgur.com/WfvLJ.png)
So this planet spins on an axis which runs through the center of the original planets, and their magnetic fields merge, as in the drawing:
[](https://i.stack.imgur.com/yFH9x.png)
Would the ridge I've depicted where they meet remain an exposed mountain range, or would it fall beneath the oceans?
Also I want my alien race, zefusians, to live happily on this planet in a number of biomes such as snowy mountains, sparse forests, semiarid deserts, tropical islands and few volcanic hot spots without constantly getting natural disasters.
[Answer]
**The easy answer is "yup! mountains!" the truth is more complex**
*Sometimes we get caught up too much in "reality." In "reality," this planet cannot exist as you've described. But what's the fun in that? Therefore, I'm going to utterly ignore all aspects of physics that would either (a) tear this planet apart or (b) force it to eventually become spherical. Instead, I'm going to answer the question from the perspective of your world and its rules.*
**All that mass must go somewhere**
Your drawing (nice, BTW) shows about 1/3 of the small planet and 1/5 of the large planet being involved in the collision. All that mass had to go somewhere. A bit of it would be converted to energy during the fissionable component of the collision, but most of it is still there.
Where is it?
* Some of it is pushed toward the center of both original masses, actually causing a bit of a dimple on the far side of each mass. So, you have some mountainous regions at both poles due to the collision.
* Some of it creates a high-density region extending more-or-less to the center of both original masses. The region is sphericalish. This creates some small (probably not particularly noticable) variations in gravity where it's weaker where you might not expect it, like the southern half of the larger sphere.
* Most of it becomes a serious ring of mountains right where you've drawn them. Sink under the oceans? I seriously doubt it! They'd be chain of mountains the circumference of the collision point that would likely challenge Everest for height. Lots-o-force involved with that collision.
**But what does that mean for my oceans?**
That ring of mountains is not a universal, impassable wall. Clouds will move around and through it. That means rain. Rain means erosion. And erosion means you'll eventually have mountain passes. If the planet is old enough, it's plausible to have "cracks" in that ring of mountains that would connect the waters above with the waters below. However, for the most part, the waters will be segregated.
**And my biomes?**
The northern and southern biomes will remain fairly segregated for a long time. Birds will get around that, and winds carrying seeds will, too, eventually. The older the planet, the more merged the biomes will become. But they will not be 100% segregated. As a wise man in a dinosaur movie once said, "life finds a way." But it finds it slowly.
**Could anything have actually survived the collision?**
Nope. At least it's mighty hard to believe. The earthquakes, dust, heat, yada, yada, yada... That was what I consider an extinction-level event. Cockroaches and dandelions might have survived, though.
**And what about that magnetic field?**
That's not actually how magnetic fields work. They don't follow the contour of solid mass unless that mass is entirely magnetic itself. And even then, they tend to smooth out. What I'm saying is that neat little tuck you show at the seam wouldn't exist. It's a small detail, though, and not very important.
What is important is that magnetospheres are thought to be created due in part to the churning liquid core — which was compromised in the collision. You can't have two independent liquid cores and over time you won't have a core shaped like your surface. Erosion, it would all smooth out inside, possibly even cooling to a thicker mantle at the north pole.
In the worst case, you'll end up with a spherical magnetosphere centered on the original larger mass that does NOT extend far enough beyond the northern pole. Lots of cancer at the north pole! Amazing Aurora Borealis, though.
In the best case the "center of the planet" shifts to something around the original tropic of Cancer1 for the original larger mass. It might very well be weaker (a consequence of that density increase I was talking about, the core is not as fluid as it once was... at least not yet. There's that age thing again).
But, it's your planet, so you might simply define the magnetosphere as you wish it to be!
**So could life live there?**
Sure! If it evolved after the collision or colonized after the collision. But whatever was on the planet before the collision is burnt popcorn (unless you declare it to be otherwise, it's your world).
**TL;DR**
The smushed belt of mountains will remain mountains forever. Eventually, erosion would smooth them out and allow some passes to form, but they would never be consumed by the sea. Too much mass involved in the collision.
---
1 *The tropics of Cancer and Capricorn aren't simply the 1/3 points of the sphere, they're defined by the solstice events, which are a consequence of the Earth's axial tilt. I'm using the Earth-reference as a literal map reference for convenience to help you imagine the point I'm talking about. Heck if I know what the original mass' tropics were, or even if it had them.*
[Answer]
Alright, I'm not an expert, but I've watched a few documentaries on planet stuff.... here's my best shot:
The center of gravity will move toward the point between the two planets, and the water will always drift toward the center of gravity. The mountains between the two spheres might not be totally submerged, but they will be volcanic and subject to frequent earthquakes/eruptions, so they will be growing as the planets merge together over time and become more spherical. This relatively rapid change in shape ("relatively" rapid, but still very slow to observers), will result in extreme weather patterns across the whole planet; your storms will be really hardcore, and the waves on the shores of that big ocean will be huge all the time. Sailing on that ocean will be very dangerous, and using a boat to get from one planet to the next will likely require finding some small passageway in the volcanic ring.
Any water on the far-end of the planets will only remain there if it is collected in basins, preventing it from flowing toward the joining-point. The air on the far ends of the planets will be very thin ("high altitude"), so the far ends of the planets might be icy, too, and that will prevent all the water from totally escaping. The massive ring of volcanos between your planets will warm the water there, and release a lot of steam, so depending on whether or not you have a moon and how it affects your wind currents, the areas nearby the coast (which get wind from the ocean) might be very warm and humid year-round, while other areas near the coast which don't get the warm wind, but still get shrouded in steam, might be very cold for lack of sunlight. The middle area between the joining-point and the far-end of each planet may enjoy a wide range of climates, so you could easily find all of your biomes here.
Any bodies of water on the surface of the planet will lean toward the center of gravity, so the middle region between the ends and the joining area will not likely have large bodies of water, unless they are inside large craters, or leaning up against mountains which were already on the planets. Likewise, people traveling from the middle to the end of the planets will feel like they're going uphill for almost the whole journey.
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[Question]
[
I was watching a program about the New Horizons space probe and was fascinated by the new revelations about cryolava/cryomagma, and the [amorphous planes covering Pluto](https://en.wikipedia.org/wiki/Pluto#Geology)(98% nitrogen ice).
I'm wondering how this might affect the idea of a human colony on an ice-world/cryo-world. In particular:
* How would you keep structures from slowly sinking into the surface
of a planet completely covered by cryolava?
* How fast would this sinking occur?
I'm assuming the habitat will need to be kept warm, and would therefore accelerate the process.
I imagine for small habitats, this might not be a big deal, as they could be on wheels and roll along the surface, although this could scale poorly to larger settlements/cities
### Addition
**Quick freezing point chart from wikipedia data**
```
pure freezing
substance point
H2O 273.2 °K
CO2 216.6 °K
NH3 195.5°K
CH4 90.70 °K
CO 68.13 °K
N2 63.15 °K
O2 54.4°K
H2 14.0°K
approx. surface temp. Pluto(for reference): 33°K - 55°K
```
[Answer]
Amorphous means non-crystalline, not non-solid. Glass is amorphous, and it's solid enough to hold a load for a long time at room temperature (the myth about sagging in centuries-old stained glass windows is just that -- a myth). Likewise, amorphous ice (whether water ice, ammonia, clathrate, or even oxygen) will be solid enough not to flow or creep noticeably, so long as the temperature stays below the freezing temperature of the substance.
As long as your habitats are insulated so the surface(s) contacting the amorphous ice plain are below the melting or sublimation temperature, you needn't worry about the habs sinking into the surface. If they get too warm on the bottom, it won't matter whether the material they're standing on is crystalline or amorphous, it'll still melt (and, in a vacuum, immediately flash to vapor). Sinking won't be subtle at that point, if there's enough heat reserve to boil off a lot of the supporting material.
[Answer]
**Buoyancy.**
[](https://i.stack.imgur.com/9U0DP.jpg)
Your ice world settlements are built on giant hydrogen-puffed Styrofoam pontoons. Each building and its pontoon is lighter than the liquid below and so it will not sink. Once could use the same method for building on a Minnesota lake of unpredictable April frozenness - if liquid or slush, your building floats. If solid your building sits.
The styrofoam also provides extra insulation between hot dwelling and frozen substrate.
] |
[Question]
[
A while back Demigan had a running series of posts about various aspects biological enhancement for the purpose of designing super-soldiers with an element of (pseudo) science behind them.
You can find his previous questions here:
[Creating a scientifically semi-valid super-soldier, part 1: Skeleton](https://worldbuilding.stackexchange.com/questions/106292/creating-a-scientifically-semi-valid-super-soldier-part-1-skeleton)
[Creating a scientifically semi-valid super-soldier, part 2: nervous system](https://worldbuilding.stackexchange.com/questions/107365/creating-a-scientifically-semi-valid-super-soldier-part-2-nervous-system)
[Creating a scientifically semi-valid super-soldier, part 3: Physical shock resistance](https://worldbuilding.stackexchange.com/questions/107635/creating-a-scientifically-semi-valid-super-soldier-part-3-physical-shock-resis)
[Creating a scientifically semi-valid super-soldier, part 4: respiratory system](https://worldbuilding.stackexchange.com/questions/108558/creating-a-scientifically-semi-valid-super-soldier-part-4-respiratory-system)
[Creating a scientifically semi-valid super-soldier, part 5: Heart and circulatory system](https://worldbuilding.stackexchange.com/questions/109503/creating-a-scientifically-semi-valid-super-soldier-part-5-heart-and-circulator)
[Creating a scientifically semi-valid super-soldier, part 6: Radiation protection](https://worldbuilding.stackexchange.com/questions/111275/creating-a-scientifically-semi-valid-super-soldier-part-6-radiation-protection)
[Creating a scientifically semi-valid super-soldier, part 7: Hearing](https://worldbuilding.stackexchange.com/questions/112777/creating-a-scientifically-semi-valid-super-soldier-part-7-hearing)
[Creating a scientifically semi-valid super-soldier, part 8: Communication](https://worldbuilding.stackexchange.com/questions/115986/creating-a-scientifically-semi-valid-super-soldier-part-8-communication)
[Creating a scientifically semi-valid super-soldier, part 9: Temperature control](https://worldbuilding.stackexchange.com/questions/118331/creating-a-scientifically-semi-valid-super-soldier-part-9-temperature-control)
One thing I didn't really see mentioned, which I was wondering about, is metabolism. Obviously, a super-solider with powered-up muscles, nervous system, etc. is going to be burning a LOT of energy, even at rest. The post about temperature control is basically asking how to deal with all the excess heat that is created as a result.
Metabolism is the process by which the body converts food/fuel into the energy it needs to function. The higher the energy needs of the organism, the greater the amount of fuel required, or the more efficient the conversion process must be.
In nature, we do see that some creatures have more efficient metabolisms than others. For instance, warm-blooded beasties have more efficiently designed metabolisms than cold-blooded beasties because they need to use additional energy warming their bodies and therefore need to use the energy that they have in a more efficient way.
Increasing metabolic efficiency would also probably help with the temperature problem a bit as well. [This article](https://www.khanacademy.org/science/biology/principles-of-physiology/metabolism-and-thermoregulation/a/metabolic-rate) notes:
>
> no energy transfer can be perfectly efficient – that's a basic law of
> physics. Instead, each time energy changes forms, some amount of it is
> converted into a non-usable form. In the reactions of an animal's
> metabolism, much of the energy stored in fuel molecules is released as
> heat.
>
>
>
Logically, the more efficient we can make this conversion, the less heat will be produced as waste.
Given a super-soldier's high rate of energy usage, how do we stop them from needing to eat constantly, 24/7? The less we have to feed them, and the longer they can survive cut off from supplies, the better. Any ideas for improving these guys' metabolic efficiency or generally finding ways to feed them a more "normal" amount while still powering their high energy needs?
To stay in keeping with Demigan's posts, a good answer needs to be limited to a biological solution, where a body can build, repair and maintain it.
[Answer]
**As high as possible, with the ability to regulate it downwards.**
When well supplied and in a combat situation their metabolisms would spike. Soldiers would be able to move and think quicker, and recover from injuries faster. If well supplied while marching this would also give them a mobility advantage compared to other footsloggers over rough terrain (any other terrain and they should be in transports).
When not fighting, they can regulate their metabolism downwards to a more manageable level. Arguably, humans are probably a little too highly metabolised for the large majority of warfare. Sitting in trenches waiting for an attack doesn't require that much energy. They can save on supplies by reducing their metabolism. Platypodes and Echidnas are able to maintain a fairly active lifestyle with body temperatures around 32 degrees celsius. Something like that would allow for a moderately alert fighting force that doesn't require quite so much energy to maintain.
When not on active duty, they could enter a sort of torpor or hibernation to reduce their metabolism as close to zero as possible. For storage during peacetime, or transport at some distance from the front lines this would be ideal. In protracted conflicts, you could always have the majority of your fighting force in torpor with only a select few alert sentries (provided you're confident you can wake your sleeping soldiers in time to respond to an attack). There's also a benefit of having an intermediate torpor state where they are still capable of some activity in case they are cut off from supplies for a protracted amount of time, but still at risk from the enemy.
[Answer]
It requires preserving blood around vital organs, allowing peripheral tissues to starve, just as whales and seals sort the body's oxygen supply by being cut off from the air. This proved so effective that over time it became the norm even among active super soldiers;
The only drawback: they will have a dead-pale color. This skin color is a strategy for increasing their fuel consumption. When lactate levels on the surface of tissues become too high - or when they feed - blood is redistributed to the skin, and their body turns red.
Also, during sleep, their metabolic activity will fall by about half of normal values.
[Answer]
# Several improvements
1. The ability to digest what we call dietary fiber, specifically cellulose, and use it for energy. All that is needed here is an enzyme that has the ability to break down cellulose and use it for energy. Making any plant or tree into a source of pure sugar.
2. Low basal metabolic rate, similar to Ynneadwraith's answer, this is the amount of energy that the soldier's body needs to maintain itself while at rest. There is no reason why this has to be high, as it is only during exertion when this needs to change. The same thing happens in all humans already, so little modification is needed.
3. Large storage capacity. Normally this is called fat in humans. The super soldier would need to be able to make and burn fat at an accelerated rate in order to charge and discharge their energy reserves (fat).
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[Question]
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This series will focus on a Worldkillers: a group of interstellar outlaws who specialize in destroying worlds.
Each question has the objective to explore a different way to kill a planet - a word that means making it uninhabitable for its "ruling race" (ex: burning all the oxygen from Earth to make life impossible to humans).
The technology level of this setting is high (warp drives, death stars, advanced AIs, multiple alien races, etc).
Their target world is Earth. They were paid to exterminate us.
## The Question
You are in the planning room of the Worldkillers HQ, in the middle of a discussion for the best method to end humans. Someone says "let's destroy their oceans".
My question is: **How much of Earth's oceans would have do be drained/vaporized/gone in order for human life to cease to exist? And how would this catastrophe be perceived by humans as the process is conducted?**
Important Note: The water volume is drained/vaporized/eliminated over time, not all at once.
[Answer]
As noted in the comments, an [RKKV](https://infogalactic.com/info/Relativistic_kill_vehicle) is by far the best way to destroy any planet, and it is pretty adaptable too. A race of alien beings living in the cloud banks of a gas giant planet would be vaporized just as easily be an RKKV impact in their planet as we would be.
However, if the desire is to heat the planet to the point the oceans boil, you would have to do some pretty heavy duty engineering. As a BTW, once the stratosphere gets "wet", the ultraviolet radiation from the sun dissociates the hydrogen and oxygen in the water vapor and triggers a [moist greenhouse](https://arxiv.org/pdf/1510.03527.pdf), effectively sterilizing the planet and rendering it unfit for future use.
The simplest "low tech" means would be to start orbiting platoons of mirrors around the Earth and focusing more and more sunlight onto the planet. Eventually, you will deliver enough energy to increase the evaporation rate and start triggering the moist greenhouse. This will also likely take hundreds to thousands of years to actually trigger a disequilibrium and get tot he runaway greenhouse, not to mention the inhabitants of the planet might have a few ideas about the subject as well.
Next on the list would be firing an RKKV into the star, triggering massive solar flares and increased solar activity. Assuming that you can deliver enough energy into the star, you will certainly send at least a pulse of energy to the planet, increasing the heat and potentially triggering the moist greenhouse again. although I suspect that you might have to send RKKVs at regular intervals into the sun to pull that off.
Finally, you can take the direct approach and build a Dyson swarm around your own star and send a [Nicoll-Dyson beam](https://www.youtube.com/watch?v=RjtFnWh53z0) at the target planet. This is the true "death star", and it will allow you to fry planets even thousands of light years away (however you need to wait that amount of time for the beam to arrive). With a bit of fine tuning, you can boil away the atmosphere, the oceans or even the lithosphere (its the only way to be sure).
[](https://i.stack.imgur.com/HNvET.jpg)
*Nicoll Dyson beam*
The Atomic Rockets "[Boom Table](http://www.projectrho.com/public_html/rocket/usefultables.php)" provides information about the amount of energy needed to deliver this and other exciting effects.
However, in the end, it is pretty messy and inefficient. Far simpler to send an RKKV to impact the planet directly.
[](https://i.stack.imgur.com/UsIp3.jpg)
*RKKV impact*
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[Question]
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I've seen many questions about tides and tidal variations on a wide variety of interesting single star, multi star, single planet, binary planet, single moon, multiple moon, and even ring system combinations and variations.
I've also seen many questions about co-orbits including trojan, Lagrangian, horseshoe, and more exotic orbits.
But I was not able to find one about the tidal effects of horseshoe orbits, so here it is: **What would tides be like on an Earthlike planet with a horseshoe orbital partner body?**
For simplicity, let's just assume that it's actually Earth, and that the object in the horseshoe orbit with Earth is the Moon, with no other changes to them other than the new orbital configuration. Also, assume that the Moon's closest approach in this new orbit is the same as it's closest approach in it's current, actual, real life orbit.
**EDIT** An explanation of how often the Moon would approach Earth, to cause these tides to take effect, isn't necessary but would be interesting if you feel so inclined to include it. For this question, the minimum information is just: a description of how the tide coming in and going out for each approach of the Moon in this new configuration would be effectively different from how current tides come in and go out for an average tide cycle in real life. Things like how long does it take to come in, how long does it stay at high tide, how long to go back out to low tide, is high tide in this new configuration higher, lower or the same height as a real tide, etc.
**EDIT 2** I'd guess that spring and neap tides would not be a thing, as I understand those to be when the moon is in line with, or opposite (respectively), the sun to either combine or counteract (respectively) each others' tidal effects, and this orbit would never cause them to line up. But I could be mistaken in my assumption.
[Answer]
Tidal effects are based on how big something is and how far away it is. The Sun is pretty far away, but really big and thus has an effect on the tides. The Moon is not very big (on a planetary scale) but is pretty close and has an effect. Venus is bigger than the Moon, but much further away, and consequently has very little effect on the tides. This change would put the Moon further away than Venus for the majority of it's orbit, thus we can infer that for most of it's orbit it will have very little effect on the Earth's tides. When it does come closer in it's horseshoe path it would have less effect on the Earth's tides than currently, unless it is coming closer than it currently orbits.
Tidal timing is dominated by the rotation of the Earth. You can see this in the ~12 hour timing of the tides (half rotation). This would not change, in fact without the Moon in it's current place the tides would become much more regular.
This leads into how often would it come closer. Something in a horseshoe orbit with Earth is going to be going slightly faster or slower than the Earth around the Sun and will take a long time to move in a full horseshoe with respect to Earth.
A good example is found on wikipedia, with nice labels for times, which demonstrates an actual horseshoe orbit of a small asteroid with respect to Earth.
<https://en.wikipedia.org/wiki/File:Animation_of_(419624)_2010_SO16_orbit.gif>
From the animation you can clearly see the horseshoe with respect to Earth, and you can see that it takes several hundred years to complete a full "horseshoe".
So the Earth's tides would be much more regular, except for approximately every hundred years when the Moon approaches the end of the horseshoe and you would have tidal effects similar, but smaller than current tides for a few years until it moves further away back along the horseshoe.
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[Question]
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I am a post-human adapted for permanent life in vacuum and micro-gravity. How might my physiology and biochemistry overcome the following challenges?
*Please note I have a strong cultural aversion to augmenting my body in order to help me survive: i.e. enclosing myself in artificially-constructed protective shells, etc.*
## Current status
**See [Part 1 on radiation resistance](https://worldbuilding.stackexchange.com/q/129268/56294)**
**See [Part 2 on temperature control](https://worldbuilding.stackexchange.com/q/129311/56294)**
**See [Part 3 on metabolism](https://worldbuilding.stackexchange.com/q/129400/56294)**
At this stage, I look similar to an enormous shining pangolin with interlocking plates of keratin-analogue that are alloyed with steel to protect against ionizing radiation. My radically engineered DNA and its unparalleled checksum and repair functions keep the doctor away. I can move these plates to help dissipate heat and - just like a Terran pangolin - curl up in a protective ball to shield my more sensitive parts. I have a reactive outercoating that allows me to alter my pigmentation (which I typically set to polished silver in order to minimise heat loss).
Space is a tough place to live and its very big, so you could say my metabolism has multiple redundancies. I can eat comets and asteroid material, using the spinneret on my tail to swaddle them in cocoons before supping on the extracted organics and minerals. I sift small concentrations of hydrogen from the interplanetary medium for use as a metabolic catalyst, and I'm a radiotroph, with the outer layer of my armoured plates coated in a melanin that helps me capture energetic rays to power my body. Stick me near a magnetic field and I'll even generate power like a dynamo.
## **Part 4: Movement**
As mentioned, I look very similar to a pangolin. However, my prehensile limbs are much longer, identical, in that they are all hands, and there are five of them - I have a manipulator at the tip of my dextrous tail-limb.
In "artificial" environments such as the vacuum cities where I live, architecture helps me move primarily through the use of my limbs. I might use my tail-limb to stabilise me against a tether or outcrop while I work, or throw out some silk (similar to the stuff I use to cocoon comets) to reach locations or retrieve objects in the medium distance.
However, I'd also like to be able to move greater distances in a reasonable time, although I can ratchet down my metabolism to a somnolent hibernation for long journeys.
I'm wondering whether my body could incorporate a kind of chemical thruster, perhaps a nuclear salt-water rocket? As far as I understand, the NSWR reactions would [occur outside of my body](http://path-2.narod.ru/design/base_e/nswr.pdf), presumably meaning that I wouldn't have to worry about heat so much. As I'm a radiotroph, I'm also wondering whether I could incorporate this into my metabolic pathways.
**How might I move at reasonable speeds over medium to long distances within the system?**
Note that I do not need to go interstellar (yet...)
**[See part 5 on senses](https://worldbuilding.stackexchange.com/q/129647/56294)**
[Answer]
If you are isolated into the vacuum, with nothing to exert a force on, you have only two options:
1. get pushed from the light, either coming from the central star or from an artificial source of light, like a laser: spread up your body as much as possible and let it act as a solar sail. Let the photons transfer momentum to you and move your body.
Yes, this is going to be pretty slow and not really versatile (how do you move toward the light source?). When you cannot use this method you can use
2. Newton third law: you eject something, and that something will exert a force on your body allowing it to move. What can you eject? Let's go through a necessarily partial list:
* gas: old school astronauts had small jets to assist their maneuvering in EVA. You can use something similar, or you can use PHART (PHysically Assisted Reliable Translation), relying on gaseous emission from your body.
* liquid: like the above, but more effective thanks to the liquid higher density. You need proper training on how to control the abdominal muscles and the sphincter, but if [Le Petomane](https://en.wikipedia.org/wiki/Le_P%C3%A9tomane) could do it, you post human can surely achieve it.
* solid: in this case you would need to throw something away, like some of the scales on your body.
Mind that in all the above cases you are expelling mass from your body. So you are bound to not overdo it, else you might be in obvious troubles. If you use the ejection method and you are in a somehow enclosed environment, you might even think of recovering part or all of the ejected material (mainly thinking of the scales, but also the other could do if needed)
[Answer]
Your a radiotrophic (you "eat" radiation) and also have a high immunity to it. As such, I would suggest constructing a small nuclear reactor (or perhaps a radioisotope thermoelectric generator) and then wrapping yourself in a big bag of water (this is your propellant) and then simply feeding the water past the reactor so that it heats up into steam which then propels you 'teakettle" style across the void. The advantages to this is that its quite simple and easy to construct, and you can steer it with your limbs, and the radiation can sustain your metabolism somewhat on the journey. However it would be a very, very long journey if you are planning on going far (say Earth to Mars) but if your living in say the Jovian or Saturnian system it can get your around quickly enough.
For more ideas and help calculating things like specific impulse and DeltaV I suggest the excellent [Atomic Rockets](http://www.projectrho.com/public_html/rocket/) website.
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[Question]
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This is not a question on whether or not floating, balloon-like organisms are biomechanically viable - I already know the answer to that, which is yes. This instead deals with the plausibility of such a thing evolving, a problem I've thought about for quite some times.
So, in my alien world, there are giant colonial invertebrates, similar to siphonophores, and they form huge balloon-like sacs, floating through the sky and filter-feeding aerial plankton. They float by means of hydrogen gas, which they produce by electrolysis (using biolectricity to split water molecules in the air).
However, I've recently discussed this concept with others, and it seems as though balloon organisms are quite a difficult thing to justify, mainly because of the energy expended in producing the hydrogen gas. A friend did some research, and according to his Google searches, it takes around 4 kilowatt hours to split one litre of water into hydrogen and oxygen gases - giving you 1,200 litres of hydrogen gas. That can lift roughly 4 pounds in an Earth-like atmosphere, giving you the capacity to lift roughly 1 pound of mass per kilowatt hour. 1 kilowatt hour, I'm told, costs 3,500 kilocalories to produce.
Now, before I continue, let me say that my planet does not have conditions identical to Earth. The gravity is about 0.85 times lower, while the atmosphere is denser - perhaps a quarter of the way or a little under between Earth and Venus. **Does anyone know if it's feasible to alter the calculations above to apply to these conditions?**
So, even in a place with an atmosphere about 20 times denser than Earth's and a gravity 0.85 times lower, I doubt that the conversion rate of 1 Kwh = 1 lb will alter drastically. Sticking with that initial equation, even if the balloon colony was so light that it weighed only as much as a human, it would still expend about 500,000 kilocalories lifting its mass, which, let's face it, is ridiculous - it's 1 million times the daily calories spent on a male human brain.
So, I guess the first thing I need to know is **how much will the altered conditions change the 1 Kwh = 1 lb equation?** If it does by a lot, which I doubt, then it's a start.
Then there's the question of **how can I go on to reduce the tremendous cost in energy of floating with hydrogen?** Their lifestyle isn't exactly the worst imaginable for reducing energy expenditure, in fact. Here are a few things which should help by cutting calory intake in other areas of life:
* Passive filter feeding lifestyle
* They are colonial and thus do not move
* Ectothermy
* Specialized zooids: only special castes of individuals produce hydrogen, the rest perform single tasks e.g. reproduction, digestion, defense
So, **here is my main question**, summarized:
**In an atmosphere 20x denser than Earth's and with gravity 0.85x that of Earth, could organisms which have the traits above float by means of a huge bladder of hydrogen gas, producing the hydrogen via electrolysis? Are there other methods of biological hydrogen production, real or speculative, that are more energy-efficient?**
Note: the gas must be hydrogen, and I would prefer if hydrogen production methods which require photosynthesis were not used in answers.
[Answer]
A living organism wouldn't produce hydrogen via electrolysis, it would use a chemical reaction (as Mike Nichols points out). In Peter Dickenson's book [The Flight of Dragons](https://www.biblio.com/book/flight-dragons-peter-dickinson/d/1125989781?aid=frg&utm_source=google&utm_medium=product&utm_campaign=feed-details&gclid=EAIaIQobChMIroPu6fOn3gIVg_5kCh159geEEAQYAyABEgKn6vD_BwE), he covers several biological processes which already exist in living creatures that produce hydrogen as a byproduct.
Second, if the creature can start very small and grow over a period of many years, the energy required to generate that hydrogen isn't at all unreasonable. A human child will consume something like 1.5 million kcal in order to grow into an adult. So 0.5m kcal isn't a lot over a period of years.
Your bigger problem is keeping these animals from cathing fire or losing all their hydrogen. Again, Dickenson talks about this in his book.
[Answer]
**At an atmosphere 20x denser than Earth's and with gravity 0.85x that of Earth, could organisms which have the traits above float by means of a huge bladder of hydrogen gas, producing the hydrogen via electrolysis? Are there other methods of biological hydrogen production, real or speculative, that are more energy-efficient?**
Noone on this planet has the expertise to answer the question. Lacking the gravity to retain such a dense atmosphere if it were composed like ours is a huge, deal-breaking issue.
The (rough) mean [air density on Earth](https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Density_and_mass) is 1.2 g/L even if the atmosphere were pure Argon the density would only be 1.78g/L, so let's go denser: Krypton - not dense enough, Xenon - no way - Were it mostly Radon, it would still only be 9.73g/L - still nowhere near enough to supply your 20\* atmospheric density. ([Oganesson](https://en.wikipedia.org/wiki/Oganesson), the next and densest Noble gas is theoretically predicted to be solid at STP.)
If the Question is to be science based then I think that you must do some handwaving regards either the atmospheric composition (invent a new gas) or regarding some kind of containment field for the atmosphere which compresses it to the density you require
Otherwise - you'd need to increase gravity somewhat.
The most probable postulate is a massive not very dense planet - near gas giant size - ie. somewhere between the size of [Earth](https://en.wikipedia.org/wiki/Earth) and [Neptune](https://en.wikipedia.org/wiki/Neptune) - nearer Neptune (look at atmosphere section [here](https://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html) plus [this for some basic calculations](http://www.sfu.ca/~boal/390lecs/390lec9.pdf).). Basically, we don't know enough yet to be accurate, you might as well speculate with relative freedom.
The principle is that gravity decreases in an inverse square law with distance from the planet's centre - so if there is .85G at the surface then the larger the radius of the planet the higher you would be able to go above the surface before gravity diminishes sufficiently to not be able to hold onto the atmosphere - the thicker the atmosphere can be and therefore the denser it will be at the surface. **TL-DR** - a bigger planet is better.
Look to comments for ideas regarding [mitochondria and hydrogen production](https://en.wikipedia.org/wiki/Proton_pump).
Or a simple [Aluminium ion V's a Hydroxyl radical](https://en.wikipedia.org/wiki/Sodium_aluminate) reaction is just fine if you wish - there are many plants on earth that [accumulate Aluminium](https://link.springer.com/article/10.1007/BF01394642) and it could form the basis of a defence system like the silica hairs found on stinging nettles - alumina hairs instead.
[Answer]
The lower gravity is effectively irrelevant. Buoyant forces are independent of gravity. So the only thing that matters is the density of your atmosphere.
The amount of mass that a given volume of hydrogen can lift is equal to the *difference* in mass between that volume of hydrogen, and the equivalent volume of surrounding air. Since hydrogen is already pretty light, if you double the density of the atmosphere without increasing pressure, the lifting capacity does not actually double, but it comes pretty close! You would do that by, e.g., filling the atmosphere with heavier gasses somehow.
Making your atmosphere CO2-dominated, like Venus or Mars, rather than N2 dominated, will increase the density compared to Earth by a factor of about 1.5, and increase your lifting capacity by a slightly lesser amount.
Another method of increasing density is to simply increase the pressure. That will increase the density of the hydrogen at the same time, but but that actually turns out to make the math simpler--everything cancels out, and it turns out that multiplying the density of gas corresponds to an exactly proportional increase in lifting capacity *per volume*. So, if you start with a basically-Earthlike atmosphere, and increase the pressure to 20 bars, without changing the molecular composition, you will get 20 times as much lifting capacity out of the same *volume* of hydrogen. But to get that volume, you need 20 times as much *mass* in hydrogen... so it's all a wash. Increasing the pressure doesn't really help--except that reducing the required volume reduces the required mass of the container, so it does actually help a little bit. High pressure means smaller, less massive, and more robust creatures can use aerostatic flight.
Another thing to consider is that you can gain lift capacity by *heating* the hydrogen (reducing it's number density, and therefore its absolute density, below the number density of the surrounding air). A large organism could effectively heat itself with the sun, without having to actually use photosynthesis, rising during the day and descending during the night as it cools down. A smaller organism, such as could exist under 20 atmospheres of pressure, would be *less* able to use solar heat (although hardly *un*able), but would be better equipped to insulate itself against loss of heat from the lifting chamber, and perhaps pump waste metabolic heat into its lifting gas as well.
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[Question]
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In the Command & Conquer series of games, there is a mythical 'plant' life called Tiberium. It ends up being of alien origin through the course of the games, but its role in the game is as a harvest-able resource.
Tiberium has an interesting property that I'd like to explore; it leaches minerals from the soil and manifests those minerals as crystalline formations, similar to flowers, on the surface part of the plant. The idea is that the crystals can be harvested simply and refined into their base forms for minimal expense, in theory a lot cheaper than mining.
So; the question becomes can a plant reach deep enough into the soil to leach minerals in industrial quantities? If so, what type of crystalline formation would make it easy to refine those minerals (or ore flowers, etc.) into useful products?
I would imagine that for this to be viable, the plant would have to be able to handle some serious mineral and metal transport, and that the roots would ideally have to reach very deeply indeed, making such a plant quite large, but I'm not convinced this that such a plant could exist in an area that would make the harvesting viable at an industrial scale, but happy to be convinced otherwise.
Of course, if this would only be possible for certain *types* of minerals or metals, that would be useful to know as well.
I plan to ask a couple of follow up questions if this one takes off; part 2 would be about the impact on the soil, whether or not these plants would be sustainable. Part 3 will explore the potential toxicity of such a plant (as per the game), but for now I'm curious as to whether such a plant could exist at all, what it would look like / how it would work, and what types of minerals and metals it could extract and in what quantities.
[Answer]
There already is,in fact, a real life equivalent of what you described caled phytomining,although nowdays it is used more in mining rejects.
In the process the plants are seeded in an area intended to be mined and after they are growth the plants are harversted and processed.
The greath advantage of this method is that the plants generaly have a higher concentration of the desired mineral than common ore usually have,also they are generaly easier to process and are more eco-friendly.
About mineral leeching ,it would possibly require some genetic engineering and or a lot of artificial selection but there are a lot of plants that are suitable for the process.
Some links for reference:
<https://www.popsci.com/german-scientists-mine-germanium-from-plants>
<http://www.kiwiscience.com/phytomining.html>
<https://www.ncbi.nlm.nih.gov/pubmed/21421358>
<https://en.wikipedia.org/wiki/List_of_hyperaccumulators>
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[Question]
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### Background
As a parody of the [super soldier questions](https://worldbuilding.stackexchange.com/q/111275/28789) and as an efficient way of organizing these questions I will now start this series of questions about Pseudo-Arthropod Primates.
Questions from later questions relating to this thread:
[Exoskeleton Mimicking Armour Plating](https://worldbuilding.stackexchange.com/questions/110833/creating-a-scientifically-semi-valid-pseudo-arthropod-primate-part-2-exoskeleto?rq=1)
[Mouth Parts](https://worldbuilding.stackexchange.com/questions/112152/creating-a-scientifically-semi-valid-pseudo-arthropod-primate-part-3-mouth-part)
As an overview of what these creatures exactly are: well, they aren't any more related to arthropods than you or me. Just think of armadillo armor placed on primates to make a humanoid arthropod look alike.
### Question
Given that dragonflies are some of the best fliers in the animal kingdom: what muscle system would be required to make dragonfly-like wings on a human?
As an explanation on where these wings come from on a vertebrate: you know your rib cage? Well, some freaky [lizards](https://en.wikipedia.org/wiki/Draco_sumatranus) have these extended rib cage. Make them *dragonfly-wing* shaped along with bat wing membrane and you got what I'm talking about.
### Requirements
* The muscles can't produce too much heat to cook the organism from the inside
* Need to be only take up half of the body and no more
* Needs to produce powered flight that looks close enough to dragonfly flight (only needs to look like it though, it can be much slower)
* Can't make the creature weigh more than 300lbs, preferably 260lbs (don't give me that crap about it couldn't possibly work because it's too heavy because the terrifying bird [Argentavis magnificens](https://en.wikipedia.org/wiki/Argentavis) actually exists)
* Needs to produce decently elegant flight patterns - not exactly like the common dragonfly, but more like it's relative [Meganeura](https://en.wikipedia.org/wiki/Meganeura)
[Answer]
Not an entomologist, so there's your grain of salt. I also don't specialize in creature design, but after a little research I found some info on the muscular structure of insect wings.
**Bottom line: you're going to fall into many of the same problems with shoulder structure as other ideas for multi-limbed humaniods/primates.**
So, to begin with, insects fall into two different classes when it comes to wings: those with direct flight muscles, and those with indirect flight muscles. Dragonflies fall into the first class, so that's what I'll be focusing on. as you can see at this link
<https://www.amentsoc.org/insects/glossary/terms/direct-flight-muscles>
you're going to need at least two muscles per wing (I think the dots in the center are vestigial). One is attached to the top of the wing's pivot point, and one is attached to the bottom.\* On your creature, the top would correspond with the part of the wing's base that faces the spinal column, and bottom corresponds with the side facing away from the spinal column. Each muscle is individually innervated and contracts multiple times per nerve impulse received.
<https://www.amentsoc.org/insects/glossary/terms/asynchronous-muscle>
That's what gives dragonflies more control over their flight than most insects. You can see an animation of this here
<https://en.wikipedia.org/wiki/Insect_flight#/media/File:Indirect_flight_in_insects.gif>
Now, in a dragonfly, these muscles anchor to the interior of the carapace opposite the wing. In a primate, that would mean going through the ribcage to anchor to the front of it - which potentially gets in the way of the heart and lungs.
Depending on how much power you want these muscles to have, you could evolve scapulae that cover more of the animal's back, with another set of processes like the scapula's spine,
<https://en.wikipedia.org/wiki/Spine_of_scapula>
except running vertically instead of horizontally, to give the muscles points to anchor to. This would also move your wings toward the center of the back, away from the arms.
However, I suspect that this will still only work for relatively small primates, such as tamarins, marmosets, and/or tarsiers.
I'd recommend looking over the [Anatomically correct multiarmed humanoids](https://worldbuilding.stackexchange.com/questions/74254/anatomically-correct-multiarmed-humanoids) post for more information.
---
\*I'm not sure what the "bar" that runs from wing to wing across the back is, so I didn't reference that in my answer. It seems like the muscle that pulls the wing up is actually pulling on that, but since the wings can operate independently of each other, that doesn't make a lot of sense. If anybody knows for certain, I'd appreciate a comment.
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[Question]
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If an organism weighing roughly 20kg existed (same weight as a dog), similar also to the structural composition a dog.
How much muscle mass would be required within those legs for it to jump 20m?
Dogs can jump up to 1.8m, their rear legs being around 10cm in diameter. Assuming the legs are half muscle, half bone the cross sectional muscle will be around 5cm. If the theoretical organisms muscles were around 20cm in diameter and rear legs were about 80% of their mass, how far could they jump?
Dogs use the method of direct muscle contraction as their method of locomotion, this is not effective for vertical jumps. Grasshoppers on the other hand employ a type of catapulting by the use of [specialized cuticles](https://www.st-andrews.ac.uk/~wjh/jumping/legsprng.htm) in their [rear knee joints](https://www.st-andrews.ac.uk/~wjh/jumping/legwrk.htm). Through using this method they are able to gain vertical momentum with much more efficiency and therefore jump much higher. If the theoretical organism were to employ this type of locomotion instead while retaining the same amount of muscle mass how far could it jump?
[Answer]
This topic really boggles my mind. It is one of the few placed where the square-cube law *doesn't* rear it's ugly head!
The first thing to note is that we are only looking at animals that can jump. Nobody cares that the millipede can't jump at all. [Elephants can't jump either](https://www.smithsonianmag.com/smithsonian-institution/ask-smithsonian-can-elephants-jump-180957921/), which is due to the way their body is structured to deal with the square-cube law. We're looking at animals that do jump, so we assume that their body has evolved to optimize that sort of motion to at least some degree.
The most obvious limitation is power. The maximum power of a muscle is proportional to its cross-sectional area. If you don't have the power to emit energy quickly, you can't use it to jump. In practice, however, this isn't a limit. Creatures that can jump are typically structured in a way that creates enough power. For humans and dogs, that's accomplished by having enough of a cross-sectional area in the legs to do the job. For the [click-beetle](https://en.wikipedia.org/wiki/Click_beetle), it's a bit more difficult. Their muscles aren't big enough to provide this sort of power. To work around this, the click beetle actually bends its shell using its muscles, then releases all of that energy at once. This gives the beetle more time to put energy into the system from its muscles, circumventing the power limits. So as it turns out, power is not the primary limiting factor.
Another factor that shows up is drag. Animals like click beetles and fleas actually get limited by drag, so they jump to lower heights than the larger animals do. However, you are interested in a dog sized animal, so this wont matter.
The dominating factor is actually energy. To jump, you need to accelerate upwards, and that takes work. The more work you can do, the more upward velocity you can have. It turns out that the energy you can exert scales proportionally with muscle mass. A muscle can only output so much energy per unit of muscle-protein, limited by the chemistry of how muscles contract. Once a muscle is fully contracted, you can't contract it again until it gets to relax and elongate, and by that point the jump is already over.
So we have a curious result: jumping energy scales proportional to mass, and the amount of energy taken to jump to any given height scales proportional to mass (potential energy = mgh). **Jumping height is not proportional to mass at all!** This highly unintuitive result can be seen in the table below, which is copied from a [text book](http://web.mit.edu/6.055/old/S2009/notes/jump-heights.pdf) from which this entire argument is paraphrased (this, itself was found on [a previous StackExchange answer](https://physics.stackexchange.com/questions/391954/whats-wrong-with-arnolds-scaling-argument-on-jumping-height))
* Flea - $5\cdot10^{-4} g$, 20cm jump
* Click Beetle - $4\cdot10^{-2} g$, 30cm jump
* Locust - $3\cdot10^0 g$, 59cm
* Human - $7\cdot10^4 g$, 60cm
Despite the fact that those masses span a range of $10^8$, jump height stays within 1 order of magnitude!
Dogs are no exception. The [current record jump](https://www.cuteness.com/blog/content/highest-jumping-dogs) is 2-3m, depending on what kind of jump we are talking about. They too fit in that 1 order of magnitude, or perhaps a little more.
So what have we learned? For a vast variety of body plans, jumps remain in the 20cm-3m range due to energy limits. A 20m jump is quite far outside of this range. It's going to be hard to achieve.
Making their body more leg will help. 80% leg as you suggest may give you more altitude, but it's not going to be a slam dunk (literally). Think about how you jump. You crouch down, right? And when you try to jump high, you use your arms on the way up so that you can use elastic forces to help you jump higher. A surprisingly large amount of your body is actually helping with the jump. It will indeed be more efficient to have 80% leg muscle, given that those muscles are in a perfectly ideal place to do the job, but I don't think it's going to give you a factor of 7-8 increase in jump. Too much of our muscle is already involved in the jump.
A simple solution like the click beetle carapace or the grasshopper cuticles won't help either. The issue is the amount of energy that can be expended with one contraction of your muscles. The carapace and cuticles only help you deal with the power issue associated with low cross-sectional areas.
The solution you need is a ratchet. You need something akin to the click beetle carapace or grasshopper cuticle, but one which permits multiple contractions of the muscle to build up energy. You would contract and relax the muscle perhaps 10 times to slowly build up energy, and then have a trigger to release it all at once.
Your question is timely. I recently just asked [a question](https://biology.stackexchange.com/questions/71381/are-there-biological-ratchet-cycles-that-are-small-in-number) on biology whether such a structure *ever* occurs in biology. I am not aware of any animal with such a ratchet. We'll see if it gets an answer. But it may be the thing you need to hit 20m.
] |
[Question]
[
Let's assume the planet has only one half the mass of the moon and is covered by shallow ocean. To eliminate water pressure at extreme depths, assume the ocean is also quite shallow, with a maximum depth of 100 meters.
How would critters living in this ocean be affected? How would life evolve? For the purpose of the question, the planet somehow has an earth-like atmosphere so the alien fish can breathe.
Edit: the ocean MUST be no more then 100 meters deep at any given point. Assume we are dealing with very shallow water here.
Edit 2: for the purpose of simplicity, the mass AND volume are exactly 1/2 of the moon.
[Answer]
Though I believe the other answer is right, in that a planet as small as you're suggesting would be unable to keep an atmosphere (and therefore an ocean) due to lack of gravity, there are ways for a smaller planet to maintain a liquid ocean that supports life:
>
> "Owing to a greater depth of hydrothermal circulation
> from thermal cracking in brittle mantle
> material, small ocean planets in the Solar System
> may have the capacity to support ecosystems that
> are stable on geologic timescales, with greater
> amounts of bioavailable energy than previously
> suggested. "
> <http://online.liebertpub.com/doi/pdf/10.1089/ast.2007.0075>
>
>
>
Assuming there is some sort of force keeping the water on the surface (not to mention the atmosphere), you'd be dealing with several things:
1. Reduced water pressure - If you've got 1/2 moon gravity, that's about 8% earth gravity, so the water pressure would be reduced as the weight of the water would be less. I'd guess that would mean that creatures would either more easily traverse greater depth ranges or be confined to smaller ranges of pressure than earth creatures. Interestingly, this doesn't mean less dense water, as water is essentially incompressible, and the difference in ocean water density has more to do with temperature and salinity than pressure.
2. Lack of light - There's a possibility of oceans existing underground or beneath ice on smaller planets, so organisms would likely have to exist either without or with very limited exposure to sunlight. In that case, this probably limits the food chain to very small, efficient organisms. Bacteria, etc. See the above-quoted article for more information on the placement of oceans.
3. Ice - If your ocean is too deep, the high pressure would turn the water to ice. So watch for that.
4. Ocean coverage - If the ocean covers the entire planet, some of the precursors to earth-like life would be difficult to come by. On earth, phosphorous is washed by rainwater into oceans from rocks on exposed land, and that's a necessary element for the development of plankton and similar life, so depending on your planet, those might not exist.
>
> "It turns out that water worlds may be some of the worst places to look for living things. One study presented at the meeting shows how a planet covered in oceans could be starved of phosphorus, a nutrient without which earthly life cannot thrive. Other work concludes that a planet swamped in even deeper water would be geologically dead, lacking any of the planetary processes that nurture life on Earth."
> <https://www.nature.com/news/exoplanet-hunters-rethink-search-for-alien-life-1.23023>
>
>
>
[Answer]
Being the Moon, with all its mass, unable to keep an atmosphere, it is straightforward that also your planet with half a moon mass won't have any atmosphere.
In such conditions liquid water is not going to last long and it will quickly evaporate.
So, your critters won't live at all.
] |
[Question]
[
Famines have dropped the population to 1 billion and global civilization has collapsed. In an effort to save future civilization some time, you want to provide some information to kick start civilization's regrowth. We assume that the tech level has dropped back to Europe in 1801. If we [knew it in 1801,](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4379645/) they will know it.
# You have to choose exactly three books or articles on medicine
(And only about human medicine. Other topics will be covered in other questions.) By virtue of a print-on-demand press and a generous internet connection (and minimal scruples about copyright law), you can get your hands on the text and diagrams of most any book/article in existence.
Any set of three books that appropriately maximizes the below criteria compared to any other set of books will be most preferred.
* Readability to a broader scientific audience though this won't be the general public. This is intended to avoid problems like Newton's Principia that's basically unreadable to someone who wasn't a personal friend or contemporary of his.
* Breadth of coverage across all three books. The effects want to maximize knowledge transfer as much as possible.
* Content of each book should be strongly connected to the other two. There will be differences in terminology that arise as concepts not described in the books are rediscovered by the future scientists (they will come up with different names for things) . Having one book lead to another minimizes this kind of problem.
* First, or first clearest expository of a foundational concept or system for that field. (Principia is first but someone else wrote a clearer explanation later. Thus, the latter work is preferred over Principia. )
* Recognizable to someone in that field, in 1801, that the material in the book is about that field.
* Corrects misinformation or model failures in knowledge in this field at the target entry time. (Pick your favorite "I can't believe the early people got that wrong" moment. Fixing those moments is important and the primary hope of these books. )
* Be as self-contained a set as possible. We cannot be sure that any other set of Three Books will be found to reinforce what's found in these books.
* No restrictions on the original language of the book. A Rosetta Stone-style translation aide will be included with these books to assist future translators.
Printing off all the medical articles on Wikipedia won't satisfy because...reasons. Downloading all the articles off [biorxiv.org](https://www.biorxiv.org) won't work either. Only actual books will satisfy.
Preserving the books and translating them into many languages are solved problems. You're responsible only for picking the three books. These won't be electronic copies as we can't be assured that someone will have access to electronics when they find these books.
*Note to Responders:* Three books was chosen as it is a tractable small number and forces hard choices about which books are really worthy. *You cannot get an entire field into three books, so don't try.* How to store these books and how to make sure they are found is outside the scope of this book.
*Further Note:* I'm not willing to minimize the scope of the question from medicine to something like organic microbiology. The point of these questions is to provide a recovering civilization with an early stage jumpstart. Once they get to where they can only make progress with interdisciplinary research, that's out of scope. (Thank you Olga saying it so succinctly.)
This question is a part of the Only Three Books series. It will grow to cover many and diverse topics, thus, the fairly narrow scope.
* [Chemistry](https://worldbuilding.stackexchange.com/questions/101887/only-three-books-restarting-chemistry-after-civilization-collapses)
* [Physics](https://worldbuilding.stackexchange.com/q/101922/10364)
[Answer]
**[Human Anatomy & Physiology](https://rads.stackoverflow.com/amzn/click/0321927044)**
Describing the structure and function of the body will be a nice start. If you know how a body is put together, it's much easier to reason about what's going on. This won't help with metabolic diseases but that requires genetics, microbiology and a couple other fields.
**[The Mont Reid Surgical Handbook: Mobile Medicine Series, 7e](https://rads.stackoverflow.com/amzn/click/0323529801)**
If you're going to start cutting someone open to fix them, it's a good idea to know how to do it in such a way to minimize complications later. This book cover postoperative and preoperative care.
**[Wilderness First Responder: How To Recognize, Treat, And Prevent Emergencies In The Backcountry](https://rads.stackoverflow.com/amzn/click/0762754567)**
We don't know the state of medicine when these books are found. I assume that they won't really have much of anything. Wilderness First Responders or Woofers are specially trained to deal with medical emergencies when the common front-country tools aren't available. What do you when there's no hospitals or EMS around? Woofers are trained to handle that kind of situation.
It's impossible to compress the experiences gained in med school down to a few books. It can't be done. These books are designed to help people get started. These future would-be healers will get a good start on saving lives. They will have to learn by sad experience, just as our doctors now learn by experience. People will die based on what is found in these books but perhaps, fewer people will die than if these books were never found.
[Answer]
The hard part of kick-starting a medical revolution isn't providing the information, it's convincing people that *your* information is better than all the other information floating around. Health and medicine is a complex, largely statistical process, with effects such as the [placebo effect](https://en.wikipedia.org/wiki/Placebo), [self-limiting conditions](https://en.wikipedia.org/wiki/Self-limiting_(biology)) or [regression toward the mean](https://en.wikipedia.org/wiki/Regression_toward_the_mean) tending to confound any attempt to study it.
In the early 1800s, anatomy was well on its way to being a mature science, and simple physical medical procedures (such as bonesetting) were well understood. Microorganisms had been known for a century and a half, but their significance was still a complete mystery.
**Book the first: A good wilderness first aid textbook.**
The first step here is to convince people your techniques work. Where conventional first aid is about keeping the patient alive for the five minutes it takes the ambulance to arrive, wilderness first aid is about using minimal equipment to stabilize the patient for the week it takes to carry them to the evacuation site. If you don't *have* an evacuation, many of the techniques (such as preventing infection) are still applicable for keeping the patient alive and helping them recover.
Further, with the exception of antibiotics/antiseptics, virtually all of the techniques can be applied using 1800s materials, though you'll need to make sure the book you pick is one that tells how to field-sterilize wound dressings -- you can't just buy prepackaged sterile bandages from the store in 1800.
As a minor benefit, this is going to have references to other procedures such as surgical treatments. It won't give anywhere near enough detail to perform the procedures, but simply knowing that something is possible is a huge boost towards figuring out how to do it.
**Book the second: An introductory bacteriology or bacterial pathology textbook**
In the early 1800s, [miasma theory](https://en.wikipedia.org/wiki/Miasma_theory) was the prevailing theory of disease. If you're going to have any hope of getting medicine going, you'll need to convince people that [germ theory](https://en.wikipedia.org/wiki/Germ_theory_of_disease) is correct instead. This textbook builds off of the first-aid textbook: where that explains how to prevent disease and infection, this explains why it works.
A good textbook is going to cover things like [Pasteur's experiments](https://en.wikipedia.org/wiki/Louis_Pasteur#Fermentation_and_germ_theory_of_diseases) and [Koch's postulates](https://en.wikipedia.org/wiki/Koch's_postulates): things where an 1800s-vintage scientist can check the correctness of the information themselves. It's also nearly impossible to write such a textbook without mentioning either [penicillin](https://en.wikipedia.org/wiki/Penicillin) or the [sulfa drugs](https://en.wikipedia.org/wiki/Sulfonamide_(medicine)); if people can figure out how to produce either, the resulting near-miraculous cures of infections will go a long way towards convincing people of your ideas. It's probably still going to take you a half-century or so to convince doctors that they should wash their hands between performing an autopsy and performing surgery.
Bonus points if this book has a section on sanitation engineering. Simply convincing people that the sewage outlet should be *downstream* of the water intake will give a huge boost to health.
**Book the third: A textbook on statistics, with a focus on study design.**
The study of medicine spent several thousand years chasing after [universal, always-works cures](https://en.wikipedia.org/wiki/Panacea_(medicine)) and being confused by the placebo effect.
This book doesn't tie directly in with the other two. Rather, it gives the *other* essential starting point for modern medicine. When the simple act of giving someone a sugar pill makes them feel better, and a cold will go away in seven days if you treat it, and in a week if you don't, you need some way of figuring out which procedures work and which don't.
There are statistics textbooks with a focus on medicine; if you could find one that also covers gambling (to give it an immediate application), that would be ideal, but I don't think such a thing exists.
] |
[Question]
[
*This question is related to the world from my [prior](https://worldbuilding.stackexchange.com/questions/101214/what-qualities-could-a-hominid-evolve-to-make-it-a-better-farmer) [questions](https://worldbuilding.stackexchange.com/questions/101314/how-fast-could-a-hominid-evolve-to-run), in which several types of intelligent hominids evolved in isolation, until they were rediscovered, conquered, and [bred](https://worldbuilding.stackexchange.com/questions/99806/how-long-would-it-take-to-domesticate-humans?noredirect=1&lq=1) into a biological caste system by a dominant species.*
## BACKGROUND
Domesticated animals often have patches of white fur. My dog, for example, has a near perfect star shape right in the center of her chest. This got me thinking about something on different lines:
I'd like it if my noble caste could breed their house servants to have heritable crests. The resulting lineages would then be associated the with other real and imaginary attributes, giving my nobles a jumping off point to trade, sell, and argue obsessively over superior bloodlines and purer stock. Edit: I should make explicit that I would like this to be at least partially delusion on their part; aside from the obvious marker and a few minor physical traits, I'd like mental differences between crest lines to have more social than biological reality.
## QUESTION
* **Could you breed a hominid to give it a heritable mark, such as a patch of discolored skin or hair, that makes a simple but clean and coherent shape?** *Edit: Preferably on the chest or forehead. The servants would otherwise be physically distinct, but more like human families than dog breeds.*
If the above premise holds I'd also like to know what would happen if you crossed the line of a crested hominid with one bearing a different crest, or no crest at all? Finally, to select for a trait this finely would the breeders require special knowledge of, say, Mendellian genetics or the like? Or could they just apply the methods humans have used since time out of mind?
[Answer]
Piebald patterns in a wide variety of mammals, like cats, horses, and mice create white spots of certain patterns that override whatever skin and hair color the animal would otherwise have.
Cats are bred for [specific patterns](https://en.wikipedia.org/wiki/Bicolor_cat#/media/File:Bicolour_Cat_Patterns.jpg) (tuxedo, mitted, mask and mantle, etc.). Horses have fewer variations, but the same general genetic white out pattern that overrides the coat pattern.
These patterns can be created by breeding, with breeders seeking out random mutations to diversify patterns, like tulip or snake breeders that have made rare colors common.
[Answer]
Well - Mandrills are a good precedent. Technically they're monkeys, not hominids, but that's close enough for a lot of medical and other biological purposes. See Link (<https://en.wikipedia.org/wiki/Mandrill>).
To see how far you can take things with selective breeding, compare a chihuahua, a great dane, and the asian red wolf. All the same species, just bred for particular characteristics.
[Answer]
Depends how specific you're talking about. If you want something like, say, "a large brown mark on the center of the chest", as far as I know there's no way to ensure that. Often the placement of such markings isn't even genetic - if you cloned an orange-and-white cat, their clone would be orange-and-white, but the positioning of their orange patches would be completely different, just like how identical twins have different fingerprints.
However, if it would work to just have one strain have purplish marks while another has brown marks or something like that, that's readily doable.
Possible genetic bases for distinctive markings for humans:
Port-Wine Stains - reddish or purplish birthmarks caused by a vascular anomaly, usually located somewhere on the head or neck. Can be the result of certain genetic syndromes, but non-syndromic port-wine stains have been linked to mutations in the GNAQ gene(1). These mutations have only been reported in heterozygous form, so it's uncertain what impact they'd have if homozygous, but Basset Hounds' short-limbed dwarfism mutation is homozygous lethal and that hasn't stopped humans from turning it into the basis for a domesticated breed. If homozygous GNAQ is lethal, they'd have to have individuals with and without port-wine stains in the same families, but might be more inclined to actively show off the ones with the birthmark.
Freckles - Small brown dots on the skin that form in response to sunlight exposure, freckles are associated with polymorphisms in the MC1R gene (2). The same alleles that cause freckles also tend to cause lighter skin tone and reddish hair. Freckles are associated with slightly higher risk of melanoma, but not a serious cause for concern. These polymorphisms are commonly seen in homozygous form, and are especially common in certain ethnic groups such as Celtic people.
Waardenburg Syndrome - Waardenburg Syndrome is associated with a distinctive facial appearance, patchy depigmentation in hair, eyes and/or skin, going grey early, and deafness. It's caused by MITF mutation. In heterozygotes, it can often result in no impairment in hearing, just an unusual appearance, but homozygotes have more severe symptoms(2). Still, you could conceivably have a noble house who is fine with having deaf servants breed them to be homozygous for one of the less severe mutations that causes Waardenburg Syndrome. They'd probably issue commands using sign language, and might have the bonus of being less likely to have servants passing information to their enemies. (Some slaves historically had their tongues removed for a similar purpose.)
There are many other potential genetic variations associated with distinctive pigmentary variations, far too many to list here. Some cause other symptoms, but anything that doesn't stop them being put to work or that only affects a minority of individuals wouldn't necessarily rule them out. After all, plenty of domestic animal breeds have been selected for features that cause impairments in their natural functioning, such as short nose syndrome in dogs or even the polled (no horns) trait in cattle (while cattle owners often prefer cattle without horns and will remove horns on breeds that grow them, in the wild cattle without horns would be at a serious disadvantage).
1. <https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4508108/>
2. <https://www.nature.com/articles/jhg201296>
3. <https://onlinelibrary.wiley.com/doi/abs/10.1002/ajmg.a.60693>
] |
[Question]
[
[](https://i.stack.imgur.com/J9Joi.jpg)
Malgrovian gliders inhabit the middle layers of the atmosphere of Malgrov, a gas dwarf. They spend most of their life gliding, preying on giant balloon-like floating lifeforms. When they get older, they slow down and begin falling. The two brown things on the top are egg sacs that are covered by a relatively thin membrane. This membrane bursts when the external pressure becomes great enough, releasing small, floating eggs that get back into habitable regions of the atmosphere while the parent dies and becomes food for creatures living near the surface.
The gliders have developed a certain level of understanding in the field of aerodynamics and ballistics in order to hunt and travel more effectively.
It can be assumed that the tissue of the living balloons hunted by the gliders is rigid enough to protect against an external vacuum.
The significant atmosphere of Malgrov extends to a height of about 400 km, with a surface pressure of about 2600 bar. Malgrovian gliders live in the central layers and feel comfortable in pressures between 1 and 5 bar. They posess several claw-tentacles they use to hook onto and cut through the flesh of the living balloons.
It can also be assumed that the atmosphere is populated by flora and fauna resembling species theoretized to live on gas giants.
My question is:
**How can the Malgrovian gliders succesfully develop space travel? Can they attain orbital flight capability or at least perform suborbital flights and return safely?**
[Answer]
Some big problems:
Materials: They're limited to what they can harvest from things living at their level. No mining....
Nowhere to put/store things: Since they can't land on the surface, one problem is that there's nowhere to store things or assemble things. You might get round this by domesticating some of the big balloons...
Where to get thrust from: They need to buid engines and fuel them somehow.
Life support: they need to be able to create a gas tight seal - and provide suitable life support.
**Most likely method of succeeding:**
1) Domesticate the giant balloons.
2) Use them (either individually or in herds) to provide a base to store/build things on.
3) Assume that whatever holds the balloons up is usable for fuel - maybe the balloons work at least partially on a hot air system, so (a) you can harvest whatever it is they combine/burn to produce heat and use that to produce the thrust you need; and presumably the skin is tough/resistant enough to build rocket engines out of (since the balloons need to do their hot air trick without setting fire to themselves).
This also gives you a heat source if you need to cook/melt/extract things from available material.
4) If the balloons have bladders that can store pressurised gas, that makes things simpler for building life support/ storing fuel.
5) Maybe whatever the balloons use for blood makes a quick setting glue when exposed to the atmosphere (would be useful for sealing wounds/punctures that might let lifting gas out). That lets you join things together...
[Answer]
There is an ancient sci-fi opera pc game called Ur Qan Masters. It has [a race of sentient beings that inhabit a gas giant](http://wiki.uqm.stack.nl/Slylandro):
>
> They are essentially sapient bags of gas (and a limited quantity of solid and/or liquid) that float through their homeworld's atmosphere. Their visual range is different from most races and it is to their great dismay when they realize that their bodies are transparent to human vision, revealing their reproductive organs, which look like "glowy bits".
>
>
>
Just like humans, these beings have a hard time facing low atmospheric pressures:
>
> Because of their unique physiology, the Slylandro inhabit only a 500 kilometer thick layer in the the atmosphere of Source. Ascending above this layer, into what the Slylandro call "Void", causes them to become giddy and behave inappropriately.
>
>
>
Since a gas giant doesn't offer much in terms of raw materials, they had to resort to external help to explore space.
>
> They are physically incapable of leaving their planet and travelling thru space, which prompted them to purchase a "Catalog Item 2418-B: Self-Replicating Robot Explorer Probe" from the Melnorme to explore space for them and report back to them.
>
>
>
Unfortunately for your creatures, there isn't much thay they can do differently from the Slylandro. There is no scientifically feasible way for them to build a ship. It takes the blood of 350 human male adults to have enough iron to forge a single sword, so think about how creatures that can only harvest materials by killing other creatures are going to build a ship.
The best they can do is penetrate a bigger creature to use it as some sort of casing, then throw themselves into a storm and hope it accelerates them into a suborbital path. Would be quite the ride, and there are risks. They may be thrown into abyssal depths. Or they may risk achieving escape velocity, and in that case they will never get back to the gas giant.
Achieving proper orbit requires maneuvering while on a suborbital path... But simply expelling gas is would not provide enough delta-v for that.
[Answer]
There might be a way. It is very unlikely though:
If they have an airfoil shape and can produce thrust, they can spin themselves out of the atmosphere. The faster they go, the higher they fly. They could, over time harden themselves to lower and lower pressures and be able to thrust for longer times. They could achieve sub orbital, orbital and escape velocities. They have to be able to survive a vacuum, cold, heat and radiation for extended lengths of time.
Look at [JP Aerospace's](http://jpaerospace.com/) Airship to Orbit (ATO) for a non-biological example of this.
The biggest evolutionary question, is: what is the first step that made it more likely for them to survive? What is in the upper atmosphere that they cannot get lower? What is in the vacuum that they can't get lower? I can think of two things that could drive this, predators in the lower atmosphere and stronger sunlight and radiation at higher elevations (or maybe they are the predators chasing prey).
As other's have stated, sentience is unlikely. There's just not that much to interact with up there. Spending a lot of energy on the hardware for thinking won't give much of a survival increase.
Also, technology is pretty much out of the question. What would they need to build and what would they build it with?
] |
[Question]
[
Snares are anchored cable nooses set to catch wild animals. There are two types, active and passive. An active snare has the wire under tension and a trigger to cause it to snap closed, while a passive snare has a one way cinch so that as the prey struggles the noose tightens and strangles the prey. Based on admittedly messy and ill sourced numbers, it seems a realistically sized spider could build passive snares to catch and kill medium sized mammals. Also of note, spider silk undergoes [Supercontraction](https://en.wikipedia.org/wiki/Spider_silk#Supercontraction) when exposed to water so tensioning an active snare might also be possible. So my actual question is, are there any impediments to a spider evolving this ability, what interesting implications might it have for the overall ecosystem?
The admittedly messy and ill sourced numbers:
* [Steel snare (capable of catching raccoons and coyotes](https://rads.stackoverflow.com/amzn/click/B005FC4U9K): 1lb/12 (37.8g)
* [Silk to Steel strength by weight ratio](https://en.wikipedia.org/wiki/Spider_silk#Density): 5
* Silk produced per [23000](https://www.theguardian.com/artanddesign/gallery/2012/jan/23/golden-silk-cape-spiders-in-pictures) [4cm](https://en.wikipedia.org/wiki/Nephila_komaci) spiders per [week](https://www.wired.com/2009/09/spider-silk/): 1oz
* [Largest spider](https://en.wikipedia.org/wiki/Goliath_birdeater): 11.9cm / 175 g
This gives 6 weeks, for a real sized spider. Which sounds like a lot, but these traps should be reusable. So the spiders would be capable of killing prey 20 - 100 times their own mass.
If someone finds better sources that lead to different numbers, that would also be great.
[Answer]
**Spider colony.**
6 weeks for a single spider. 80 seconds for 50,000 spiders.
[](https://i.stack.imgur.com/3qOGP.jpg)
<http://texasento.net/Social_Spider.htm>
<http://www.bbc.com/earth/story/20160122-meet-the-spiders-that-have-formed-armies-50000-strong>
>
> Anelosimus eximius, the species I encountered in the rainforest, is
> not the only kind of social spider in the world, but it does construct
> the biggest webs. Some can reach more than 25ft (7.6m) feet long and
> 5ft (1.5m) wide. A web that size could contain as many as 50,000
> individual spiders. That is a lot of legs, eyes and fangs.
>
>
>
There is no reason these spiders could not make a sticky web that, when an animal blundered into it, would fall on the animal and progressively bog it down.
The other thing some spiders have is venom. Like snakes, spiders use venom offensively and defensively. If you pin a rat in a web it is never going to quit chewing its way out. If you pin it and then inject a few hundred spiderworths of venom, it will settle down.
As regards not having enough enzymes to process large prey, I do not think that would be a problem.
\*disclosure: web in image is from a different species than that discussed in pasted text.
[Answer]
Spiders don't seem to need snares, and they don't seem to need large prey.
First, spiders employ glue in the spiderweb, which is fairly strong. If you ever get caught in a fresh spiderweb, you know that it is easier to snap threads than scratch them off your clothes/skin/hair. So, if a spider can spun a web that can hold large prey, there should be enough glue in that web to hold that prey captive.
Second, spiders are feeding by injecting digestive enzymes into captured prey. If they capture a prey that is much larger than the spider, there is no way they have enough enzymes to process this prey, and most of it would just be rotting.
[Answer]
A single strand noose would not be very useful for a spider, but spiders have evolved lots of different hunting strategies which have analogues to things we are familiar with.
The common orb spider (which most people are familiar with) weaves the nets we are familiar with. While the net is not a noose, different species of spider weave different configurations of nets. Some are very tight (one reason is the spider sits not the web and feels for the vibrations, which alert it not only to the fact the prey has been trapped, but even the location on the net where the prey is.
Other webs are much looser, and could be comparable to a fisherman's net with fills and area where prey could be expected to fly into.
Large numbers of species of spiders actively hunt their prey, running on the ground and chasing them down so they can bite and inject their venom into the prey (these include dangerous species like black widows and brown recluse spiders, which can kill humans with their venom).
Other spiders ambush their prey, like trap door spiders, which hide un small holes dug into the ground. Their webs extend outwards from the camouflaged cover, and alert the spider when their prey is close enough to flip open the door and pounce on their prey.
Bolas and net casting spiders come closest to your idea of a snare, bolas spiders use a single scented strand to lure prey in then try to entangle the prey, while net casting spiders actually throw their web over the prey!
Some examples can be found in [this article](https://www.wired.com/2011/05/spider-attack-gallery/)
] |
[Question]
[
I am making a world to be the setting of my future fantasy works, which is to say I really have no story planned but I want to have a world for it when I do and I want said world to be likely give me story ideas.
I want to make things look different but be functionally similar to earth's own circumstances for the purposes that I like science and just because magic is a thing doesn't mean that it is a thing I want to use to hand wave physics. As such I have done a lot of math to determine how this system would work.
As of now the system is a binary star system made up of a main sequence star with a mass of about .5 solar masses and a radius of .8 that of the sun's, and a white dwarf with the mass of .5 solar masses and a radius of 10,000 km. The surface temperatures of both is such that their total luminosity is equal to that of the sun's.
The planet on which my stories will take place is on a double planet, with two planets slightly larger than that of Earth that orbit around the stars while orbiting around a central point between the two of them. This is where my question comes in: **how big would the tides be if the distance between them is about 3 times that of the distance between the earth and the moon so about 981,540 km apart from each other.**
I am having a hard time of finding any math about that so I could just calculate it myself. Also these planets are not old enough to be tidally locked yet, and the orbit around their common center of gravity is about 28 days (cause even numbers are my friend).
To restate my question: **How large would the difference between low tide and high tide on this planet be?**
[Answer]
The scale of the tides exerted on one body by another can be calculated rather easily. (This is from Stephen Gillett's excellent book *[World-Building](https://www.goodreads.com/book/show/1992184.World_Building)*.) The formula is
$$T = {M \over R³}$$
where $T$ is the tidal acceleration, $M$ is the mass of the body that exerts the tide, and $R$ is the distance between the two bodies. It is assumed that $R$ is much greater than the size of the bodies themselves.
This works if you use relative terms. So if your planets are the size of Earth (about 81 times the mass of the Moon each) and they orbit one another at three times the Earth-Moon distance, you can plug the numbers in and get:
$$T = {81 \over 3³} = {81 \over 27} = 3$$
That is, the tides produced in each of your planets by the other planet will be roughly three times as strong as those exerted on Earth by the Moon. Incidentally, if they're not tidally locked yet, this would be massaging their interiors quite forcefully.
To these mutual planetary tides you should add the solar tides. The Sun produces tides on Earth which are about 45% as strong as those produced by the Moon.
P.S. You actually asked about the difference between low and high tide. That's a tricky one, since even on Earth there are extremely different ranges. Tidal acceleration is not that difficult to calculate but how that plays out on on actual physical body depends on the overall shape and distribution of the continents and seas, the winds, the ocean currents, and even the shape of the coasts. I suppose you can hand-wave most of the fine detail here and go for whatever is useful for your story, within reason.
] |
[Question]
[
I am going into considerable detail designing a magic language for a game system. The world is a classical high fantasy type world, with most of the tropes that might be expected from old school D&D. The magic system is somewhat unique in that I am designing it around effects, functions, and operators. I have developed what I believe to be a pretty comprehensive list of effects that can be combined in different ways to produce most of the classic "spells" that exist in classical fantasy literature.
Effects will have associated costs in energy (which will boil down to a points system which is not too relevant to this question). A "spell" will consist of one or more "Effects" which can be combined using functions. There is no upper limit to how many effects can be combined into one "spell", but there should be an exponentially increasing point cost as more and more effects are added to a single spell.
My question is: in order to achieve a flexible "language" that can be used to develop many different types of spells with (as of now) 26 "Effects", what operators and functions do I need? Also, I need to ensure that the point cost becomes prohibitive after 4-5 "Effects", and I think I need to associate a cost to the function, which would increase by a multiple of how many functions there are.
I've looked into symbolic logic, but there is a lot of focus on true/false statements, which is not necessarily what I am going after. I am thinking of something more along the lines of a very simple programming language. I do not want something massive and complicated, so what would be the minimum number and type of functions to be useful and flexible?
[Edit] In response to queastions:
I am looking for some specific things as far as operators. I need to the ability to "add" an effect to a "spell". I need the ability to designate that one effect comes before another one. Conditional behavior would be a good thing. "If this, then X, if something else, then Y". I want to limit the amount of conditional elements embedded in a single spell because I don't want someone to be able to just hit the "this does everything spell" which has basically all effects embedded, so embedding conditions should have a cost. I want the ability to delay an effect: "wait X time before doing Z".
I think there are some other basics that I should include just for completeness sake.
[Edit II] In response to comments.
Here is what I envision as a use case more or less:
"I am a cool adventuring wizard guy in an online game, I found this scroll that has a "Burning fingers of flame" spell on it, I am going to take it to my magic workshop and edit it to create a custom spell. I am going to remove the "burning" component by using a visual scripting type editor in the UI. In it's place, I'll put in a "cold" effect, add a timer function to delay the effect for 3 seconds, and add a "darkness" effect that takes place immediately. Now my custom spell will cause darkness, and then drop a cold frost effect on a target when cast. I'll rename it "Cold Dark Hands" and save it to a scroll.
For reference, my list of "Effects" (these will each represent a "spectrum" from very minor to very major, with point costs calculated on that basis):
1.Force
2.Flame
3.Cold
4.Darkness
5.Change Weather
6.Water
7.Energy Bolt
8.Lightning
9.Transform Caster
10.Transform Target
11.Invisibility
12.Change Size
13.Levitate Target
14.Drain Life
15.Flight
16.Conjure
17.Teleport
18.Curse/Bless
19.Alteration
20.Illusion
21.Conjure Stuff
22. Mind Control
23. Force Field
24. Lore/object read
25. Dispel Magic
26. Light
[Answer]
I'm not entirely sure on what you want but if I have imagined it correctly a psudo-coding interpretation may be something like:
Functions take in the effects and other properties such that you could have a scroll that, in a basic for says:
`burning fingers of flame:
fingers(fire, burning,0,40)`
Where you could have a function for each part of the body and a generalized form may look like:
`Scroll Title:
object( Primary_effect, degree_of_primary_effect, primary_timing, secondary_effect, degree_of_secondary_effect, secondary_timing ...,mana_level)`
This function could also take in other features of an effect other than timing, shape, projectile, static, rune...etc
The details of the function would look like:
`object( Primary_effect, degree_of_primary_effect, primary_timing, secondary_effect, degree_of_secondary_effect, secondary_timing ...,mana_level):
time = 0
whilst(mana_level>0):
if time>=primary_timing:
if mana_level-Effect(primary_effect,degree_of_primary_effect).ManaCost >0:
object.Set.Effect(primary_effect,degree_of_primary_effect)
mana_level=mana_level-Effect(primary_effect,degree_of_primary_effect).ManaCost
if time>=secondary_timing:
if mana_level-Effect(secondary_effect,degree_of_secondary_effect).ManaCost > 0:
object->SetEffect(secondary_effect,degree_of_secondary_effect)
mana_level=mana_level-Effect(secondary_effect,degree_of_secondary_effect).ManaCost
time+=1`
Now this doesn't actually give you all the details for how your function performs this task but it could give you the freedom to write the function:
`Hand( cold, freezing, 3, Darkness, gloom,0 ,200):`
Which, going through the general code above, would:
* Check that the mana it had been given hadn't dropped to 0 (in this case our scroll wants 200 mana given to it) and loop over what is required until all the mana is used up.
* Check to see if we have reached our primary time (time=3 for our case so for the first three seconds we move on).
* Moving on we get to the secondary timing (0 in our case so we enter the if statement)
+ Now we check if we have enough mana (ie mana\_level is higher than the manaCost of the effect)
- If we have enough we enter this second if statement and apply the effect to our object and remove the required amount of mana to perform this effect.
We loop through with time increasing by a second as we go and each effect running for only as long as the mana we've provided can manage.
No idea if this is what you're looking for but I enjoyed myself writing it anyway - hope it helps though.
[Answer]
In order to discourage munchkin behavior, you're going to need to balance costs with combinations. If you don't, you're going to get some rather creative combinations of seemingly small effects to pack a punch that's going to cost relatively little. At the same time, the more powerful combos will be rarely used and put a damper on game play.
you want to use a formula that increases at a multiplicative level with a base cost, the greater to be used.
so, to write some pseudo-code for you....
combo cost minimums would be....
X, X + A, X + B, X + C......
then the costs could be computed....
E = effect
Val = E1(cost) \* E2(Cost)
if val < x val = x
and so on.
So, you could make a base cost of a single effect, the cost of the effect.
For argument's sake, lets say Heat has a cost of 2 and cold has a cost of two, and by multiplying their costs, you get four, but you set a base cost of 6, so the combo costs six, where light with a cost of 3 and heat with a cost of three would ALSO be six. Light with a cost of three and dark with a cost of three would be nine, not affected by the minimum.
You can tweak the formula from there.
[Answer]
Have you ever read the GURPS Magic sourcebook? It contains a verbal language for magic that basically requires each spell to contain a Noun and a Verb like as a spell, with skill points in the nouns you know and the verbs you know. It provides a couple of examples, but it's listed as an optional rule, so it only gets about half a page of text in the rule book, if memory serves.
But that framework may work better than having a list of all possible spells. Set up a simple grammar and then let the players pick their Mad Libs style spell lists.
So a spell has, perhaps, a structure like *Adjective* *Noun* *Verb*.
So then the PC might have spells using that structure like:
* *Flaming Arrow Shoots* that is roughly equivalent to the (A)D&D Magic Missile spell.
* *Warm Hand Heals* is a simple touch-based healing spell.
* *White Lightning Blasts* fires a bolt of lightning at a target.
* *Glowing Light Strengthens* might cause a sword to be stronger (and glow).
and so on.
But I would focus on the rules of the grammar rather than a predefined list of all possible words/spells. This lets your players have more creativity, and also makes magic itself more unique.
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[Question]
[
My goal is to try to make a population size algorithm. What I learned is that a simple equation can do that (I have to look it up to give you it) year by year. One of the variables in that equation is Fertility Rate and that's where the problem is.
There are 3 things that determine Fertility rate:
1. Children Survival rate
2. GDP per Capita
3. How Developed the Area is which breaks down into:
* Health
* Education
* Living standards
The first is easy to figure the things that affect that.
The third is likewise pretty easy to figure out, and I'm pretty sure there is a site that states it for the research...
So that leaves GDP... In the modern world we can just measure through jobs, but in the past, I'm completely stymied (First time I've ever gotten to use that word ^.^) I have no clue how to go about determining GDP for Hunter-Gatherer, Nomadic, bronze-age, medieval age civilizations... I mean, what qualifies as GDP and how do you determine it? Should farmland for yourself/family be considered part of GDP? Should a buffalo that you hunted and are eating that day be considered?
[Answer]
You need an index. A good index is something that is a substitute good, so that it can be compared. In modern world it is cash, because you can exchange it to anything. In your case it could be salt, bone, fur, tools... GDP answers to a question: "If you would exchange all of your goods produced, during a time interval, to the index for a current market price, how much would you get?"
GDP is a measure of productivity. A higher GDP means ability to produce more or higher quality goods. It's an abstraction for modern world, in your case GDP may not make sense, because the food has a great value already for a survival. GDP would fluctuate a lot. Maybe carrying capacity <https://en.wikipedia.org/wiki/Carrying_capacity> might make more sense.
EDIT:
An example:
```
Population consumes 90 buffalos per year for food
Index is salt
Year 1:
100 buffalos hunted
after consumption 10 buffalo meat to sell
=> willing to sell for some amount of salt, because the meat would anyway rot
market value of a buffalo meat 1kg salt
GDP = 100kg of salt
Year 2:
80 buffalos hunted
for consumption 10 buffalo meat to buy
<= willing to use infinite amount of salt to not starve
market value of a buffalo meat 10kg salt
GDP = 800kg of salt
```
Less buffalos hunted, but they are much more valuable on second year, leads to 8 times higher GDP. On first year there was a surplus, but on a second because of the deficit the GDP is higher. GDP does not reflect what you are looking for.
EDIT 2:
<https://en.wikipedia.org/wiki/Purchasing_power_parity> That may help in a way. It would lead to right valuation in the example, but there is still the problem that it would remove the value of other goods. The main point is that survival leverages the value of goods disproportionately.
[Answer]
There is a floor of private consumption of sufficient low quality food to prevent starvation, and minimal clothing and shelter for the environment (the less hostile the environment is the lower this threshold is since clothing and shelter are less necessary and easily available food and water may require little work to produce). This is going to be true for every society no matter how it goes about securing these things. From there, think about long lasting tangible personal property and structures and food reserves.
Another way to think about it is to look at what percentage of the population is engaged in food production. In the poorest society, 100% of the labor force spends all of its time feeding itself with no resources to support anyone doing anything else. (Within those societies, the percentage of the population in the food producing labor force as opposed to caring for and being children and dependents, and the number of calories per person per day can be good proxies for per capita GDP.)
[As of 1800, in the United States](http://www.nber.org/chapters/c1567.pdf), 1,405,000 people out of a labor force of 1,900,000 were engaged in direct food production. So, the standard of living that could be supported was about 35% higher than one in which everyone was engaged in direct food production.
Right now, about 2% of the labor force of the United States is engaged in food production, while the other 98% of the labor force is free to do other things, so the standard of living that can be supported is about 5000% higher than one in which everyone is engaged in food production.
The percentage of people engaged in direct food production has declined almost every single decade from 1800 to the present.
This isn't a perfect measure (e.g. it doesn't distinguish between different levels of productivity of non-agricultural workers), but it is a good starting benchmark that can be estimated from information that isn't completely impossible to obtain, and can be used as a staring point. Figure out how many people who rulers, scribes, entertainers, priests, soldiers, craftsmen, bankers, traders, etc. and use those estimates to figure out what percentage of the population was engaged in direct food production. Then convert that to a percentage and multiply by a base number for minimum subsistence.
For much of early history, society was largely Malthusian. Per capita GDP was kept fairly constant and any excess resources were used to increase population until the theoretical floor of private consumption was reached.
[Answer]
>
> Should farmland for yourself/family be considered part of GDP?
>
>
>
No, GDP is Gross Domestic **Production**. Land is wealth, not production. Plowing the land or planting crops would be part of GDP. The land itself is not. You could calculate [Owners' Equivalent Rent](http://www.investopedia.com/terms/o/owners-equivalent-rent.asp) and include it that way. But it might be simpler just to neglect land altogether.
>
> Should a buffalo that you hunted and are eating that day be considered?
>
>
>
Yes, although it usually isn't in current statistics.
The larger problem is that GDP statistics are meaningless without accurate prices. But if there are no transactions because everyone consumes only what they produce, there are no meaningful prices.
I would consider using a GDP value of zero and seeing what happens. Presumably you're also going to be using low values for health, education, and living standards.
I'm not sure that GDP is the best measure to use with a hunter gatherer society. Fertility is more likely to be affected by more direct measures like quantity and regularity of food. The formula most likely uses GDP as a proxy for that and other measures.
The primary reason to use GDP modernly is that it is commonly calculated. But in your societies, it wouldn't be. It might be easier to find a different formula than to approximate a GDP value.
[Answer]
Well, google says that the following equation is used to calculate the GDP:
GDP = C + I + G + (X - M)
**or**
GDP = private consumption + gross investment + government investment + government spending + (exports - imports).
this can be simplified at times depending on what you are going for, for example, if you want to calculate for hunter-gatherers decide on a monetary value for things like meat, furs, wood, tools, etc etc.
Then, selecting a number for the starting population, calculate what they would use themselves (say one family uses 80% of what they gather and hunt, add the two values and multiply by .8), what they would use for the community (the .2 not used by the families) government investment might, in this case, relate to trades with other tribes(exports-imports) as well as what tribe leaders might give to families in need etc, etc, and then because of the more simplistic government they might have, assign government spending a value of 0.
So starting out this is going to be hard for you because you have to select how many people there are and then calculate families, average income per family based on the values to materials you assigned and so on, but if you keep this information after you calculate it, it's scalable and you can reuse it.
So I hope this helped :)
Good luck.
] |
[Question]
[
This idea is based on a problem that I see in real life, that a group of citizens who are... Oopsie... who I perceive as frustrated/utopian/uninformed want to try a really brilliant idea, and as it is a democracy if there is finally majority supporting it, then they are right.
In the most clear cut scenario the idea actually involves a combination of spending and taxation ideas that terribly mismatch, and not only I am prejudiced against such idea but it seems that basic mathematics says that the numbers do not add up. Sometimes the idea is more subtle, like basing the brilliant plan on some perceived harm from outsiders and hoping that closing the border for trade or for foreign investment would solve the problem. Or introducing some law because of some high ethical ground or patriotism, that after closer inspection looks like poorly veiled vested interests of some minor group.
The aim is:
1) To let some bad idea actually being tested on some area, instead of trying to introduce it on country level at start. Instead of heroic fights who would get the majority even an idea supported by minority would get some chances. As result after voters seeing the result, the politicians would not only no longer support it, but actually claim that they were against it from start.
2) To ask populist politicians to test their brilliant plan in such province (even if by all metric the plan even more or less work, they would have to prove themselves as administrators who have to make hard choices and not only as great speakers)
3) Actually from time to time a scorned idea may turn out to work quite well. So it would be just seen as working and introduced at central level
4) Under perfect scenario - if the regulation worked quite well, then actually local people would benefit from it sooner than the rest.
Would it be possible to implement such policy?
When thinking about it I found a few problems:
1) What if policy works locally but the cost are being transferred to the rest of country. Ex. Running a tax heaven. Or selling locally lots of unmonitored weapons, or drugs that sip to other provinces. Or polluting whole region.
2) What if such experiment works a bit better and effectively is a big version of walled community? Which works indeed a bit better than the rest of the country thanks to keeping some undesirables out.
3) Would it actually convince many people, if their pet idea failed? Maybe as I've heard concerning communism, the problem was not flawed idea but not trying hard enough and not keeping enough orthodoxy? Or just in case always good explanation that idea failed because of some impressively vast conspiracy?
4) What about people with varied brilliant ideas? Should maybe such province be divided in to a dozen of experiments?
(Or maybe such idea is not worth fuzz because it would neither provide a safety valve nor let worthy ideas being tested?)
[Answer]
## In real life, no, the degree of coordination and agreement is just too high
The bane of any Utopian ideal is that it requires coordination and discipline to achieve the desired state. Even the statement of "sacrificing a territory/state/province" requires a high degree of agreement both by the greater country and the current occupant of the sacrificed area. One would need to get everyone in that area to agree to an experiment, then the terms of the experiment, how to keep costs internalized, how to abort the experiment should it go very very wrong, and the enforcement mechanisms to ensure the experiment actually tests the hypothesis. The list goes on forever.
*While none of the experiments can be done explicitly, they can be done implicitly.* Human history is a very long history of people finding an idea and wanting to try it out. The French did it with the French Revolution. The American's did it with their revolution. Russia did it with theirs. Some of these experiments are successful, others fail catastrophically. Darwin has his way with all these entities, both nations and the smallest town. We've seen that free-market capitalism is really great at outperforming command economies; witness the collapse of the USSR vs the USA.
As an implicit example, the people of the state of Kansas are trying their own experiment in fiscal conservationism by cutting incomes taxes and hoping that enough business will come in and enough wages will be made to pay for the required cuts in school services. So far it doesn't appear to be working out the way they hoped according to this [review by the Chicago Tribune](http://www.chicagotribune.com/news/opinion/zorn/ct-kansas-conservative-brownback-economic-disaster-zorn-perspec-0518-jm-20160517-column.html).
[Answer]
## You still won't reach a 100% majority for the entire country on any topic
Let's pick a real-world topic as an example: **The legalization of marijuana**
Suppose this is introduced into the community. Our example community will be Colorado, part of the United States. There have been many positive changes as a result of Colorado's pot legalization - crime rates have dropped, the state's economy has improved, medical research is booming - but also negative changes - more people are driving under the influence of drugs, more minors have access to drugs that are still illegal for them, and pot-related hospitalizations have increased by 82%.
Other states use Colorado as an example to support *either* claim - they use the pros to support legalization, or the cons to support keeping marijuana illegal.
These communities will clear up the facts, but opinions as to if the pros outweigh the cons will still **differ** to some degree. Rather than resolving the problems once and for all, this will make it more clear what the problems are. A change, but maybe not the one you desire.
## *No, I don't want to move, thank you.*
So you solve the above problem. You divide the country into regions based on voting results to keep people happy - but, using America as a case study again - this will not work perfectly.
We have two major parties - **democrats**, who are more liberal, and **republicans**, who are more conservative. While there may be more democratic or republican states, you can always find a population of the opposite party in any one of them.
And yet they never move - democrats may stay in republican states and vote for what they want - and republicans may stay in democratic states and vote for what they want - but moving to a different state is a hassle.
Given the above information, you will never find a region that agrees enough on one topic to adopt consistent regional laws. Further dividing into towns, then districts, based purely on landslide opinions will make a country that is impossible to lead - and impossible to police.
---
Notes after reading other answers
>
> Agreement is achieveable
> - Another answer suggests facilitating this government cannot work because people would not agree to the experiment. This is wrong for two reasons:
>
>
> 1. The fact that people will disagree does not mean "no", it means some will say "no", and others "yes". Surely at least one region, town, state, province etc. you ask will say "yes" as is the case with any vote in real life - instead of "no" because people are disagreeable.
> 2. Agreement can be determined at the country's Constitutional Convention - where it decides how to run things. Perhaps if this idea
> were introduced and the logistics were worked out then it could work
> from the start - rather than being a change in an existing nation, even though that is possible.
>
>
>
[Answer]
You could argue that this is **already happening** in the US. The independence of the states allows them to try various different styles of government. But comparing the states based on state-level debt or GDP doesn't work. Because how good those numbers look depends on whether it's people with high or low per-capita income **who are moving there**. A bunch of selfish, xenophobic rich people can form a mini-state that looks great on paper.
[Answer]
It s a dangerous slope. If everyone starts creating their sub region over any topic where they disagree, it s not long before you end up with a million of tiny tribes.
How do you maintain order in stuch an organisation?If each group lives in autarcy, the notion of country would collapse, technological advances would stop. If they don t live in autarcy, how do you handle conflicts between groups? You would need some kind of supervising group which makes sure that such thing don't happen. How do you handle disagreement within that supervising group?
A concrete example, in my region murder is legal. What happens if I murder someone from another region?
[Answer]
Many separatist movements are driven by ideologies (although they generally tend towards National Socialism in real life), but the real issue is the parent nation isn't just going to let people walk away with valuable real estate, resources and taxable citizens just to test out an idea.
Most real world scenarios either end up with political scessesion movements which run around gumming up the works and generally demanding a bigger piece of cake from the remainder of the nation (i.e. Quebec in Canada), but can escalate to civil disobedience, armed insurgencies or even civil war. Most people agree that these are not desirable outcomes, but generally speaking, unless governments are going to go right to the mat (like the Siri Lankan government vs the Liberation Tigers of Tamil Eelam), insurgencies of this sort are difficult to extinguish, and can last decades or longer.
The best real world solution to date is a federal system much as envisioned by the American Founders, who conceived of "These United States" as a group of sovereign nations who collectively pooled resources to the Federal Government for a very limited and clearly defined set of duties. The "Enumerated Powers" doctrine: Article I, Section 8 of the Constitution and the Tenth Amendment (***The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are reserved to the States respectively, or to the people.***) strictly limit the powers of the Federal Government, although this has been increasingly observed in the breach (particularly since the "New Deal").
In the Founder's conception, each individual State had the right and indeed duty to experiment with laws, customs and social and political institutions. Successful innovations would be adopted by other States in due course, or unsuccessful states would see their economies and even populations decline as people headed for "better" States (such as the population exodus from California today).
With a more limited role of the Federal Government, individual States could function much more like the Founders intended, and at least some states could evolve towards "utopian" systems, so long as these systems actually worked.
] |
[Question]
[
So I have a planet that has had it's atmosphere clogged with artificial clouds for some five thousand years. Basically a prolonged ash winter; everything died. (Or, almost everything. Would I be right in thinking there might still be life in the oceans? It's been implied that there were areas with underwater volcanic activity.)
Now my highly advanced civilization has come to the planet and cleared away the artificial cloud layer. They want to revitalize the surface; make it livable again.
They have a lot of tech at their disposal. Advanced medicine, genetic engineering, bio-engineering, nanotech, pretty much you name it, they've got it. They've got tons of "seed material" (plant and animal), too, with which to kick off various ecosystems.
So my question is, how quickly could this be expected to happen? How soon would the temperatures rise once the sun could reach the surface again? How fast would reintroduced plants and animals take hold? How soon could people begin living on the surface, and under what kind of conditions?
Specifically, what might this formerly dark and frozen world plausibly look like after about fifty years of artificial revitalization?
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I assume your planet didn't have its atmosphere artificially removed or anything like that; assuming there's still atmospheric pressure, some hints of a breathable atmosphere, byproducts of former life and decay, etc.
First, we can't say that everything would have died. Fungi and lichen could have lived on for a surprisingly long time, feeding on the dead biomass left behind. Chemosynthetic bacteria in hot springs would have a field day, with no large animals around grazing on them, and their population could support a variety of filter feeders and microbivores. So you've probably got at least some biosphere to work with.
In the areas that didn't have any life left, you'll have a situation similar to the area around a recently active volcano, or a landscape recovering from recent glaciation. This is a process called [Ecological Succession](https://en.wikipedia.org/wiki/Ecological_succession), and specifically [Primary Succession](https://en.wikipedia.org/wiki/Primary_succession). In short, you'd start with the introduction of simple lichens, mosses, and algae. These species would live directly on the sterile rock or former soil. They may need some support in the form of bacteria to help them break down certain rocks, but they're designed for this sort of thing.
These pioneer species would break down the rock into soil and enrich the local environment; they'd also begin modifying the atmosphere. In a surprisingly short time they can create an environment that can support larger plants. An excellent example of this is the [island of Surtsey](https://prezi.com/id4od8oakil0/succession-on-surtsey-island/) - it emerged from the sea as a brand new island in 1963. In 1998, the first bush was found growing on the island. There are now around between 30 and 60 species of plants growing on the island, which started as bare volcanic rock just fifty years ago.
I'm afraid I can't help with the question of how quickly temperatures could climb, but I'd be inclined to suggest "pretty damn quickly". Especially if there's a significant amount of CO2 or methane in the atmosphere, which would be natural byproducts of the death of an entire biosphere, a surprising amount of heat could have been retained during the 'ash winter', and it could maintain a pretty solid greenhouse effect in the early days.
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Welcome to the site, WrittenEmber. You have worded your question masterfully and the topic is quite interesting too! I would love answering it according to my (limited) knowledge.
You have not specified what is the extent of this ash-winter. Has the Earth/planet completely frozen over into a [snowball Earth](https://en.wikipedia.org/wiki/Snowball_Earth) like condition (extreme case) or is it that the layer of ice is only a couple feet thick at most places and the oceans are still liquid? I would assume the second scenario here, as this stage is easier to cure.
**1- Would I be right in thinking there might still be life in the oceans?**
This is your world. Make it the way you want. If you want that extremophiles living around deep sea vents survive, so be it. If you want everything dead, declare it so. Your world, your rules.
If it were my world, I would have the extremophiles survive in deep sea vents and a few critters surviving on land.
**2- So my question is, how quickly could this be expected to happen?**
Once sunlight starts reaching the surface, the ice on equatorial regions would start melting soon (as in, within a couple months). Then, as the ice goes on melting in higher and lower latitudes from the equator, it will create a **lot** of rivers, lakes, flash floods and a lot of topsoil would be eroded away into the bottom of these new rivers, and sometimes be permanently lost into the oceans.
It is only after several years (I would guess 5 years) of the removal of permafrost that the soil would be once again fit for growing plants. Hardy plants at first. Grasses, followed by shrubs and bushes, then small trees and finally wooded regions would appear. From the removal of frost layer to the appearance of first small jungles, it would take nearly 20 years.
Once there is enough food for the grazers (after 10 years of removal of frost layer), you can introduce small animals such as hares, goats, sheep, deer etc. Only after their population is naturally established in an area, you can introduce small predators such as bobcats, snakes and solitary wolves. After the habitats are firmly established (after 20 years of removal of frost layer), you can finally introduce larger animals such as buffaloes, bison, giraffes and zebras, followed by (after 5 years) large predators such as lions, cheetahs and tigers.
One thing you must pay special attention to, is that I have assumed that your nitrogen-fixing bacteria have survived under the frost layer. In case those bacteria are lost, you would first have to introduce those bacteria to the soil, before you plant the first seeds.
**3- How soon would the temperatures rise once the sun could reach the surface again?**
This depends entirely on the area and its climate. For example, something resembling Africa or South Asia would have its climate return to temperate (notice they are tropical right now, which is warmer than temperate) within around 10 years of the removal of frost layer. As you move up (north) or down (south) from the equator, regions would require longer time frames to return to their pre-frost conditions. For example, England would require at least 20 years to return to normal, after the permafrost is gone. Northern Europe, Canada and northern Russia would require even longer times. Perhaps 30 years or so, before the climate is stabilized. And of course polar regions would remain frozen as before, unless ...
**4- How fast would reintroduced plants and animals take hold?**
Read above.
**5- How soon could people begin living on the surface, and under what kind of conditions?**
*People* are the hardiest of all mammals. We can live in almost any place, if we have the support of our technology available to us. Even on the permafrost layer, people could live in igloos and in caves.
*Normal* living conditions (as in, building houses as we know them today) won't start be possible until a very long time, though. That is because we are extremely dependent on the technology for this purpose. You would need wood (at least 25 years after the removal of permafrost layer), cement (only possible after you set up cement manufacturing industries, which would be at least 35 years after the removal of permafrost), metals (only possible after metal refineries are set up, which ... I don't know when would be possible, since you need to know where the ores are located, and also have an already functioning society to have people working in them) and bricks. Thankfully, bricks can be manufactured the earliest of all other ingredients. Nearly 4-5 years after the permafrost layer is removed.
So the initial human colony (the people who came in the spaceship) would be built on the permafrost layer. They would probably live within their spaceship for the most part of their time, only venturing out to see how their technology is helping thaw the world. Once the permafrost layer is gone, they can start building brick furnaces and bake bricks, which would enable them to build primitive homes and cabins. Only after they have wood available and have set up metal refineries, that they would be able to build proper homes as we are used to, today.
**6- What might this formerly dark and frozen world plausibly look like after about fifty years of artificial revitalization?**
Mostly normal (as in, as it exists today). Although 99.99% of the surface would be natural habitat of plants and animals. The first long-lasting human structures would be starting to be built. These would include metal refineries, housing colonies and small factories.
Animal populations would be very less than modern times, unless the people are continually pumping in more individuals through cloning, every year.
Climate would have been stabilized. Seasons would have returned, although winters would still be somewhat longer than the summers.
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The planet will not be completely sterile. Hydro-thermal vents deep in the ocean will support bacteria, barnacles, snails, worms, etc. You'll probably have bacteria living deep underground, similar to Earth.
The surface will be Antarctica - covered with glaciers, and completely sterile (Antarctica is not).
Once the clouds are removed, the planet's albedo will remain high (ice is a great reflector) so melting the glaciers and the ice caps will take hundreds or thousands of years.
An advance civilization will be able to set up outposts on the surface, but realistically speaking they would have to terraform the planet and that will likely take hundreds of years.
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I am trying to build a truly alien form of life, and easily found several replacements for water, such as methane or ammonia, with there own unique advantages and disadvantages (Wikipedia has a wonderful article on this). But I am having difficulty finding a good atmosphere that a creature could breathe other than oxygen.
The one gas I have found is a compound of sulfur oxide, which is currently used by certain types of bacteria that live near underwater volcanoes instead of oxygen.
What other gasses would work?
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Oxygen, in our (aerobic) respiration system is used to *burn up* the ingested food and release the stored energy in it. If you want your aliens to operate on a similar respiration system (as in, they use a gas to burn up their food and release energy), then you have few choices other than oxygen.
**Chlorine:** The problem with chlorine is that it is very reactive and nearly impossible to find freely in the atmosphere. However, you can have chlorine compounds (HCl, CFCs etc) in the atmosphere which the creature can inhale and absorb these compounds through lungs and then use solar-cell like organs to electrolyse them and release the chlorine. They would then use this chlorine and use it in their respiration.
**Self sufficient salts:** This could be an interesting choice, considering that you obtaining everything from one food source. Your creatures would be *eating* salts (NaCl, KCl etc) and then using the above solar-cell like organs to electrolyse them in water-solution and release hydrogen and chlorine. They would absorb these gases in different chambers and transport them to the organs in different channels. Within the organs, the hydrogen and chlorine would be allowed to mix, releasing energy. The *waste* product (aka HCl) would then be excreted out of the organism.
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You don’t need a metabolism that is exactly analogous to what you know. For cells, like with combustion engines, it’s handy to half one of your reactants available always in the environment and not have to carry around that weight in fuel. But it would be more alien if the life-form did not behave in that manner at all.
If the life-form does use some atmospheric gas, it could very well be for a role that is *not* analogous to how we use oxygen. For example, plants use CO₂ but as a source of carbon atoms which eventually wind up forming tissue, but it’s not analogous to our *food* either because it requires energy rather than provides energy.
Gasses in the air are handy but not necessarily handy *enough*. Plants get carbon and oxygen using organells that have become part of the cell. But they never bothered [taking that step](https://en.wikipedia.org/wiki/Endosymbiont#Endosymbiosis_theory_and_mitochondria_and_chloroplasts) with the bacteria that extract nitrogen from gas. Well actually, [one organism did](https://en.wikipedia.org/wiki/Nitrogen_fixation#Endosymbiosis_in_diatoms) and others keep them at hand but with a [less integrated relationship](https://en.wikipedia.org/wiki/Nitrogen_fixation#Root_nodule_symbioses).
Whether use of a particular substance is analogous to breathing oxygen is a detail, and part of a far larger spectrum of possibilities.
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I won't find links now, but reaction
CH4 + H2O + light -> [sugar] + 2H2
is possible and requires 4 times less energy than normal photosynthesis.
Therefore, the reverse reaction of *reducing* sugars with hydrogen should be exothermic and yield 1/4 the energy - probably not enough for warm-blooded creatures, but surely enough for muscles and nerves to function.
Just a thought.
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Whatever gases you choose for your atmosphere will need to be stable at the ambient temperature.
Also, whatever reaction occurs from the gases reacting with solar radiation in the upper atmosphere will need to proceed at a low rate or be more or less reversible.
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There are actual anaerobic organisms on Earth, and [before plants came along and spewed out toxic waste everywhere](http://www.slate.com/blogs/bad_astronomy/2014/07/28/the_great_oxygenation_event_the_earth_s_first_mass_extinction.html) there were probably many more.
So, there are known working metabolisms you could crib.
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[Den Den Mushi](http://onepiece.wikia.com/wiki/Den_Den_Mushi) are snails used for communication in the One Piece universe.
I'm pretty sure trying to make it exactly as in One Piece would be absurd, but here's what a Den Den Mushi should be (imho) in order to be able to be considered so:
* Ability to connect with other Den Den Mushi it already meet.
* Connection should be reciprocal.
* Once connected every sound one Den Den Mushi hears is reproduced by the other, as similar as possible.
* A human should be able to force and terminate those connections (maybe having pheromones or something else from the Den Den Mushi he/she wants to connect with?).
How could a Den Den Mushi do so and how would it evolve to be such a curious creature?
[](https://i.stack.imgur.com/mpdJZ.jpg)
[Anatomically Correct Series](https://worldbuilding.meta.stackexchange.com/questions/2797/anatomically-correct-series/2798#2798)
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The Den Den Mushi communicate with each other via telepathic radio waves. This is, alone, a way of the species communicating internally.
As noted in the series by Franky, people take advantage of their curious ability to communicate by attaching the basic parts of what is essentially a phone to them, in order to facilitate long distance communication. This could also be how they choose who to contact. If the installed devices give a specific signal, it wouldn't be hard to pick up that signal over others.
It has been demonstrated that this does have a limit, as seen with the video Den Den Mushi having a weak signal on island far out during the a Navy broadcast.
As for how they evolved to attain this power, it can be assumed that they have some sort of electrical signal within them. Over time this signal likely became stronger and began to emit radio waves. Even farther along, they learned to communicate along those radio waves to one another.
Sorry if this doesn't 100% answer your question, but it's all of the details I can think of off hand.
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So, I've made... a lot of subterranean worlds. It's a favorite of mine. And, every single time, the major form of vegetation and light was blue, glowing mushrooms, and glowing crystals. While I think light sources are no struggle, I've had issues avoiding the ever-present trope of glowing blue mushrooms, lichens, mosses, etc. Definitely vibrant, preferably edible and/or useful for tools and buildings, but not necessary.
So, **what vibrant vegetation would fit thematically aside from them?**
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## Mold
Molds are a classic thing that grow underground. According to [this site](https://web.extension.illinois.edu/healthyair/mold.cfm)
>
> Molds need moisture that can come from water leaks, flooding, high relative humidity, or condensation. And, molds require oxygen, but not light. Without the proper conditions, molds may not grow but become dormant. Then when conditions are again right for growth, they begin to regenerate.
>
>
>
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## Oozes
Oozes also don't need light to grow. (they're one of the quintessential D&D monsters). Examples are slimes, gelatinous cubes, and the ooze itself.
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## Fungi
So too are fungi (mushrooms). Believe it or not there are vast networks of mushrooms underground that support life above the surface in the jungles. Without this under footing of mushrooms, many plants wouldn't be able to survive!
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## Moss, Ferns, etc.
According to [this site](http://www.caveslime.org/kids/cavejourney/caveJourneyWhatPlants.html), while not adapting to the dark per se, mosses, ferns and/or liverworts may be in the twilight zone, which are low-light areas where light decreases from the full intensity of the surface. Such organisms are adapted to the very low light regions where the twilight zone meets the darker areas of the cave and like the constantly cool, moist environment provided by the cave entrance.
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## Roots
Roots can grow into the cave. Even though they aren't a separate entity that exists from the plant above the surface, they are still something that grows into caves. Keep in mind that root structures weaken caves, and if there's sufficient weight above the surface, it'll cause it to collapse into the caves below.
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So the kind of slimes I'm thinking of are those with a nucleus or crystal core of sorts that acts as the slime's brains. Their body would be made of something like nerve cells that stick to each other in an elaborate mesh. This allows the core to control their body. They would be able to eat most stuff but the slimes would evolve to suit what they eat [say, if they were eating plenty of bones, they would evolve to be more corrosive, thus allowing them to eat/dissolve the bones faster becoming an Acid slime].
The slimes are not capable of communication [they don't know what that is] thus it's a slime eat slime world where bigger nasty slimes devour their smaller cousins [and whatever in their way - they make great lawn mowers]. However their size won't grow forever, they will stop at a certain limit depending on their evolution [can't have them bigger than the world]. When they reach their limit, they become capable of splitting into two.
**But what kind of animals and plants would have evolved among these conditions and in general what kind of world would it be like?** Assuming that the world composition is something like earth with the core, mantle and crust, oceans and whatnot.
I'm looking for what might be able to **predate** on the slimes and what **adaptations the plants can have to counter the slimes**
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Ever changing types of poisons would be employed by plants for protection. So that when a slime type manages to evolve an immunity to that poison, that plant would be producing another type of poison. Flight would be more common as it would be easier for flying animals to survive. The path leading to slime would not be much different from the slime on earth. Just one day slime manages to capture neuron cells of an organism and manages symbiotic relationship to it. [Siphonophorae](https://en.wikipedia.org/wiki/Siphonophorae) is a similar type of symbiotic colony.
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In this world there could be a whole host of insects that predatorize these slimes. Imagine a mosquito sized insect that lands gently on the surface of a slime. Maybe the mosquito is so light the slime does not notice. or maybe this particular slime evolved to mainly feed on plants or significantly larger animals. In either case the insect lays its eggs in the slime. This might be a simple way to protect its offspring till they are ready to fly away. Or the slime maybe a source of food for the larva. Just as a tapeworm on this planet begins its life after entering the host digestive track this insect begins its life inside the slime.
There may be snail/clam creatures with hard shells that prove to be resistant to the slimes digestive enzymes. Whenever a slime comes around they just retreat into their shells and pretended to be an indigestible rock till the slimes passes.
If these slime prove to be environmentally devastating (they eat everything), then other forms of life might prosper in places that the slimes cannot reach.
Are the slimes aquatic? Maybe sea life is the second dominant life form.
Can the slimes survive below zero temperatures? Maybe penguins and polar bear like critters live long prosperous live free of the slime nightmares.
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The world would have to look more like a giant cell were the slimes can move in all directions. If the slime world had slimes just living on the crust, then It would be easy for the slimes just to dry out from wind, heat, and etc. If anything, the planet would look like a giant ocean. as far as a environment, Can't really see much **because they consume all!** Maybe that is goal of your slime creatures... to consume all and become so big that they actually become a planet or consume planets!
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So, let’s say that at some point in the hopefully distant future, the second law catches up to me, some random part of my body just craps out and stops working right, and I die.
Luckily, through the power of foresight, I have a post-mortem plan! Despite the chaotic, hellish merry-go-round that is life, there are still some parts I like about it, and I’m not ready to give up just yet. I have made arrangements to have my body cryogenically frozen immediately after death, to minimize further cell damage, and to be woken up at some point in the future, when they have the technology to cure this kind of thing.
The problem is, that the future is a really long way away, and I need someone on the other end to bring me back to life, so I can start doing stuff that isn’t spending hundreds of years in a tube again. Assuming that humanity hasn't progressed to the point where there are just reanimation stations on every street corner for whatever reason, repairing 80-somewhat years of damage to a human person is going to take time, money, and resources. Someone has to have a pretty good reason to want to reanimate some stiff from the 21st century. And if I don’t have that critical man on the inside, then I’m essentially going to stay dead until something gets unplugged, and I start to decay past the point of possible re-animation. I could have some sort of message go out, but I have no idea if anyone would have the backwards-compatible tech to even receive it anymore, like sending a telegram to an iPhone, and even if they did, they could just disregard it as a hoax. I could have someone else pass down a message from generation to generation, but that could be distorted really easily, and the gravity of it would probably wear off to the point where even if someone still remembers, it would just be as, “Oh, I was supposed to resuscitate so and so! Eh, I’ll do it later.” I could stockpile some sort of monetary reward to whoever wakes me up, but the awareness of that could also fade, and because of inflation, the amount could be laughably small, or even completely unusable, like confederate money. I need some sort of reasonably-foolproof way to make sure that someone, *anyone*, brings me back to life, so I can continue to enjoy the future.
To be clear, I’m not super picky, nor am I aiming for a certain date. As long as I get woken up at all, more than 100+ years in the future, I’m happy. Also, in this hypothetical situation, I’ve died of natural causes, not any specific disease or injury, just general cellular decay. My brain is still intact, as well as most of my important limbs and organs, they just need a tune-up. I’m still all in one piece, and for the sake of convenience, let’s say that they put me somewhere safe, but still accessible.
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## Plan D: All of the above
The odds of anyone (that is not you) caring about your preserved corpse more than all the decomposed ones in graveyards will be fairly low, so you need to have layers upon layers in your plan.
## Caretakers
A small or medium company will be the best caretaker, but stay away from family run businesses, as you are almost guaranteed to get either a complete incompetent or someone with no interest in the business at all within 3-4 generations.
If you amassed a sizable fortune, the best choice is a museum or a non-profit with some charitable goal that is likely to remain relevant for a long time. Respect for the founder/donor will get you some of the way, but the priority is to have a thorough selection and training program for the CEO to ensure focus and loyalty, and a succession program that can survive a few resignations or accidents.
Lock down ownership of the building, grounds etc in a trust beyond the reach of the company itself for as much as that is possible.
You could have a second company somewhere else in the world that manages enough money to buy the location/non-profit that houses your body if things go wrong, but the odds are much worse for this to succeed, so I wouldn't bother.
## Time capsules
Let's assume the caretakers lose interest, fail or disappear for some reason. You don't want your facility to be easy to find, because you don't want to be found by a hobo that will dump your corpse so he can store his booze in the "fridge", looters that will strip the lab for valuable metals instead of waking you or even a random well-meaning person that presses the "thaw" button and then leaves when nothing seems to happen...
With the facility well hidden, time capsules are you next layer. Put them in the museum itself, but also in places that you expect to last for at least a hundred years before they get torn down and rebuilt. It's hard to find those nowadays, but count on the power of neglect and budget cuts to stretch renovation time frames.
Once activated or revealed, the time capsules should not directly point to your location. Address them to universities and research hospitals. Even if those don't exist anymore, people will get the right idea and bring them to a similar institute. Put some ambiguous and cryptic hints inside, spell out an encryption scheme and encode the vital information in DNA strands. This will ensure that only people with the right kind of equipment and knowledge (as well as a professional interest in seeing if they can revive you) will know where to look for you.
Extra bonus option: send a satellite with the same info into space on a long elliptic orbit that will not bring it back to Earth for a few hundred years.
## Emergency broadcast
Similar to the time capsules, but more direct: If your containment facility is threatening to fail for some reason have it send out broadcasts with increasingly clear information. There is a definite risk you will attract the wrong kind of people this way, but rotting away is a certainty if nobody comes to revive you... or is it?
## The final contingency
There is *one* way to ensure that someone other than you will be there at the time of your (intended) resurrection: You find someone with the medical and general skills to find help for you, who also has a fatal but not debilitating disease. That person will be frozen first, during your life and will be woken up first when the time is right or the machines are close to failure.
They will be motivated to find help and if they do get cured, deeply in your debt, so the odds are good they will try hard to have you revived too.
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Take a leaf from [Jeremy Bentham](https://www.ucl.ac.uk/Bentham-Project/who/autoicon)'s book and have yourself put on display in the main hall of an organisation you've founded. A major academic institution would be ideal for this.
You're now a fixture in the day to day lives of the people attending said organisation and they're highly unlikely to forget about you.
As a condition of the trust that funds this organisation they're required to resuscitate you at the point in the future when the technology to reliably do so becomes available.
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**Have Lots of Offsprings**
With having lots of offsprings its almost guaranteed that in some generation somebody would take interest in family history and respect your well-known wish.
**Radioactivate A Large Piece of Land**
Large piece of land, on the level of hundreds of square kilometers would be too much for people of future to let go without using. Just set the radioactivity level so that it remains high enough for no life to survive in it beyond hours (not enough time to fully explore it) (dont worry about robots, radioactivity high enough as stated would guarantee that all electronics in such robots would be fried before it can actually found anything); and put a large stock of precious metal at a place where if anybody enter some mechanism in place get fired and your resurrection starts.
With large stock of precious metal in place its guaranteed that somebody enter in and start digging and do some heavy work that fire the mechanism. With radioactivity in place its guaranteed that nobody and no robot survive long enough there to pre-maturely start the mechanism.
With large piece of land locked up in radioactivity its guaranteed that enough people try to explore and utilize the land for long enough time that radioactivity dies down to the extent they reach your place.
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The answer is money.
You've already selected a company that is interested in cyogenics and accepted that they will cryogenically freeze you if you die. All you need now is a fund located at a lawyer firm (and some investors using it in safe investments to keep it a viable source of money). This fund will pay the cryogenics to keep your body stored properly and occasionally be inspected. A lump sum is paid to whichever company has the technology to revive you, with a massive fine for anyone who tries and fails. Just in case the lawyer firm will also get a lump sum for succeeding in reviving you, paid by you personally ofcourse.
This encourages people to store your body and for someone else to revive you, and for the people in charge of the money to also actively get you revived so they get paid well. There are also systems in place to make sure the cryogenics does not keep your body forever or says "we already get paid get rid of the stiff".
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A theory about [One Piece](http://onepiece.wikia.com) comes to my mind recently: the series contain a lot of impossible, non-existent and "fairy tale"-like elements, such as various giant animals, bizarre cross-species, giant or simply [impossibly tall](http://onepiece.wikia.com/wiki/Donquixote_Doflamingo) humans, sapient but animal-shaped species, and such.
Despite all these facts, the series tends to be much more realistic than actual fairy tales, making it surprisingly consistent and believeable. Moreover, a lot of similarities to actual human history and culteres also appear, implying that civilizations in this world developed *near identically* to some Earth countries, which is, I think, *extremely unlikely*.
Thus, I started wondering if One Piece takes place on Earth, but millions or even billions of years later.
In this question, I'd like to be interested **only in the biological, to be precise: the genetic aspects.** 65 million years was enough to evolve from rats to humans and enormous amount of other mammals, so evolution is pretty strong at making exotic species into existence, but what about such extreme results? Also, what about humans?
Is it possible that during either a natural or a supervised evolution, giant humans, giant animals, other intelligent species and other similar "fairy tale"-like beings form and live? Or is there a boundary for genetic recombination?
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I think you might be able to get away with some of this...perhaps not all...by altering the world to include much greater climate variations and extreme isolation.
Giants are actually one of the more challenging aspects to justify...the size of a species is directly realted to the environment they are in. Rich oxygen environements are much more likely to produce gigantic creatures (small creatures actually perish to oxygen toxicity. [For source.](http://news.nationalgeographic.com/news/2011/08/110808-ancient-insects-bugs-giants-oxygen-animals-science/) ). How exactly you could get concentration high enough to giant size some but not others is beyond me. Giants would require increased oxygen levels just to live.
That said, extreme isolation between populations will created diverting evolutionary traits...what is good on one island might be disastrous on another. Such badly isolated populations are your best bet in arriving at such mixed variations on life.
Editting to add:
Im not a fan ofnthe cross species, such as the centaur and other such creatures. The centaur either has the digestive track of a horse, in which case this includes flat teeth and the ability to gnash prior to eating and would require the jaw and muscle structure to support that (horse face much?) or reversely, its a carnivore....and then you get into the questions of how it feeds and gets enough energy to support its horse self (remeber, functionality of the brain requires a huge amount of digestion support) and why itd have several traits favorable to a herbavore and not a carnivore? This really gets rid of the potential of them naturally evolving to such. However this does not exclude some mad scientist successfully combining the two (sew a pigeon to a rat and call it the first ratbird?). Whether or not these are sustainable is a bit out there...frankenstien was sustainable enough for a story, no? Especially if there is some degree of 'magic' present.
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Evolution will produce organisms based on the parameters you give it to work with. Earth's evolutionary process produced humans - we're perfectly adapted for the terranean environment. That means
* 101kPa mean surface pressure
* 0-30oC temperature (with modern materials and techniques we can survive more)
* 78% nitrogen, 16% oxygen, 4% carbon dioxide, 0.04% argon atmosphere
* 9.81ms-2 gravitational acceleration
* No major predators
If you supply a different environment, you will get a creature out with very different adaptations.
* To get giants, you would likely need to reduce surface pressure and gravitational acceleration. People would naturally be taller. You could also put all the major food sources in tall trees, so that survival of the fittest kicks in and only those who can reach the best food survive.
*Supervised evolution* is known as **selective breeding** - you have a population, and you select the individuals with the traits you're looking for to breed with each other. Eventually, those traits prosper and you evolve the population to have that trait intrinsically. To get giants, don't let anyone shorter than the 95th percentile of height reproduce.
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## Yes, it is possible, in a world of abundance
When humans, elephants, bats and dolphins have all evolved from some lemur-like proto-mammal, it seems that there are nearly unlimited possibilities with the same starting DNA. The problem is whether the species survive in the long run.
## Survival of the Fittest
On our planet, the plants and animals most optimized to their environment are the most successful. A plant may grow flowers and fruits, but only big and energy-rich enough to be just a little more attractive than its neighbors to the insects or animals it uses to spread its seeds.
A plant that puts all its energy into huge fruits would likely lose out to a plant that puts more energy into strong/healthy seeds or reserves for bad seasons. For animals, it is the same. Using up too much energy on non-essential features makes an animal vulnerable to competition from more efficient species, especially when conditions turn bad for a while and there are resource shortages.
## Survival of the Coolest
Many of the fantastical features (giant growth, winged humanoid, etc) you ask about are essentially inefficient or sub-optimal in our environments on Earth, which is likely why we don't see them. If the planet/ecology was much richer in resources, and rarely affected by droughts/freezes/plagues, efficiency would not be as strong a factor in the evolution of species, since more varieties can survive and thrive. Instead, species could be selectively breeding according to their own criteria, be they height, pointy ears or ability to glide from tree to tree (fairies).
The ideal environment would probably be a (sub)tropical paradise, seeing how rainforests on Earth also house the widest varieties of species.
## Maintaining the Balance
However, there would need to be one more factor that is not present on Earth: Some process or entity that prevents single species from crowding out all the rest.
The most likely candidate would be a sapient species that's maintaining the balance (very unlike what humans are doing).
Another way could be that the "have few offspring, invest a lot in each of them" strategy has been universally adopted for some reason.
Finally, some kind of endemic virus common to all species may be fairly benign, even helpful, but turn deadly if a critical mass of creatures is reached in one location. This would weed out rapidly breeding creatures, but also prevent the formation of cities until the species finds a way to prevent triggering the virus's deadly reaction.
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As twelfth has already mentioned, genetic modification is not your only concern here.
To answer your question: yes, you can alter a creature's genes to make it look the way you want it. However whether that creature will be able to sustain its life in its ecosystem is a completely other thing. It is quite complex and difficult to play around with the anatomy of a creature and then get away with it. Most of the time you would end up with a creature which would die very soon due to one reason or the other. In some cases your subject would survive but with some long term consequences.
A very tall human would have issues with bones (specially backbone). Most very tall humans have had these issues which required surgical procedures. Feeding issues might also be present. Then there is hormone balance. The endocrine system is very sensitive and hormones affect each other too, besides facilitating an organ-related action.
So all in all, creating very tall or bizarre creatures is not only limited to making them *appear* so tall or bizarre but also involves some very complex structuring and math about how to balance things internally which would enable the subject to function properly.
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Over millions of years it's certainly possible to see a massive range of genetic variations, just look at the various species of great apes but then consider that voles, elephants, dolphins and moles are all mammals too.
Creating the variation isn't the problem, the only thing that is a problem is giving those variations a reason to exist and to stay separate. Great height comes with a cost in calories, in bone strength, etc. If there is a big advantage you would expect everyone to become giant. If there is no advantage you would expect a normal range in sizes.
So you need to separate the populations for long enough that they become different enough that the genes are unlikely to mix back into each other again when they do meet.
Explaining giants and trolls are easy enough though. Even explaining dwarves and elves could be done.
If you want literal fairies with wings on their back able to fly around then almost certainly you can't get that through standard evolution and even if you could they don't really add up in terms of being able to fly.
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Could there be life on or around [Planet Nine](https://en.wikipedia.org/wiki/Planet_Nine) (a real-world planet in our Solar System, which has recently been discovered through indirect methods)? Of course, it probably receives nearly no solar energy, but there are other energy sources. For example, [Jupiter's moon Europa may get energy from tidal and volcanic sources that may support life](http://www.space.com/26905-jupiter-moon-europa-alien-life.html).
How plausible is it that there is:
* life
* intelligence
* civilization
* society similar to our own
on Planet Nine or one of its moons (or otherwise around it)?
[](http://mediaassets.caltech.edu/evidence_of_ninth_planet)
Note: I was thinking along the lines of them having originated there, not having migrated there.
Note: I would like answers to be at least somewhat scientifically sound (I was debating whether or not to tag this [hard-science](/questions/tagged/hard-science "show questions tagged 'hard-science'").)
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The major problem here is that, while we don't know for sure what this planet is like - after all, the paper ([Batygin & Brown (2015)](http://iopscience.iop.org/article/10.3847/0004-6256/151/2/22;jsessionid=9DAB98EED9CB30448604A2F4CA0F8752.c5.iopscience.cld.iop.org)) was based on simulations of the movements of Kuiper Belt Objects that matched observations - Batygin and Brown have implied that it may be the core of a 5th gas giant. I wrote [an answer on Astronomy](https://astronomy.stackexchange.com/questions/13310/how-was-the-hypothetical-ninth-planet-kicked-so-far-out-of-the-solar-system/13311#13311) detailing the basic mechanics of the planet, but that's mainly irrelevant.
So if we allow for the first possibility, we have a core of about 10 Earth masses floating along at a couple hundred AU from the Sun on an orbit with relatively high eccentricity (it's believed that e~0.6). This is, quite frankly, a terrible situation for life, for a few reasons:
* The core is most likely not composed or compounds making it suitable for life.
* There is most likely not geothermal activity.
* The Sun is extremely faint, so photosynthesis isn't easy.
What if the planet retained some of its gaseous envelope, as Brown has suggested? As a side note, this also arises from those theories that this planet is actually a rogue planet, although I'm not sure which one is more prevailing at the moment (I would think it's the former). We now have a [mini-Neptune](https://en.wikipedia.org/wiki/Mini-Neptune). This would mean that we have an envelope of hydrogen, helium, and water, ammonia, and other compounds in lower concentrations.
The possibility of life here is low - certainly not life as we know it. The best chance may be for life on a moon of the planet, which could squeeze out - pun intended - some energy from tidal heating, thanks to its parent planet.
But the odds of this are low - not zero, but low.
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An advanced technological civilization can survive and even thrive everywhere there's any matter to use. Fusion, anti-matter, etc. You can have whatever aliens you want there.
Biological water- and carbon-based life however would have about as much chance of existing/surviving there on their own as a molten-iron-based life-form would have on the surface of the Earth.
But let's be nice. Perhaps Planet Nine was once a nice, inner-system Neptunian World with an Earth-sized companion satellite. The planet itself is too big for Earth-like life. The oversized companion moon would have had lots of water, carbon, all the good stuff.
Later on, just a few million years ago, through an unfortunate interaction with a nearby star and Jupiter, Planet IX (locals call it Cthulhu) got expelled into the cold outer reaches. Talk about bad luck. The highly advanced civilization on IX decided not to invade Earth, which was lacking the requisite technological infrastructure. A small genetic modification was induced into one of the ape species on Planet III (the Waterplanet), as part of the IX-iforming process. The apes would build the industrial infrastructure, and the IXians would later come and use it once in place.
While they wait, 99% of the population was put on Cryo/Virtuality, and a small crew on a billion of the Elder race maintains the industrial plant and occasionally keeps an eye on those Earth-apes.
When the time is ripe, C̱͔̲̙̳͐̓̔̉ͭ̀t̨̾͋̀ͫͧ͒̚҉̮̟ͅḣ̛͍͎̰̬͇͉̫̆ͮ͛̌͌ͯu̴̬͚̼͇̰ͮ̍̋l̤ͮͦ̋̚h̰͚̜ͭͣͬ̊̒ͨͨ͆͡ů̯̜͓̪̉ͪ̄͋̔̈́ ̨͈̰͍̙̤̟͍͑ͤ̌͛̄w̪̳̣̣̌͊̂ͩͦį͎̣̤̥͕͎͙̦̍̀͊ͥ͂ͩl̥͓̖̪̥͖̦̼̦̓̾͑ͤ͗̅̏̃́l̏̓̈ͧ͏̱̹̫̙͕͔͜ ̯͖̗̦̠̯ͤ̑̏̃̈́ͨ̏̎͝rͧ̔҉͉̻̜͇̙̪i̶̬͖̠͔̼̖͒͗̉̂͊͝s̍̀̈́̐̿͋͏͎̜̻̦̼͙͖ę͈̂ͩ̔ͥ̓̓̾̕ ̈́̈́̆҉̶̡͕͓̞͇̬͙ậ͙͇̠͔͈̗̲ͯģ̯͍͕̳̿̊̋̓̈́͠à̷̡̱̹̞͐ͬ̾̈́̌ͧ͛i̵̷̴̙̳̲̦ͦͤ̂̈n̜̯͇̹̲͐̈́̋̈́̑͠
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The problem you will have is the absolutely ridiculous cold and lack of any energy source. Life needs a source of energy in order to be able to do anything. Even on earth our best [cold adapted life](https://en.wikipedia.org/wiki/Psychrophile) is limited to -15 or -20 degrees celsius.
We're not aware of any life based on other substances that are liquid at much lower temperatures, but that does not mean it could not exist. We just don't know.
Assuming carbon/water is the only option for life though then the only realistic way to get temperatuers high enough at this distance from the sun is geothermal in a planet or tidal heating in a moon. How viable that is would depend very much on the nature and composition of the planet.
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Imagine we have a multi-cellular 'mammal-like' species which is K-select and usually has only one young at a time. Now imagine that this single young regularly has multiple fathers. Specifically the mother may mate with multiple males and the resulting embryo having half of the mother's DNA but the other half of the child's DNA may come from multiple males the mother mated with. This species would likely have to have slightly different genetic encoding then our DNA, but you could imagine something along the lines of certain chromosomes came from male X, others from Y and others from Z, all combining to make up one half of the child's DNA.
I'm wondering how beneficial such a mechanism is, and how hard it would be to evolve in the first place. The species does not need to evolve on earth or be tied specifically to earth's method of encoding DNA, or even using DNA, but should evolve under similar pressures to earth and result in something similar to a mammal in basic functionality.
I'm mostly wondering if this species could exist, or if there is any evolutionary hurdle that makes it impractical I'm unaware of, though any thought into how a species like it could work would be welcomed. For example the main questions that come to mind are:
1. Would such a species be able to evolve and gain evolutionary advantage from having more diverse genetics?
2. Is there a limit to how many fathers could provide DNA or how intertwined different parental DNA strands can be?
3. Could such a species exist with either conscious or subconscious mate selection, ability to prefer use of DNA of a preferred male?
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Two-parent sexual reproduction gives a maximum of a roughly 50% increase in the progeny's genetic variability over binary fission. To add a parent and have three parents, you get at most a 66.6% increase in variability, with four parents, you get a 75% increase in variability, with five you get an 80% increase in variability, and so on. This approaches a limit of 100%, but never gets there.
The *actual* increase in variability depends on the differences between the parents.
However, having all these additional parents has a cost in that they must be mustered to provide their genetic material at the appropriate time, and the more parents, the harder to arrange.
So, from an evolutionary point of view, the greatest advantage comes from 2-parent reproduction, and with the diminishing returns and additional complexity of higher numbers of parents, having higher numbers of parents is of a lower degree of fitness than just two.
However, evolution is 'survival of the adequate', so if a three-sexed reproductive system occurred in the absence of a two-sexed system, it would likely provide sufficient advantage to be retained in future generations. However the likelihood of this is quite low, but not beyond the bounds of all probability.
In addition, such a three-sexed reproductive system would be vulnerable to competition by newly occurring two-sexed species which can reproduce faster and more easily.
**EDIT**
It is generally not possible for a female to provide 50% of DNA and for an arbitrary number of males to provide parts of the other 50%.
You may have a situation with a genome having a [ploidy](https://en.wikipedia.org/wiki/Ploidy) of 2N, where male and female contribute equal amounts of DNA (N each).
With a ploidy of 3N, the female may contribute 2N and one male contributes N, or the female and each of two males contributes N, or the male 2N and the female N.
With a ploidy of xN, (where x > 3), there are many combinations of what multiple (m where sum(all m) = x) of N the female and each male involved (up to x-1 males) contributes. You cannot have an *arbitrary* number of parents; the system will dictate that there are *specific* numbers of each sex involved.
To violate ploidy typically results in either death of the offspring or a greatly reduced fitness.
Consider bananas: the ones we eat have a ploidy of 3N, resulting in the seeds being very small and infertile. Otherwise, if we were eating 2N ploidy bananas, we'd be spitting out the pips. This means that cultivated bananas *cannot generally reproduce without human assistance*. This is a typical minimal consequence of violated ploidy.
Another example is chickens: They are typically 2N, but they can reproduce [parthenogenetically](https://en.wikipedia.org/wiki/Parthenogenesis), resulting in N offspring, which are - on the rare occasion when they hatch at all - considerably less healthy than their parent.
Since evolution will typically configure an organism to have a certain amount of genetic material, having 50% from a female and 50% from an arbitrary number of males would require some sort of mechanism to select *which parts* of the male 50% to take from each of the arbitrary number of males. This is highly unlikely to evolve naturally.
If such a reproductive system was to evolve, having 2 parents would provide a 50% advantage in variability as normal, 3 would provide at most 62.5% advantage, 4 would provide a 61.11% advantage, 5 would provide a 51.56% advantage, 6 would provide a 50.16% advantage, and so on, approaching 50%.
I had to run these numbers several times to verify that they were correct; it seems that the advantage is greatest with two fathers, and actually decreases thereafter. It seems counter-intuitive, but that's how the math works out.
It is more likely that if an arbitrary number of males contribute to the genetic makeup of a female's offspring, having 1 male parent would result in 50% of the offspring genome originating with the female, but having 2 males would mean that the female and each of the males contributes 33.3%, or 3 males means that each parent contributes 25%, and so on.
In the latter situation, the more males fertilise the female, the less the offspring would be related to the female, and hence it would not make evolutionary sense for the female to allow more than one male to mate with her.
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Taking the questions one at a time:
1. Would the species be able to evolve and gain evolutionary advantages?
Yes, but evolution would likely be even slower than it is on Earth. Any time that you're passing on genetic information, evolution can happen, but the problem here is that we don't know whether information IS being passed on. Consider the case where there are three fathers, just as an example. Each father gives about a sixth of the offspring's genetic code (a third of the male half). Now, suppose that one of the fathers had some evolutionary advantage from sheer random happenstance. Even supposing it's a dominant trait, there's only a 1/6 chance that it gets passed on - if the code for it was in an sequence that a different father provided, it's not helpful for the kid. An interesting corollary here is that evolutionary changes go faster when the mutations occur in the females, because then they're more likely to be passed on.
2. Is there a limit to how many fathers there could be?
Theoretically, we'd have to go into deeper detail on how exactly the reproductive process works -- does the paternal mixing bowl take place on a chromosomal level? A sequence level? A base pair level? Whatever the minimum level is, the upper bound on the number of fathers is however many "blocks" of that minimum level there are. If it's on a chromosomal level, then (assuming similar genetics to humans) there could be 23 fathers (one for each chromosome). If it's on a base pair level, there could be a hell of a lot more. Practically it comes down to how much sex the mother can have -- how many sperm can she get to her egg.
3. Could such a species exist with conscious or subconscious mate selection, the ability to prefer use of the DNA of a specific male?
Realistically, doubtful, if only because that (as far as we know) isn't how genetics works -- no amount of wishing is going to manipulate the genetic code of the fetus growing inside of you. However, if you're making this world, you make the rules, so if you wanted that to happen then go for it. I would say that subconscious would probably work better than conscious choice, if only because that way you don't end up with people crafting humans for specific purposes, but it's your choice.
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I think it would make more sense if you had one "female" gender and a previously selected number of "male" genders. These males would each provide some parts of the child's DNA, while the mother gives the child the rest of the DNA and births it. However, you would need to have some way to differentiate between these "male" genders.
Each different gender could have something it's better at. Now, while this isn't totally true, bear with me. Men are generally more muscular and stronger than women. Women are more articulate and detail oriented. For your species, one male gender could be physically strong, another extremely intelligent, and a third would have heightened senses. Then you'd have the mother, who would be more like a regular human woman.
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In a story idea I have, there is a race of humanoid creatures that evolved on earth from organisms that originated from another part of the universe and possibly another dimension. Their brains are unnaturally advanced and they seek to learn all that can be through experiments, sometimes at the expense of innocent people.
My idea was to include my own concept of arcane. In the story, the race's definition of arcane is something that seems impossible to those without the knowledge of how to do it. For example, conjuring a ball of energy would be preformed by, say, thinking of a certain alien image while twitching fourteen specific muscles in a quick sequence, or something like that.
That way I could get away with saying that magic is just things that normal people are mentally incapable of thinking of, as it would break their understanding of reality and induce insanity.
Thoughts?
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That's pretty much all that magic is anyway.
If you were to go back in time and show people something that we would consider entirely innocuous and mundane, like a projector projecting a video onto a screen or a wall, they would likely call you a wizard and a conjurer of images.
Somebody else advanced coming from the future to our time (or in the case of your story, another race, which I'm assuming is set in the present) and summoning a ball of energy is something that we would consider magic too, simply because we don't have an explanation for how it has been accomplished.
The only reason that the myth of magic has been dispelled in our society these days is because most things that we may have considered magical we can now do with science and technology (conjuring fire in the palm of our hands can now be accomplished with a lighter that we can purchase with pocket change).
In terms of writing, most writers setting things in medieval era can get away with things just being 'magic', because within the context of the setting the characters would understand it simply as that, without needing an explanation.
Setting stories in modern day cannot get away with this, as most in society understand that magic is not real, therefore people using magic would be questioned by everybody, so this would either need to be part of the story or would break the suspension of disbelief.
Therefore in a modern setting I would **strongly encourage** that you have an explanation for how magic works. There are other ways to have believable magic in modern day settings, but having another race that can control energy with muscle movements and thoughts that humans physically cannot perform is a good idea, so long as the rules of your world remain consistent.
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One of the dangers I worry about when I see questions like this is that you're trying to world build yourself into a story rather than building a universe around the story you want to tell.
* Start with a great story. World building can help you get there to some degree, but once you have a story to tell then give the world building part a break and get on with the story.
* Make stuff up about how the magic works - don't worry about figuring out the exact scientific mechanics of how it would work... just make it up. You're the author, so you get to do things like that.
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In the world I am building there are rat-like primates called iolasae, or mane-beast, which are the new world equivalent of great apes. In this family of primates there are sentient humanoid creatures called lokk, They have digitigrade legs, long arms, short legs and prehensile tails. I would like for them to have two [prehensile](http://dictionary.reference.com/browse/prehensile) tails. Is it possible and if it is how much weight could these tails support?
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## **Yes, but..**
...the animal probably won't be very big.
While not a prehensile tail, an elephant's trunk is capable of [lifting 300kg](http://www.elephantsforever.co.za/elephants-faq.html#.VdIimhRVhBc) and it contains no bones whatever. Note that an elephant's trunk is attached to an absolutely enormous animal of around [4535kg](http://www.elephantsforever.co.za/elephants-faq.html#.VdIimhRVhBc) for a lifting capacity of 6% of body weight. On the smaller end of the scale, a [spider monkey](https://en.wikipedia.org/wiki/Spider_monkey) is completely capable of holding itself up by it's tail alone. Note that this follows the trend of smaller creatures lifting many times their body weight, such as [ants](http://www.treehugger.com/natural-sciences/ant-weight-lifting-champ-hoists-100x-its-own-weight.html) lifting 100x their body weight.
[](https://i.stack.imgur.com/gAyuz.jpg)
## **But two!**
An animal could be designed to have large powerful prehensile tail(s) but it would need to be designed that way and supported by an interesting evolutionary history (if your story needs that kind of evidence). I'm not sure of an examples of an Earth animal with two tails so that will be a very interesting evolutionary history. There are many instances of Siamese twins that have convergent or divergent spinal columns. Having two tails is definitely possible, it's just a matter of making them that way.
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We've created a series of mechanisms to terraform the temperature and atmosphere to be Earthlike. My geologists are screaming at me, because a lot of features are being rapidly eroded by the new hydrological process. Anywho.
**I still don't have soil.**
Our agronomists are great with hydroponics, but to plant small trees and root-based plants, I need real soil. [Soil formation takes time and organic processes](https://worldbuilding.stackexchange.com/questions/15364/resources-to-justify-long-distance-space-mining-missions/15369#15369). A lot of both; neither of which I have. And while we really scored with the atmospheric science, we haven't progressed past 2015 for 'creating soil;' **how can I get the massive amounts of needed soil**?
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Note 1: I read the book, The Martian, where he makes soil for potatoes from poop and Martian regolith. I was skeptical, and a friend who worked at the National Resources Conservation Service (specifically with soil survey), said, "That simply can not happen; that much soil would take forever to become viable." And a lot more than just poop\*.
Note 2: I was admonished ([down-voted](https://worldbuilding.stackexchange.com/questions/15364/resources-to-justify-long-distance-space-mining-missions/15369#15369)) for stressing the importance of soil previously, so my question is not whether we need it; it's how do we get it.
Note 3: \*- I look forward to the day that poop gets its own tag, since I've seen it in WB frequently. [ Done. —ed. ]
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There is a good treatment in [*The Martian*](https://en.m.wikipedia.org/wiki/The_Martian_(Weir_novel)), where he uses his own *night soil* and composting all organic waste. With geometric growth it will cover "land" in short order, given water and labor to spread, mix, and prepare. (Weir's characters all refer to all dead regolith/crushed rock as "soil" too, which bugs me).
Heinlein's *Farmer in the Sky* describes the work of doing that on a holmstead-sized scale.
What's your friend have against it? It might be just fine *in a closed planting box*. It also doesn't need to be self-sufficient as an ecosystem, just allow the plant roots to work. Plants can be grown hydroponicly, so a large planter is possible.
In general, you want to carefully prepare both the microbiome *and* other self-replicating agents that extract power and resources *in situ* while doing the task of mixing and spreading further. E.g. earthworms, grubs, and various bugs.
Given crushed mineral matrix as a pre-existing starting point, you need to add water and inoculate the biome. If optimally mixed/layered/tended it will double in a few days, and you can divide that and repeat.
Using plots larger than you can tend explicitly, you want a small, patch to grow outward, which will be less efficient moving from soil to plain rock and only along the border which is growing linearly not geometrically.
So you improve it two ways: transplant into new disjoint patches as much as you can, and somehow coax it to spread in a fractal pattern.
RAH's farmers made stripes which grew together. How about controlling the irrigation to lead the growth in a pattern? Also engineer the "bugs" to cause dispersion to new areas.
Back to your friend's objections regarding the time scale and input. First, you are a well-prepared mission not a castaway with nothing but his own poop and one living plant. You can have a complex mix, *multiple* different mixes for different stages, and even engineered species.
The difference between "big pot" and "self-regulating ecosystem" is not all or nothing. For good story, you can imagine managing the *degree* of hands-on regulation needed vs. the size that can be handled with available labor and logistics.
Amending the soil while plowing and planting, adding fertilizer to irrigation, and weeding and checking pests, is all *normal* in agriculture which is more productive than nature. If you can add stuff— nutrients or new bacteria and fungi— to the irrigation water, you can easily give it whatever it needs on a day-to-day basis. So maybe you don't need anything more than crushed stone, essentially doing hydroponics on the ground.
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This actually sounds like two unrelated questions: How do I stop erosion?, and, how do I transition from hydroponic agriculture to soil based agriculture?
For a fast means of providing ground cover, I might suggest that the ecological engineers start tweaking bacteria to create a strain (or strains) which form biofilms which cover the landscape. As a bonus, the bacteria start the process of terraforming soil and provides a source of nutrients for the next "generation" of ground cover. As noted in JDługosz answer, the cover should be spread in a fractal or checkerboard pattern to maximize coverage and infill.
For feeding a growing population, hydroponics and related techniques provide a compact and reliable means of providing food for the colony. Since we are living in a closed ecology, diverting poop to reconstitute soil outside of the colony is actually not a viable course of action. the waste materials will need to be processed to recycle the nutrients and water back into the system.
This also means the growing population will need to be mining the Martian crust (and possibly asteroids and Jovian moons) for minerals and trace elements to increase the capacity of the system. Some of the materials will also be diverted to the Martian surface to build the soil (although the timescale on this may be a millennium).
So the Martians will be spreading their bacteria on the soil for a millennial soil building project, while keeping their internal economy internal to provide food and oxygen to the colony. Even the external vegetation for the successive phases of terraforming will be "imports" in order to keep the closed cycle life support systems viable.
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Mars already has dust fields.
Add water to the dust and you get mud.
Add seeds to the mud and you get plants.
Wait for a year and you get dead plants.
Spray the fields of dead plants with the right bacteria and they will decompose back into the dust and you will have soil.
repeat this process for a few years and then it will become self sustaining. The soil will gradually get deeper and richer like earth.
Plants grow in mars dust:
<http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0103138>
Select carefully the most suitable Earthplants, or even genetically engeneer them to increase the effectiveness of this plan.
But then, if plants grow in mars dust, why did you want soil?
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Your friends objection is irrelevant. We are teraforming a planet with near future technology. "Quick" is not in our mission statement. So go back to your friend and ask what he means by "forever". If this is shorter than "we need more waste than 200 years of hydroponics would generate", there is simply no concern. It will take a long time, but we are in a slow process.
Your geologists objections is a bit weird. Almost certainly any plant growth and athmosphere will start in protected environments. There should be minimal impact beyond our walls. By the time we are able to start moving plants outside, we will have decades of growth of plant matter that we allow to decay to form our soil. Also, we are terraforming Mars with near future tech, keeping any landmarks recognizable is probably not in our mission profile.
Rapidly terraforming Mars, ie. within a generation or so, does not seem achievable with near future technology. Soil is a problem, but my guess is that athmosphere is a greater problem. Deeper into the future we would probably be able to create soil rapidly from a combination of genetically altered plants that grow hydroponically and nanobots.
Edit:
I see that you specify that we get athmosphere "for free". In which case, yes soil production is a real problem. However, in respect to your linked answer, bringing soil from earth remains a poor solution, it's just too expensive to transport that much mass.
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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 [this question](https://worldbuilding.stackexchange.com/questions/8651/what-are-the-possibilities-of-a-dwarf-planet-orbiting-opposite-earths-orbit), it's pointed out that the L3 Lagrange point, where a "true" Counter-Earth would lie, is in fact unstable, and over time any object there would drift into a different orbit.
Obviously this means that if we're going to put a habitable planet there, we need to give it some means of station-keeping, to adjust itself as it drifts away from the desired point; this is how the [titular planet of the Gor series](http://en.wikipedia.org/wiki/Gor) remains in its orbit.
My question is, how much energy would be required to keep a habitable world in Earth's L3 point? Assume a world that's roughly 85% the mass of Earth, though an answer where any mass could be plugged in easily would be stellar. And let's not worry ourselves with the means just yet (let alone questions of efficiency in converting a power source into thrust), and instead just focus on the energy output required: How much energy do we need to expend to maintain our orbit?
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The scenario you have proposed has more problems than just the L3 point's instability. You also have issues with mass, interaction with other planet's gravity, and the shape of Earth's orbit.
Starting with the mass problem: In order for a Counter-Earth to exist, it must have precisely the same mass as Earth does. This is because orbital equations mandate that orbital velocity is a factor of mass and distance from the gravitational body. Assuming a circular orbit to simplify things...
$$
v = \sqrt{\frac{G(m\_1 + m\_2)}{r}}
$$
...where $m\_1$ is the mass of the body in the center (i.e. the Sun) and $m\_2$ the mass of the body orbiting it (i.e. the Earth or the Counter-Earth).
If you wish to maintain velocity with a smaller mass, you must move it closer to the body it is orbiting. The L3 point has forces that try to hold you at a similar orbital velocity, but they wouldn't be strong enough to hold an entire planet there. If your planet had a lower mass, and thus higher velocity than Earth, then it is going to have a wildly elliptical orbit with a different orbital period (meaning we'd have probably crashed into each other by now if we are in the same plane)
Orbital shape is also an issue. Since Earth sits in an elliptical orbit, in order to sit constantly in Earth's L3, Counter-Earth would need a matching elliptical orbit that is precisely the opposite of Earth's. Your energy needs for station keeping would vary depending on the time of year.
For a lower mass planet, with Earth's same orbital velocity, your challenge would be keeping the planet from sliding further out on Earth's orbital path because of its lower mass.
Now, on to the Lagrange Point issue. The L3 point is the spot at which Earth and the Sun's gravitational pulls line up, so there is no angular force tugging you off-station. Beyond that, it is your centrifugal force from orbital velocity that holds you on-station with respect to distance from the sun. With a mass smaller than the Earth, you would tend to drift further from the sun, so station keeping would mandate that you exert an force propelling you inward towards the sun. Further complications will be introduced by the orbits of other planets, particularly Venus, which will tug inwards.
Now...on to the math. Ignoring Venus for a moment, lets calculate the gravitational force generated by the Earth/Sun system that you are in the L3 point of. Note that I am also ignoring the in/out drift of Earth and Counter-Earth for this in the name of simplicity and am using the Average distance. If you want to calculate minimum and maximum energy requirements, swap out the distances for the Earth's aphelion distance and perihelion distance. (Remember to double the distance for the gravitational pull between Earth and Counter-Earth)
Force of Gravity can be calculated like so...
$$
Fg = \frac{G\*m\_1\*m\_2}{r^2}
$$
So, to get total Force of Gravity for the system...
$$
F = \frac{G\*m\*1.989\times 10^{30}}{149,597,870,700^2} + \frac{G\*m\*5.972\times 10^{24}}{299,195,741,400^2}
$$
Where $m$ is the mass of your planet and $G$ is the Gravitational Constant, $6.6726\times 10^{-11}$
Plugging in the '85% Earth Mass' value that you gave, we get a force of gravity equal to $3.0119\times 10^{22}\text{ N}$. In order for our planet to neither fly away, nor fall into the sun, we need for its centrifugal force (+ generated force) to be equal to the force of gravity.
So, calculating the natural centrifugal force of our planet, moving at Earth's orbital velocity renders this equation:
$$
F = \frac{mv^2}{r}
$$
For the sake of simplicity, we are going to ignore the fact that the orbital center is not the center of the sun...it's a little bit off, but not by much. So, plugging in values gives us this finalized equation...
$$
F = \frac{m\*30,000^2}{149597870700}
$$
Again plugging in our 85% mass, we get a Centrifugal force of: $3.0539\times 10^{22}\text{ N}$
This leaves us having to make up for $4.2015\times 10^{20}\text{ N}$ of Force on a constant basis. These forces give the planet an outward acceleration of $.0000828\text{ m/s}^2$ (using $a=\frac{F}{m}$). Calculating for displacement using...
$$
x = vt+.5at^2
$$
Shows that our planet will attempt to slip off station by $.0000414\text{ m}$ every second. This is a quite small number, but we have to keep it perfectly balanced. The further we slip from the sun, the weaker the cumulative gravity of the sun and Earth is, so the faster we'll fall away. And if we fall away, our orbit will restabilize with a higher eccentricity and a different orbital period...likely ending in gravitational interactions with Earth that will either cause a collision or fling one of us out of our orbit (chaos theory, yay)
So, calculating our energy requirements, we convert over to joules.
$$
J = F \* d
$$
Plugging in values, we need a constant feed of $1.739\times 10^{16}$ joules (17.3 petajoules) per second ($1.739\times 10^{16}$ watts) to maintain our position.
This works out marvelously for a basic 3-body problem...as long as we are ignoring the effects that this other planet has on Earth...and every other planet in the Solar System. Venus would be the biggest troublemaker, applying anything between $2.421\times 10^{16}\text{ N}$ and $2.863\times 10^{18}\text{ N}$ and is usually not pulling in-line with the Earth/Sun arrangement. This is going to require further adjustments as well to keep it all lined up. And again, you can't drift in or out...if you do, your instability will grow exponentially. To roughly ballpark your energy demands, I'd suggest tacking on a few extra petajoules as your upper end, and understand that you are likely to have to vary your output and direction constantly. Also note that this is joules of kinetic energy...I'm ignoring energy waste here and assuming perfect conversion to kinetic.
You said not to worry about 'how,' but 1 petajoule is about equal to the biggest boom ever made by humans: The [Tsar Bomba](http://en.wikipedia.org/wiki/Tsar_Bomba). We need that much energy every second.
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As I understand this problem, the amount of energy needed would be dependent on the accuracy and responsiveness of your guidance system. If you keep it exactly on coarse then the amount of energy to keep it on course would be very small because the gravity pulling it in either direction would be equal. It's only once it deviates significantly that it becomes a massive job to move it back into position.
<http://www.reddit.com/r/askscience/comments/1lxms5/why_are_the_lagrange_points_l1_to_l3_unstable_but/>
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I’m currently working on fantasy setting with a strong focus on sea based adventures. To try and make the setting clearly different from Earth I thought I make large landmasses virtually unheard of, with numerous small island being common instead.
Are there any rational ways I could explain why this is so besides the lazy ‘a wizard did it’ excuse? Additionally is there any logical consequences I should be aware of in regards to weather and such on the islands?
On a final note, are there any features I could use to create natural or unnatural barriers to travel between different area of a vast global ocean?
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There are several novels about ocean planets or planets with only small islands. I never felt it needed any kind of special explanation. If the Earth had only a bit more water, we'd have something like an island planet, because only the mountain ranges would look out.
As for the weather, there are two things that I can think of. There is a lot of rain on islands because of the surrounding mass of water. Look at pacific islands.
And there will probably be a lot of wind, always from the same direction (East). The Earth's rotation is causing the atmosphere to "slip", and on the surface that "lag" of the atmosphere is perceptible as wind. On the Earth that planet-rotation-wind mostly happens in high altitudes, because mountains and the high and low air pressure areas that are caused by the land masses break that wind closer to the surface. On a planet with a plain and uniform surface there won't be anything breaking the wind and it will be strong and continuous. On Earth, that wind is called "[trade wind](http://en.wikipedia.org/wiki/Trade_wind)".
Vegetation will adapt to that wind. On Earth you can see this in [windswept](https://www.google.com/search?q=windswept&tbm=isch) trees, or, if the wind is stronger, in trees only growing in the cover of ridges.
There will also be a lot of rain on the windward side, but only to a cetain altitude. Above that will be very dry.
The [source page for that image](http://www.wunderground.com/blog/weatherhistorian/comment.html?entrynum=73) explains the phenomenon in detail.
In genereal I would think that researching the climate of pacific islands will give you a good idea of what to expect on an ocean planet.
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Coming from one of the larger islands of the Pacific I can tell you that distance would probably be one of the biggest barriers to ocean travel. Typically the pacific Islands are volcanic due to the ring of fire surrounding most of the ocean. This gives the area a very large number of small islands that, while very fertile due to the volcanic soil, are lacking in resources normally needed for long ocean voyages. This would result in smaller boats (two to ten people each) as opposed to the larger ships that Western Civilisations used to cross the Atlantic / Explore the pacific. Even the Maori Waka Taua (War Canoes) which would have been some of the biggest boats in the area until Europeans arrived were mostly used for coastal travel and in rivers. [Wikipedia Article on Maori Waka](http://en.wikipedia.org/wiki/Waka_%28canoe%29#Waka:_traditional_construction "Waka on Wiki")
Worth noting that the largest Waka could potential hold up to 80 people, but they were used for warfare (which traditionally was with other coastal tribes) and had to be prepared for years before the tree was cut down. Even these larger canoes weren't used on the open ocean.
If your world consisted of islands that were really just the peaks of undersea mountains formed by tectonic movements and not by volcanic eruptions; you'd probably be left with less fertile soil and less resources to dedicate towards unnecessary exploration.
What you'd probably end up with is many smaller groups of people doing very well for themselves on the islands they've settled on, but not putting too much effort into leaving for places unknown unless they had no choice. People would only venture onto the ocean if their islands could no longer support them. Inter-island trade would be fairly common, but only with islands in the area.
Add to that, the faster winds resulting from having no major landmasses to block them, and you'd find ocean voyages much more dangerous than Real Earth. Higher winds would be a much bigger challenge than normal in a small boat, and if there was a storm while you're on the open water you'll find the waves much bigger and the winds even fiercer.
I don't think you'd need to add any major obstacles (natural or otherwise) to discourage people from leaving the safety of their islands. Just lots of room.
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A simple way to explain the prevalence of small islands would be to have the book set in, well, an area with small islands, and then use the explanation that areas outside the group of islands are unexplored. For example, if the story was set in the Pacific in the distant past, the natives of the area would have been exposed to the islands created by the Ring of Fire but very little exposure to the larger continents.
Which leads me into your question about weather: small islands are usually formed by volcanoes.
For barriers, you could use large reefs or other underwater structures providing hazard to ships, or possibly heavy fog (see also: Legend of Zelda).
Hope this helps.
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A interesting insight into some of the logical effects of geography on culture and politics.
So if I go for the mostly volcanic origin for the islands, they are unlikely to lead to cultures that would expand much or build large ships because they lack the resources to build, but would likely be rich in term of agriculture?
So logically a volcanic island heavy world would likely lead to lots of small communities, with a tendency not to travel much… but that would make the few larger land masses extremely important from a tactical resource point of view.
I do want to have a few small scale empires in the setting, but it seems I will have to make sure they all have a valid reason behind there ability to become ocean going powers when no one else could. Course since my setting is a fantasy one, it does mean I can use magical reasons (like say a orb that lets you control the weather), but I think knowing the base hard geography underneath is important before you throw any magic into the mix!
I also like the idea of a island resources being pushed too far and causing some kind of political upheaval….
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Often in science fiction, writers attribute the enormous energy capability of an advanced civilization to Dyson spheres. I've never heard of a detailed schematic of how the energy from the star is utilized. My question is "What is the most energy absorbant form of a Dyson sphere?" Would lining the inside with solar panels be the best option? What about a water heat transfer? Also, what would the most cost-efficient way of transporting this energy be? Long wires? Microwave electricity (Look it up. It's awesome.)?
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Nothing will be 100% efficient.
It will certainly be **solar panels**, *if* the end product is electricity. Using [carrier multiplication](http://en.wikipedia.org/wiki/Multiple_exciton_generation) and [radiative recombination](http://en.wikipedia.org/wiki/Carrier_generation_and_recombination) the [maximum theoretical conversion from sunlight to electricity is 86%](http://en.wikipedia.org/wiki/Thermodynamic_efficiency_limit).
At least we can do better than nature. Plants, through photosynthesis, [max out at 11%](http://en.wikipedia.org/wiki/Photosynthetic_efficiency) for our solar spectrum.
Depending on the output energy type, other technologies might be used to cut out the photoelectric effect middle-man. But 86% is pretty good and it might just be simpler to use the gathered electricity to generate the other energy types.
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Yes, I think our best option to capture the sun energy will be **solar panels**.
In his book "**[The High Frontier: Human Colonies in Space](http://en.wikipedia.org/wiki/The_High_Frontier:_Human_Colonies_in_Space)**," **[Gerard K. O'Neill](http://en.wikipedia.org/wiki/Gerard_K._O%27Neill)** mentions some alternatives like mirrors combined with different gases; but our current solar technologies have become a lot more efficient and cheaper during these years.
Also don't forget that solar panels are a lot more efficient in space, because the almost continue exposure to sun and inexistant clouds or atmosphere.
As for the transmission of energy, we could use microwaves or laser rays, both of them transfer the energy in highly efficient ways.
Don't think that the idea of building a Dyson's sphere is too far away in the future, how hard could it be to build several small satellites exclusively to collect solar energy? Also if we already have space stations in our time, what could we do in the future with asteroid mining or moon mining?
I even think that we will start building satellites to collect sun energy and with time also space stations (eventually space cities) and this complexes will evolve in huge orbital hives that eventually will become our fabled Dyson sphere.
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All of the energy of the sun is contained within the Sphere. If the wall was too good an insulator the insides would eventually cook. You could use the temperature difference between the inside and outside to generate power.
In addition, unless you enjoy constant sunlight, you would need something to provide shadows for 50% of the time. Either mirrors to direct the sunlight to a solar furnace or solar cells to collect it directly could be used. Assuming that's 50% of the suns output gathered at any one time... that would be quite a lot of energy.
I would think it getting too hot (too much energy) within the sphere would be the greatest problem.
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I have to disagree with majority on the solar panels. It is almost impossible (not quite since we are assuming superscience anyway) to build a solar panel that absorbs the entire spectrum output by the star efficiently. Solar panels also do not absorb the energy of the solar wind and are in fact damaged by it which would require significant energy to be spent on maintenance. You also need to consider the energy needed for manufacture and technology that requires precise patterns of specific materials can't be that efficient if the scale is large enough you need to worry about material supplies.
Instead build an inner shell that receives the energy that the star puts out and is heated to thousand degrees or so. The material or structure is not sensitive, but higher the temperature your alloy or ceramic can sustain, higher the efficiency. And the structure should be robust enough not to need constant maintenance and conduct heat relatively well.
Then build an outer shell radiator that probably also needs decent thermal conductivity and reasonable robustness (should be able to survive impacts from micrometeors left over from construction).
Then put insulation (mostly vacuum and some reflective surface) and a heat engine in between the two shells. The heat engine will maintain a stable and high temperature differential and generate energy from it.
You also need a system to stop the sphere from colliding with the star. I think a system of light sails you can spread over the inner surface to use the light pressure to move the sphere would be sufficient. The energy loss is minimal since the reflected photons will simply go heat the surface of the star or some other part of the sphere. And this requires no propellant. Besides you need some system to shut down sections of the sphere for repairs anyway.
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Imagine surviving in a modern day densely populated city where there is a recent zombie outbreak...
The cause of infection is identified to be a type of fungi, this fungi contains a unique unknown chemical that can survive in strong acidic environment such as our stomach. The chemical will be easily absorbed into our bloodstream and trigger a nasty response in our nervous system it is also known to evade our immune system completely. The chemical spread via blood vessels and capillaries and it cannot be spread by having a skin contact with an infected person.
This chemical will invade every cells in the host body therefore my question is can I save myself from becoming infected by severing off a limb that is bitten by a zombie?
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I can't imagine any way this wouldn't work on an "expendable" limb. I think the question truly becomes how fast does it need to be done. If it's spread through the blood, then it's going to come down to how fast your heart is beating and how quickly it spreads. While I couldn't find any hard numbers to go with that statement, I'm sure they're out there. This quote from tvtropes kind of gets the idea across though:
"Sometimes when sucking out the poison isn't enough, someone simply cuts off the limb in question, above the problem. Naturally, this is not recommended in real life as blood flows faster than an arm or leg can be cut off, amputation is dangerous enough as is, and amputation to prevent infections are an old and largely outdated medical practice." - <http://tvtropes.org/pmwiki/pmwiki.php/Main/AmputationStopsSpread>
Hardly a scientific explanation on the matter, so perhaps someone can go into the details on that. In short though, if you have a tool capable of taking the limb off quickly enough than theoretically sure, you could stop it, it's just unlikely you have such a tool.
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For what it's worth:
I don't have a reference, except a description in [Jadoo](http://rads.stackoverflow.com/amzn/click/1933665734), a book by John Keel. I have no particular reason to think that this book is accurate in any particular - it seems, if I'm recalling it correctly (I read the book a *long* time ago) to be a sort of hybrid of Baron Munchausen and Aleister Crowley - in other words, largely invented. However: even books of tall tales usually have an underlying layer of accurate observation, upon which the fabrications are built. This bit is more plausible than most.
Keel describes cobra catchers in Egypt carrying straight razors as part of their field kit. In the rare case of an unfortunate accident, they will promptly lop off a finger that gets bitten by the cobra.
**This is actually a reasonable proxy for your zombie bite.** Cobras have a documented tendency to *hang on and chew* rather than delivering the lightning strike characteristic of [vipers](http://en.wikipedia.org/wiki/Viperidae) with their more effective hypodermic fangs. From the [Fascinating Earth article on the King Cobra](http://www.fascinatingearth.com/node/252):
>
> Scientists estimate that the king cobra, with large poison glands containing highly potent neurotoxic venom, can deliver 120 times the amount of venom needed to kill an adult human. Moreover, to make sure it delivers an ample amount, the king cobra hangs on when it bites, chewing away at the wound so that the venom penetrates.
>
>
>
Again, I don't know whether Keel's account is truthful; but it certainly is plausible.
If cobra catchers really do use emergency amputation to save themselves from the highly toxic venom of cobras, then it would follow that emergency amputation would be a reasonable means of preventing your postulated zombification.
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Imagine a present or near-future setting where there is a breed of humans (lets call them elves) that can live up to around 400-500 years old. After puberty, their life is simply extended.
These long-lived people would impact the economy, from retirement plans to life insurance to healthcare to inheritance to a black-widow opportunist that just outlives her husbands. Assume they have the same rights as others.
What would be the impacts, and what laws or measures could be taken to lessen the impacts?
I am still unsure if they are a separate ethnic group or random births among human population. If it makes a difference in your answer, you can assume one or another. Also, they are no different physically from a human. Only genetic testing (and the obvious fact that they look 4 to 5 times younger than their age) can distinguish them.
But the world has been aware they exist for some time, and all those "*are they human, do they have rights/soul/go to hell/heaven*" discussions have already been settled. They are people, they can suffer some prejudice from random groups, but the population at large know they exist, and have adapted to them. My question is about this adaptation, in the economy dimension.
These measures should not create a second-grade citizenship between the elves and normal humans.
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## Retirement Plans
Obviously retirement vesting would have to change. The long-lived would have to work a good four hundred years before retiring for the system to have any chance of working. Since the long-lived would outlive many corporations and some governments, it is less likely that they will accept defined benefit plans and more likely that they will do their own saving.
## Young Adulthood
You say that aging slows after puberty. For our purposes, consider young adulthood to end at twenty-five. So how long does it take to get to twenty-five in development? The same twenty-five years? Seventy-five is probably about right if it's proportionally longer after puberty. Anything in between can be justified.
If young adulthood is longer, then something special will have to be done to handle things like voting and the drinking age. Otherwise, you'd have the equivalent of a fourteen-year old able to vote and generally make adult decisions. Can't drink until the equivalent of fifteen.
It's also unclear how much of age is experience versus physical changes.
## Accidents
Accidents will almost certainly stay the same on an annual basis after the initial adjustment (accidents are more common among the young and then drop around twenty-five). The much longer adulthood gives far more time to have accidents, so fewer would die of old age.
## Life Insurance
Life insurance would be cheaper on an annual basis but more expensive on a lifetime basis. Not much if any cheaper during most of adulthood but distinctly cheaper during the senior years. Note that this is for term life insurance. Whole life insurance spreads costs out better, so it would be cheaper sooner.
## Healthcare
Well, accident costs will increase. As will many diseases.
It's unclear how it will affect healthcare otherwise. Will cancer rates, etc. stay the same? If so, healthcare would get more expensive as cancer's a cumulative probability. The longer you live, the higher your chance of getting cancer.
Another possibility is that the chance of getting cancer over a lifetime will stay the same. So it will get cheaper on an annual basis while keeping a similar lifetime cost.
I'm assuming that aging related diseases will stay proportionally the same. So Alzheimer's, etc. won't take effect until proportional ages. These will increase in absolute terms but take a similar portion of lifetime earnings.
## Intermarriage
There would be many challenges in a marriage between the short and long-lived. That distinguished older gentleman that she married becomes the seemingly younger partner. She wants to retire, but he's still in his prime earning years (with a hundred year retirement for which to save).
How long do their children live? Are they short, long, or medium-lived? If medium, we have a whole new problem as that makes the actuarial tables even more complicated. Do all five eighths long-lived people live similar spans? Or do some live close to short spans while others live close to long spans? Can they even have children?
Note: it would be fine for the children to be either short or long-lived depending purely on random chance. How that might feel for the children could make for interesting subplots. Perhaps the eldest is seventy-five but looks twenty-five while the seventy-four year old sibling looks like a grandparent.
How would long-lived parents of a short-lived child feel? One long-life can easily produce eight short generations, outliving four or five. Perhaps two long-lived parents always produce a long-lived child. Although if that's so, the long-lived population would tend to increase relative to the short-lived population. They can have more children for a smaller investment of their lifetime. Perhaps modern birth control would slow that.
## Abortion
Would parents abort children who aren't long-lived? If it's genetic, it seems like it would be testable. This sounds like something controversial. Note that some nations ban abortions based on the sex of the fetus.
## Inheritance
Our inheritance laws are pretty flexible if you leave a will. This may impact spousal relationships though. How will a short-lived family feel to see their memorabilia going to someone who is not a blood relative who may not pass them on for generations? Also, how will things like family businesses work? One long-lived partner may live through generations of short-lived partners.
Inheritance laws that are pitched towards making sure that wives have something after their husbands die may change to add additional flexibility in the case of mixed marriages. Should a short-lived child who will be dead before the spouse is ready for retirement be able to get an inheritance now rather than never?
## How Long?
How long has this been happening? People from the sixteenth century could still be alive.
## Resistance to Change
The long-lived may be more resistant to change than others. The old are traditionally more conservative. The long-lived have more time to be set in their ways, and their ways may have developed centuries ago.
## Judicial Appointments
Many judicial positions have lifetime terms. A long-lived judge might easily have been appointed hundreds of years ago. Perhaps they still remember slavery as a part of normal life. Perhaps the entire Supreme Court would be long-lived. Stable but very static. The Dred Scott justices could still be on the bench.
## Concentration of Wealth
The long-lived may accumulate wealth over time. Since they rarely die, this may tend to concentrate wealth. For example, consider where we'd be if John D. Rockefeller was still alive. Also, the long-lived need to have more money, because they stay retired as long as five short-lived people.
This might create pressure for wealth taxes in addition to income taxes. Income taxes keep the rich rich and the poor poor. Wealth taxes attack concentration of wealth directly. However, wealth taxes also work against saving, encouraging immediate consumption.
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# A typical life span of an 'elf'
An incredibly important question to answer is how their learning capacity changes over time. At the speed of modern development humans have trouble coping with all the changes in society by the time they hit around the 40 or 50 year mark. Now, intuitively you might think that this would be similar to the 250 year mark for such an 'elf', but realistically speaking they would get 'stuck in time' just as much as the rest of us provided they don't have a significantly differently functioning brain (e.g. in one short story I wrote ages ago you had semi-immortals whose memory would only span the last 100 years and thus never got bored (or out-of-date)).
What would this practically mean? Their lives would typically be pretty similar the first 70 years or so, but after that point the jobs they would do would *relatively* speaking become simpler and lower class.
Now, of course 'elves' would somewhat adapt by choosing their specializations a lot more carefully then the rest of the humans and there are definitely some jobs more suited to 'elves' than humans (e.g. historians), but what you have to realize is that even those jobs would become more and more difficult and technology advances and they are virtually incapable of using whatever the smartphone or computer equivalent is in 300 years. True, you would have exceptions like celebrities or people who have hit the jackpot in some other way, but even those are in general subject to the whims of time.
# Effect on the economy
So, combine advances in technology causing more and more automation and the last few lower class jobs being taken by the 'elves' (as they could get the jobs before any competition was even born in the first place) this would leave no lower class jobs for the rest of society. In one extreme you could get a lot of pressure to make work optional in the first place (thus the majority would just get a minimal salary from the government) or the opposite extreme is that everybody of low intellect just dies of as they don't have the brains to keep up. Whatever direction you decide to go, it's mostly down to choices you simply have to make which have little to do with the 'elves' themselves and instead their presence just accelerates certain typical issues you have to think about when building a scifi world.
# So, what simple changes can be predict?
**Life-long subscriptions/positions/etc.** - Anything that's typically for the rest of your life will start to specify specific lengths instead. So you won't get updates to your application for the rest of your life and instead just for x years. Nor will you be a judge for the rest of your life, but instead you will be appointed for the next 100 years (why not for the rest of your life? Because the world changes and you don't want to get stuck with incompetent people).
**Life insurances** - Provided 'elves' can just as easily die of injury as humans do it will be a 'simple' recalculation of the risks involved, but in the end nothing really changes (the value of the life of an elf would be slightly higher than of a human life, though by the logic explained in the first parts of the answer it would be as much as you might intuitively expect).
**Children caring for their parents?** - If I understand it correctly this 'elf'-condition is non hereditary and occurs randomly. In that case the children of an 'elf' will of course die before their parents which will cause a lot of pressure in cultures where there is still an expectation to take care of your parents as children (unlike western societies where we simply lock our parents up in elderly homes or have them euthanized).
**Inheritances** - Would an 'elf' parent be allowed to 'gift' a child 'early' his inheritance without paying the huge tax penalties that come with gifting?
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First, you don't say what percentage of the human race this group is. If it is like 1 in 1,000,000 (or less) it will be different than if it is 1 in 1,000 or more.
There is also parenting, a woman could have 200+ years to produce offspring, a man (in theory) 4-500. Either could marry 5+ different (normal) spouses for 50 years each! Though it might be weird/terrible having your wife/husband age away, and many of your children die before you start to look old. This would likely cause many to seek each other out (especially after the first relationship when one discovers that they are long lived.
If they are very rare, then they will likely have a small impact on an economy unless they actually try to do so. As you pointed out they would have a much longer lifetime to accumulate wealth and be able to enjoy it. However, most people are not very good money managers. I would expect that however many there are %90 or more would die between penniless and a reasonably comfortable nest egg.
Now the 1-5% that are driven and capable can make a difference, though after the first 100 years they would likely take a seat behind the curtain so others really don't know how much influence they have over how much. They would work with proxies and likely be extremely powerful, maybe even buying a small country or two.
Dictators that happen to be 'blessed' with this gift could see their countries become the 'utopia' they dream of, though having a much longer life expectancy means they have a much greater chance of assassinations.
Now if the long-lived are a significant number of the population, then they will tend to gravitate to positions of power, both in government and business (there will just be enough with the 'drive' to take over) and as we can all see, those with power generally use it. So the long lived will not be '2nd class citizens', ever. Quite likely they will become the 'elite' whatever the rules/laws say.
Also remember most governments today have been around for less than half that 500 year life time. These people will see governments come and go, and being the 'wise ones' who've seen it all, will also help gravitate power in their direction.
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**There would be a second grade citizenship for somebody.**
My first reaction to the scenario is that unless it is an occasional aberration between two short lifers, the elf people are going to become the dominate species on the planet. It will go from humans liking the new elves, but as the elves become more prominent in society, the humans will start to become more biased toward them, because the elves represent a threat. And the elves will start to become more bias towards the human, considering them something less then an elf.
Whatever it is that makes the elves live longer is in their genetics. Elves would tend to mate with elves since they would want their children to live as long as they did. Maybe not so much at first because there are not many elves to pick from and humans and elves still get along pretty good. However as time passed and more elves were around they would tend to mate with each other with more frequency.
My rudimentary understanding of how cells work, is that cells contain a clock work of sorts and a mechanism that limits the number of times a cell splits. When the mechanisms fail, we develop cancer. Essentially the cells reproduce erratically and grow into tumors and such. The elves would simply have this cancer like quality to their cells, but instead of the cells growing into unhealthy body mass they would be healthy cells that kept the elves healthy, young looking and long living. The traits that made this possible would need to be passed on from elf to elf with reproduction.
The elves would first segregate from the humans in small and large ways than they would dominate the humans and eventually the humans would become so marginalized that they would cease to exist as a society and eventually die out. It would be an evolutionary event, similar to others in human evolution were the once dominate humanoid just became a trace in our genes.
Two things are very strong factors in the elves coming to dominate just by virtue of their long life spans, Acquisition of wealth and power, and reproduction. Humans will simply not have the time the elves do to do these things. When resources become scarce, and they well, the elves will win the day and eventually the world. Human kind will have evolved in to elves, and the short lived will be no more.
Society would be very different then it is now. Marriage would be out, retirement would be different depending on the resources society has. It would be difficult for most of the people to acquire enough wealth to retire for a long period toward the ends of their lives.
* Marriage
This is an institution that will dramatically change. It will not be idealized as the lifetime commitment that it is now. It will be some kind of commitment that is relatively short compared to ones life span. It may not exist at all. Elves will engage for a few decades to a one night stand to reproduce. How long they might stay a family would just depend. But certainly with youthful urges not many are going to last for the 4-500 year duration of life. It maybe something you do many times over the course of a life. With the number of children possible to have and the number of decedents possible to be living during your time family is going to take on whole new dimension's that may or may not be important to a elf.
* Retirement-work-death
Retirement at the end of a long life like we know it now is simply not going to happen for most people that live 4-500 years. The genetic clock running out is not likely to be the cause of death for most people. Untimely deaths due to accidents and disease will kill many more people then old age. Planning for retirement may very well be considered an exercise in futility for most people.
It is extremely difficult to come up with a number for people that die accidentally. About 250,000 of 2.4 millions of Americans who die, die accidentally each year. Of everyone who dies in a developed country, 7 out of ten of those deaths are people over the age of 70. With that in mind we can say that accidents and disease account for about 30% of the death rate each year, or about 800,000 people die of the 300,000,000 in the US. If your multiply the one third of a percent that dies of unnatural causes each year you have roughly 3% of a population dead every decade, about 30% every century who die from accidents and disease. We could lower that figure by removing a lot of deaths that occur from heart attack, making an assumption that we would not tend to drop dead from heart attack so much because at fifty we would have the hearts of twenty year olds. And perhaps when you add war into the equation the rate might go up. If you consider super bugs that are making antibiotics less effective, then the figure might go up to plague like stats in some years. Over the course of 500 years a lot of things can happen that make it the exception to live to be a 500 year old.
This kind of begs the question, at what age does social security kick in?
Anyway back to retirement, you would not retire. At some point in your life you might become disabled, unable to work and there would be some program to take care of you.
For most people, depending on how mundane the job is, short retirements more akin to sabbaticals would be the norm. You might take a couple of years off to play. You may after fifty years in a job decide to change careers and go back to school for a decade then get a new job. You might sell a business and be able to cruise for a couple of decades, dabbling in shuffle board and basket weaving until the money ran out. You may just have a very good time with your career and never do much besides vacations.
* Medicine-Health
The emphasize would shift from end of life medicine to quality of life medicine. Research would be mostly in accessing risk factors and mitigating those factors. Smoking would be abolished. Other risky behavior would also be looked on as much more serious. You would after all be risking a life that has the potential to last five hundred years as fairly healthy, rather then a life of 70 years that starts to degrade health wise the older you get. People would eat better to make sure their heart and other vital organs do not give out prematurely. Many drugs like ibuprofen for example, that have long term health risks like kidney damage would not be allowed. The elves have solved the biggest medial problem we face today, the genetic barrier to a long life. They would now focus on the other things that end life prematurely.
* Law, Crime, Judicial
Law is going to go through changes as the ratio between elves and human changes. At some point as the group of elves grows larger and the fear of them becomes more real, the laws against them will start to resemble the racial laws of the south, the Nuremberg laws of pre WWII Germany and other status against groups in other countries. This still will not stop the eventual outcome of the elves becoming the dominant humanoids on the planet. At some point the balance will tip in favor of the elves, and they will do about the same to the humans as the humans had done to them.
This may not only be in legal matters it may be that this leads to war like conflicts at about the time the two powers are about equal. Still the elves will come out ahead, just because they can produce many more battle worthy citizens for soldiering then the humans can out of about the same size population. Any population that the elves loose during a war can be replaced much more robustly.
Crime and punishment for elves will be much different from today. The main problem being is locking someone up for life. Can they afford to keep someone in prison for five hundred years? Or would this mean that rehabilitation takes on a new urgency and meaning.
Term limits for judges and politicians would become the norm.
* Insurance
unfortunately, there will always be insurance salesman and adjusters to make sure your wasting your money.
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**Closed**. This question is [opinion-based](/help/closed-questions). It is not currently accepting answers.
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Our cats learn to vaguely express desires vocally (with different style meows for *'I want to eat'* and *'I'm scared'*, for example) and can do some simple tasks that suggest they are capable of slowly figuring out the world around them, such as knocking on the door knob when they want out of a room.
If one cat was chosen to live for a million years, after the million years were finished, is it possible that the cat would have learned enough to function at a higher level than cats do now?
E.g. would it be able to converse to some degree with humans? Open its own food? Other things?
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The simple answer is no, cats have a limited brain capacity and internal connectivity/complexity.
An adult cat will learn some new skills still, but over time old skills will fade away so there is a finite limit to just how much can be learnt and there are some things (such as human speach) that they don't have the physical or mental capacity to ever learn.
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I am currently designing a world for a series of short stories and have started looking at what kind of weather patterns would be present in certain regions. For simplicity's sake, we can assume the planet is very earth-like.
I designed a mountain range that runs west to east. To the north of the range are icy and snow plains and in the south lies the rest of the continent. There is a small bay of ocean water to the west of the mountain range (roughly a third of the size of the Hudson Bay in North America). I would like runoff from the mountains to form a river that travels west to east at numerous points. The mountain range comes out to roughly 60 degrees north latitude, around the border of the Ferrel and Polar cells. I did some research online and used the following information to make an assumption:
1. The area around the polar front has high precipitation.
2. There is a noticeable temperature difference between the opposite sides of the polar front.
3. The polar front moves South during the Winter and North during the Summer.
4. The rain shadow effect.
The assumption: During the Winter, the polar air moves South and hits the mountains. The air rises and causes snow. The land to the South of the mountains sees little rainfall as a result and the river dies down. During the Summer, the air from the body of the continent moves North and rises to the Southside of the mountain causing rain and the snow in the mountains to melt. Both contribute to the river, causing a flood plain further downstream. The land to the North of the mountains becomes drier. This progresses slowly during the other seasons of the year.
Is the information I am using correct? Is this assumption sound? If it isn't, then what would the climate around this mountain range actually be and could there be a location that has the type of climate I've described?
EDIT: I've included a rough draft map of the continent. It is by no means complete and includes basic features I would like to include (I have done little to no research on forest or desert formation, but comments are welcome). As a reference of size, mountains 1 are at 60 degrees north latitude and desert 1 at 30 degrees north latitude. In region Alpha, I plan another mountain range running along the dotted line the triangle is on. In region Bravo, I would also like to place another forest (likely pine) south of mountains 1. Forests 1-4 are planned deciduous.
The map:
<https://i.stack.imgur.com/fwlMu.jpg>
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There's a few issues here that might not give you the intended effects...my knowledge is a little more specialized with the north and south running mountains as the globes rotation drives the winds. The east vs west orientation of this makes is a bit different...air would be pushed east west across it and the end effect might be the northern air becoming completely isolated from the southern air on the other side of the mountains.
1) The area around the polar front has high precipitation.
This is one half of the equation. The area around the polar front is warm moist air mixing with cold air that creates precipitation. So you need that source of moist air to create precipitations. Where does the warm wet air come from, and how does it move over the mountain to come into contact with the polar front? If the warm and wet air gets pushed up over the mountains, it may well lose most of it's moisture before coming in contact with the full polar front, no?
3) The polar front moves South during the Winter and North during the Summer.
Will it? This is the part I'm having problems seeing...for it to move south, it would have to go up over a mountain range and back down the otherside.
I end up having the vision of two very seperate weather systems forming. On the north side, the wind would rush along the mountains East to west (polar easterlies) and then loop back west to east futher north. On the south side, you'd have winds that travel East to West further south, and then the circle of the winds East to west along the mountains. Er..or reverse of that.
With East west mountain orientation, I guess the main part that I'm not sure on is what would drive the air to move south/north over the mountain range...or would it remain two separate cycles independent of one another instead?
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You mentioned there was a bay in the west but you never mentioned if there was an ocean somewhere.
about your assumptions:
1. Yes, and I should add than places at high latitude are usually cold enough to stay humid even with little precipitations. Think like in Siberia for example.
2. Yes but it is constantly changing. It alternate between cold and hot fronts, bringing precipitation and affecting the temperature. Keep in mind that the front is a wave moving around the Earth. It's not static line, it bends.
3. Yes, 60 degrees north is probably the maximum extent of the front. Maybe 30 degrees north during the summer is the minimum.
4. Yes, the mountain could block the winds if they are tall enough.
The rest: In winter, the poplar front is far to the south, beyond the mountains.In Siberia and Mongolia , it is very cold and dry during the winter. Some places receive almost nothing in precipitation like Pyongyang. It's like the Mediterranean climate but in a cold winter. But if your continent is smaller, like North America, you can still expect to have snow. It gradually decreases as you move away form large bodies of water (because that's where the water come form). The norther side would have little precipitations in winter but a moderate amount in summer.
Would the area south of the mountain be dry? It depends. If there is a large water body like an ocean not too far south: it's probably a temperate climate. Otherwise, where would the water come from? Or, if there is a large ocean in the west/east: large precipitations along the coats and decreases gradually when moving away form the coasts.
So, if there is a source of water not too far (in fact, it can be quite far if the land is flat) The south would probably be temperate with a moderate amount of precipitations in summer and winter.
The snow wold only melt partially , in the lower altitudes. At this latitude, areas over 1000m or 1500m over sea level will always be covered with snow.
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**Edit** following the world map you provided:
Your continent reminds me a lot of Asia, except that it's larger and located closer to the pole. It would be affected by something similar to the [Siberian high](http://en.wikipedia.org/wiki/Siberian_High) during winter, causing dry weather over large parts of the continent.
You should expect to have a monsoon during summer in the south. The effect could go as north as **forest 1**. This also makes desert 1 implausible because it's affected by the monsoon too. It might be hot enough to be some sort of savanna.
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My world is almost like a fantasy steam/solar-punk set up and my main character has a metal left limb. I guess I shouldn't try to worry too much, but it always bothers me that I'm not sure if I have a truly logical explanation for how his limb functions.
I do have an idea for how it works and it's probably the best I'll be able to manage but I just want to make sure that there are no other solutions out there.
The set up I have so far is he has a metal plate in his shoulder that connects his nervous system to the "wires" in his limb that function as artificial nerves and connect to joints in his arm and hand that allow him to move his limb.
So I guess my question is: **Is there anyway to make my set up more believable or are there other solutions to make this believable?**
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That's similar to how things are done in the real world, with the exception being that the sensors for detecting nervous system activity are place on the skin. This is the technique used by DARPA to connect the mechanical limb seen [here](https://www.youtube.com/watch?v=suwZ5D9bk0M) to the guy using it. These electrodes (the sensors on the skin) don't actually pick up the nerve activity. Rather, they pick up electrical activity from skeletal muscle remnants around the base of where the arm was and transmit that data.
The issue with such things in a steam-punk world is transforming the signals back into action. Most of the time, steam-punk means no computers, which are, by far, the best way of doing this. It maybe possible with the right analog components, but analog will, of course, be bulkier.
Of course, if your setting contains computers, you can just give him an arm controlled by those. It worked for DARPA, right?
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You should take a look at [shape memory alloys](http://en.wikipedia.org/wiki/Shape-memory_alloy) with a bit of hand waving for the electrical current and joule heating requirements. The arm could generate locomotion by shape memory metal acting as tendons and muscles. Gears could be actuated with shape memory coil springs that allow for joints to rotate.
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Perhaps this doesn't apply as much to steam punk world like yours, but artificial limbs could be biological instead of technological. Some sort of creature or symbiot that they intentionally connect to the severed end.
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I'm working on a future cyberpunk setting in which I would like to explore posthumanism as a main theme. Among some of the ideas I have I want to use the very well explored "decking" trope.
The idea is that at some point in time humanity managed to create a crude brain-computer interface, that allowed not only access to silicon machines, but also running programs using brain's terrifying processing power. Hence, Technological Singularity followed, with wealth represented by physical production facilities becoming obsolete, as with the excess processing power brute-forcing trade and political forecasts became feasible. Finally, technology demands caught up with the supply and humanity's most relevant stock is now carefully traded processing power. Countless people have been contracted to trade in the power of their brains in exchange for remuneration and it just so happened, that average level of intelligence turned out to be the easiest and most efficient to utilise.
Now, most people work by plugging in to the data processing cloud for a set amount of time. The contracts vary, with a significant amount of people enjoying games etc. while being plugged in and trading in a set percentage of their brain activity, some having only passive reception of data with minimal amount of interactivity left to the brain's owner. The most extreme (and well paid) employees would lay comatose while nearly 100% of their brains are being devoted to stock trading or running AIs. Of course, majority of the population would unplug for at least a couple hours every day to enjoy real life. That also assumes that entertainment and similar services moved on to the new medium, Neuromancer-style.
That would leave only the misfits living mostly in the physical world - the geniuses, the morons, the weird and strange minds that are too different to be a mass resource. They would too be able to plug in, but extracting processing power would be too inefficient for them to provide a reliable source of income.
What would be the social and economical implications of such a world? Keeping in mind that Joe Average literally sells his brain time to someone else and his mediocrity and predictability is prized and promoted, what sort of man would he be? What sort of values would he hold, what would he believe in, what would he want in his life? How would he spend his time off and how would he spend his time? I'm looking for a kind of stereotypical Everyman definition, the same way we recognise the idea of "mid-range corporate employee" or "middle-class big city dweller".
In response to comments:
I imagined the transition to processing power as an aftereffect of general transition towards virtual life. Of course main expenditures would still be rent, utilities, food etc. However, a person might forgo all earthly things and basically occupy a coffin rigged with life support gear, while living his life in virtual environment. Now to create such an immersive environment the power of brains of others would need to be utilised, effectively balancing the processing power budget. The excess would be utilised towards human advancement - even if that just means more sophisticated virtual goods (experiences). Generally, it would seem, that at any given point participants in this "cloud brain" structure would be divided into suppliers and consumers, with one creating processing power for the others. Apart from human consumption I would imagine there are AIs who require immense number of brains, but enabling technological singularity and - being sentient - having an attitude towards human suppliers. Of course, different variations are possible, such as Matrix scenario where AIs would harvest power by oppression or a more caring one, where proliferation of brains is actually achieved by AIs genuinely forging a better future for humanity.
I would imagine in a world that derives wealth from processing power, other resources such as food, construction materials and energy would be harvested automatically - using AIs and self-sustaining plants. Work for the incompatible geniuses would be most likely centred on frontier areas - where network is not sufficient to sustain automatic AI or it is not feasible - such as space exploration, colonisation. I would imagine that such a civilisation would be probably halfway to becoming a Type II, according to Kardashev scale.
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Any "above average" would probably take up creative works - putting these resources to use; creating programs to run on the brain clusters, designing art and architecture, entertainment and so on. Things, that are not possible to create by "machine mind" no matter how much computational power you throw at them. Design better "clusters", invent machines that are controlled by the AI, perform scientific research. They wouldn't need to be outcasts at all, but they would need more than sitting idly, being entertained while their brain earns them money all by itself - they would need to work for real.
or, of course, live off welfare as jobless bums, if they prefer so.
The "bottom" would either live off welfare (society of surplus; way enough to provide for everyone's basic needs) or take up menial jobs where a "human face" is valued: servants, frontdesk workers, secretaries, bartenders, caretakers of children and elderly - jobs that either need empathic (even if not very smart) listener, or simply positions that *appear* to be more prestigious if handled by actual human rather than a machine.
I'd imagine best restaurants would still employ actual waiters and cooks, while "fast service" cheap bars would run on machines, and while possibly providing food of the same quality, they would lose points on soulless automated service replacing actual human waiters.
Also, the values would shift: creative works - art, music, architecture, design, movies, fashion - would increase in price and value; there would be artificial scarcity (and increased price) created for the more elaborate ones - ones that required more *talent* to create, things that required brilliance, not just "optimized for function and aesthetics by machine". Common goods off the production line would become abundant and cheap.
And as result, the middle class would probably live in a constant schizophrenia; trying not to stray too far with thought processes, while building up image of individuality and class by purchasing custom-designed furniture, obtaining hand-made paintings and crafts, attending theater plays, and generally striving to appear "cultured and elaborate" but only *appear*...
Of course there would be still a plenty of common stuff, computer-generated sitcoms, mass-marketed food, standard corporate commerce which would be far from elaborate and appealing to a large part of the society.
I think *crime* would be the most interesting domain though. Optimized synthetic drugs and forbidden entertainment involving bottom-feeders who want to earn easy money quick through prostitution of more "deranged" kinds. And while brainpower theft to perform clandestine calculations (cracking secrets, inventing drugs) would be a problem, worse problem would be *planting ideas* into brains hacked into. You could turn people into your slaves, make them desire goods you provide, have them attack people you want dead, and generally use them as your puppets.
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Well it would make middle class the center of the bell curve. Most people would have plenty. This would tend to lead to fewer major conflicts because a strong middle class tends to want stability, doesn't need it enforced from above.
There would be a lot less worry about the future, since if you were 'normal' you are guaranteed employment. It is also possible that it leads to stagnation as a society. The brain can be trained and modified within reason and so everyone would be trained to think as close to the 'ideal medium' as possible.
The big problem will come with how we treat the smart people and worse the geniuses. They will likely be ostracized quite a bit more. Now they can be looked up to for unique and interesting ideas for current problems. If we are depending on computer power based on average humans to fix our problems (whether a good idea or not) then what are these people going to be doing? They are the ones who tend to push us into new realms of thought and bring out new ways of viewing the world, (I am including great artists in this as well as mathematical and scientific innovators). Will being average be so important that we will miss out on greatness?
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I think the most interesting problem that develops in such a world is how to raise the children. Nowadays, we send our kids to school where they quickly start asking why they're learning things they'll never use in real life. We tell them that it's not the facts themselves, but the ability to learn that we're teaching them, but in a world where the best brains are the empty ones, will we still want to raise another generation of thinkers?
So maybe instead of teaching our children to think for themselves, we teach them how to think for a computer. On the basic level, computers follow simple instructions. These instructions can be converted from binary to machine code, then to higher programming languages. I'd imagine somewhere along the line there would be a 'human' language that would translate the instructions for easy processing in a human brain. The best brains for the job would be ones specifically wired to complete these instructions quickly and without error. The best way to complete simple tasks quickly and without error is with constant practice, so I'd imagine school turning into twelve or so years of busy work.
The effect of this becomes obvious: people will not be able to think for themselves. They will be taught to follow instructions, and so they will want to follow instructions all the time. You could not hold a conversation with these people, because our language is naturally ambiguous, and computers don't do well with ambiguity.
While this has obvious problems for 'normal' society, I forsee smart, nonconformist people having a lot of power. You'd have masses of people, ready and willing to do whatever anyone tells them to. You may not be able to get a job because your brain doesn't process well enough, but all you'd have to do is tell someone to give you money and they probably would. Obviously, they wouldn't want to lose money, but they'd been trained to think that compliance was a good thing, and so doing what you ask becomes its own reward. One of the things I love about fictional AIs is that they're often incredibly stupid when it comes to human affairs: now imagine that, only for the entire planet.
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This answer builds somewhat on some ideas already posited by @DaaaahWhoosh.
Basically, if the middle class is just going to accept their fate and be as average as they possibly could, the manipulative and socially outcasted geniuses would feel very little remorse for manipulating them. This could lead to a scenario where one of those geniuses actually becomes president (or something similar) because effectively no one would deny him, and he'd just twist their arms as much as he wants!
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I cannot see any problems with this economic model - it will work, and it will stagnate.
As for what the people will be like, people going into the systems in adulthood probably won't change much - the way computers and more recently smartphones haven't really changed today's older generation.
The younger generation however, as many people have said, will not learn to think for themselves and be manipulated by the geniuses.
I think eventually, everybody would end up plugged into a virtual world, while the misfits enjoy real life. A bit like the matrix.
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Can a habitable planet having complex life exist in a binary star system with a Red Giant? I am not talking about close binaries, but distant binaries (100 AU or more). Planets can orbit some smaller stars (F, G, K, M class) in an S-type orbit, in order to have a steady source of light and heat. Does the red giant in that large distance affect the habitability of this planet? Is a similar setup possible with a Yellow Giant?
Edit: In the original question there was a typing error when I wrote that separation of binaries is 100 ly or more, but I intended to write 100 AU.
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In a binary system where the stars are separated by 100 Astronomical Units (AU), the effect of a red giant on a planet circling a smaller star (like F, G, K, M class) would probably be minimal. Neptune is about 30 AU from our Sun, and the Sun's direct effects (solar storms for example) at that distance are already much weaker than the effect they have on Earth for instance.
Red giants do release a lot of mass through stellar winds. However, at a distance of 100 AU, these wouldn't cause much trouble for the planet. Recall that our Sun, when it becomes a Red Giant, might expand enough to consume even the Earth, which is 1 AU away. Thus at about 100 Astronomical Units the planet would be safe from any effects. Especially if it has a strong magnetic field in place take care of a possible stellar wind. The yellow giant star case would be thus similar.
So, a livable planet orbiting the smaller star should be mostly fine, even with a far-off red or yellow giant. Mainly, the planet's livability depends on its own star and local conditions.
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Having a Red Giant 100 AU away is probably fine for your habitable planet as explained in cconsta1's answer but getting there may not be.
Note that a [Red Giant](https://en.wikipedia.org/wiki/Red_giant) is a relatively short phase (in astronomical terms) in the evolution of a star. So this red giant was a star somewhat similar to our sun for billions of years before it became a red giant. This phase is even more harmless for your habitable planet. However, the shift from sun-like to Red Giant might have caused a [helium flash](https://en.wikipedia.org/wiki/Helium_flash) and this is probably very bad for the habitable planet:
>
> This runaway reaction quickly climbs to about 100 billion times the star's normal energy production (for a few seconds)
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Red giants eject planetary nebulas. It's speed is tens of km/s and mass is 0.1 to 1 solar masses.
Surface of the sphere with 100 AU radius is 2.5 10^27 m^2 so that is about 100-1000 kg of gas per m^2 (only 1-2 orders of magnitude less then the mass of atmosphere) incoming at ~50 km/s.
So I suspect that this is enough to sterilize the planet.
But this ejection happens at late stage of red giant life so it can easily be hand-waved away.
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My friends and I have a huge hyperrealistic worldbuilding project (yes, I do suffer from Worldbuilder's Disease) that involves speculative biology. I am currently using [diagrams.net](https://diagrams.net) to make the cladograms, but food webs are a bigger challenge. Do any of you know software that could be used to make a food web? It would have to work on Chrome OS.
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After quickly asking Mr Google “food web maker software”, here’s what I’ve got:
* [Creately](https://creately.com/lp/food-web-maker/)
* [Insight](https://insightmaker.com/tag/food-web)
* [Visual Paradigm](https://online.visual-paradigm.com/diagrams/templates/interrelationship-diagram/food-chain-interrelationship-diagram/)
This is by no means a comprehensive list, but hopefully this helps :)
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I'm designing an Earth-like planet and I'm concerned about whether or not it would have ice caps. Originally, I assumed it would be too warm, with a climate similar to Earth's during the Paleocene-Eocene Thermal Maximum. However, upon considering the rest of its parameters, I realized this might not be the case. They are as follows:
* Average surface temperature: **25°C**
*As mentioned above, this is similar to PETM Earth. Then, polar conditions were too temperate for permanent ice caps. The global climate has been around these levels for the last 18 million years following a period of industrial global warming.*
* Axial tilt: **6.2°**
*Less seasonal temperature variation would create more consistently cold polar conditions, letting ice remain frozen there for longer periods. **EDIT**: I remember reading somewhere that planets with a lower tilt should have a warmer overall climate, but I can't find the source.*
* Sea level pressure: **2.43 atm**
*A thicker atmosphere would be able to circulate heat more effectively. This would create more even temperatures across different latitudes, potentially making polar temperatures warmer.*
* Surface gravity: **1.28g**
*I'm not sure how this would effect ocean and wind circulation. It could slow down currents near or at the surface, though I'd imagine a planet's topography would be a bigger factor. That being said, this would lower the maximum height limit for mountains and increase erosion from rainfall, creating a slightly flatter topography, so maybe it would even out?*
* Ocean coverage: **80%**
*Along with the higher surface gravity, this would create an overall flatter topography, allowing ocean and wind currents to flow more efficiently. It would also decrease the planet's albedo, though this could be counteracted by increased cloud cover from evaporation.*
* Landmass Properties
*This planet's landmasses are concentrated around the equator and in a longitudinal great circle. This is due to the scorching equatorial climate as well as the tidal influence of a mars-sized moon it's locked to, which creates a permanent 800m tidal bulge. They tend to be smaller and more broken up with jagged coastlines and inland estuaries. Mountains are a bit shorter on average. While there are landmasses at the poles I'm not sure if they would be isolated enough to have a situation like Antarctica, in which thermal isolation would allow it to remain frozen even after the climate increases.*
* Rotational Period: **43.125 hr** @ **322 m/s**
*On one hand, a slower rotation would create a greater temperature difference between the day and night sides, increasing the potential for ice to form at night. Furthermore, a reduced Coriolis force would slow down ocean and wind currents, lowering circulation to the poles.*
* Surface area: **637.59 million km^2**
*More surface area may reduce the effectiveness and distribution of solar heating.*
* Apparent brightness of star: **1.0486*L*☉**
*The star's true luminosity is only .168L☉, but it appears brighter based on the planet's semi-major axis, which is 0.4 AU.*
Based on these provided factors, should my planet have polar ice caps to any capacity?
[Answer]
**Short answer: No, it is too warm.**
This is a bit beyond my expertise, but since no one else seems to be interested to answer, I will try my best:
If we look at the current climate, we have an average temperature of ~18°C and the North pole is almost ice-free in summer and most other ice sheets are melting at an alarming rate. I guess, seven degrees warmer would mean the total disappearance of all ice sheets, even if it takes millenia.
In addition, keeping an ice sheet stable is much easier than creating new ice sheets. Once the ice sheet exists, albedo is reduced due to the white color. The poles might still experience lower-than-zero temperatures over the whole respective winter, maybe even permafrost but no big ice sheets.
The low axial tilt is not really working in favor of the ice sheets. As mentioned before, forming the ice sheet is the hardest part and this is less likely, if the seasonal variability in temperature is low. Otherwise the ice might be able to form in the winter and can make it through the summer due to the lower albedo (as is it currently happening on the North pole but probably not through the next decades).
[Answer]
## Frame challenge
You're not thinking in the long term.
I'm no expert on climate change, but I'm going to pose this thought anyways. What you've given us is a snapshot of your planet: "here's the current weather, here's the current axial tilt, here's the current surface temperature, etc." and then asked "should my planet have ice caps." Here's the thing: planets *change*.
Over the course of several millennia, the axial tilt might give rise to more drastic seasons or less so, depending on the change. In the 1990s, Earth underwent a [major axial shift](https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL092114) caused by [melting glaciers](https://news.climate.columbia.edu/2021/05/19/melting-glaciers-shifted-earths-axis/). Speculation has it that a similar shift in axial tilt may be responsible for the climate change we're seeing today.
Surface temperature changes, too. Earth experienced some [major heat spikes](https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been) in its early years, as evidenced by the PETM period you are simulating. In recent times, Earth's [temperature has risen](https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature#:%7E:text=Earth%27s%20temperature%20has%20risen%20by,based%20on%20NOAA%27s%20temperature%20data.) by approximately .8 degrees Celsius per decade, and is currently rising by .18 Celsius per decade, a significantly increased rate of warming.
I could keep going, but I think I've made my point. If you want to determine whether your planet has ice caps, you need to determine not only its current state, but its long-term patterns. It's 25 degrees Celsius now, but is it recovering from an Ice Age? If that's the case, it probably has ice caps and they are probably melting fairly quickly. On the other hand, if it's coming off a molten period, ice caps are out of the question.
What you need to do is determine not just you're planets *climate*, but it's *climate change*. As I said, I'm no expert on climate change, but here's one basic pattern you can keep in mind:
**Climate change works by positive feedback mechanisms.**
Have you ever wondered how Earth got *so hot* or *so cold* (and we're talking extremes: the [deep freezes](https://www.climate.gov/news-features/climate-qa/whats-coldest-earths-ever-been#:%7E:text=Brutal%20cold%20struck%20again%20during,fell%20into%20a%20deep%20freeze.) of the Cryogenian period and the [molten](https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been) period known as The Hadean)? Many causes, obviously. For instance, the thaw after the [Neoproterozoic Era](https://www.climate.gov/news-features/climate-qa/whats-coldest-earths-ever-been) may have been caused by erupting volcanoes. (Which, by the way, illustrates my point. If you asked if there should be volcanoes during a deep freeze, I would have said not. But there were, and that is what pulled Earth out of its period of frost. Because planets *change*.)
However, when it comes to extremes, one helpful thing to keep in mind is that climate change works by [positive feedback](https://en.wikipedia.org/wiki/Positive_feedback) mechanisms. That is, warm temperatures cause warmer temperatures, which cause even warmer temperatures. And likewise, cold temperatures cause colder temperatures, which cause... you get my drift (okay, pun intended).
Case in point: During PETM, there was a [shift in ocean currents](https://ui.adsabs.harvard.edu/abs/2006Natur.439...60N/abstract) which brought warmer waters farther out into the sea, creating warmer conditions. A mechanism like this could trigger a more drastic change in ocean currents, bringing hotter water out into the sea... and the cycle continues. The opposite is true, too. When the [Earth is covered in snow](https://earthobservatory.nasa.gov/features/Milankovitch/milankovitch_2.php), more of the sun's energy is reflected into space. Hence, causing further cooling.
So in a nutshell: you need to determine where your planet came from, and where it is headed. But assuming a general trend in which the PETM conditions you laid out continue to exacerbate, causing even warmer conditions, should your planet have ice caps? My answer would be no, but that's an opinion.
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I'm confused about the relationship between partial pressure and concentration of a gas, in relation to the biology of respiration. If I have a planet with high atmospheric pressure - maybe like 10 atm - but the O2 concentration is lower, maybe around 10%, what effect would this have on oxygen-breathing life? On Earth, oxygen makes up 21% of our atmosphere, with a partial pressure of 0.21 atm. In a 10 atm atmosphere, with oxygen at 10%, this would be 1 atm, which is higher than on Earth, obviously. Would an atmosphere like this provide higher or lower access to oxygen than on Earth? I guess what I'm wondering is, is partial pressure or concentration of oxygen more biologically significant?
[Answer]
Take a look at the Hyperbaric chambers for both medical purposes and treating decompression sickness. Some of the hard chambers go up to 8 atmospheres and include 100% oxygen , but with scheduled air breaks where the oxygen percentage is brought down to 21% to reduce oxygen toxicity.
The [Navy dive manual](https://www.navsea.navy.mil/Portals/103/Documents/SUPSALV/Diving/US%20DIVING%20MANUAL_REV7.pdf?ver=2017-01-11-102354-393) is interesting reading and there is quite a bit of we know this happens but maybe we don’t know why when it comes to oxygen toxicity. As mentioned in the comments a lot of that uncertainty is suspected to be the role of the inert gasses. The tolerance to oxygen is higher when dry than wet for example. Why? Not sure, but you treat wet suits different than dry suits. Take someone off oxygen, and they go into convulsions why? Shrug, it doesn’t seem to be that bad and is like a “vigorous workout”. What is the role of CO2, it matters…. So it is pretty empirical document, but it has lead to a field of hyperbaric medicine. Some claims are probably unrealistic.
Heliox (mixtures of helium and oxygen) are used for two reasons medically there is less resistance when breathing so that helps with breathing difficulty in a medical context. It also prevents nitrogen narcosis or rapture of the deep and the anesthetic nature of inert gas.
Trimix is cheaper, and has enough helium to minimize the chance for narcosis.
So for your planet, it seems that you have some license to have some realistic leeway with the oxygen percentages and the effects on people and how they respond.
With the partial pressure you also have some influence on how flammable things are. But around 21 percent that shouldn’t be that big a problem.
[Answer]
It's the partial pressure that matters for biological processes. There is a minimum pressure of oxygen you need to live. There is a somewhat higher total pressure you need to live because at the minimum oxygen pressure you get too much water evaporation in the lungs.
Otherwise, all that matters is toxicity and stability. (You can, for example, breathe perfectly well in 20kPa O2 and 80 kPa H2 but one spark and everything goes boom.) Everything you could breathe has a point where it becomes dangerous. Deep sea diving reaches a depth limit not because of what the pressure does to a person, but what you can breathe.
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[](https://i.stack.imgur.com/DjBOV.png)
*Dumbledore fights Voldemort from the Harry Potter series of films. Nothing says "opposites" like two different colors incapable of overcoming each other and dripping like magma to the floor.*
New worldbuilders tend to think of their magic systems from the outside in. They think in terms of fire and wind, or necromancy and life... all those wonderful adjectives that give a story flavor but mean little to nothing when it comes to establishing the rules of a magic system.
No magic system is complete unless there are consequences. Some consequences are personal, meaning the price the magic user pays for the privilege of using magic. This may be reflected in *mana* or some measurable resource that can be depleted. Or it may be reflected in the body requiring rest or the magic threatening death. (And you can see how those are both the same thing, a consumed resource that limits the use of a powerful tool. Whether you call it "mana" or "life" is just window dressing.)
This question asks about what it means to have *opposites* in a magic system: two or more expressions of magic that act in opposition to one another, and how that opposition can be described in a magic system.
When considering this question, keep the following in mind:
* Your advice will be used by new worldbuilders trying to develop their magic system. Your answer should be more than, "this is how I did it." The more valuable explanation is, "this is why I did it."
* Try to avoid the window dressing. "Fire" may be opposed to "water" in your magic system, but when it comes down to brass tacks what you have is one force in opposition to another (a positive and a negative, at worst) leading to consequences when used in proximity or against one another.
* The ideal answer will explain both why opposition is necessary and how it acts to balance the magic system.
* Obviously a magic system need not have opposite powers at all. Such a discussion is outside the scope of this question, which is meant to educate new worldbuilders in the what, why and how of using opposing powers, not the rationalization of why it's unnecessary.
* While I do not intend to select a best answer, you should be writing as if I will. Your answer should be complete if not canonical. It should be something you spent a bit of time thinking about rather than pounding out quickly. Your answer should be universally applicable to anyone developing a magic system.
**Question:** What advice can be given to a new worldbuilder about implementing opposition in their magic system?
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***Background***
*Questions like this appear to be very rare on this Stack. This question is as much a test of whether or not we can practically use the Worldbuilding-Process tag as it is an honest effort to provide useful answers that can help a wide range of worldbuilders. To that end I ask that you carefully consider how you use your up/down votes and votes to close as they'll set a precedent.*
*An obvious problem is Stack Exchange's "best answer" context. A question like this may violate SE's rules about every answer being equally valid and open-ended. I hope I've provided enough conditions and limitations to overcome that concern. The result may be a popular-vote "best practice" answer. But this is also part of the test. Can we teach people how to be worldbuilders here, or are we consigned to only asking solve-just-your-problem kinds of questions?*
***Up/Down Voting & VTCs***
*Therefore, an up vote means BOTH (a) This question is well-asked AND (b) this question is appropriate for this Stack. A down vote means EITHER (a) This question is inappropriate for this Stack OR (b) this question is not well-asked (I'd hope you'd try to resolve a not-well-asked issue in comments before down-voting, though).*
*While is is not normally required for anyone casting a VTC to explain themselves, I invite you to please do so. That explanation will contribute to a better understanding of both (a) is this type of question appropriate on the Stack and (b) what are the inherent problems with asking questions of this type?*
***Why isn't this on Meta?***
*Because Meta's only purpose is to establish policy. I could have tried to ask about the expected use of the Worldbuilding-Process tag on Meta, but it would have been a limited discussion without a test case like this one to reference. How this question is received will determine both if a Meta post is required and, if so, what that Meta post will ask about.*
[Answer]
# Summary
As a summary up front, for once, you can view generating opposites for a magic system in terms of *changing a variable in an equation* or *opposing themes.* The success of these approaches depend on the hardness or softness of the magic system being created.
Note: This advices comes to you from a prolific literary analyst and amateur game designer of at least a decade. Yes, I have had academic training from experts in these subjects, but no one has paid me to do this. (Writing and game design just doesn't pay too well.) I have made several magic systems in addition to the many I have analyzed over the years.
# [Hard Vs Soft Magic](https://habitwriting.com/hard-magic-vs-soft-magic/#:%7E:text=Hard%20Magic%20System%3A%20A%20type,by%20the%20reader%20or%20audience.)
This is a big question, but it can inform how opposites should be defined. Let us take a quick look at these and some approaches for each of them.
Hard magic systems have clearly defined rules: you define it like you would a system of physical laws. This is good when magic's role is more of a tool for solving problems. Examples include most of Brandon Sanderson's works, Eragon's magic system, and many video games. In such a system, ***opposites may be viewed as things which increase/decrease some (usually physical) variable***! This could be things like *fire* vs *water/cold* (changing temperature), *pushing* vs *pulling* (changing force), *draining* vs *energizing* (equally changing emotional states or adjusting blood sugar levels), etc.
Soft Magic systems have no set of clearly defined rules, but serves more to support a character's theme(s). This is good for movies, books, and other non-interactive media, as the writers get to determine what is appropriate or not for that setting/character/situation. Examples include Lord of The Rings, Harry Potter, Avatar: The Last Airbender, Star Wars, and many mythologies as well as supernatural beliefs. (Yes, "the Force" serves the same purpose as *magic.*) In such a system, ***opposites are better defined by opposing themes.*** A thesaurus is helpful here: *hate* vs *love*, *good* vs *evil*, *control* vs *freedom*, etc.
You must determine if your system is more on the hard side or more on the soft side of the magical-rules spectrum. These approaches can be combined, but these approaches work better depending on the hardness/softness of systems. Hardness/Softness is admittedly subjective, but it is a helpful construct to form your system.
# But Why Opposites?
Magic can serve many purposes, but fundamentally it provides tools for propelling conflict(s). Conflicts have opposing sides, with conflicting desires, and that's where a lot of reader/player/viewer enjoyment is to be found.
And this is also why you also want opposites. It underscores differences between the two (or more) sides and can also serve to reinforce fundamental differences between them. In the broadest of terms, the choice of magic types bring in themes (or even secondarily associated themes) to those sides. The mechanics of those magic(s) can then raise questions in the reader/player/viewer's mind.
For example, an invasion from a bunch of necromancers raises issues about "means meeting ends", "reverence for the dead", and even "the eventuality of death." An invasion from a bunch of healing-focused magic users will raise different themes and questions, like "autonomy of governments" and "is it always better to heal/extend mercy?"
[Answer]
When creating a world with magic, you must consider the effects on the world as a whole. You cannot just slap on wizards to 1400s Europe and expect everything else to be the same.
A world where wizards can do any of (a) teleport, (b) send messages long distance instantly, or (c) change the weather, will have huge influence on an otherwise Western Medieval world.
To prevent huge influence, one solution is to limit which spells can be cast. Either rigidly define what kind of spells exist, or allow broad magic but with a high cost. For example you must sell your soul, make human sacrifice, or give up years of your life to cast a single fireball.
However, for any ruleset you design, you can expect savvy readers to take this blueprint and come up with combinations of spells that interact with each other in unexpected ways.
Combine this fire spell with this ice spell and some gears and pistons arranged exactly so, heat here while simultaneously cooling here, and a single wizard can construct a cheap perpetual motion machine and provide infinite power to the entire world.
To prevent this you can introduce spell opposition. Spells from opposing schools cannot be cast by the same wizard. The cost of casting fire magic is the opposite of the cost of casting ice magic. A wizard who casts a fire spell will find it harder to cast an ice spell than the novice who has never cast anything.
Of course that just means you need two wizards working in tandem to operate the machine. To prevent this, the next step is to declare opposed spells cannot interact. If you try casting a fire spell on one end of a pipe and a cooling spell on the other end, you will not get a flow of heat. You will just get the two spells eating each other and a normal room-temperature pipe. No perpetual motion for you today.
The law of non-interaction is also important if your spells have permanent costs. For example Necromancers must ritually pluck out their eyeballs before they can cast 6th level spells. That is why Necromancers also pay the cost for Earth magic and Glamour magic so they can (i) see through vibrations in the ground and (ii) disguise their lack of eyes.
Thus by cross-classing you can build a totally OP wizard. Having schools of magic cancel each other, or limiting the wizard to a single school is a way to prevent this sort of minmaxing.
I believe the Elder Scrolls II had a way to abuse the system by making your character 1000% vulnerable to poison. This huge penalty gave you more points to make the character strong elsewhere. But then you play an Argonian, which makes you immune to poison and cancels the vulnerability.
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In fantasy stories, wolves or even large dogs are often depicted as mounts, and in the recent *Monster Hunter Rise* game, canid-like monsters called Palamutes are used as both companions and mounts. There's just one problem: **it does not work.**
The muscles and skeleton of a dog, no matter how large, are not built to support a human's weight. They're just not. But no one ever said that someone, through breeding or even genetic engineering, couldn't *make* it work. And dogs can be strong-they've been used to pull carts and kill bears-and they have very, very variable genes.
However, in the end, I've been told that making a dog that can be used as a mount is making a horse look like a dog. [This question](https://worldbuilding.stackexchange.com/questions/138023/would-it-be-feasible-to-have-a-wolf-as-a-mount/138051#138051) has also been called a duplicate of mine; I see why, there is a similarity, but that question concerns the feasibility of *normal* wolves as mounts while **I'm asking how one could make a dog work as a mount for normal people, using breeding and genetic engineering, without making it a horse.**
After all, wolves eat carrion, they are (distantly) related to bears and could develop a similarly mesocarnivorous diet, and one could genetically modify the spine and bones and muscles for load-bearing right? They will almost certainly become somewhat *like* a horse, but **I'm specifically looking for** a canid that actually works as a mount, not a pony that acts like a dog (though that would be interesting).
**TL;DR:** I understand wolves are not designed to be rode and that there is a question about riding carnivores. However, I'm asking about a specific type of carnivores (canids) being modified through genetic engineering and breeding to work as mounts, not about modifying a horse to resemble a dog, as interesting as that may be.
Or, in other words, this is like trying to modify horses so they have society, tool use, and speech (a la My Little Pony) rather than turning horses into hominids-in my case, modifying wolves into a species that can work as a mount rather than turning wolves into horses. I may just be crazy, it may be impossible, but I'm investigating the possibility and feel there is a difference between the two examples above.
**By Request-Traits of a Rideable Wolf:**
1. Wolves are carnivores. These rideable wolves may be mesocarnivores to lessen competition for food, or else really like carrion, but they must be carnivores.
2. While these rideable wolves may be larger, with reinforced skeletons and musculature to support human weight, and they'll obviously be altered for weight-bearing and endurance, they must still be-if one looks at them or reviews their physiology-still wolves. They may be somewhat horselike, of course, that's inevitable, but the point is to have a wolf that can be rode, not a wolf that is for all intents and purposes a horse. This means fur, tail, limbs, and so forth should remain relatively unchanged.
Preferably, one would look at horse evolutionary history, how they got here, and how wolves could be *similarly* adapted, into an efficient carnivorous transport. The hero shrew (which can survive a man standing on it), gives me hope for the spine. Cheetahs have paws, not hooves, and everyone knows how fast they are. And of course rhinos and hippos may seem bulky, but they can peak at 30 mph per hour, so why can't wolves with sturdier legs?
[Answer]
**Bendy Spine**
As discussed at length in [this answer](https://worldbuilding.stackexchange.com/a/138051/14322) the problem is dogs' backbones are designed to bend while running. Some of the running power comes from the spine muscles.
[](https://i.stack.imgur.com/eChBN.png)
The downside is that if you put weight on the dog's spine it will bend the other way which is (a) bad for the dog and (b) stops it running.
Horses on the other hand have the spine stay straight while running. The power comes from their legs and shoulders.
The solution is to not put weight on the spine at all. Put the weight on the shoulders. If the dog is big enough put all the weight on the front shoulders. This leaves the spine free to flex.
For a smaller dog, the saddle is a platform connected to both pairs of shoulders. Haunches and withers if you want to be fancy. Since the shoulders move relative to each other while running you need movable springs that pivot where they attach to the shoulders.
[](https://i.stack.imgur.com/qYw3W.png)
The fact this is a hyaena is important. I suspect it is better to have the front shoulders higher than the back shoulders, as this will lead to more weight on the front than back.
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The animal is small, around the size of a rat or pigeon. Its activity level is on par with a rat, but it can fly and is rather more intelligent, and thus uses more energy. Their excretory system produces uric acide as in birds. It is omnivorous, and the relevant population has a diet consisting of around 20% fresh fruit, 20% insects and small prey, 10% foliage and grass, 10% mushrooms, 10% wood and paper, and 30% processed foods from humans. They also have gastroliths
It has a chimeric digestive tract with many organs. Its mouth has grinding molars as in many herbivorous mammals, which it uses to grind up the food it eats. Its teeth can also chew other sorts of food like most omnivores. They chew their cud when digesting foliage or woody matter. The stomach is a 5-chambered structure where each part is used as required. The chambers are the crop, which stores food, the rumen and reticulum, which ferment wood and leafy material as in ruminants, the stomach-proper, which works as a stomach usually does, and a gizzard, which helps rechew meat and other such foods that bypassed the fermenting stage. They have a liver, but no gallbladder or distinct pancreas. Their small intestine has a spiral valve like the intestine of a shark, but they also have a large intestine that ascends and descends as in mammals. They don't have much of a caecum. At the end of the digestive tract is a rectum in which the feces is stored. They do not have a cloaca
Given its diet and the structure and processes of its digestive tract, what sort of fecal matter would they produce?
[Answer]
Given that this creature produces uric acid rather than urine, but does not have a cloaca, then its uric acid excretions would be seperate from its digestive excrement, and need not be excreted simultaneously as they are in birds.
So, there would be renal excretions, consisting of a white splat of uric acid, much as is the case with birds, save that no digestive excrement would necessarily be present.
Of more interest would be the digestive excretions. Given this animal's varied diet, its feces would also vary according to what it had been eating recently. Fruit, insects, small vertebrates and fleshy invertebrates, mushrooms and processed food would contribute a soft, pasty material to the feces, with the inclusion of seeds if eaten with fruit, and finely divided exo/endo-skeletal material if present in the diet.
Foliage, grass, wood and paper would be present in the feces as finely divided and partially digested particles.
Given the lack of a gall bladder, bile would be produced and excreted at a constant rate rather than being released as required, so all the feces would be a uniform brown colour. Given the multi-part digestive system, the different components of the feces would tend to be excreted seperately rather than being intermixed, leading to droppings with different consistencies.
[Answer]
**Splat.**
[](https://i.stack.imgur.com/Eb0r7.jpg)
Flying animals need to be super lightweight. They cannot afford to sit around for hours fermenting their bodyweight worth of plant matter.
Your creature only holds a small amount of food at a time. The food stays in the body for an hour or so and is partially digested. The simple carbohydrates and other highly reactive compounds are extracted. The remaining fats and complex proteins are sprayed out the other end as the creature majestically takes flight.
Because the food passes through the animal so quickly, it needs to be loose and sloshy. It is still loose and sloshy when it comes out the bumhole.
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First time posting, so thanks in advance to everyone!
I am working on creating a life form that is made of complex or “dusty” plasma. My inspiration is a 2003 [study](https://www.researchgate.net/publication/222296315_Minimal-cell_system_created_in_laboratory_by_self-organization) showing plasma forming into [cell-like](https://amp.theguardian.com/science/2003/sep/25/farout) structures in a lab and a 2007 [computer model](https://www.sciencedaily.com/releases/2007/08/070814150630.htm) showing dust particles in complex plasma can form double helix structures that have similarities to DNA.
Currently, I plan for my living plasmoid to be found in the ionosphere of an earth-like planet, possibly among noctilucent clouds, which are [considered naturally occurring examples of complex plasma](https://phys.org/news/2020-07-image-noctilucent-clouds-nlc-knowlton.amp)
My current evolution of these life forms is:
1. Self-replicating double helix structures form in the complex plasma of noctilucent clouds in the ionosphere (2007 study).
2. They become enclosed in a cell-like structure with a double layer of charged argon plasma acting as a “cell membrane”, as described in the 2003 study. Also as described in the study, they feed on neutral argon plasma, charge it, and assimilate it into the cell.
3. The plasmoid cells reproduce and evolve, varying in size and construction until they become specialized.
4. Symbiotic relationships form between these different cells which combine to form a more complex cell with organelles, analogous to eukaryotic cells. Among these organelles are a nucleus and the DNA-like structures.
This however is where I get stuck. How does such a cell power itself? What is its “food”? I know I mentioned argon earlier but I’m guessing by this point the cell is sophisticated enough it needs a dedicated “powerhouse” organelle. Ice is prevalent in noctilucent clouds, could the plasmoid melt it and use water in their structure somehow?
In summary, is my plasma based microbe plausible and how would it feed itself or produce energy? Any and all feedback or suggestions are truly appreciated:)
[Answer]
A quick glance through your source papers basically suggests that:
* These kind of organisms are "complex space charge configurations" in plasma.
* They can absorb neutral plasma and add it to their complex structure.
* They can have their structure depleted by collisions.
* They can lose energy by radiation and collision, effectively cooling over time.
This probably means that they need a continuous supply of fresh, warm plasma sufficient to replenish their losses.
You can imagine a class of organisms that sit at the bottom of the food chain, doing the basic job of assimilating neutral plasma and turning it into plasma cells, and other classes of organism that consume these producers, adding the structure of their prey to their own.
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That's entirely up to you. There's no particular reason it needs organelles at all, you can simply declare that they don't, if that's what you wanted.
Consider that "feeding" could be more akin to "hacking"... ingested complex space charges are re-arranged to form part of the consumer's body, rather than being broken down and then re-assembled into fresh cells. You don't have to recapitulated terrestrial biology here, if you didn't want to.
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> Ice is prevalent in noctilucent clouds, could the plasmoid melt it and use water in their structure somehow?
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It takes a lot of energy to melt ice, let alone even partially ionize it, and it isn't clear why doing so would be useful. Expending large amounts of energy for little to no reward isn't something you see very much of in most species. If you want them to use ice for some nebulous purpose, of course they can, but that would be up to you.
>
> In summary, is my plasma based microbe plausible
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>
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Lets just say it isn't completely implausible, given what we seem to know at this time.
The biggest problem I have is the short-lived nature of noctilucent clouds. It isn't a great environment for something to evolve and persist in. Maybe your organisms evolved elsewhere and were transported here by one of the usual suspects in [panspermian theories](https://en.wikipedia.org/wiki/Panspermia), but it seems like a pretty harsh environment for them to survive in.
] |
[Question]
[
**This question asks for hard science.** All answers to this question should be backed up by equations, empirical evidence, scientific papers, other citations, etc. Answers that do not satisfy this requirement might be removed. See [the tag description](/tags/hard-science/info) for more information.
<https://en.wikipedia.org/wiki/Whipple_shield>
What I'm looking for is the best possible materials for the outer layer of a whipple shield. From what I understand, the outer layer turns a hypervelocity projectile into smaller and spread out pieces so it can easily be absorbed by an inter layer. So they need to have these following criteria.
1. **It must be lightweight** - The impact from the hypervelocity object would cause parts of the outer layer to breakoff and hit the inner layer, preferably the outer layer must be light weight so its spall could be easily absorbed by the inner layer.
2. **It must be flexible** - If the material was brittle, it would spall more easily and add more strain to the inner layer.
3. **It must be hard** - In order to break the projectile apart.
4. **It must be able to spread out the spall** - Should be able to spread the spall over a wide angle. I am curious if a corrugated outer layer would be better at this than a flat one since a corrugated surface would have weird angles that could defect some of the projectile.
[Answer]
There has been increased interest in metal foams including their use for ballistic protection. Some of the ballistic protection approaches use a composite that has a thin ceramic layer to assist in shattering the incoming projectile. The foam metal structure deforms and redirects the energy.
So it seems conceivable that you could advance the foam technology instead of just metal foams could have ceramic or composite foams and adjust it to fit your needs in the story.
BTW these are are not flimsy things like aerogels. Think more of something like solid steel in its hardness but with a porous network of small spheres.
[Answer]
Your four requirements aren't necessarily correct, but rather than explain in detail why each criterion is slightly wrong, I'll make a long rambling post on hypervelocity impacts, because I've done that a bunch of times before on this site and apparently nobody can stop me.
The first, and most important thing to remember is that hypervelocity impacts aren't like normal things smacking into each other. The impact pressures vastly exceed any plausible yield strengths, which means that both the impactor and impactee undergo plastic flow... this means they're more like liquids splashing off each other. This is a complex thing to explain, so you could have a read of this lengthy PhD thesis for more detailed explanations: [Penetration of a shaped charge](https://ora.ox.ac.uk/objects/uuid%3Accfed903-94a1-475b-be13-e6ac38089f1e).
Or you can just take my word for it.
Modern shaped-charge weapon research gives us a handy equation ([A Jet Penetration Model Incorporating Effects of Compressibility and Target Strength](https://www.sciencedirect.com/science/article/pii/S1877705813009302) calls it the Hill-Mott-Pack equation, but other names are associated with it too including Birkhoff and Tarantello, but I digress) and it looks like this:
$$P\_d = \ell \sqrt{\rho\_j \over \rho\_t}$$
Where $P\_d$ is the depth of penetration, $\ell$ is the length of the penetrator, $\rho\_j$ is the density of the penetrator (with j-for-jet, as the authors are thinking of shaped charge jets which are handy present-day hypervelocity military hazards) and $\rho\_t$ is the density of the target. (Note: this isn't a perfect model for *all* hypervelocity impacts, especially against armor plates that can deform instead of massive thick slabs of metal, but it serves to illustrate the problem. Real world penetration depths are likely to be *higher*!)
If your armor is thinner than $P\_d$, then your spacecraft is going to have a bad day. However, big thick shells of dumb armor are heavy, expensive and probably impractical... you're probably not going to put a meter thick shell of tungsten around your space station, for example.
Whipple shields don't remove that all-important $P\_d$ term from the above equation, and they're not usually thick enough to substantially reduce the velocity of the impactor.
What they do, is to reduce the $\ell$ term.
As you should already know, [Whipple shields](https://en.wikipedia.org/wiki/Whipple_shield) are not expected to stop everything. Here's what happens in an impact:
* The impactor hits your Whipple shield.
* It is probably denser than the shield and longer than the shield is thick.
* The impactor and shield act like liquids and splash off each other.
* Most of the impactor will continue on through the shield.
Your Whipple shield needs to be thick *enough* and dense *enough* that an impactor won't just blow through it without noticing. On impact, the tip of the impactor and the Whipple shield itself will splash out of the way, and unless the impactor is very small (like bit of gravel) most of it will carry on through.
The energy of the impact, however, will send a shockwave up through the impactor, and at least initially that shockwave will be strong enough that the molecular bonds holding the impactor together will not be able to resist it, eg. the end of impactor will explode. (I don't have any useful figures on the nature of this disruption... the design of Whipple shields shows that it happens, but the details of the *why* and *how much* are very hard to come by and might even be classified. Research on the effects of high-density projectiles is [limited](https://ntrs.nasa.gov/api/citations/20140006492/downloads/20140006492.pdf), and only seems to note that "they go through more armor").
The cloud of debris from the disrupted penetrator will initially still be very dense, and very dangerous, so you need to give it room to expand. How fast it expands depends on too many variables to consider here (the strength and density of the penetrator, the thickness and density of the Whipple shield, the spacing material or lack thereof between layers, the speed of the penetrator, etc etc). This is why Whipple shields require a *standoff* distance, to let the cloud of debris expand.
Instead of one long deadly penetrator, there are now a number of much smaller penetrators, spread out over a much larger area. The $\ell$ term is therefore much lower, and your armor thickness can therefore be much less.
[](https://i.stack.imgur.com/oLDTH.png)
(Image taken from [Micrometeoroid and Orbital Debris Environment & Hypervelocity Shields](https://ntrs.nasa.gov/api/citations/20120002584/downloads/20120002584.pdf), showing how important the standoff distance is.)
So, back to your four requirements:
1. **Lightweight**. Everything on a spacecraft needs to be lightweight, really. Bits of the shield *will* hit the craft in the event of an impact, but they can't be any more dangerous than the penetrator itself even if they're made of something really heavy, because physics doesn't work that way. The outer layer needs to be heavy *enough* to disrupt expected incoming projectiles.
2. **Flexible**. What you probably mean here is *tough* and *strong*. This prevents the hole made by the penetrator from being any bigger than it has to. Steel isn't particularly flexible, but it is quite tough and strong, for example.
3. **Hard**. Doesn't really matter, because at the impact pressures involved everything is behaving like a fluid and fluids can't meaningfully be "hard". You want a certain minimum amount of *areal density* in order for the penetrator to release enough energy when it hits to disrupt it. This means you can have a thin, high-density shield or a thick, low-density shield.
4. **Spready**. This isn't a property of the shield material... indeed, as it is behaving like a fluid in the impact, it can't really have many useful properties from its shape beyond plain old thickness. The spreadiness of your Whipple shield is a factor of its stand-off distance, eg. the spacing between layers. The more spacing the better, but obviously you are limited by the design of your spacecraft.
Here are some diagrams of real-world shields on the ISS:
[](https://i.stack.imgur.com/5R2f3.png)
Note use honeycomb and corrugated aluminium components, but for intermediate layers where they do a better job at catching hypervelocity crud without adding too much weight, not for outer layer spreadiness, see [page 27 of the MMODE&HS presentation](https://ntrs.nasa.gov/api/citations/20120002584/downloads/20120002584.pdf)). There are two kinds of shield which don't have a solid outer layer at all, using either [basalt fibers](https://en.wikipedia.org/wiki/Basalt_fiber) or woven metal threads. The non-metallic shields use *much* more spacing for the same protection. Other work mentioned in [Shields for Enhanced Protection Against High-Speed Debris](https://ntrs.nasa.gov/citations/20110023906) talk about
>
> exterior “bumper” layers composed of hybrid fabrics woven from combinations of ceramic fibers and high-density metallic wires or, alternatively, completely metallic outer layers composed of high-strength steel or copper wires. These shields are designed to be light in weight, yet capable of protecting against orbital debris with mass densities up to about 9 g/cm3, without generating damaging secondary debris particles.
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So what do we end up with? Well, its a bit boring and closer to old-school wet-navy battleship materials than cutting-age space age magic. Metal sheets work just fine, though if you're really weight-limited then fancier materials, especially in woven form, can also perform well. Aluminium sheet is OK... denser and tougher metals might be better, but research is lacking.
Really, all the clever stuff is in the inner layers... the bits where you have to deal with large volumes of low velocity debris, where being able to absorb energy by deforming or shatter projectiles with hard layers can actually have a useful effect. That's a much harder question to answer, but happily it isn't the one you asked!
---
Consider also, though:
* Hypervelocity impacts are not the only hazards in space.
* Metal sheets are good at breaking up hypervelocity impactors, but are ineffective against neutral particle radiation (eg. neutrons from nuclear weapons) and downright dangerous against charged particle radiation (due to [bremmstrahlung](https://en.wikipedia.org/wiki/Bremsstrahlung)).
* Steel is a lovely easy material to cut with a laser.
A more general purpose outer layer on a military object in space might look more like [enriched boron](https://en.wikipedia.org/wiki/Boron#Enriched_boron_(boron-10)) nitride nanotubes (tough, refractory, good neutron absorption cross-section) and [UHMWPE](https://en.wikipedia.org/wiki/Ultra-high-molecular-weight_polyethylene) to catch charged-particle radiation... but again, this isn't the question you've asked, but is definitely a problem you should be thinking about.
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[Question]
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My world has a variety of creatures which evolved from arthropod-like ancestors and became more similar to vertebrates in many aspects despite still having exoskeletons. One of these creatures, as I envisioned them, is a 6-legged predator no bigger than 30 cm long and strongly inspired by mole crickets, being a capable digger while still being able to fly.
*cutting to the chase, the simplest explanation for why they need to be able to both fly and dig is that I'd like them to be able to both fly and dig.*
My main problem when designing this creature's anatomy however is centered around 2 main "issues":
* Rather than classic insect wings, my creature has membranous wings evolved from the first pair of limbs, counting from the head, and has somewhat long limbs.
* I'd prefer to leave the other 2 pairs of limbs closer to its back adapted mostly for grappling prey and moving through the soil, as I'd like to stray from a design that's too "dragon-like" as much as possible, meaning a body plan that involves the frontal limbs being adapted to dig and the middle pair for flight is something I'd like to avoid, especially since I failed to find a way to make them "retractable".
Now the problem with such preferences is that I've met a point of contradiction: a creature highly adapted for burrowing have somewhat short limbs and powerful shovel-like forelimbs, while a flying vertebrate often has powerful, but proportionally longer forelimbs which tend to engage in a motion that's fairly different.
I tried searching for other real-world burrowing creatures that could help me flush out the anatomy of my creature, but other than the mole cricket, the closest examples of animals that are still capable fliers while still being highly adapted to burrow through the ground were the burrowing owl, which is itself anything but adapted for digging, merely altering existing burrows with its claws and beak most of the time, and the new Zealand short-tailed bat, of which I found very little regarding their ability to dig. As for the multi-use of wing-like limbs, the best examples were vampire bats, the burrowing bat and pterosaurs, which as far as I researched do not include any known species that's good at burrowing.
As for alternative methods of digging, creatures that don't use their limbs to dig, as far as I found, were comparatively much slower at digging through the ground, making such options less than ideal for my predator.
With that out of the way: **what are the limits of adapting limbs with membranous wings for burrowing without completely compromising the ability to fly?** Shorter wings are certainly an option I already considered, but I couldn't find anything regarding adapting the wings to also be used in digging. The wing limbs have 3 digits that can be adapted into a more shovel-like configuration, and it can tuck its membrane closely to the body to prevent damage while moving on the ground. If it matters, the overall structure of the limb and how it works is very similar to a vampire bat's, if it had 3 thumbs instead of one and used an exoskeleton.
[Answer]
**At least one kind of terrestrial bat can burrow**
>
> The two mystacinid bats, named the Greater (Mystacina robusta) and Lesser (M. tuberculate) Short-tailed Bats, are the most terrestrial of all the 950 or so bat species in the world. They spend much time at night running up tree trunks and along branches or burrowing in the leaf-litter and humus on the forest floor searching for food. They also burrow into rotten logs and trees to excavate their own roosts or use seabird burrows as both roosts and feeding sites. This "un-batlike" behavior is possible because they have a unique method of folding their delicate wings to protect them from injury. They are able to walk on their robust hind legs and feet, using their fore arms as front legs. Their fur is short and velvet-like, similar to that of moles and shrews. This terrestrial behavior probably evolved over millions of years because of the complete absence of mammalian predators. ([Source](https://www.batcon.org/article/new-zealands-unique-burrowing-bats-are-endangered/))
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And that quote helps you a lot.
* The bats learned to fold their wings to protect them.
* They learned to use their hind legs (I assume to help push them during burrowing and removing litter).
* Their fur is more conducive to burrowing.
But it also gives you limitations:
* They burrow in leaf-litter and humus on the forest floor.
* They burrow into rotten logs and trees (I assume "rotten logs and rotten trees").
* They burrow into other creature's dens.
What this tells me is that you could have the following limitations:
*To protect the membranous wing your creature would believably burrow only in soft soils, like sand, peat, or loosely compacted sediments. Rocky soil would be right out. They would be unlikely to burrow deeply unless your design toughened the wings and the bone structures of the arm, but do that too much and you begin compromising flight. I could imagine that they would burrow into the dirt surrounding tree roots to take advantage of the root structure's ability to add to the purpose of the den.*
But what I like the most is that your creature is a *predator.* This means that the burrowing ability can be used to chase food. additional limits would be the need to dig a short distance very quickly before the prey runs deeper into its den and to avoid the need to move litter aside. I would think this creature would favor chasing prey larger than itself so that it's burrowing ability allowed it to move faster without depending on the need to significantly (if at all) widen the hole. Just a thought.
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[Question]
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Once up on a time, in a world not our own, there was a piece of land inhabited by seven races of animal-people (like cat-people/dog-people, bird-people, and mermaids/mermans and such). Being animal-people, humans discriminate against them and tried to conquer their land from time to time. So for these seven races of animal people gradually becomes clans of warriors and promote bravery and sacrifice as a virtue. The understanding of how craftsmanship and agriculture can affect a war are known to them, so farmers, miners, and craftsmen are respected, but not as much as a warrior. Businessman often have to deal with demon beasts and bandits, and are great intelligence gartherers, so they are respected as well. The leadership of each of the seven races are, not surprisingly, are required to be great warriors. The only people not getting any respect are the scholars. People who research agricultural/metalurgy science are mostly already ironsmith or farmer already and receive due respect. But astronomy, economic, and natural philosophy researchers are treated like outcasts and have to live alone to avoid presecution.
These seven races are not really in friendly terms with each other, they fight from time to time and would only stop their battle if a human invasion is known.
So here comes our main character--MC. MC comes from the modern world and isekaied into this world. Seeing the humans are in the verge of industrial revolution, MC seeks to help the seven races. After uniting them into a single nation--think of a much more cohesive Austria-Hungary Empire, MC seeks to tech up these people. However, just using MC's own magic to create modern weapon and give it to them is not an ideal solution. Education is much needed for this nation so they can develop better technology themselves and understand themselves and the world better. But how to convince these muscle-for-brains that education and critical thinking is needed?
[Answer]
Hmm. If I was an artist-like society, I would try convincing them the importance of science by showing them soundwave art; the beauty of different celestial objects; or the poetic tragedy of life. Something like that xd
So maybe something similar for this warrior society? Painting and turning the otherwise uninterest studies of science, philosophy and economy as predator,warrior-like concepts. And maybe start shunning any resistance as *cowardness* of the unknown?
Sorry for the mediocre answer, but I hope it helps you, assuming your story is a bit more heartlighted. I could see something like that happening the other around in our world tbh :p
[Answer]
## Force invention into overdrive and hope for the best
I'm not going to delve into the isekai element because I've become pretty disgusted with the genre, it started alright at first but now it's just over-saturated with poorly written, self-insert power-fantasy.
As far as your problem of putting education before brute force goes, there's really no definitive way of doing so due to the simple fact that violence is the ultimate authority from which all other authorities are derived. Yes that's a Starship troopers reference and the book seriously delved into this matter (which I highly suggest reading just for the sake of exploring that subject). The movie only made it a passing joke, but when you think about it all the rules of society are ultimately crutched on the concept of violence. Roosevelt perfectly summarized this concept with his "walk softly and carry a big stick" mentality, clearly showing that no matter how ideologically or technologically advanced you might be compared to your opponent, he can always beat you into submission with overwhelming, sheer force if he decides to pursue that course of action.
If you want to promote education, the best possible way to do it is to put all of your efforts into invention in hopes of pushing it into overdrive, that way there's a chance that the concept and mentality of exploring new knowledge for the sake of discovering new advantages takes root. Without a doubt the best example of this were the two world wars, during which the invention of new technologies often turned the tides of battle, acting as an effective force multiplier which the losing side simply could not keep up with.
When it comes to logistics, that's really a no brainer, working SMARTER is always far better that working HARDER in the long run. Again, the best example again comes from both the world wars as the losing sides failed to keep up by not being able to match the enemy in that department. Most notable was the difference in tanks in the latter half of the second world war, as the Reich focused its efforts into creating effective tanks that excelled in a single dedicated role, the Allies relied on a concept of building balanced tanks which could fulfil a multitude of roles with ever-improving technology. The aviation also underwent a similar change, at first the Stuka's were the undisputed rulers of the European skies but as time went on and mainly better engines were developed, they fell behind and faded away.
Speaking in the application outside of warfare, perhaps the most notable invention to change the development of the human race was refrigeration. At first the main focus behind preserving large quantities of food lied in storing them in cold places, such as caves or large dugouts or simply streams or riverbeds, but as we learned to artificially create these environments the world population slowly increased. Then the early 20th century came along and as the refrigerator was invented and became a common item in every household the world population instantly shifted into overdrive.
Invention of drugs to help fighting illnesses improved our lifespan, the invention of better birthing methodology and better care lowered the infant mortality rate, invention of better clothing allowed us to survive in increasingly hostile environments, invention of better mining technology allowed us to reach further than we were able before and draw resources from spots we couldn't even speculate to reach. If you need inspiration why you should nurture invention you should simply take all of the things we take for granted today and analyze them in-depth, find out how they came to be and what was life like before they came around.
[Answer]
# Technology promotes better warfare
In history we can see that winning sides favour two things most of all. Numbers and technology.
If you can convince a warrior clan that their strength and skill are better if they are educated they can start respecting it. It can mold the warrios in warfare as well as out. Psychology can make them march in unison and fight fully motivated and as a single unit. Knowledge of fields and forests can can help with setting up and breaking down the encampment orderly and quickly in a strategic place, as well as helping with foraging and moving fast. But also inventions themselves make a difference. Stirrups and horseback riding help with speed and power. Bows can get longer range and accuracy. Brass vs iron makes huge difference in a fight. Especially for the underdog a good strategy can make a huge difference. Even for catapults you need to have a good understanding of force.
Good education can make your warriors better before, during and after battle, or even when having no fighting to do. As it can augment the soldiers they should jump on the opportunity when they realise the benefits. To do this, you can start with direct warfare applications, then expand further and further into other directly or indirectly supporting sciences.
[Answer]
**Breed for scholarliness. Cull the aggressive ones through war with humans.**
Humans have this in their power. Maybe they are already doing it with the beast people, accidentally. Your visitor foments wars between humans and beast people. The humans always eventually win because they are humans. Aggressive and warlike beast people bring only devastation to their people. Those who survive are humiliated and are not allowed to breed. They might even be castrated.
Scientific and scholarly minded individuals on the other hand can benefit from peaceable association with humans. Over generations, these individuals (who are also usually survivors of conflict) have more and more influence on their societies and leave more descendants.
I stole this idea from Larry Niven and the Man-Kzin wars! Aggression was bred out of the beast people (the Kzinti) by the use of war with humans to cull the most aggressive members of their race.
<https://larryniven.fandom.com/wiki/Kzin>
>
> A total of five additional Man-Kzin wars take place by the time
> Beowulf Schaeffer commented "The Kzinti aren't really a threat.
> They'll always attack before they're ready".[6] With decreasingly
> impressive logistical and technological advantages, each war results
> in the confiscation or liberation of one or more colony planets by the
> humans...
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> The Kzin reverses were deliberately engineered by the Pierson's
> Puppeteers, who lured the Outsiders to We Made It in the first place.
> The Puppeteers had hoped that the culling of a quarter to a third of
> the more aggressive members of the Kzinti with every war would result
> in a more peaceful race, or at least one that was capable of
> coexisting with other species without trying to kill and eat them at
> every turn.[8] This shift in Kzin attitudes succeeded spectacularly,
> although the Kzinti themselves do not think very highly of the
> changes, nor of the price they paid to achieve them.
>
>
>
---
The trick is to have this turn out differently than Niven did. Maybe most of the beast people are culled to nonaggressiveness like the Kzin, or are largely wiped out. But under this evolutionary pressure, one race of beast people changes in an unexpected way...
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[Question]
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It's fairly common to see discussion of different chirality for amino acids and sugars whenever people ask for advice on plausible alien designs or biochemistry (e.g.: metabolizing left-handed sugars and with proteins made of right-handed amino acids, compared to our R-sugars and L-amino acids). However, I've never seen anyone ask about a species using both chiralities in some way, so aliens who can digest both R-sugars and D-sugars, and/or who who have proteins built from a roughly even amount of R- and D-amino acids.
I've been considering trying to develop aliens who use roughly equal proportions of both chiralities of amino acids to build proteins. My questions then are A) is there any reason life couldn't incorporate both L- and D-amino acids into its biochemistry (this is of more interest to me), and B) could life evolve to digest both L- and D-sugars?
[Answer]
The reason why chirality is a thing in living organisms is because amino acids and sugars and so are made by enzymes and other such bits of biochemical machinery in cells, and those have chirality too. Thus they would assemble molecules preserving their chirality - which includes the next generation of cells. Since all living things have a common ancestor, you end up with every descendant cell keeping the same chirality. There isn't any evolutionary reason to create a whole new biologically incompatible set of systems.
You could potentially obtain a both-chirality alien if the planet the aliens live on have some sort of non-biological process that produces sugars or amino acids. Such processes would produce molecules of both chiralities, and perhaps organisms might evolve to take advantage of both being around. It's very unlikely that such an organism would use both chiralities the same way though. It would be more likely that you'd end up with an organism that initially evolved to use one chirality and then developed a secondary ability to use the second in some way so as not to be poisoned as its environment became rich in the other chiral type.
[Answer]
We have both righthand and lefthand gloves to go on the respective hands.
If your creature uses both, because of the issue of fitting together like the glove, it would probably be an obligate user of both. It could not simply slot a right-handed molecule into a left-handed process.
This is imaginable but not more efficient.
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[Question]
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This is for a base that has been built up into a big, complex place. For the radiation safety of long-term residents, the walls are very thick. There are windows, that are quite large. They have quite strong glass, reinforced and double glazed with about half a meter between the panes, so the outer layer acts as Whipple shielding against meteoroids. The rockets are nuclear but their fuel is hydrogen, so there isn't radiation exposure from them. Still, I put the nearest landing pad half a kilometer away in case of explosions. But I wonder if I'm being too conservative.
[](https://i.stack.imgur.com/6yFBg.png)
The ships do use liquid oxygen in an afterburner design, it's injected into the nozzle just after the throat so it's never exposed to the nuclear reactor. So the ships are carrying LOX and liquid hydrogen, but they are in separate tanks, in a vacuum. (The LOX is in the smaller tank sticking out near the bottom, the LH2 is in the larger tank to the left of it.) Does the low explosion potential of that arrangement allow the launch pad to possibly be even closer? Or does prudence say just never do that? These ships fly themselves - to hit other structures they'd have to be quite off their final approach and their emergency systems would have to all fail. (I don't know that 'self-destruct' is the way to go in this case. Maybe...)
[Answer]
The velocity of a detonation wave in a suitable hydrogen-oxygen mix is probably not going to be higher than [about 2km/s](http://www.hyresponse.eu/files/Lectures/Dealing_with_hydrogen_explosions_notes.pdf) for a well mixed cloud with ideal fuel-oxideser proportions, and what you'll be dealing with is not going to be a well mixed cloud. Lets take that as a worst case figure.
Bits of debris are not likely to come firing out of the blast any faster than that. The blast is going to be approximately spherical, which means that most of the shrapnel will not be heading towards your viewpoint. It'll arrive as a cloud of irregularly shaped chunks of lightweight metal and composites.
This compares favourably with the speed that you might be expecting meteor strikes to have, which could come in a *lot* faster than that... up to 72km/s, in the extreme.
The minimum safe separation distance, then, is a function of how much energy your windows can absorb per unit area, and some model of the most dangerous bits of debris coming out of the explosion. That seems entirely too hard to work out, as far as I'm concerned, but with suitably over-engineered windows you could handwave almost any distance away.
>
> does prudence say just never do that?
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There are good reasons to be cautious here. You're flying a nuclear reactor strapped to a bomb in front of a viewing deck.
Personally, I'd consider being about 1km away from a debris cloud propagating at 2km/s to be an OK distance. Consider that you have half a second to activate emergency protective systems... a set of safety radars might be able to trigger an explosively-closed blast-shutter fairly promptly, throwing up a curtain of rock and metal that could be as over-engineered as you saw fit.
>
> These ships fly themselves - to hit other structures they'd have to be quite off their final approach and their emergency systems would have to all fail. (I don't know that 'self-destruct' is the way to go in this case. Maybe...)
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One possible scenario here is an uncontrolled descent onto the spaceport at de-orbit velocities, which is *also* going to be at about 2km/s, only there's going to be just one big lump of debris instead of an expanding cloud most of which will miss you.
The roof of the any of the buildings on the surface will probably be quite thick! You might consider that point defense systems (that after all, might be powerful fast tracking laser weapons that could present a serious threat to anything hundreds or even thousands of kilometres away) or [range safety systems](http://cn.cgwic.com/LaunchServices/Download/manual/Chapter%209%20Range%20Safety%20Control.pdf) that would allow someone to remotely destroy a ship, problematic for other reasons (especially for the owners and any passengers!) but then you're in the territory of viewing areas being too risky to allow.
There's also an additional problem you may want to consider.
A bang which throws up debris at 1-2km/s in a vacuum is going to throw that stuff a long, long way. A lot of it is going up and out, and it could pose a serious threat to anything in orbit. That's a reason why you have landing pads by the way, instead of landing on unimproved regolith, because otherwise the debris kicked up by your landing burn could trash the person behind you in your original orbit...
[Answer]
**"This is for a game, this decision is for convenience of good visuals and game navigation."**
I found that in the comments. That is key! Leave the pad where it is. Then when something blows up the players can see. When it blows up real good it will mess with the base, knock stuff over, hole the windows etc. Best - the players will see the flash and then see and hear the rain of stuff coming across and down. No shockwave though being as it is the moon.
Stuff blowing up is one of the main reasons to play a game! If nothing blows up you might as well stick to cribbage.
I love the idea of the crumple zone on the roof too. Because a player might then survive having something big come down on the roof, then go out and survey the crumplage. That is a French word I am pretty sure.
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[Question]
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I am writing a story and the world it takes place on orbits a binary star system. Two stars, one a yellow dwarf like our sun, and the other a small, dimmer star. It takes the planet about twenty years to complete one orbit of the set of stars. The kicker is that when the planet is nearer the dim star, a deep winter overtakes the planet, which thaws out when it swings around to the yellow dwarf. So.. the planet spends about 3/4s of its rotation with the larger star, then about 1/4 of it's orbit near the dimmer star.
So.. (again).. The two stars orbit each other with the planet in a wide orbit around them.
The orbital mechanics needed to figure the rotation speed between the three things is obviously much too complicated for here, but a rough draft guess is most welcome!
Anyone have a better grasp of this that could hazard some numbers for the orbits needed to do this?
[Answer]
Decades ago, textbooks said that such an orbit was unstable and was not expected to exist. Today, it's called a *p-type* orbit. Seems they can be stable *enough* to last for millions or billions of years.
However, your ideas on the close-passing orbit is exactly the opposite of what it takes to make it work. What you described is actually a three-body interaction that will eject the smaller one.
A distant planet orbiting a binary star will see the strength of the gravitational field increase and decrease as the stars orbit each other, since the mass is *not* arranged in a symmetric ring but in two separated lumps.
A smaller analog is seen with Pluto. The central Pluto/Charon binary is orbited by four smaller bodies at a much greater distance.
The moons' orbits are actually chaotic, as the irregular and changing gravity of the central binary will nudge it this way and that way constantly.
Factors that keep it in this state include:
* *circular* orbits, *far* from the primary binary.
* nothing else passing near by to perturb them. Pluto's resonance with Neptune keep them far away from each other at all times. For a star system, it would need to not be in a dense cluster and happily not have had close passes with other stars in the galaxy.
* Multiple bodies in near resonance. The perturbations are shared, and they try and fall back into the common state. You can't easily nudge *one* of them, as the siblings cooperate to nudge it back. At any one time, the buffeting from the binary orbiting will be one way for one moon and a different way for another moon which lies in a different direction, so they cancel out to some extent.
* lack of features that would induce eccentricity. You want them to circularize and stay that way once the (near) resonance develops.
[Answer]
Have your stars be separated between 0.15 and 0.5 AU. And your habitable planet in the habitable zone and at least 4x the distance of the maximum separation between your stars. Also your stars have to have a minimum separation of 0.1 AU.
If you don't know the equations then this video from Artifexian will tell you. <https://youtu.be/1nV2ygdKZ3s>
It is also my source for the numbers above.
[Answer]
Short Answer:
What you ask for might be possible if your planet and another planet or star in the system have a long enough synodic period.
And it might also be possible if your planet and another planet are co-orbital. How could another planet help to heat up your planet? That will be explained in the long answer.
Long Answer.
Part One Of Nine: A Complaint.
Your title is misleading. The planet doesn't orbit around "two binary stars" which would be a total of 4 stars in two pairs, it orbits around a single "binary star" which is one pair of two stars, or it "orbits around two stars which are a binary system".
Part Two Of Nine: Problems with a Habitable Planet with a Long Cycle of seasons.
There are big problems with having a habitable planet in an orbit which takes about twenty Earth years. The question didn't say "Earth years", just "years" But since one orbit by the planet is one of that planet's years, one orbit can not possibly equal 20 years of the planet. So I assume that you mean Earth years instead of Mercurian years or Neptunian years.
For a planet to be habitable - the question doesn't specify that, but since it is a science fiction story I assume that the planet should be habitable for liquid water using lifeforms in general or even for humans in particular - it has to have a relatively steady inflow of radiation from it's star or stars, and for a very long time, billions of years.
As far as I know, the main scientific discussion of the requirements for a planet to be habitable for humans is in *Habitable Planets for Man*, Stephen H. Dole., 1964.
<https://www.rand.org/content/dam/rand/pubs/commercial_books/2007/RAND_CB179-1.pdf>
Chapter Four: the Astronomical Parameters, starts with a section describing the properties of a habitable planet. The proper age of a planet is discussed on pages 61 to 63. The plant Earth didn't becme habitable for humans until about four billion years after it formed.
Dole concludes with:
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And there is a section about Properties of the Primary (the star) on pages 67 to 72.
Stars shine with fairly stable amounts of solar radiation durin the main sequence phase of their "life cycle". After the main sequence phase the luminosity of a stars has drastic changes which should kill all life on its planets - in some cases the star will actually totally destroy some or all of its planets.
As a rule, more massive main sequence stars usually have much more hydrogen to fuse into helium during their main sequence phases. But their luminosities, the rates at which they emit radiation (and thus the rates that they use up their hydrogen to produce that radiation) increase at a higher rate than their mass. Thus more massive stars spend shorter periods of time in the main sequence phase of their existence.
On page 68 Dole says:
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> The only stars that conform with the requirement of stability for at least 3 billion years are main sequence stars having a mass less than about 1.4 solar masses-spectral types F2 and smaller-although the relationship between mass and time of residence on the main sequence is probably not known with great accuracy and is subject f to futue revisions (see figure 25). Stars havng masses greater than 1.4 solar masses spend less than 3 billion years in the main sequence and then go into evolutionary phases in which the energy ouput changes rapidly.
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The answer by user177107 to this question
<https://astronomy.stackexchange.com/questions/40746/how-would-the-characteristics-of-a-habitable-planet-change-with-stars-of-differe/40758#40758>
Has a table giving the characteristics of stars of various spectral classes. It also give the calculated orbit of a plenet receiving the same amound of energy as Earth receives from the sun, including the length of the planetary orbit in Earth days.
For a F2V class star the orbital distance would be 2.226 Astronomical units or AU (the distance between Earth and the Sun) and the planetary year would be 1,018.01 Earth days, or about 2.78 Earth years.
And perhaps that might be the longest possible year for a planet that receives exactly as much radiation from its single star as Earth gets from the Sun.
But the star is supposed to be a binary star so the planet gets radiation from two stars that it orbits around.
If we make both of the stars F2V class stars, the distance to an Earth equivalent orbit will be increased by the square root of 2, which is about 1.141. So the Earth equivalent orbit around two F@V stars would be 1.141 times 2.226 AU, or 3.148 AU. And with an orbital radius of 1.141 times, it will also have an orbital circumference 1.414 times as great. So if the planet orbited at the same speed, its years would be 1.414 times 1,018.01 Earth days, or 1,439.466 Earth days, or3.941 Earth years.
But doubling the mass that the planet orbits must also increase the required orbital speed. Thus the length of the planet's year will not increase by as much as 1.414 times. Without doing the calculations, I can't even predict if it will increase at all.
I also note that since the two stars are orbiting much closer to each other than the planet is to the pair, the orbital periods of the stars around each other will be only a fraction as long as the orbital period of the planet around the two stars.
Thus even if you could get the planet to have an orbit around the stars that was twenty Earth years long, the alternation between the brighter star being closer to the planet and the dimmer star being closer to the planet would happen several times during the twenty Earth year orbit of the planet. Thus there would be several complete cycles though the seasons during one twenty year planetary orbit.
Part Three of Nine: Suggestion One:
It would be easy enough to give a planet a year 20 Earth years long. Put it in orbit around a spectral class O or B star where it would have an orbit 20 Earth years long in the star's habitable zone. The planet would have to be very young and terraforemd to be habitable by an advanced civilziation. Or else it could be an old planet that naturally became habitable and was moved from it original star to orbit around a hot young star.
But if the planet orbits around two stars, for reasons of stable orbits the distance between them has to be small relative to the distance at which the planet orbits the pair, so that they will make several full orbits during each planety orbit, and thus alternating periods of more and less stellar radiation, and thsus planetary seasons, will happen several times during the orbit of the planet.
And that is true regardless of which spectral type of stars the planet orbits and what its orbital distance is.
The same will also happen if a planet orbits one star and there is another farther away in the system. The two stars will be far enough apart for reasons of orbital stability that the planet will make several orbits around the near star for each orbit of the two stars around each other.
One way to handle that problem would be to make the orbits of the two stars rather eccentric so at times they get much closer, and make the farther star much more luminous than the nearer one, thus creating summers when the two stars are closest together. I think that I discussed the mathematics of such a situation in an answer to another question.
Possilby ths one:
[Could an Irregular Orbit Cause Significantly Longer Seasons?](https://worldbuilding.stackexchange.com/questions/211464/could-an-irregular-orbit-cause-significantly-longer-seasons/212541#212541)
Part Four of Nine: Synodic Periods.
Another method would be to use the synodic period of the planet and one of the stars instead of the orbital period of the planet.
The synodic period of two objects that orbit a third object is the time it takes for the two orbiting bodies to return to the same relative positions again. For example, it could be the time between two consecutive moments when two planets are on opposite sides of their star, or the time between two consecutive moments when the two planets are lined up on the same side of the star and approach each other the closest.
So the synodic period of two objects orbiting the same object is a mathematical relationship between how long their orbital periods are relative to each other.
And here is a link to an article which has a curve showing the lengths of the synodic periods of solar system planets relative to Earth.
Note that the greater the difference there is between the orbital period of a planet and that of Earth, the shorter the synodic period will be, while the smaller the difference there is between the orbital periods of the planets the longer the synodic period will be.
So if the second star in the system orbits just within or just outside of the orbit of the planet, the synodic period will be many times as long as one orbit of the planet around the first star. By making the difference between the orital periods of the second star and the planet small enough, the syndoic period between the second star and theplanet can be made arbitrarily long, which includes a synodic period of 20 Earth years if that is desired.
So if the planet orbits just inside or just outside the orbit of the secondary star, the planet would get farther and farther away from the heat and light from the second star during half of their synodic period, and in the other half of their synodic period it would get closer and closer to the head and light of the second star. So for part of the synodic period of the second star and the planet the planet would be close enough to the heat and light from the second star and hte planet would heat up significantly.
Problem solved.
Part Five of Nine: The Flaw in the Synodic Period solution.
Except that as I stated earlier in this answer there has to be a big difference in the orbital distances, and thus the orbital periods, of the planet and the second star for their orbits to be stable over billions of years. If the planet and the second star obit the first star in orbits which have similar radii and thus similar orbital periods, and thus have a long synodic period, the system will be unstable and the planet, being much less massive than the second star, will be the one that is ejected from its orbit - which will be very bad for life on the planet.
Part Six of Nine: The Synodic Period with Another Planet instead of Another Star.
The only way to avoid such a problem would be to put the planet in a orbit very close to the orbit of another planet orbiting the planet, thus giving the two planets a very long synodic period, which can easily twenty Earth years long if you wish.
But how will the planet be heated up by the other planet when they pass close once every twenty year long synodic period? Planets are notorious for only reflecting light and heat from their stars and not generating any heat and light of their own.
So the planet which acts like a smaller sun to your planet will have to extremely hot for a planet, glowing red hot, to emit enough heat and light to warm up your planet during close passes.
Part Seven of Nine: How to Make a Planet hot Enoough to Act Like a Star.
So maybe your planet formed in a different solar system and gradually became a habitable planet over billions of years. Its star began to swell up into a red giant which would soon kill all life on the planet. But a super advanced civilization moved the planet from its original star into orbit around another star - a very young star with very young planets. The planets in the system had formed so recently that they were still glowing red hot from the heat of their formation. And the advanced civilization moved the planet in your story to an orbit very close to the orbit of one of the glowing red hot planets, which gave the two planets a synodic period of about 20 Earth years. And once every synodic period your planet would pass close to the red hot planet and be heated up by its visible and infrared radiation.
And that would continue for millions of years as the young new planets gradually cooled off.
Or possibly the planet in your story is in your its original solar sytem and all the plannets are billions of years old and thus cooled down to normal temepratures billions of years ago. Your planet's orbit is very similar and close to that of another planet, so they have a long synodic period and pass at their closest once every synodic period. And the two planets look very spectacular in their skies during the close approach, but they don't heat each up up much.
In the early periods of star systems, planets form in unstable orbits, which gradually become stabilized as the planets with the most unstable orbits fall into the star, are ejected into interstellar space and become rogue panets, or else collide with other planets. And after a few hundred million years, almost all of that is over, and the remaining planets are in orbits which will be stable for billions of years. But it would still be possible, though rare, for planetary orbits to be destabilized and two planets collide, even after bilions of years when that never happened.
So perhaps after billions of years without any orbital problems, minor perturbations finally add up to enough to force a planet in the system out of its orbit into a new orbit which puts it on an eventual collison course with the neighbor planet to your planet. the two planets collide and are shattered into incandescent vapor and red hot lava, and most of the pieces gradually reform into a new planet with an orbit similar to that of the neighbor planet. Thus the new planet also has a synodic period of about 20 Earth years. And now, whenever there is a close approach to the new planet, it emits a lot of light and heat and warms up your planet, a situation that should continue for millions of eyars during the cooling off period.
For close approach to a red hot planet to work, you will want the two planetary orbits to be very close in relative terms, to have a very long synodic period, and also to be very close in absolute distance so the close passage is close enough for the red hot planet to warm up your planet signficantly.
Part Eight of Nine: Can Planetary Orbits be That Close?
The planetary orbits in the famous *TRAPPIST-1* system are quite close in both relative and absolute distance.
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> The orbits of the TRAPPIST-1 planetary system are very flat and compact. All seven of TRAPPIST-1's planets orbit much closer than Mercury orbits the Sun. Except for b, they orbit farther than the Galilean satellites do around Jupiter,[44] but closer than most of the other moons of Jupiter. The distance between the orbits of b and c is only 1.6 times the distance between the Earth and the Moon. The planets should appear prominently in each other's skies, in some cases appearing several times larger than the Moon appears from Earth.[43] A year on the closest planet passes in only 1.5 Earth days, while the seventh planet's year passes in only 18.8 days.[41][37]
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<https://en.wikipedia.org/wiki/TRAPPIST-1#Planetary_system>
The orbital period of planet f is 9.206 Earth days, and the orbital period of planet g is about 12.353 Earth days, giving a ratio of about 1.341, the smallest ratio of orbital periods in the system. According to this synodic period calculator:
<https://www.omnicalculator.com/physics/synodic-period>
The synodic period of f and g is 36.137 days, which is 2.925 times the orbital period of g and 3.948 times the orbital peirod of f.
So for two planets to have a synodic period of 20 Earth years and have relative year lengths in that same proportion they would have years that were 5.06 and 6.837 Earth years long.
And as I calculated much closer to the beginnng of this answer, habitable planets probably can not have orbital periods that long.
And if their orbital periods are that long and their orbits are that wide, the absolute distances between the two orbits is likely to be so great that even a red hot planet would not heat up its neighbor much.
If the synodic period was 99 times the period of the outer planet, and 101 times the period of the inner planet, and equalled 20 Earth years or 7,305 Earth days, the orbital period of the inner planet would be 72.326 Earth days long and the orbital period of the outer planet would be 73.787 Earth days long.
Using the synodic period calculator using orbital periods of 72.326 and 73.787 days, the calculated synodic period is 3,652.785 days or 10.00078 Earth years.
If the synodic period was 999 times the period of the outer planet, and 1,001 times the period of the inner planet, and equalled 20 Earth years or 7,305 Earth days, the orbital period of the inner planet would be 7.297 Earth days long and the orbital period of the outer planet would be 7.312 Earth days long.
Using the synodic period calculator using orbital periods of 7.297 and 7.312 days, the calculated synodic period is 3,557.044 days, which is actually shorter than the previous example..
Using periods of 98.5 and 99.8 days, I get a synodic period of 7,028.678 days, or 19.24 Earth years, which seems close enough to 20 years.
Using periods of 49 and 49.33 days, I get a synodic period of 7,324.758 days, or 20.054 Earth years, which seems close enough to 20 years.
Using those shorter periods, the planets can be closer to their star and thus closer to each other, making it easier for a red hot planet to heat up your planet when they pass close to each other.
And no doubt there are many other possible combinations of orbital periods resulting in a synodic period of 20 years.
But those arrangments require the two planets to have orbits which are relatively much closer than any known examples. Is it possible for two planets to have orbits so close together both relatively and absolutely?
Part Nine of Nine: Co-orbitals.
Actually it is possible for two astronomical bodies to be co-orbital, sharing the same orbit though at different positions in it.
Theoretically it is possible for two objects to share almost exactly the same orbit, with only a slight difference in the semi-major axes of their orbits. Thus they have very long synodic periods. And when the slightly inner and slightly faster object finally catches up with the slightly outer and slightly slower object, their gravitational interactions causs them to change places, so the former inner is now the outer and the former outer is now the inner.
Astronomers know it is possible to have a reasonably stable orbit like that, because one has been discovered decades ago.
Epimetheus and Janus are two moons of Saturn which share the same orbit in such a configuration. The differenc in the semi-major axes of their orbits is only about 50 kilometers, which is smaller than their radii. Their orbital periods are both about 0.694 Earth days, with a difference of about 26 seconds in orbital period. The synodic period of the two moons is about 4 Earth years, or about 1,461 Earth days, or about 2,105 orbits.
If two planets had a synodic period of 20 Earth years or 7,305 Earth days which was about 2,105 times as long as their orbital periods, their orbital periods would be about 3.47 Earth days long with a difference in length of about 130 seconds or 2.16 minutes.
If two planets can have orbits that close, it might not be necessary for one of them to be composed of red hot lava. When the two planets are orbiting almost side by the side, the other one will reflect a lot of light onto the inner one, and their tidal interactions should create a lot of tidal heating. And they should be travelling close together for a signficent percentage of their total synodic period, and the summers caused might last for a significant time.
And that is even more the case if the two planets actually switch orbits once in each synodic period.
As they get closer and closer planet A may be the inner planet and get more an dmore heat reflected from t palnet B, the outer planet, and the tidal heating on both of the planets should get stronger and stronger. At the moment of orbital exchange the tidal heating should be at its strongest, and then it should gradually diminish over weeks, months, or maybe years as the planets gradually separate. And after the switch, planet B will now be on the inner orbit and get a lot of refelected ehat from planet A which will now be the outer planet.
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[Question]
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I'd like to use a story with a sapient swarm intelligence because I find the idea interesting, but I'm having trouble developing some of the finer details of how this intelligence would interact with humans and aliens similar to humans.
**Current traits of this species**
A swarm of this species is comprised of ant-like insects with a widely varying phenome. Each swarm gives rise to a swarm intelligence, but different intelligences within the species do not compete. Instead, if one swarm comes close to another, the intelligences merge into a single whole, and only split if enough members of the new swarm move out of communication range. The larvae act like chemical factories, synthesizing complex molecules for use in biology-based technology. This technology is advanced enough for the intelligences to be space-faring. The intelligences are sapient, which for my purposes I've defined as:
1. Able to understand the world in terms of abstract concepts and able to reason quantitatively
2. Able to learn and plan
3. Able to sacrifice short term interests for long term gains
4. Possesses theory of mind. Each swarm intelligence is aware of itself, and aware that other creatures outside its species have their own minds.
However, due to the fact that there is no real "individual" intelligence in this species, only different instances of the same intelligence, I'm currently planning for the species to not have inherent aptitude for communication like humans do. Single insects of this species communicate with each other to form their swarms, but the intelligences do not.
**Details I'd like help on in this question**
* Is it possible for such an intelligence to learn how to communicate with humans, or for humans to learn how to communicate with such an intelligence? For example, could it think about and articulate such things as goals, wants, desires, or does sapience guarantee the ability to think about those things? Or would such a swarm be varelse, to use Card's [Hierarchy of Foreignness](https://enderverse.fandom.com/wiki/Hierarchy_of_Foreignness)?
* If it *is* possible for intelligences of this species to communicate, what would those communications look like? For example, would we need to hook up translators to models of human society, and exchange information that way? Or could we talk with an intelligence the same as they might any other human?
Edit: I altered the line regarding theory of mind to be more specific.I altered the line regarding theory of mind to be more specific. I also included a note regarding the technology level permitting space travel.
[Answer]
You yourself are a swarm intelligence. It takes billions of little neurons interacting together to produce the emergent behavior called intelligence. It makes little difference whether the "neurons" are glued together in close proximity or are free-roaming.
As for your question, there's no reason to suppose aliens (especially exotic ones) to communicate vocally the way we do. There are many modes (correct word? not a linguist) even among humans. There are whistling languages, sign languages (and so many!), even the perennial joke of "communicating via interpretive dance".
They might have experience with two or more modes, and thus the ability to imagine *other modes* of communication.
The bigger problem, is of course, that science fiction writers tend to imagine aliens as being *just like us* even if they look weird. Intelligence doesn't mean "human-like", after all. It's merely a survival adaptation that allows an organism to anticipate dangers and rewards, to avoid the former and pursue the latter. Even if they were essentially human-like in their psychology, the vast (nearly infinite) range of motivations, beliefs, compulsions, perspectives, values, and norms among purely human cultures means that the mechanical concerns of translating alien languages leaves alot of mystery to be resolved... none of which we can help you with.
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In regards to a pheromone-based language, I would like to point out that this probably reduces the rate of communication (dependent on the details). For instance, as I type out this answer on a keyboard (full-sized!), I'm probably topping out at a rate of 60wpm. I can speak vocally a bit faster... some quick Googling suggests that 150wpm or perhaps slightly higher is possible (and this varies language to language, some will have a far lower wpm rate, but each word conveys more meaning because words have so many declensions and modifications).
For typing, I have approximately 100 symbols, and the appendages to switch between them quickly... a fraction of a second surely. For speech, I have the 30 or 40 phonemes of English, plus maybe some vocal intonations (just a few in my language). And again, the ability to switch between those in a fraction of a second.
With Earth biology, how quickly can an organism start or stop secreting a substance? This is more of a chemistry question I suspect, less of a biology one... because even after they have stopped secreting a pheromone, the substance will persist at a perceivable level for some time (seconds or minutes, unlikely hours). They are likely to have far fewer "phonemes" to work with, the switching rate is far lower (3 or 4 orders of magnitude), and they might need a high overhead of error correction (even we need to repeat ourselves from time to time).
This has nothing to do with whether they are slow thinkers (as you see in some stories), but does mean they're probably slow speakers. A fast thinking, slow speaking alien might develop the compulsion to pack as much information as possible into a given communication (more so than my wall-of-text answer here), which if you wanted could be a plot point in your story.
Other implications are harder to discern. You might think that, whatever other factors make the gulf between humans and swarmies vast, at least they can communicate about the objective universe around them. They can agree on a periodic table of elements, the mass of the proton, and so forth. And well they might... but they might not. Greg Bear posits a species of alien for whom the idea of *integers* is completely foreign. To them, you never count anything precisely, but only approximately and statistically. Their math allows them a similar level of technological sophistication. There are other similar examples out there at least in fiction.
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We imagine any hive would struggle a lot with the first interactions. If this hive has some kind of psychic link, they might be mortified by the idea of anything existing outside of it, with its ideas of self and completely independent thoughts and means of communication. It will take a very long time to come to any kind of understanding with these strange individuals. Maybe it'll never happen.
If the hive communicates through other means (phermones, vocalizations, body language, etc.), it's probably a pretty rudimentary system, since everyone in the hive is kind of, by nature, on the same page all of the time. We think this would make first contact a little easier, but we aren't sure if the individual drone would even really recognize the alien as anything more than an intruder and threat to the hive.
As for the hive itself, we can't imagine they care for much except keeping themselves fed and spreading out to new planet-nests. Unless the Intelligence really passes its own judgement on the xenos, we can't see it really doing all that much in the way of traditional diplomacy without really changing the way the hive works into somethong far less alien or flattering.
We think any interaction would likely be very... symbolic. And mostly relying on the efforts of the individual intelligence, more than anything getting the drone's attention and holding it in a positive manner long enough to achieve anything, and even then abandining any attempts at language or cultural relation. We're thinking less treaties and diplomacy, and more cautiously convincing the hive that the individuals are not a threat while also coaxing their hordes of hungry drones from their nice little colonies, thank you very much.
This is a really difficult question! I hope some of our ideas helped in some way, and remember: EMBRACE THE SWARM. *insectoid chattering*
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I am not sure such intelligence would recognize at first glance a human (single or in group) as intelligent, because it would lack the hability to merge.
More or less the same we human have long debated if humans from different parts of the world were intelligent only because they didn't have some hability deemed as basic.
Without the recognition of intelligence, there would be no push to communicate, not past the communication level we have with dogs or other animals.
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Is there any biological or environmental factor stopping animals or plants to be farmed for their metal absorbing qualities? Consider we are also counting creatures created through selective breeding, forced hybridization and grafting.
10'000 kilograms of pig liver contains 1.79 kilograms of pure iron, the same amount of mussels contains 0.67 kilograms of iron and around 0.37 to 0.8 kilograms when counting leafy greens like spinach.
In order to make metal farming feasible, organisms must absorb and store more iron than that, is there anything stopping life forms from absorbing up to 100 times more iron than the above examples?
I'm using iron as an example but any other similar metal is fine.
[Answer]
Living organisms are bound to natural selection, which is a harsh mistress and an even harsher accountant: when checking the bills of the expenditure of each organism, any surplus expenditure will be punished if not justified.
This come to answering your question: what is the tangible benefit for a living organism in concentrating that much metal to make it worth spending a lot of energy in doing it?
Don't forget that the homeostasis keeping an organism alive is a very delicate balance of many chemical reaction, in which the slightly excess, both in the too much or too few direction, can be lethal.
[Iron](https://en.wikipedia.org/wiki/Iron_ore) is one of the most abundant metal on Earth, and
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As you can see those figures are waaay bigger from what you quote as iron content in living beings, at least 4 orders of magnitude.
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# Yes, with some hand waving
There are efforts to breed plants that can absorb different types of materials. This approach is called [bioremediation](https://en.wikipedia.org/wiki/Bioremediation). [This article](https://www.nytimes.com/2020/04/07/science/superfund-plant-microbiome.html) covers one approach. You could use a little handwavium to have scientists lab-engineer plants or trees that could slurp up valuable minerals. Then they could be harvested. Each plant would contain a small level of minerals, so you would want to pick a low maintenance plant that wouldn't require much effort to grow.
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Iron, shmiron. If we are going to use biology to make metal we want valuable metal! This is one of my favorite late afternoon musings: how to get bacteria to get that gold out of seawater.
<https://www.livescience.com/61804-bacteria-poops-gold.html>
[](https://i.stack.imgur.com/X9ryv.jpg)
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> The soil-living, rod-shaped bacterium Cupriavidus metallidurans is
> famous, biologically speaking, for being able to survive massive doses
> of toxic metals. Now, new research reveals that special enzymes within
> the bacteria are responsible for changing toxic versions of gold into
> inert solid gold, which creates miniature gold nuggets.
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The idea would be to farm sheets of bacteria in waters containing trace amounts of valuable elements, then harvest the bacteria and purify out the elements. A big farm of bacteria like the one depicted at river mouths would be ideal. The problem is finding places with adequate concentrations of the metals you want. This is where GMO comes in - augment the bacteria with hugely more metal avidity than their ancestors. That is pretty easy GMO.
Gold will bring in the crazed cash-fat investors but there are other less sexy but more lucrative ions one could collect with this method.
There are many different ways in which biology can sequester
metal. I had a scheme once upon a time (oh my gosh so long ago) using antibodies in algae to accomplish this end.
<https://www.halfbakery.com/idea/GMO_20Ocean_20Mineral_20Harvest#1042218000l>
[Answer]
**A believable path could be created, but there is no way to justify it in reality**
*But, then again, why are we here if we're bound only to reality?*
I agree completely with L.Dutch's answer. It's hard to see past the efficiency of iron ore.
Here's the problem: the amount of metal bound within a living organism can never exceed the capacity or need of that organism to live its life. As an example, no more iron could be bound within the human body than would allow that body to move to forage, propagate, and live its life. It cannot unreasonably weigh down muscles, it cannot threaten immune systems, it cannot compromise the oxygen cycle or digestion. life, after all, is a delicate balance.
However, people swallow coins and live their lives with bullets in their bodies. Fragments of metal continue in war survivors. I'm not suggesting that any of these general examples suggest it's easy, only that it's plausible for a life form to be believably presented as having a higher metal content.
But, said another way, iron ore will always be a simpler, more efficient way of obtaining iron than farming a biological factor no matter how well crafted to maximize its metal-carrying abilities. The density of iron ore will always exceed the density of metal in living organisms by many orders of magnitude.
*But that's boring*
I could suspend my disbelief to enjoy a story that required farming living organisms for metal so long as the substantial inefficiency involved was justified. IMO, it's not enough to rationalize higher metal content in living organisms...
*...you also have to rationalize why it doesn't exist in mineable quantities — and yet exists in sufficient dispersed quantities — such that it makes sense to farm animals at all. Then, you need to explain why evolution allowed all that metal to bond to living creatures in the first place.*
**Let's chase that and see where it leads us**
**Disclaimer:** Biology is ***NOT*** my strong suit. If someone practiced in the art reads this and find themselves capable of typing a comment to point out my error amidst their convulsions of laughter, I'd be grateful.
>
> Lactoferrin is a nutrient classically found in mammalian milk. It binds iron and is transferred via a variety of receptors into and between cells, serum, bile, and cerebrospinal fluid. It has important immunological properties, and is both antibacterial and antiviral. In particular, there is evidence that it can bind to at least some of the receptors used by coronaviruses and thereby block their entry. ([Source](https://www.frontiersin.org/articles/10.3389/fimmu.2020.01221/full))
>
>
>
We have a world that has a lot of iron, but for some reason, that iron is never found in a chunk bigger than the tip of one's finger. It's thoroughly dispersed through the soil, where it can easily be picked up by plants. Plants will draw almost anything from the soil, but I want to jump a step further and justify that extra iron in an animal.
The quote above explains that there is a mammalian protein that binds iron: Lactoferrin. The animal will consume iron via the plants thanks to the high concentration of what we'll call *molecular iron* in the soil. The lactoferrin gets it into the body and has the potential of keeping it there.
*But why?*
As L.Dutch said, evolution is a harsh mistress and an even harsher accountant. For example, in humans too much iron can [compromise zinc absorption](https://ods.od.nih.gov/factsheets/Iron-Consumer/), and that compromises the immune system. But that same link explains that we humans need iron to produce *hemoglobin,* a protein in red blood cells.
Cool, so why would life on your planet need higher concentrations of hemoglobin? Among its uses, it [carries oxygen to cells and carries away carbon-dioxide](https://www.mayoclinic.org/tests-procedures/hemoglobin-test/about/pac-20385075).
Which means, using suspension-of-disbelief as the criteria, you could suggest that your planet has a higher percentage of carbon-dioxide in its atmosphere, requiring a greater quantity of hemoglobin to better carry in the limited oxygen and carry out the too-abundant CO2, which means more iron is needed... and we have Lectoferrin as one possible rationalization for how to do that.
And as mentioned earlier, it's all because on your planet there are no iron deposits anywhere. Perhaps (and I'm skipping to a simple explanation because I'm out of time to write this answer), volcanism is long-past on your world, and erosion has scattered the iron and bound it with oxygen (helping to rationalize the limited oxygen supply). In other words, your world has rust dust *everywhere.*
*But no iron mines anywhere....*
**Conclusion**
I believe you can rationalize higher metal content in living organisms such that they could be mined for metal. But even with the increases you're suggesting, it's an horrifically inefficient process. This suggests that you need to further rationalize why no iron mines can exist on your world — and binding the two together as cause-and-effect can solve your problem.
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In RL there are areas more likely to have storms which affect ship design (and in premodern era routes).
**Are there any rules of thumb to predict which waters would have frequent storms on a fantasy map?** I mean for example how to designate a spot to put some equivalent of Cape of Good Hope at which people used to look a bit nervously?
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Storms are driven by energy. So you need to consider how and where energy enters your fantasy waters.
Some main rules of thumb:
* **The larger the expanse of water, the more wind energy can interact**, driving small ripples into large waves and adding energy to water.
* **Ocean waves might appear shallow but the oceans are deep so quite a bit of the energy enters the water column** - the vertical space that waves and shallower currents occur in. When that water column hits shallower water or a conflicting current, the energy it contains may lead to wilder, larger or less predictable waves.
* **Cyclonic and anticyclonic storms (cyclones, hurricanes) are driven by heat and evaporation**, the warmer the water the more intense the storm. They die after a while over land when they are cut off from their ocean power source.
* **Areas where powerful wind/current systems tend to meet, will have more variable weather**. For example, the UK, sitting on the gulf stream and the jet stream, between warm Atlantic/Europe and Scandinavia/Russia/arctic, and between a large body of water and a large land mass, has variable unpredictable weather, compared to many places.
This is why storms build up around the southern ocean (deep, no land mass blocking wind or water flow), and across the Atlantic and Pacific, but not really across the Arctic ocean (broken up by land). Its also why the storms we associate with the tropics, forming across the Atlantic/Pacific, tend to be cyclonic (heat driven hurricanes/cyclones) while those in the southern ocean are more often very high winds and waves without a formal cyclonic/anticyclonic structure.
**Bad waters aren't always storm driven. Expanding on the question, intense waves and water currents can exist where currents conflict, or are forced into a narrow area - especially a deep and narrow area with room for large water movements**. So also consider where waters meet.
This is a large part of why the Cape of Good Hope (southern Africa tip) and Cape Horn (southern Chile tip) were both so ill-reputed to sail - conflicting currents between the oceans that meet there, as well as the winds around there. Both built up over thousands of miles of ocean surface, too. Its also the reason for tumultuous passages like the Maelstrom in Scandinavia.
Last, consider **land topology such as mountains**. These can block wind and weather systems, or funnel them - sometimes causing conflicting wind systems. They also tend to create a rain shadow, and may give rise to a desert on the far side.
Finally, not predictable at all, but rogue waves can appear anywhere, even far out at sea, from random wave energy behaviour. They can be more likely in some areas, but are essentially randomly formed, not storm created.
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What causes capes in the South to be so difficult to navigate is the lack of continental masses which can slow down the winds. These winds, blowing unrestrained all around the ocean, end up producing the so called "[Roaring Forties](https://en.wikipedia.org/wiki/Roaring_Forties)", Furious Fifties and Screaming Sixties.
Therefore your rule of thumb is "the more a wind can interact with a body of water, the stronger phenomena it can produce".
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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.
It seems like the Jupiter system is especially attractive in terms of natural resources, and while I assume the majority of any extraction labor will be performed by machines, I also figure there will be a skeleton crew of human overseers on-site, and it's not hard to imagine that footprint eventually growing into some small orbiting colonies. (I figure the colonies stay in orbit as long as possible, because when you climb down into a gravity well, you're making a *real* commitment.)
It's also my understanding that Jupiter has a wicked magnetic field that's filled with all kinds of powerful radiation.
I have a cluster of questions related to how that radiation would be managed by humans in that area:
* How would small orbiting colonies protect their inhabitants from radiation? (Small: < 50 per "station")
* Would they have to do anything special to compensate for the radiation when communicating with Earth or other distant locations? Would their radio antennae wear faster if exposed to Jupiter-like radiation, or anything like that?
* What special considerations would need to be made when exchanging cargo and people with supply and relief ships? (I imagine every colony tries to be self-sufficient but has to supplement its own production with regular imports.)
Assume realistic technology in the near future, perhaps around the year 2100. Also, here I'm asking about Jupiter, but I think the radiation problem would be normal around gas giants, so feel free to tackle it from a general context if you want.
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The wavelengths used by communications are not the ones in which the larger portion of the radiation in Jupiter's are emitting. What's more is that even with a background noise, as long as you can create an amplitude change in a very specific wavelength, you can still communicate, so that shouldn't be to big of a problem. For details you can research the communications equipment of NASA's Juno mission.
As far as radiation for people goes, the best location in the system is Ganymede. Ganymede has it's own magnetic field, giving it a surface radiation of about 50 to 80 msV about a tenth of Europa's 540 msV. Despite this additional protection would still be needed, since that is still enough to kill given sufficient time (two months?) but this would be relatively easy, considering that's around on par with the moon. Mounds of dirt will go far for this purpose.
For spaceships or free floating colonies you'd probably want something lighter. The best bet here is liquid hydrogen. Because of it's relatively dense concentration and being almost incapable of becoming a source of radiation itself, it's an ideal radiation shield. NASA are actually considering it: <https://www.techbriefs.com/component/content/article/tb/pub/techbriefs/manufacturing-prototyping/26330>
Obtaining hydrogen is best done by electrolyzing water from Europa, since getting into the Jovian atmosphere and back out will take crazy amounts of thrust.
P.S. Metallic hydrogen might work too, but that's not real quite yet.
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**Use Europa!**
Europa has 2 advantages for a Jovian endeavor.
1: **Europa has a magnetic field.**
[](https://i.stack.imgur.com/G1kSX.jpg)
<https://europa.nasa.gov/resources/174/induced-magnetic-field-from-europas-subsurface-ocean/>
Jupiter's magnetic field induces an opposing magnetic field in Europa's ocean. A magnetic field is what you need for deflecting Jupiter's radiation, which I understand to be charged particles and not electromagnetic radiation.
You could build on the surface. Or if you are keen to stay in orbit, orbit Europa. The magnetic field will extend out from the surface a ways. Choose a low orbit to stay under the umbrella. if you let stuff hang out of the field, particles might get you.
2. **Ice, ice baby.**
[](https://i.stack.imgur.com/5O2d9.jpg)
[source](http://www.chinahotelsreservation.com/The_Harbin_Ice_Lantern_Festival/Ice_Building.html)
This one would be easier down on the surface. Europa's surface is ice. It will be easy to build with! Your colonists can live in thick buildings cut from the Europan ice. Ice offers good protection against radiation. Plus for your fiction you will have more interesting architectural options than the typical Expanse / Outland sort of thing.
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You could create a mini magnetosphere around your station. A magnetic field strong enough to divert the highly energized, charged particles away from the station. Just like the earth does for us.
Safe to say this would probably require a massive amount of energy to sustain. Could go with a nuclear reactor. Depending on how much you can automate the reactor this far in the future I figure it would still take a medium to large staff of technicians, engineers, operators, and managers to maintain. I could see this at least doubling your 50 per station number, if it doesn't make your reactor staff the overwhelming demographic on the station. [This Quora post](https://www.quora.com/How-many-people-does-it-take-to-run-a-nuclear-power-plant) says the typical U.S. reactor employs around 700 people. I could see this being greatly reduced and automated in the future but it could still be a much higher number than 50. Additionally, I couldn't say if that 700 person reactor would be way overkill or underkill for this use. Possibly you could do with a smaller reactor with more automation and far less workers.
I would predict that to go this route would still take a number of additional workers that would warrant or even necessitate making your station staff as a whole bigger to even justify the operation.
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## [Radiation shielding 101](http://www.projectrho.com/public_html/rocket/radiation.php)
Radiation is everywhere, not only around Jupiter. We only start caring about if if the energy levels get too high. There is electro magnetic radiation that is very energy intensive per photon (UV, X-ray and Gamma) the issue here is that, unlike with longer wavelength light, the photons don't just move or exite electrons, but can push them away from the atom or might even be able to punch protons from the nucleus. This kind of radiation ist best delt with with sheelding materials that have huge nuclei and a high density. Think the lead you use when you get an x-ray.
Normal electromagnetic radiation can be dangerous if the intensity gets too high. One can fry an egg on a fighter aircrafts radar. As long as you don't get too close, you'll be fine.
What you care about in the Jovian system is particle radiation. These are particles (electrons, protons, nuclei or heavy ions) that move at a high velocity. This is pretty much equivalent to atomic scale bullets. The way you shield yourself against these is by using materials, which contain a lit of hydrogen. The particles will get slowed down in these materials (water and plastics are great). Be careful however, as this creates bremsstrahlung (literally breaking radiation), so you want a metallic ray shield below the particle shield.
Interestingly a magnetic field can also help against particle radiation, as it deflects the particles away. As long as the particles are charged anyway. Neutron radiation, which is produced by fission and fusion plants, goes through any magnetic field and, depending on its velocity, might make whatever it hits radioactive in turn, pass straight through or punch holes into the atomic structures.
The general takeaway is that while special shielding is great, any large amount of matter you and a radiation source is great. Think the atmosphere of Earth. It shields us against the dangerous UV light the sun emmites.
Also, the link up top is to Atomic Rockets exelent writeup on the matter. Now, onwards to your question.
## Jupiter's Wrath
It is a common misconception that the Jovian magnetosphere is representative of gas giant magnetospheres. It isn't. The issue at hand is the innermost moon Io, which spews charged particles from its hundreds of vulcanos. These make the Jupeters orbit especially rough. Not that the other gas giants are harmless radiation wise, but Jupiter is the worst.
If you truely want to settle the system, you're most likely going to clear out the radiation in the long term. This has already been investigated for Earths magnetosphere. It isn't that complicated, it just takes long tethers, which use electric fields to capture the charged particles. Energy is practically free around Jupiter, as you can just tap the magnetosphere with long cables, which move with your stations.
In the short term, you'll most likely use radiation shelters inside water tanks for your ships. If you use certain engines, like minimag-orion drives or anything else that uses massive magnetic fields, these could double as radiation shields. Or vou builed anti-radiation magnetic cages around the spacecrafts. Be careful that the magnetic fields don't become dangerous for people.
As for bases, if you go down to any of the major moons you should just burry or melt yourself down. Under tens of meters of ice or rock (in case of Io) you don't care how much radiation is on the surface. Additionally it is quite likely that we will heve quite decent medication against radiation damage. Damage to DNA is quite important when it comes to longjevity research and this is likely to become a huge area of interest in the next decades.
I'd guess that you'd want resource bases on each of the major moons. The center of the system is in my opinion going to be Callisto, as you can work on its surface and it is likely to have decent mineral wealth.
Orbital bases can also be build into the many irregular moons of Jupiter. These are mostly captured asteroids and comets. You can just hollow them out and build spinning space stations in them. This will be the preferred solution if it turns out that humans don't only have poor health in zero gravity, but also in low gravity (we just don't know yet, zero gee is very from any gravity at all). Additionally you got materials, no gravity which could interfere with construction or manufacturing and a great spaceport.
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There are fictions where we can travel to the past, but it often raises causality paradoxes.
There are others where we can see into the future, and it has also some implication on free will.
But what if we could see in the past. Which is what we do every night, looking at the stars. But what if it was a much developed capability, to look exactly what happened where. No paradox in sight, we could watch:
* how the pyramids were built, or how the dinosaurs disappeared ?
* Who killed Kennedy, who didn't killed Epstein ?
* did Jesus left the tomb after 3 days, did buddha really said what is written on my fortune cookie ?
* who stole my beloved pen ! where did I left my umbrella...
I'm fascinated by this underrated super power ! But if movies like "minority report" explore the implications of pre-cognition, I'm wondering in what kind of society we could live if we could see the past. It is well known that bigger sentences have a much lower effect on criminality than ineluctable sentences.
Would the crime rate drop ? The amount of conspiracies decrease ? Could a single video/audio of a crime be enough to settle a trial, even in complex sexual assault case ? What about religions !? And last but not least kind of abuse of this power could be devised and how to avoid those...
**Update, After reading your contributions:**
Indeed, this power could not be for everyone. I was imagining it, at first, only at the service of the justice, but it is mainly because I live in a country with a low level of corruption and where the judiciary system seeks for truth (Napoleonian code), not for compromises (common wealth system).
But even in the hands of a system, it looks like in this kind of world, dictatorship would be ineluctable :)
Thanks @Joe Bloggs for the suggestion of ['The Light Of Other Days’ by Arthur C Clarke](https://en.wikipedia.org/wiki/The_Light_of_Other_Days), and @Allan for ['E for Effort' T.L. Sherred](https://en.wikipedia.org/wiki/E_for_Effort), I will look at those
[Answer]
Society gets a lot more honest for good and ill.
**Crimes of passion** increase slightly. People still have individual perspectives but you can't hide things like infidelity, abuse, or indiscretion. so people will still commit murder, assault, and other crimes of passion. Everyone still has their own personal narrative.
**Theft and fraud become basically non-existant**. there is no point to these crimes any more, it becomes nearly impossible to get away with them. Premeditated crimes become nearly non-existent. There is no point in stealing someone else password because they and the police will know you did it. In the long run it becomes nearly impossible to get away with crime which will prevent some crime and not others. Only petty theft still exists where the theif relies on going to the police being too much of a bother. people will still shop lift candy bars, no one will ever rob a bank account.
**Law** still exists because large populations still limits individual knowledge, I still don't know how trustworthy you are when I meet you, but it becomes much easier to shun untrustworthy people in the long run. Serious crime drops like a stone.
For day to day events people will rely more on biometrics and physical security. a locked door is still a locked door even if you know what the key looks like. So you will not have unauthorized personnel wandering into places they could do a lot of harm. combination locks will become worthless, key locks and timer locks become more common.
People will still have personal bias because they are limited by what they choose to see at night, people can still lie to themselves although it does become harder. Ironically **politicians become much much more honest**, since public figures no longer have secrets.
**Public indecency laws may disappear**, after all, any and all sex is public for all intents and purposes. Celebrities will be far less common, only exhibitionists will want to be in the public eye.
**Social progress** with either advance quickly or grind to halt, nothing is truly private, parents know what you did yesterday, so society will either let go of many hang ups about sex and gender or become a repressive and totalitarian. We see this in hunter gather societies where privacy is rare, sex either ceases to be taboo or the taboo is rigidly enforced. Taboo's become few and far between but the ones that persist become rigidly enforced.
**Religion shows a drastic down turn**. Only the less restrictive religions can survive, religious that are too restrictive or rigid collapse under exposed hypocrisy and infighting. Only low impact religions survive.
We see the opposite in science, experiments and duplication become much easier. **Science becomes much easier**. Historical sciences explode as the become only limited by what questions you think to ask. Bias still comes into play so their will still be debates but observational evidence is much much more accessible on all fields. this brings up questions about the limits of such abilities, can I "see" subatomic phenomena, or do I still need a machine to test them. Can I see the movement of fish in absolute darkness or can I only see thing that have been illuminated.
**War grinds to a halt**, without secrecy surprise attacks become impossible. Small scale conflicts can still erupt be cause of self delusion but much of the motivation for large scale war disappears. Again politicians can't lie effectively, and generals can't keep secrets. Every government will have teams of people sleeping in shifts to have up to date intel. if an attack cannot be planned and launched in a few minutes its not a surprise. At first you would think this would drastically favor super powers, but it doesn't since cooperation becomes so much easier coalitions can happen in hours. Unless a conqueror can take on the whole world by themselves they are screwed. Dictatorships become so hard to maintain you that they can't exist on the large scale.
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First, the benefits. Historians, physicists, astronomers, bioligists... pretty much every science-based profession will have the knowledge to develop origin stories, whether it be the beginning of life or the universe. Technology will definitely benefit as a result.
Next, the privacy concerns. Privacy is dead. Every moment of everyone's life could be under scrutiny by someone in the future. Yes, crime would drop and wrong convictions would drop to near zero. But the downsides of this would be very large. Celebrities, and really anybody who is liked or hated, will have their entire life scrutinized by people in the future. Likely, this will lead to a society that is much more tolerant of neuroses, as they have no way to hide them behind closed doors.
Needless to say, all of these will also go out of style: surprise parties, secrets, undiscovered landmarks, intellectual property, art(why buy an art piece when you can watch it be made, or at anytime in it's life?), trade secrets, losing things(rewind and watch where you placed it), unsolved crimes, mysteries of any sort... and probably more I can't think of right now.
Practically, humans live in the past. We take milliseconds or more to respond to external stimulus, so all of our actions are in response to something that occurred in the past. This means that you can watch in essentially real-time(delayed by a Planck-second) the entire world around, giving you access not only to the past but also to the human present. I can imagine this ability being leveraged by authoritarian leaders to completely subdue their population. With no way to hide or spread without being exposed, how can a resistance movement ever grow? You get a strong AI and hundreds of government agents monitoring the past and present, looking for signs of insurrection, and you get an unstoppable regime.
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**The world would end in nuclear holocaust right after the post-cogs emptied our bank accounts**
Just a few of the things post-cogs would destroy.
**No Password is safe**
Seedy post-cogs would use it to learn our usernames and passwords. All the post cog has to do is watch some rich person log in to their bank account and clean them out.
**Vegas would close down as divorce rates rocket upwards**
Every wife would be able to get a high-light reel of their husband's "work trip" to Vegas. One in four spouses cheat on their partners, so the courts will be backed-up for years as angry lovers use post-cogs as proof in their divorce case.
**Mass incarceration because plea-deals are moot, every cold-case is solved, and everyone has broken the law at least once in their life**
No need for plea-deals anymore. Call your post-cog and find out exactly what happened. Make sure to record it for the jury to get the maximum possible sentence
Dude acting suspicious? Call a post-cog! Don't like the guy hanging out on the corner? Call a Post-Cog! Want your rival out of the way? Call a Post-Cog!
**Chaos in the streets as all agencies get hacked at the same time**
Almost all records are only stored digitally, which thanks to the post-cog hack is no longer trusted (see #1).
Millions of prisoners have their sentences change and will be released today. Every person with any savings has been cleaned out by post-cogs, and no one accepts electronic or paper money anymore because of rampant post-cog thievery. We're back to trading in ounces of gold.
Rioting and looting start as people realize they have no money, but need necessities like bread and water.
**Finally nuclear holocaust to stop the post-cogs**
Finally, people will begin to realize post-cogs must be stopped at all cost. Several countries have stock-piled nuclear weapons, and still use pass-codes (see #1). A few post-cogs find the nuclear launch codes and poof - no more post-cogs, along with the rest of humanity.
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Let's reduce this to absurdity.
If everyone had this power to see everything in the past, there would be no reason for memory. Everything that ever happened could be 'seen', not 'recalled'. No reason to clutter up the mind with 'data storage'.
If there is no reason for memory, there is no reason for learning. The individual would have access to everything, every analysis, every event, every data point, every piece of information, every analysis. The individual would not need to 'learn' anything, since all knowledge would be instantly available.
Since every individual has this ability, there would be no need for intelligence. Someone with more or less 'intelligence' would have no advantage.
Since no individual would have 'intelligence', no individual would have a personality any different from anyone else. No one would have any unique qualities.
Since all people are the same, have the same knowledge, the same intelligence, access to the same information, what is left is nothing but a collective hive mind. All individuals are fungible. You can replace any individual with any other individual.
And there would certainly be absolutely no resemblance, no likeness, no similarity to the world we live in. Humans as we now know them would not exist.
So something may have this ability, but it would not be human.
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Imagine you've suddenly awakened to immense powers. But this isn't the Marvel universe, so you're the only human with these abilities. For the purpose of the question let's say these abilities are heightened strength, perception, and healing touch. You can lift cars and heal mortal wounds. Again, this is pure reality and you aren't the main character of any story. You are the only superhero who will ever live.
"How would a sole superhero on Earth seek therapy?"
Along this same branch, what psychological effects would arise from a neurotypical human being gifted with powers that defy natural law? Contrary to elation or excitement in popular fiction, how could they cope with the isolation or pressure? Does the person need to climb a mountain in Tibet and become a monk, alter their philosophy, numb certain areas of the brain?
You, a newly minted super human enter a therapy office. What questions do you ask someone who doesn't believe in superheroes, what are your worries and thoughts? What is your plan of action moving forward?
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In response to the question “what psychological effects...?” It probably depends on the overall worldview or social situation of this person before they become a superhero. Some people would be much more stressed out by this than others.
A [utilitarian](https://en.wikipedia.org/wiki/Utilitarianism) would probably feel an overwhelming moral obligation to use their newfound powers to improve the lives of as many people as possible. A utilitarian who is a normal person may feel a relatively low level of obligation, since most people do not have the ability to affect far-reaching societal changes. However, these superpowers would greatly amplify an individual’s potential to improve society. With great power comes great responsibility, which would probably be very stressful. (To consider an extreme case, what would [Peter Singer](https://en.wikipedia.org/wiki/Peter_Singer) do if he had superpowers?)
A religious person who believes in a God that directly interferes in human affairs would probably also feel a heightened sense of purpose. Such a person would probably reason that God must have awarded them special powers for a specific reason, so the obvious question following this realization would be “why?” Like the utilitarian, this person would feel an overwhelming obligation to put these new powers to good use, though not necessarily to increase the overall happiness of society. Perhaps this person would use their powers to spread their religion, or seek a “villain” who needs defeating.
A member of a struggling political movement or repressed minority community might use their powers to further their cause.
For a person with no significant religious, philosophical, or political agenda, the psychological effects would probably consist of elation (“cool, I have superpowers!”) followed by paranoia (“oh god, what will they do to me if they find out I have superpowers?”). The latter would probably prevent most people from seeking professional help for fear of being ratted out and scooped up by the government. Most likely, a person would confide in/seek help from a trusted friend or loved one.
Now for some more fun examples. A radical anarchist might use their superpowers to personally dismantle the government and generally cause chaos. A solipsist or nihilist might be unfazed and just continue living their normal lives, using their powers to complete their everyday tasks more easily (as well as for the occasional chuckle).
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Many of the pressures on a superhero would be analogous to those on the super wealthy or politically powerful and so they could masquerade as one of them when seeking therapy. People with power (superpower or mundane) have many pressures and demands on them: people trying to recruit them to their cause (often with ulterior self-serving motives), a lot of soul searching about which causes are "good" and worthy of their limited time and attention, many people begging for help with genuinely heartbreaking stories but not being able to help them all, the trauma of trying to help a person/cause only to have it go wrong (analogous to a physician who has a patient die despite their best efforts). As a consequence of this, probably the biggest questions they would have of a therapist is how to deal with constant stress, how to deal with others who are demanding, how to deal with the isolation of being different (powerful), etc.
Another aspect is that super powers are used in super dangerous situations. Here they might masquerade as a soldier or firefighter and speak to a therapist about how to deal with fear, how to deal with the trauma of seeing the death of others, how to avoid PTSD and so forth.
[Addendum] You ask as well about how the superhero would cope. The answer is: badly. The superhero received super powers but not super intelligence, super knowledge, or super wisdom; their actions can change the fate of the world but they will be always uncertain what the right thing to do is. They also didn't get super emotional resilience either so they're no better at coping with this than any ordinary human. The most likely consequence that the superhero must become, even at best, emotionally detached and somewhat callous. And that assumes they don't go off the deep end outright; it's notable that physicians, who have a similar burden of helping people, have an extremely high suicide rate.
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## What are you looking to get out of therapy?
To the best of my knowledge, this is the first question a therapist asks during an initial session.
This is an framing question. It helps the therapist know what the patient needs.
**Possible answers to this question (by the patient) are:**
* I'm freaking out. I need to know that I'm sane.
This is very likely the first question. The need is independent confirmation that what appears to be powers isn't : () some sort of psychotic break, () some sort of terminal illness, () some sort of awful joke. The Therapist's job, then, is to help the patient find the truth for his/her own self.
* Why me? This is so unfair.
The patient in this case has come to grips that the powers are real. He or she is imagining (maybe) that there's an expectation to put on a costume and start listening to police scanners. The Patient might not want to change his/her life. Maybe he hasn't told his parents, or partner, or kids. How do you tell someone you love about something like this? The Therapist might put the Patient in touch with a lawyer to help come to understand what (if anything) the law might require of him or her when using powers. Does accidentally thumping someone and breaking their nose count as assault? Is getting angry and yelling, knocking down a nearby house, terrorism? The Therapist can work through the Patient developing his or her understanding of how her role, rights, and responsibilities have all evolved.
* What am I supposed to do about this?
In this case, the Patient has accepted (maybe not completely) the new powers, and maybe has a sketched-out idea of how his or her role in society has changed. What this Patient needs is for the Therapist to guide the Patient to figuring out what he or she wants to do with these changes.
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As a certain someone pointed out, this is not a single question but ok.
So in short, there is no good answer for your question. No human is the same, and we would all act in a different way. And what we end up doing is dependent on so many factors, it is sort of impossible to predict.
In saying that, a few thoughts on the topic.
Everyone has a different understanding of "the perfect world". For some, religion is a major part of it and other think its the evil on earth. For some, a perfect world is where everyone is free and there are no Governments. For others, a single world wide government is the way to go.
If you suddenly gain the ability to be so powerful, what you think a perfect world is, becomes really important. Let's look at a character from "The Boys" for that. In this case, Stormfront. She doesn't think she is evil, for her everyone that isn't a certain "race" is a subhuman. That's what she believes in, thus what she works towards.
In saying all of that, I doubt someone will just go and seek therapy. And even if, what is there to fix? You just are a Superhero now, and what happens next depends on what you believe in. Most people don't and won't believe or admit to themselves that THEY are the problem. And not everyone else. So why should this person with superpowers do anything different?
Thus, I believe that the sole superhero on the planet would not seek therapy but rather start to think of him or herself as something superior. A sort of god complex if you will. Even with such limited powers as you gave them, it wouldn't take to long to have a cult following this "hero".
In the end, we can be happy that there are no superpowers.
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Is it possible that a body of significant size - at least several hundred kilometers in diameter - is **entirely liquid**, having **no solid core**? It can be either made of one homologous liquid or of multiple layers. How would the tides appear if it were passed by another body or orbited a larger one - would it fluctuate and change its form in a noticeable way?
An atmosphere or a surface membrane is permitted if really necessary, but I would prefer things that are liquid in vacuum and do not need additional protection, e.g. just a big blob.
You do not need to address the problem of formation (let's assume that technology to create whatever you come up with exists) and of meteorites/dust that would form a solid core eventually (preventing that will be another question to satisfy the rules).
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If such a body is constructed and maintained, yes, it is entirely possible - up to a certain size.
Under very high pressure (gigapascal range), water turns into one of several [phases of ice](https://en.wikipedia.org/wiki/Ice#Phases), even at fairly high temperatures (see graph). For comparison, the centre of the Earth has a pressure of about 330 to 360 gigapascals.
[](https://i.stack.imgur.com/GojIE.png)
Beyond the [critical point](https://en.wikipedia.org/wiki/Critical_point_(thermodynamics)) at the right end of the graph, gaseous water cannot be liquified by pressure alone. Above the critical point there exists a state of matter that is continuously connected with (can be transformed without phase transition into) both the liquid and the gaseous state. It is called supercritical fluid.
Hence, if you keep temperatures between 0 and 350 Celsius throughout your body, and keep pressure below ca. 400 megapascal, you can have a fully liquid water planet. I don't think a few hundred km diameter will be a problem, but with more than about a thousand km diameter, the pressure will likely grow too high.
As the surface of the body is liquid, there will be some evaporation, forming a thin atmosphere of water vapor. Water vapor is an extremely efficient greenhouse gas, so the body should be carefully placed so that there is no runaway greenhouse effect, yet also no freezing of the water, even at the poles, which might be difficult to achieve. Also, if the atmospheric pressure drops below a certain (very low) level, liquid water cannot exist - it transitions directly between ice and vapor (see graph). If you count the atmosphere as part of your planetoid body, then an entirely liquid body hence cannot exist.
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chameleon dragon are closely related to Parson's chameleon and some basic characteristics of them include:
* being ambush predators
* use active camouflage (similar to cuttlefish and some octopuses)
* are 10% smaller than a komodo dragon
* having chameleon like eyes
* have sharp claws
* having a komodo dragon like tongue
* having a Iguana like tail (but can't drop them)
* mostly live on the ground
* are good swimmers similar to Iguanas (optional)
* live in packs of two or three (optional)
* have a Iguana like neck dewlap
Given these characteristics, could such a creature realistically exist and what evolutionary pressures would lead to them?
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*Cuttlefish.*
First off, camouflage. To be fair you mention that the function of your camouflage is unlike chameleon camouflage, which is static. What you’re asking for is active camouflage, which does exist - in cuttlefish and some octopuses.
*Hunting.*
A few of these characteristics are less important for believability I feel (especially the dewlap) but some of them are potentially detrimental to the camouflage of the creature:
1. Size.
It is much easier to look like something if you are the same size or smaller. This is why most camouflaging animals are small. Chameleons can sometimes get large, but always able to be obscured by a clump of leaves. If your dragon is just smaller than a Komodo, it may find trouble breaking up its outline.
2. Packs.
Pack hunters don’t hide very well. More hunters means more chances of being spotted - camouflaged hunting favours a solitary predator. This is reflected in big cats. Only one big cat is a social hunter, the lion, and they have one member of the pack deliberately be spotted and push prey into the hiding members to hunt. They would not get close enough otherwise.
Since it’s an ambush predator, they wouldn’t benefit from hunting in the same area, they’d have better chances waiting different locations so that potential prey don’t overlap. 9/10 hunts are failures, having all three-four dragons waiting in the same area means if no prey move through that area they all go hungry.
*Evolution.*
First off, the confusing one.
Why are they good swimmers? Is their environment plentiful in large bodies of water? Or do they serve a similar niche to leopards? I assume they don’t since they ‘mostly live on the ground’. Leopards can drop down on prey from trees into rivers, which is why they can swim well. I can’t think of a reason for swimming to be selected for in a non-arboreal or aquatic creature, so I’d need more info on its niche.
So the niche of this animal is unclear. A ground-based camouflaged predator with adaptions common in ambush predation is the gist of what I can gather. I’ll try and tackle the other characteristics individually.
Those chameleon eyes are for ambush hunting - great field of view so you don’t need to move your head, great depth perception for aiming your surprise attack. Mantis have similarly functional eyes. A stalking predator has forward facing eyes, so unlikely to have independent swivels. Since you clarified ambush, this is a trait shown to be selected for in chameleons, so it is believable here.
The dewlap is a heat regulating surface in iguanas and a communicating display in other lizards, heat regulating can be important in large creatures and communication is important in packs - completely believable.
Sharp claws are a reasonable adaption for a predator, especially since it doesn’t have the chameleon’s tongue.
Size is dependant on prey size and availability. I already mentioned the detriments of large size to an ambush predator, though then again the wobbegong exists so maybe it’s plausible.your dragon would only have to grow this large in order to overpower their prey.
Tail is no problem, ancestral trait - loss of arboreal lifestyle means regression of prehensile trait. The green iguana uses its swimming ability (powered by this tail) for escape from climbing predators and apparently for finding prey (I can’t find what exactly they eat from rivers). It’s hard to draw predator parallels since green or marine iguanas are both herbivores.
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>
> * being ambush predators
> * use active camouflage (similar to cuttlefish and some octopuses)
> * are 10% smaller than a komodo dragon
> * having chameleon like eyes
> * have sharp claws
> * having a komodo dragon like tongue
> * having a Iguana like tail (but can't drop them)
> * mostly live on the ground
> * are good swimmers similar to Iguanas (optional)
> * live in packs of two or three (optional)
> * have a Iguana like neck dewlap
>
>
>
If it evolved once, it can evolve again and will, as it has always did.
Your creature is just a boring lizard with an extraordinary camouflage ability evolved as an ambush predator or as a form of defense.
Eventually the lizard developed social behaviour and started using their camouflage abilities to communicate with their packs.
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Could a creature use lightning (or any other source of electricity) as a sole energy source, and not need to eat? Would any additional organs be needed to store or use the electricity?
I have a race of animals, kind of like oarfish, although much bigger, capable of flight. I'm not sure how, but probably some lighter than air gas. If they chased thunderstorms, with the intention of getting struck by lightning, and were able to attract it, could they get usable energy from that?
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If we're going hard science, we would have to imagine some kind of biology which evolved from the beginning to use lightning energy. It's hard to imagine an animal acquiring that talent from a different evolutionary line without getting fried.
So let's imagine how a single-celled organism might use lightning.
On a planet with the right chemistry, and a lot of lightning, there would be ions in the atmosphere or in the ocean. These ions could be used as a kind of energy source. A multicellular organism might evolve a membrane to selectively acquire these ions and use them to build up more complex organic molecules.
Could we imagine this kind of organism making the leap to getting energy by being shocked? Maybe! If it already had efficient ways of moving ions around, maybe it would be somewhat more immune to a lightning strike. And that gives it an evolutionary path to being totally unharmed by one, and then perhaps seeking them out. Then your organism would be collecting raw elements from the environment and seeking lightning to convert them.
I'm not a chemist or biologist, but maybe looking at the biology of electric eels will be instructive.
The real problem is that a lightning strike is so unpredictable that your organisms aren't very likely to ever get hit, no matter what they do. Unless...
Maybe, they can float like balloons, and they can link themselves together in a long line, like an ant bridge. Then they can form a wire - connecting different layers of the atmosphere - with a much greater chance to have energy flow. Perhaps they *really* evolved to exploit energy differences between layers of the atmosphere, and the lightning is just a neat trick they do sometimes.
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Could a gold shell around a planet exist, suspended by a magnetic field (gold is diamagnetic), given the following constraints?
* A gold layer enveloping a planet, **arbitrarily thin**.
* **Unspecified height**, likely to be where atmosphere is less dense with fewer jumps of pressure.
* a strong magnetic field that repels the gold and keeps it suspended **thanks to gold's diamagnetic properties** exists or was created.
* **No specific function has to be performed by the sphere, just aesthetics**. Make the planet shiny as a gold ball.
* An alien race has sufficient energy reserves (e.g. huge uranium deposits) to avoid relying on solar panels. They prefer being shiny instead of using solar power.
* The sphere should not be built, it just needs to be kept suspended ( so I do not need to know how it was built, that's another problem, just need to know if it can be maintained)
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Not likely, but maybe you could use dust?
First, as mentioned by @JustinThymetheSecond, the magnetic field around a planet is not static. Earth's magnetic field is pushed around constantly by the Sun, meaning anything that tries to be kept suspended by this field would quickly be pushed apart. A related issue is that as this foil is pushed around, large eddy currents will form - likely melting the foil.
Second, anything that reflects light will also be pushed by the "light pressure" - the same concept that is used for solar sails will ram any gold foil into your planet.
Third, unless you have openings in this gold foil, it will slowly inflate due to the planet off-gassing. Normally, a planet's atmosphere slowly boils away into space, being replenished by gases released from natural or other processes on the planet. This inflation will eventually rip the foil apart.
Cool idea, and you could maybe use gold dust, or some other "shiny" **particle** to get a similar effect - just note that it will need to be continually replenished. Particles would avoid most of these issues, but there will be a "trail" of particles both into the planet's atmosphere and streaming outward from the planet away from its sun. They will still block a lot of the incoming light, as well - depending on the concentration.
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Freeman Dyson's theory was never talking about an actual sphere built around a star, but a swarm. encasing a star around a sphere is impossible with existing materials, so the best you can get is building a dyson swarm. I.E. a cloud of stations or panels enveloping the star.
the same can actually be done with planets, Albeit never as powerful as an actual dyson swarm given you can only harvest a billionth of the energy from the star.
we see such things in the Mobile-suit Gundam anime, albeit not what you are directly asking.
but as for making the swarm of panels look like a sphere, you can simply use orbital mechanics to orbit the plates. and enough of them would make the planet from a distance look like a gold sphere.
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My main character is one with the gift to control electricity. Despite this obvious flaw in reasoning I try to keep it as scientifically accurate as possible so he cannot for example zap someone from miles away but must touch him or be really close (within a meter) and expend a lot of mana. My idea is as follows:
In a dire situation he uses all of his mana to power an electrical current in his body and induces a magnetic field which will induce an opposite electric current inside the bullet which in turn will create an opposite magnetic field which will fight it out with the one created by the MC thus diverting the bullet.
Is my thinking and understanding flawed in this? If so is there any way to achieve this effect?
(He doesn't die because he has been blessed by the mana. Yes I know not very scientific)
Thank you all for your time and answers
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**Melt the bullet with ohmic heating**
**[](https://i.stack.imgur.com/TQdXT.jpg)**
<https://www.youtube.com/watch?v=qkeRp8h3soo>
Lead bullets are not ferromagnetic, so no stopping them with electromagnetism that way. They are weakly diamagnetic and repelled by a magnetic field but it would need to be phenomenally strong to stop a bullet. A bullet traveling thru a magnetic field could induce a magnetic field in the bullet, producing an opposing force - lead is a decent conductor and so it could work the way proposed in the OP with a strong enough field.
But stopping bullets with magnetism - so Magneto! Been done, been done.
Your hero instead magnetically generates an electrical field inside the bullet. Electrical resistance then melts the bullet. That is what is happening in this video. The lead melts pretty quick.
The former bullet is still coming through the air, and it means the hero gets splashed with molten lead. It does not have penetrating power but it will splash him with molten metal which will burn and smoke. The former bullets will probably stay mixed with his clothes. Hopefully he is not wearing his favorite jacket.
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High current atmospheric discharge localized on the bullet. The plasma will find a discharge channel created by the energetic burn of the propellant.
[Specific heat of vaporisation for lead (aka latent heat of fusion) = 4.799kJ/mol](https://www.nuclear-power.net/lead-specific-heat-latent-heat-vaporization-fusion/)
1 mol of lead = 207g - a bullet of [7.62x39mm weights 7.9g](https://en.wikipedia.org/wiki/AK-47#Cartridge), so the energy required to vaporize the lead in bullet is somewhere around 200J (to account for the energy require to heat the lead to melting point). Then, the copper jacket left behind is lightweight enough to go astray due to the drag.
Let's make it 10x that to account for losses and you get 2kJ to vaporize the lead in the bullet.
Putting 2kJ in perspective:
* equivalent of lifting 102kg over a height of 2m
* the average energy intake for a human is 8,700kJ/day - 2kJ is 0.023% of that
Now, I'm too lazy to compute what it would be to use tungsten bullets.
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**Won't Work Given Your Constraints**
I'm taking you at your word that you want to *divert* (aka, deflect) the bullet. Not melt it. Not destroy it. But move it out of the way.
On the one hand: Old cathode ray tube (CRT) TVs did this with electrons all the time: but pay attention. Tens of thousands of volts were needed to deflect *one electron.* Bullets are just a bit bigger than electrons.
On the other hand: Consider how much power it takes to operate a rail gun. The projectile needs [up to 25 megawatts](https://www.popsci.com/article/technology/navy-wants-fire-its-ridiculously-strong-railgun-ocean/) to do its job. But, rail gun projectiles are just a bit bigger than your bullet.
Finally, let's assume you have a third hand, upon which we find that when it comes to magnetism, [lead stinks](https://terpconnect.umd.edu/~wbreslyn/magnets/is-lead-magnetic.html). In other words, you might need every joule of those 25 megawatts to move your bullet.
But, after looking at all those hands... can your superhero do it?
Sorry, no.
Worse, your superhero had better have super-observation and mental acuity. Using the average velocity for a [7.62mm NATO round](https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO) of 2,700 ft/s, a bullet fired from 300 yards away would only need 0.33 seconds to travel from the gun to your superhero's heart. That's a third of a second to realize what's going on, figure out a solution, spin up the magnetic field, and divert the bullet. Those reflexes alone would make Superman look like a chump.
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Assuming all the primary hurdles in building a space elevator are overcome, would it be structurally feasible to attach intermediate stops along the length of the tether (between the planet and GSO, and/or between GSO and the counter weight) without causing instabilities?
Thank you!
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As part of the premise, we now have a space elevator, a rope of material you can climb. You can climb up it and suddenly be in Geo-Stationary Orbit (GSO). Not only is that a long ways away, but launching rockets just became super cheap. So could there be stops along the elevator - a "floor" to stop at?
The biggest consideration is:
# Tensile Strength
The premise is that we have something that solves the tensile strength issue for space elevators, but *how well* we overcame this determines the margins for floors' weight. Those floors are supported on the elevator by the main cable. If the cable breaks, not only does the elevator go away, but so do those floors!
Additionally, those extra floors contribute to another thing:
# Drag
I know that space is characterized by its profound lack of stuff. Around earth, where at least some part of a space elevator must operate, things get really busy.
The transition from atmosphere to space is not a sudden jump. It is more like a smooth transition from many particles to only some to fewer and then basically none. The lower ends of the cable will still encounter some number of particles which then (in turn) exert some amount of drag. Adding a "floor" to the elevator increases the amount of drag because the "floor" increases the odds of hitting particles.
All that drag exerts *yet more* forces on the space elevator, increasing the tensile strength requirements. Drag can also alter the orbit or cause a slight torque: this is also no good. (There are other schemes, like [Skyhooks](https://youtu.be/dqwpQarrDwk) which may enjoy this.)
# Center of Mass and Orbital Mechanics
Space elevators are large enough structures that shifting center of masses becomes a concern. If the CoM for the whole elevator/floors/people system changes too much, it will alter the orbit. This is **bad news** for something trying to stay in GSO.
Adding floors and then putting a lot of stuff on those floors may be too much! Of course, a heavier counterweight may be the key to staving this off, but that's just kicking this problem so far down space-elevator-loading road that it isn't a problem.
All this really comes down to the one and only true answer on Worldbuilding SE: **it depends**. The tensile strength is likely the largest factor, followed by the size of these floors and orbital mechanics.
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Contrary to what is commonly believed, perhaps we can build a space elevator with existing materials. The point is that we don't think about how to build this structure in a really appropriate way, as the authors of [this paper](https://arxiv.org/pdf/1804.06453.pdf) or this [other paper](https://arxiv.org/pdf/1908.09339v1.pdf) claims.
The structure should have elasticity to withstand the tidal forces of the Moon, which will have some kind of replacement due to the attack of micrometeoroids, shields to protect from radiation, protection against the actions of the atmosphere, support of solar panels throughout the entire structure , piping for water, oxygen, nitrogen [1], basic structure material, plus exclusive service rails for AI-controlled machines that will take care of repairs, different tracks for getting on and off, which do not really need to be different for cargo and passengers, in addition to perhaps a possible expansion of the structure in order for new tracks to be built.
Anyway, this structure will be huge in itself, even without stopping stations.
You aren't going to make a space elevator economically interesting to build as long as the volume of cargo can be taken into space or brought to Earth through other ways [2], so if you have reached the point of building one or more space elevators, it is because your society it has a big trade between the sides of the atmosphere.
All of these loads going up and down through the elevator will generate forces that the cable must resist and balance, which requires that it be dimensioned much higher than what would be simply a string of diamond nanotubes, graphene, carbyne, duct tape or any other supermaterial.
Here is an interesting point: if the load moves too fast, you will not need many intermediate stations, but the forces of this whole movement will require an oversize of the cables. If the load moves slowly you will need more intermediate stations, and they will require more of the cables as well.
**In conclusion**, any type of intermediate station, with some type of hotel with panoramic views, maintenance of the cars, emergency services, escape pods, restaurants, etc., will not present a significant effort in the structure of an elevator, unless you want to do a small town.
[1] *I don't really know why most science fiction stories or Mars terraforming suggestions ignore the importance of nitrogen in atmospheric composition.*
[2] *methods that are already and will be in use by society then, the proposal for a space elevator will always looks like radical until its construction be an inevitable necessity.*
[3] *user535733 deserve all upvotes for mention the last book of Clarke's Space Odyssey.*
[4] *I failed in learn how make decent footnotes here, someone please edit it*
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**Sure, but you'd lower cargo capacity**
Using materials that are currently available, it is not possible to build a space elevator. There are studies into materials that might be up to the task, but nobody has figured out how to make long enough pieces to get to space. So in your story, you're starting with a different reality than the real world. If you create a material that's strong and light and easy to manufacture at scale, then you can make it strong enough to support intermediate stops. You might even build them using a similar material as the cable to keep the weight down. Remember that whatever weight you put on the cable will reduce the cargo capacity of the space elevator.
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'The culture of good place-making, like the culture of farming, or agriculture, is a body of knowledge and acquired skills. It is not bred in the bone, and if it is not transmitted from one generation to the next, it is lost.' (James H Kunstler, *The Geography of Nowhere*)
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Urban sprawl, which is notable in places like the US, is a post-World War 2 phenomenon associated with dirty air and water; mutilated drainage patterns and agricultural land; actual cities' falling into disrepair after residents are seduced by the suburbs; and obviously roads, pavement, utility lines and buildings that span excessive distances.
Suppose we were to tweak history to cut **US** urban sprawl drastically. **How small a societal change could we make and still succeed?**
* The suggested change or changes should occur no later than the first half of the 20th century.
* The suggested change or changes aren't allowed to kill urbanisation. Keep forms of urbanisation that are still profitable but frugal (in land, energy, water etc) and human-centred.
* A sufficiently small change is indistinguishable from the effect of chance (things 'could have gone either way'), or at least that's what's preferred.
* Other than the improvement in urbanism, the US should remain as similar as possible to the real US, except where your suggested change(s) necessarily has/have higher-order effects.
* No need for certain prevention of urban sprawl; just make it as likely as possible for urban sprawl by any reasonable definition to remain negligible by the present date.
Bonus: cut urban sprawl **worldwide**, also according to the specifications above.
[Answer]
Disclaimer before my answer: I'm not American, nor have I lived in the United States. But I have formally studied suburbanisation as part of my work. Therefore, my answer is derived from my second-hand readings of United States history rather than first-hand experience.
The one "small" change I would advocate would be to ***substitute the automobile boom of the 1920s and highway construction during the New Deal with a railway boom instead*** (carrying on the older railway boom of the 19th century).
It's not really small, but it's one change with a significant impact and I've explained why I think so below.
From what I know, a significant factor that drove suburbanisation in the US was the cheap availability of capital left over from the second world war which could be put to other uses, thus starting a manufacturing boom in the 1950s. Cars, concrete, household appliances, hardware - all effectively became cheaper to manufacture, distribute, sell, purchase, and replace. This was combined with a sudden boom in consumption, as young soldiers returned from the war, obtained jobs manufacturing and marketing this newly cheap stuff and used their wages to buy the same stuff in the market. Low prices meant a single household could buy a lot - a car, a washing machine, an oven, a refrigerator, furniture and so on. However, land prices in cities were too high to own enough space for such a lifestyle. This is ultimately what drove young households to suburbs - Cheap land and housing that allowed for an expanded lifestyle driven by the manufacturing boom.
However, a crucial factor was the automobile and its associated infrastructure such as freeways and highways, whose development had started taking place in the 20s and 30s, but whose effect took off in the 1950s. The combination of highway+car promised that a household in the suburbs could never be too far away from work or entertainment in the city. The overall effect of this combination had a huge impact on how households lived - not only did it promise freedom to move between suburb and city as and when the household pleased, but it also promised that a household need not bind itself to any particular location for any reason at all. You didn't need to live within walking distance of shops if you could just drive down. You didn't need to live close to a doctor or a hospital if you wanted care. If all these things could be located within a 10-15 minute drive down a motorway (as opposed to a 10-15 minute walk or bus ride), you just needed access to the motorway. What this meant was that households could spread out, more and more. Their homes could get bigger and their neighbourhoods could cut deeper into rural areas with their only limit being the capacities of their cars and their access to the highway.
Therefore, if there is one "small" change I would suggest to cut down on urban sprawl, I would suggest extending the 19th Century Rail Boom to the 1920s and have rail lines replace road laying during the New Deal. Rail creates very different effects from the automobile. Households will still need to cluster and locate themselves closer to railway stations in order to access services. Factories, shops and key centres like hospitals can be located near stations to better access manufactured goods. Suburbanisation will still take place, but it will be of a very different form, consisting of denser, tighter railway towns and the sprawl is more likely to be linear, taking place around major arteries connecting primary cities, as opposed to sprawls that go in every direction. This also allows for more centralised infrastructure in towns, reducing resource wastage and hopefully, more connected communities that participate more actively in town planning processes.
[Answer]
You mention the timeframe and thus the ultimate cause of (sub)urban sprawl in the US, and therein lies also the answer.
**Kill most of the soldiers.**
Short and sweet and to the point. The reason why we experienced suburban sprawl was because loads of battle experienced soldiers came home with a discharge in one hand and a GI Bill in the other. They came home to a prospering economy, loads of new technology, new opportunities, a need for a place to call home, and the inevitable baby boom to follow. You know, wife, 2.4 kids, a turkey in every pot and a car in every garage.
If you reduce the population of returnees you reduce the need for living space. Traditional cities can continue to handle the reduced population growth.
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## Simply having higher petrol prices throughout history will drastically alter the way our cities develop
If petrol was not abundant and cheap, and instead harder to extract, process and deliver, then this would drastically affect urban form.
The invention of the Automobile was in 1886, but it was not really until 1910's that it started being mass produced enabling cities to grow and transport between them to be easier - however it wasn't apparent until the post WW2 years, and subsequent 'baby boom' that the car became ubiquitous and the 'every-day' family could afford and use.
This suddenly **transformed all growing cities into car orientated, hierarchal road transport networked cities** as ordinary *middle-class* (and also lower-class) families could afford to live further from where they work.
Also this enabled the 3-tiered stratification of cities: **Separating industrial from commercial from residential**. By using the car, it is possible to separate them (which they did) - now considered a major contributor to urban sprawl.
Higher petrol prices however might push the car into the realm of the unfeasible *for ordinary people* (not necessarily for wealthy or for industry) and thus the stratification of cities and hierarchal transport network could potentially be unviable too.
This change would still enable most other cultural and scientific (and political) development to occur, on a world-wide basis, and would fulfil your criteria.
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Is there a feasible setup where the Sun has expanded enough to make the Earth uninhabitable, but some of the other rocky bodies in our solar system (past Earth) become more reasonable colonisation prospects?
For the purposes of this hypothetical, let's hand-wave the why and focus on different solar radii and what they do for habitability through the system. I suspect most of the useful range sits between what we have now and substantially less than red giant, but let's work that through!
[Answer]
A decent proxy for habitability and long-term colonizability is the effective temperature of the planet - essentially the surface temperature. A planet's effective temperature scales as $T\propto (L/r^2)^{1/4}$, where $L$ is the luminosity of the star and $r$ is the planet's orbital radius. We want our planet, moon, asteroid, etc. to have an effective temperature of roughly Earth's. Knowing the distance between a body and the star makes it easy to calculate how bright the Sun needs to be to make that body habitable.
Let's take an example: Mars. Mars lies 1.52 AU from the Sun. If we plug that in, we see that it could reach Earth-like temperatures (assuming identical albedo and greenhouse effect - more on that later) when the Sun reaches $L\sim2.3L\_{\odot}$. That's going to happen at the end of the Sun's subgiant phase - a portion of time after it's left the main sequence but before it becomes a red giant. To take another example, consider Europa, an oft-discussed place for life to arise in the future. Europa requires the Sun to reach a luminosity of $L\sim27L\_{\odot}$, in the early stages of the red giant branch. The same holds for any of the moons of Jupiter, and Saturn wouldn't be too far behind.
Towards the far end of its life, when the Sun ends the red giant phase and enters a brief portion of its life we refer to as the *asymptotic giant branch*, it will reach peak a peak luminosity of $L\sim5000L\_{\odot}$. That's . . . well, large. At this point, a body about 70 AU from the Sun would receive roughly the same flux as Earth does right now, and therefore have a similar surface temperature.
The point is, if you wait long enough, **virtually any body in the Solar System you'd want to colonize will reach Earth-like temperatures**.
Up to this point, we've ignored two things: the albedo of the planet (how well it reflects and absorbs light) and the greenhouse effect. Thinner atmospheres mean less of a greenhouse effect, so for many bodies, our estimate is a little bit off. Still, it's a decent enough approximation, for our purposes - give or take a factor of a few.
[Answer]
**Ganymede!**
In the red giant future of our sun, the habitable zone will expand to include Jupiter.
<https://www.dailymail.co.uk/sciencetech/article-3592960/Is-alien-life-hiding-red-giants-Older-stars-pushed-habitable-zone-process-turn-Jupiter-s-icy-moons-lush-worlds.html>
[](https://i.stack.imgur.com/FIsaq.jpg)
These scientists modeled what would happen with a "hot Jupiter" - a gas giant with moons in tow migrates closer to a sunlike star. In your scenario it is the reverse - the star expands outwards, but I assert the net effect is similar enough for fiction.
[The Longevity of Water Ice on Ganymedes and Europas around Migrated Giant Planets](https://iopscience.iop.org/article/10.3847/1538-4357/aa67ea)
>
> The longevity of such an atmosphere depends strongly on the distance
> from the host star, and the mass and radius of the exomoon. The
> smaller the star–exomoon distance, the warmer the icy exomoon will
> become. As an icy exomoon approaches a distance of ~1.1 au around a
> Sun-like star it will enter a runaway greenhouse state when the
> surface melts. However, this cutoff is dependent on the albedo of the
> moon, which was set to 0.2 in this paper...
>
>
> If the exomoon sits beyond this runaway limit the surface water may
> persist much longer. Beyond the star–exomoon distance of the runaway
> limit, there is an exponential relationship between mass and water
> longevity. For an icy moon of Ganymede's size around a Sun-like star,
> surface waters will likely persist indefinitely. Large moons of this
> size will maintain their atmospheres for long periods in the habitable
> zone and could potentially maintain a liquid surface for timescales
> greater than 1 Gyr. Thus, such moons could be habitable...
>
>
>
Ganymede! It is earth like in several respects - lots of water and a fair bit of rock. It is almost as big as Mars. When it melts it will get an atmosphere, and will be an ocean planet with salty seas and we are familiar with that.
An aspect I am less sure about is magnetic field. You need a magnetic field to protect against charged particles from the sun raining down on you. Ganymede has a little bit of a magnetic field. Jupiter has a monster field. Its protection against solar wind might extend to Ganymede but I worry about charged particles originating from Jupiter. I was reading about how the [Juno probe](https://en.wikipedia.org/wiki/Juno_Radiation_Vault) has super thick radiation shielding. I had not known Jupiter generates so much radiation! Hopefully Ganymede is at an adequate distance that it is not pelted by Jovian charged particles.
[Answer]
Your feasible setup can simply be our sun entering its red giant phase in some billions years, nothing fancy.
As it expand, presumably some satellites of Jupiter can become habitable (Titan ? Europa ? Who know this...) also if we cannot know how they will look like.
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[Question]
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So, dragons are hexapodal creatures, slightly larger than most draft horses (around 190-200 cm at the withers). Compared to the Quetzalcoatlus, dragons have twice the muscles mass in the pectoral region, but the length of the fibers stays consistent. Basically, the chest is just as deep, but the length is extended.
The extra muscle is attached to the heavily modified humerus. Dragon bones are very strong, due to their microscopic structure, which mimics limpet teeth.
That's how dragons remain volant, despite their size. Now, their breath weapon is a two-component acid, aqua regia. Its constituents, nitric acid and hydrochloric acid, are stored separately for safety reasons and only combine moments before exiting the dragon's mouth. Still, having too much acid could interfere with the dragon's ability to fly.
On top of that, the dragon's saliva and mucus are only able to stall (but not completely stop) and (with sodium bicarbonate) neutralize the acids, when present in large-enough quantities.
The breath weapon is useful for dealing with humans and their equipment, but not for much else.
Dragons usually spray targets with the acids, so the two components don't really have a chance to stay combined.
**Given that, what's the realistic amount of aqua regia (so, the sum of the two components in liters) a dragon should store?**
[Answer]
My acid spitting dragons use sulphuric acid, not hydrocloric acid.
The chemistry is pretty simple. When an acid is put in water, it disassociates into H+ ions. Hydrocloric acid is already in water and mostly disassociated with a ratio of 30-40% acid and the rest water. Sulphuric acid on the other hand is 98% acid and 2% water, so it is seeking water to disassociate with.
When my dragon breathes his acid breath on the human trying to kill him, it immediately dehydrates the skin it comes in contact with, the skin carbonizes resulting in 3rd degree burns.
Your aqua-regia dragon is more into processing and refining gold than dealing with humans or other beasts that might attack it. The Hydrocloric acid will burn eventually, but the affected areas don't immediately react to the acid.
In both cases, the dragon's mouth and surfaces that may have been affected by the acid would be doused in glands that create a base mucous coating that stops any major damage from the remaining acid. This mixture causes "drooling" and is a way of disposing the mixture off of the dragon.
[Answer]
Draft horses weigh around 900kg, modern estimates for the weight of the Quetzalcoatlus are around 200kg (lower-bound) to 400kg (upper-bound). Also, the Quetzalcoatlus is about the size of a giraffe with the wingspan of a small cessna. Assuming your dragon is about the same size of the Quetzalcoatlus then it will probably have difficulty going from stationary to flying if it weighs more than 500kg.
Having that stablished it's easy to determine how much aqua regia it carries. Just pick how bulky your dragon should be and subtract that from 500kg, the remainder is your available aqua regia storage.
If it fits within your story you can also say that the dragons have a much bigger acid storage (thus exceeding the 500kg limit) but when they're full they cannot takeoff, so before flying they have to spit enough acid to make themselves lighter.
Another possibility if you want them to be heavier is to choose their natural habitat so that they don't need to takeoff from the ground (i.e. if your dragon lives on cliff-edges then it can fly by jumping from the cliff edge and gliding).
[Answer]
Ok so we have a dragon the size of a horse with some special anatomy. In this case, as you used quetzalcoatlus and considering it's wings have similar size and area, I'll just assume your dragon weights as much as the heaviest quetzalcoatlus estimate to allow for flight (around 250 kg) since despite smaller it has added weight due to the extra muscle and bone for the 3rd pair of limbs. I'll also assume it's predominantly a carnivore.
Apparently you're going for aqua Regia both because it melts most metals as well as due to the fact it can heat up to over 100 degrees celsius (232 Fahrenheit) once you mix both acids (so that's why you want them separated?). However, with flight being the main tool here, your dragon is already at basically the weight limit (though I'd think it can likely get a bit heavier due to its powerful muscles, let's not rely too much on that). So we need a quantity that doesn't make it too much heavier to allow for flight. Additionally we don't want a volume too large for our dragon, so we need to watch for that.
Considering aqua Regia (luckily or unluckily) has a density of about 1,21 grams per cubic centimeter, we see that a kilogram of aqua Regia would occupy a volume of around 0.826 or approximately 0.8 liters. Since horses have a total volume of around 416 liters and your dragon shouldn't have as much guts (herbivores requires larger digestive systems to process plant matter while carnivores don't need them as long to process meat, which is why a herbivore tends to have a body cavity twice as large as a similar sized carnivore) I'd say, on a moderate estimate of someone with very little expertise, that your dragon should be able to store in the best of cases (in a moderate estimation), that it could potentially store from 10 to 20 liters total of aqua Regia. The issue with this is that every 10 liters of aqua Regia would result in an increase of 12,5 kilograms. This much weight added would almost certainly hinder flight, so we have a dragon that can't store much aqua Regia if it plans to fly, unless it acts like a vulture that just fed and begins to empty its reserves every time it wants to take to the skies. Based on this, I'd say the best outcome would be a storage space of around 1/4 of a liter, which would still result in a. 3,125 kg increase in weight, but should be an acceptable one as to not make flight a problem.
If I got something wrong in my calculations please let me know. For now, it seems like your dragon likely act like a skunk, carefully choosing when to use its Aqua Regia spray (remember you'll need compartments capable of containing said acids though, so we might have a slightly smaller amount than that available).
[Answer]
Did the dragons evolve, or were they birthed with magic? If birthed with magic, then it might as well just be matched to the average amount of humans they run into in a day.
If they evolved, then actually how much acid breath they have has nothing to do with humans, because dragons evolved before them (or at least before humans had weapons).
So if not evolved for humans, what was the original purpose of the acid? This is important because sometimes evolution works so hard on one thing that it is an impediment to other things. Just try and imagine a male peacock trying to escape a predator.
If the original use of the acid was something massively essential for survival and selection, they might carry so much that it actually hurts their flying distance and limits their lifespan by slowly dissolving their teeth (an animal that can't chew starves). A fun opportunity to consider their past situation and enemies.
But if they used it for something less, like maybe occasionally burning holes in rocks to hide eggs, a liter is more than enough (one human a day worth).
Although as AlexP points out, this particular acid is worst case scenario for a dragon, since its claim to fame is it dissolves gold. That's more of a curse you would put on a poor hoarding dragon who just wants to lick his treasure!
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[Question]
[
Incidentally, this isn't for a current project, just curious about an old one. When I was in High School, I started then sort of abandoned a LOTR-esque novel idea. In this world, the elves' main gimmick was that they had crystals permanently embedded in their sternums and visible from the outside. I think it was supposed to be a source of magical power, but didn't really define what it did. Mostly it was there because it's *diiiiiffereeeeent.* I now fully admit to this being a stupid idea.
The crystals were about the size of a thumb, of varying shapes and colors depending on the tribe; High Elves from the forest of the living goddess had white rhombuses, "Dark" Elves from the west had black, Fire Tribe had orange teardrop/flame shapes, Swamp Tribe had green circles, etc.
I imagined the elves would for their coming of age ceremony undergo a painful surgery where part of their skin is removed and the sternum is carved out to set the gem in, then it's placed with, I don't know, silver hooks? Resin? Magic? I don't know if I thought that far.
The premise of these gems is that they're a source of power but an individual needs to create an exclusive bond with a single gem and always have it both visible and securely attached to the body, hence the very difficult type of implantation.
This comes with a lot of problems:
1. Could you have such a large gem set in without digging in to the marrow?
2. How do you keep it clean?
3. Would it fall out or dig around the bones under normal physical activity?
4. If it's not feasible to put it in the sternum, then what about the forehead? Yeah probably not, but still...
5. If it's not feasible to put it in any bone and still be visible on the outside, what's the next most permanent way to embed it in the flesh?
[Answer]
# Yes is is possible
You can do it without resorting to "it's magic." However, there are some issues that can be alleviated with magic.
1. You shouldn't have to worry about marrow except in the long bones. However, the outer layer of bone is the strongest and putting any sizable break in that would create a weak spot. I wouldn't want to get punched in the center of my chest with a weak spot in my breastbone. However, if the gem was magically fused with the bone instead of surgically grafted, that would do away with some of that.
2. Keeping it clean will be difficult for some of the more porous stones (opal, tiger eye) but solid crystal stones (ruby, diamond) will keep stuff out once the skin seals around it. It will still be an easier source for infection unless the wound is magically healed and the skin is made to seal against the stone.
3. Once the bone healed around it it wouldn't come out without breaking the bone. Magic would help but isn't strictly necessary.
4. The forehead would be about the same as the breastbone. Except that you are weakening the protection for your **brain**.
5. I would not try to put any but the smallest of gems into any of the arm or leg bones since that would weaken their structural integrity.
[Answer]
You want implanting? What you want?
Magic tooth (infortunatelly we are currently unable to bluetooth memorystick in your tooth implanted)? NO problem. I have a Zirkon one (no, they won't let you keep the transparency).
You want diamond one to cut through steel? No problem.
[](https://i.stack.imgur.com/hV56e.png)
You know that elves have this super hearing and wear diadems? It's magic hearing diadem with special enchantmens
[](https://i.stack.imgur.com/p6HbD.png)
And now! My favourite! A gem! In Tooth.
Mayans loved to do that
<https://www.elitereaders.com/ancient-mayans-dentistry/>
Of course it was easier to put a gem in bare teeth but it show that the only obstacle you need to face is caring for proper treatmen of the wound. So it will scar nicely around gem without any infection. If you need a metal to hold the gem (A scarab so to speak) and attach that to the bone you just need to think about metal that is non-reacting with blood, muscles and fat. Silver or gold.
Or some elven titanium.
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Assuming humans remained hunter-gatherers, would it be **anatomically possible for us to evolve digitigrade legs**? Or, is our anatomy too specialized and are we stuck the way we are?
I am not asking about any advantages or disadvantages of being digitigrade, just if it is possible.
[Answer]
We are neither digitigrade nor plantigrade exclusive because as hunter gathers, we have evolved to take advantage of both which is more selectively fit than one or the other. Our feet are designed to flatten out when we need to cover long distances, but when we are ready to stalk, fight, and chase, we go up on our toes just like digitigrade mammals.
If a person were digitigrade exclusive, then he would not be able to keep up with the migration distances of hunter gatherer societies. He would develop neuromas or other foot problems at an early age causing foot pains that would make him vulnerable to predation or death in battle; so, to answer your question, people are more likely to evolve digitigrade exclusive feet now that it is no longer selected against than he would have as a hunter gatherer.
Mammals that evolved to be digitigrade did so not because they were hunter gatherers but because they were quadrupeds. Quadrupeds can distribute their weight over more appendages; so, specializing makes more since for them.
[Answer]
Yes, but also no.
Evolution often mops specie's into a corner were they cannot evolve out of traits they have. This is absolutely not a case of that. so yes, because our anatomy is not limited in a way that would prevent it.
*But*
No, because we are in a position were that couldn't possibly give us an advantage. Not because our anatomy is mopped into a corner, but because our current tool set is so much better for everything we actually do that developing digitigrade feet would be a strict downgrade.
Now, things that may seem like "evolutionary downgrades" do happen, but they need a reason. And this is one that doesn't work. In theory, you could have an isolated group of hunter gatherers gan this trait as a mutation, but humans in general are too cosmopolitan, and natural barriers do a laughably poor job of isolating us. The hight of our isolation was our agrarian phase. And do to physics reasons, that was the point of our development were a digitagrade gate would be the most disadvantagous.
It's just doesn't flow from our niche.
[Answer]
Yes, it is entirely possible. It is a little known fact that a small number of humans are in fact obligate digitigrades. For most this results in extreme disability since ts the result of infantile paralysis arising from causes such as childhood polio. In other cases it seems to have originated as a result of childhood behaviour. In the west it may be more common among women due to starting ballet training at a very young age. In some cases, myself included, it is a complete mystery as to how we got that way. However, in these cases they provide a good counter to all the arguments as to why evolution favoured plantigrade in humans since we are often highly functional physically. In my case, several black belts and a good competition record at just sub Olympic level in several combat sports, as well as the ability to tab 20-30 miles across country in a single day with full pack.
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[Question]
[
This question's information is based on the answer in my previous question about [what the aquatic creature need in order to live or survive in my acid water?](https://worldbuilding.stackexchange.com/questions/154036/what-the-aquatic-creature-need-in-order-to-live-or-survive-in-my-acid-water/154041?noredirect=1#comment484789_154041)
The thing that's not in the description is my sun is not strong. It doesn't generate much light or heat due to the cold climate, something like a taiga forest. Hence, I don't think a plant design entirely covered by a proton pump, which requires a lot of energy, would be a good solution.
I want to know what would silicone plants, especially trees, look like and can they still use photosynthesis or do they require different chemicals or methods? (I don't have knowledge about chemistry, so if the answer is actually obvious or I get something wrong, I'm sorry.)
My plants (including trees) have an aquatic plant type, either plain water or salt water (all of this is acid water, based on my previous question description) like kelp, lotus, and flowing on the water surface like water hyacinth. For trees, something like mangrove, and cypress swamp. I want to know is it still possible for silicone based plants to manage it.
Feel free to suggest different types or solutions if silicone is not possible for some that I describe (even better if some parts of the plants are edible by humans). I know there's a tree with high silica in it which seem like a good substitute, but I'm curious about what silicone based plants would be like.
[Answer]
**Pretty much like any other plant.**
Until you look *really* closely. Some relevant considerations are as follows:
A silicone-based tree will require both a carbon source and a silicon source--however, because carbon plays such a reduced biochemical role (have been replaced in many functions by silicone polymers), the carbon source need not be as accessible. The large surface area of leaves on terrestrial plants serves two functions: increasing light-gathering area, and increasing gas-exchange area. Because of reduced carbon needs, a silicone-based tree will not require as much gas exchange surface. The need to gather light may result in leaf morphology ending up no different from terrestrial carbon-based leaf morphology after all, but microscopic inspection will probably reveal an unusually low density of stomata (i.e., gas exchange ports).
There are very few gaseous compounds of silicon, and even fewer stable ones, so a silicone-based tree will not be getting its silicon source from the air as it (and terrestrial plants) can do with carbon. Instead, a silicone-based tree will need to absorb solvated silica through its roots. Carbon-based plants already have pretty large root surface areas, which they need to absorb water (and in your case, sulfuric acid) and other solvated nutrients (e.g., phosphate, nitrate, metal ions, etc.); the need to gather large quantities of solvated silicone, dwarfing uptake of everything else except biosolvent liquids (the water and sulfuric acid), may require proportionately increasing root surface area relative to the trunk and canopy, but I'm not sure how noticeable that would really be.
Silicone-based water plants would do just fine. They would grow faster in more acidic waters, which would have a higher concentration of dissolved silica for them to absorb.
Making any part of such a plants edible for a human, however... that's not gonna happen. If properly neutralized (say, boiled with baking soda), some parts of silicone-based plants may end up being non-toxic--but we just aren't equipped to be able to extract any kind of nutrition from them, beyond maybe trace mineral micronutrients. If you have a mixed ecology (such appears in the H. Beam Piper novel [Uller Uprising](http://www.gutenberg.org/files/19474/19474-h/19474-h.htm)), with primarily organic animals protected by molecular proton pumps, your human may be able to derive nutrition from native silicone plants indirectly by eating organic parts of native animals which have evolved to eat and extract nutrition from the native plants. I.e., much like humans do with pigs (which turn garbage into food), goats (which turn inedible plants from unfarmable land into food), and seals (which, through the mediation of several other sea creatures, turn plankton and seaweed into people-food).
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[Question]
[
Scenario:
* When one thinks of elemental transmuters from [mythology](https://en.wikipedia.org/wiki/Midas) or [comic books](https://powerlisting.fandom.com/wiki/Elemental_Transmutation?fbclid=IwAR0BsGaHTcQQylvVB5uBb4r1DSKNX7MwXXDh4PUR-NctyqoNyyJ7ng0xHUQ), one thinks of single touch by the transmuter to a large, multi-elemental structure (like a human body) that causes cascading changes across a wide variety of elements, resulting in a complete conversion to a totally new material, targeted by the transmuter, irregardless of whatever the source materials used to be.
* However, the more "practical" view of an element transmuter is that he/she is only able to flip a few ounces of a single element into a different element, based upon familiarity with both the source material and the final result. This enforces severe limits to what the operator can do, and the scope of the consequences. A Bachelor's Degree in Chemistry would be extremely useful to such an operator.
* The details of the character in question are irrelevant at this point, other than he/she was researching the Biological Transmutation Theory of Corentin Louis Kervran (see [here](http://bionutrient.org/site/library/reviews/biological-transmutations?fbclid=IwAR2kGhKmNAbLKcdWo_kWm9otX2QNo01KSfalPeer5rIb7GmN0wl4lV8FHQI), [here](https://etherealmatters.org/book/transmutation-elements?fbclid=IwAR0ROEpK_5A2ys-Q-XodB6fI24R6CIRjyFeTtn3_7jEt7rk79Kj0YxYNQps), [here](http://www.levity.com/alchemy/nelson2_8.html?fbclid=IwAR21kOirOrEexJOoC5P2kog4hSNgLQcGr-oGN8fXG0_xlnh8JetutJ8YNKI), and [here](http://www.foodforthoughtstore.com/biological-transmutation/?fbclid=IwAR3kFO2ndaCXgJJwsFdIL6b5NXK4KpvmsJvc_LnF_wnoCbeFh8ZIUNDVbLc)), notably the transmution of sodium to potassium within the human body.
* Sodium and potassium are essential electrolytes, a dietary requirement for us humans. Sodium helps regulate the amount of water that's in and around your cells. A 50 kg person would contain around 200 grams of sodium chloride – around 40 teaspoons. It plays a key role in many functions, from the quality of blood to transmission of nerve signals. Potassium protects the heart and arteries, and may even prevent cardiovascular disease. The total quantity of potassium in the human body lies somewhere between 110 and 140 grams, and while most of it lies in the red blood cells and brain tissue, its final value depends upon muscle mass. It serves mainly as a nerve stimulus, in muscle contractions, blood pressure regulation, and protein dissolution. But, sodium and potassium can only operate within a narrow range of values. Outside of that range, they both turns into nasty, caustic agents.
* It was during the aforementioned research that the character discovered that he/she could replicate transmution of sodium to potassium on a macro scale (again, the mechanics are irrelevant at this point)...which induces sudden, severe, simultaneous *Hyponatremia* (sodium starvation) and *Hyperkalemia* (potassium poisoning) – bringing about rapid brain swelling, paralysis, and/or heart failure in the subject.
Note: while this process could be extremely useful in a life-or-death fight, it's rather mundane in nature for someone with superpowers.
So, here's my question: could this process lead to other, somewhat more spectacular methods of offense/defense?
For instance, potassium reacts rapidly and intensely with water (an exothermal reaction which heats it to such an extent that it burns a purple flame), forming both a colorless basic potassium hydroxide solution, and hydrogen gas (which reacts strongly with oxygen and ignites). Sodium also reacts quickly with water, to produce sodium hydroxide and hydrogen gas. And since 60% of the human body is water...could this volatile reaction lead to something approximating [Spontaneous Human Combustion](https://en.wikipedia.org/wiki/Spontaneous_human_combustion#Suggested_explanations)?
[Answer]
This person would be an omega level mutant in the Marvel Comics scale.
[This is what non-crackpots say about Kervran's work:](https://en.wikipedia.org/wiki/Corentin_Louis_Kervran#Biological_transmutation)
>
> In the 1960s, Louis Kervran claimed to have conducted experiments and studies demonstrating **violations of the law of conservation of mass** by biological systems, according to which the amount of each chemical element is preserved in all chemical reactions. Specifically he claimed that organisms can transmute potassium into calcium by **nuclear fusion** in the course of making an egg shell (...)
>
>
>
Let that sink for a moment, specifically the part where it says:
>
> **nuclear fusion**
>
>
>
This is the proccess that powers stars. It generates more power per mass than atomic fission. If the character can do that with impunity, then even just a few grams of salt are enough to level a small town.
Fusing hydeogen to make a single gram of deuterium releases 1012 joules. A back of napkin calculation puts that into the proximity of a 2,100 or more tons of TNT blast. And that's just adding one humble nucleon to hydrogen. Going from Sodium into Potassium requires eight protons and some neutrons to go with them.
You know, at this point I believe Kervran's [igNobel winning theory](https://www.improbable.com/ig/ig-pastwinners.html) could be the pseudo-scientific explanation for the powers of [the villain that started the whole Civil War saga, Nitro:](https://en.wikipedia.org/wiki/Nitro_(comics))
>
> As a result of genetic re-engineering by the Kree, Nitro can transform his body into a gaseous state and explode with a maximum force equivalent to 350 lb (160 kg) of TNT - which can however be multiplied under influence of MGH - and reconstitute himself.
>
>
>
>
> (...) could this volatile reaction lead to something approximating Spontaneous Human Combustion?
>
>
>
Given what the character can do, spontaneous combustion is the least of your worries. They've got to be able to reassemble themselves to survive anyway.
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[Question]
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**Information**
I am writing a fantasy sci-fi, that is almost the same as our reality, the only difference being humans in this world are capable of using drugs (serums in their world) to improve their bodies' capabilities since ancient times (pre-agricultural).
Like making the body more efficient in order to survive extreme environments for weeks or months without the need for crucial gear, enhancing the body's immune system to cure diseases and toxins in record time, heightening alertness, keeping the body in peak physical condition for vast periods and, most importantly, cutting training time by raising neuro and muscle plasticity.
Even with all those miracle drugs they never were capable of creating serums capable of improving the body's regeneration. Until someone discovered something and the rest is history.
I want to use the regenerative serums, as a plot device for an army super training regime program. Fundamentally, they train hard every day wihout stopping, if an average human did this, he would tear a muscle or break a bone sooner or later. Using the regenerative serums, they heal overnight. Creating super dense muscles and bones after repeating the process countless times, forget swimming, even floating is impossible, any large bodies of water for that matter, their very own kryptonite, maybe I will use it in the story.
**My Question**
Is muscle plasticity the same as muscle regeneration from wear?
If it is can I change muscle plasticity for muscle memory?
I want to differentiate the serums capable of accelerating physical and mental training from the regenerative serum's used to create the super training regime. The reason is to have more diversity and complexity in my world, having soldier highly skilled for special missions and super grunts for the heat of battle.
[Answer]
# Muscle plasticity is **not** the same thing as regeneration.
>
> Muscle plasticity is defined as the ability of a given muscle to alter
> its structural and functional properties in accordance with the
> environmental conditions imposed on it....
>
>
> From birth until death, skeletal muscle is in a constant state of
> remodeling in order to adjust to changes in load, activity, or
> innervation. This unique plasticity allows muscle to alter its
> structural and functional properties in accordance with its imposed
> environmental conditions. This is widely recognized in sports, where
> muscle changes imposed by training in athletes leads to obvious
> phenotypic modifications that optimize the specific performance of the
> muscle. The number of muscular contractions (activity) and the degree
> of loading appear to be the dominant stimuli for training-imposed
> muscle changes. For example, body builders perform low frequency, high
> load contractions that result in muscle growth (i.e., hypertrophy) and
> an increase in force-generating capacity. On the other hand, marathon
> runners perform high frequency, low load contractions that are not
> associated with hypertrophy, but cause muscle fibers to assume a more
> fatigue-resistant phenotype. Although genetic pre-disposition is also
> important, these adaptations, substantially contribute to the
> different physical attributes of body builders and marathon runners. ([ref](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3962767/))
>
>
>
Exercise does break down muscle fibers. When you sleep, your pituitary releases growth hormone which helps in rebuilding the muscle to be stronger. The exercise doesn't build the muscle directly, though of course it's the catalyst.
>
> After you workout, your body repairs or replaces damaged muscle fibers
> through a cellular process where it fuses muscle fibers together to
> form new muscle protein strands or myofibrils. These repaired
> myofibrils increase in thickness and number to create muscle
> hypertrophy (growth). Muscle growth occurs whenever the rate of
> muscle protein synthesis is greater than the rate of muscle protein
> breakdown. This adaption, however, does not happen while you actually
> lift the weights. Instead, it occurs while you rest. ([ref](https://www.builtlean.com/2013/09/17/muscles-grow/))
>
>
>
While you might call this normal nightly rebuilding (something that happens every night, regardless of activity, if you have enough growth hormone) regeneration, it's not the magic regenerative serum you reference in healing injury. I'll note that you refer to "wear and tear" but your examples are about injury.
When you tear a muscle, you literally tear it. I've had hard workouts that have left me sore for a couple of days. But one day (literally in a fraction of a second) I tore my calf muscle. It wasn't even that bad a tear (level 2 out of 4), but I was on crutches for 2 months.
When you tear a muscle or break a bone, you can not put weight on it while it's healing. And healing takes time. It was 2 weeks before I was allowed to put *any* weight on my leg and another 2 weeks before I could gently walk with most of my weight held up by the crutches. Broken bones take longer. (Where the break or rip is will change the timing, but it doesn't change the reality of healing.)
If you want to use magic for this overnight healing, sure, go ahead. Or if you want to call it science fiction and handwave how it works, okay, it's your story. But you're asking for [science-based](/questions/tagged/science-based "show questions tagged 'science-based'") and the science simply isn't there. Might it be in the future? Perhaps to some degree. But only in that it will speed healing, not make it unnecessary.
When your soldiers train while they are injured (this is implied by your wording, even if it's only for a couple of hours, it counts), they are compounding the injury many times over. Training hard again the next day would compound the original injury as well.
My frame challenge to you is in how you incorporate the idea of outright injury into this program. That's not how you make soldiers stronger faster (or ever). Perhaps you didn't mean to put it that way, but I can only answer the question in front of me, not the one that's actually in your head.
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