kerbiloid

Absolutely all organical compounds contain less than 4 g of Hydrogen per 12 g of Carbon. Mostly, 2 g of Hydrogen per 12 g of Carbon. P.S. Btw, I remembered a nice sample of what you mean with extremophiles. Going to the South Africa and digging 1.5 km below the ground, you can find a lot of working miners, Going to Tibet, you can find a lot of peasants working 4-5 km above the sea level. This means that humans can live 5 km above the ground and 1.5 km under the ground. Of course, you know that Kamchatka from your link is not a regular place, but one of the most active volcanic regions on the Earth, especially famous for its Geyser Valley and abnormal hot springs activity.

Designer - one who makes signs on a piece of something. Artist - one who makes art. But why they call engineer them, who doesn't make engines? Perhaps, a game engine programmer is engineer, while a electronical or chemical engineer - isn't.

Robots work better in predictable and formalizable jobs, So, scientists and caretakers do their work better than robots. Hmm... Late Ancient Rome. Slavery was being widely replaced with institute of colonus, I.e. a former (or still formally) slave is granted with a land allotment and works paying fixed tax for his former (or still formally) owner. All what he gains above this tax, is his unalienable profit. Widest usage of libertines, i.e. a former slave, juridically made a free man, but again juridically staying a junior member of his/her former owner's family. Having their own business but with duties to his patronus. Confederate States of America, The same with colonuses, Early XIX century Russia. Statute labor on the landlord's field (up to 6 days per week) - "barshchina" is being widely replaced with a fixed payment - "obrok". Not so easy, though... Only in jobs where a worker must only flitter wit a pickaxe or axe, without any care for result, For example, this is why Ancient Egypt and Mesopotamia were the pioneers in slavery: their farming was based on a channels digging. So, take a prisoner, give him a pickaxe and let him rock. Hard to simulate an idiot in such primitive work. In other places (Europe in wide sense, etc), channels weren't required — the care was. And slavery was much less efficient, so slaves were more like personally constrained tribesmen with the lowest status, or were used in mining,

OK, in some places there can be several kilometers deep wells where extremophiles can survive. Need to compare how many microbes can survive there and what we usually mean as biosphere? Okay, bacteries had been found up to 30 km high above the Earth surface, so, according to your logic, height doesn't matter.

Please, read your links, They talk about 265, 300 meters, once - about a 1 km (sure, in this case they studied some porous place with hot springs). This is "in the ground". This is not 10 km above or 10 km below.

This argument makes no sense. You are trying to say that chemosynthetics live 10 km deep under bottom? They live in the upper layer of ground, above 100 or so meters depth. That means: "in the ground". Which 1500 C? Proteins begin to decay at 42 C. Chemosynthetics live in a boiling kettle, not in molten iron. Probably you can give an example of chemosynthetics more efficient than photosynthetics? P.S. Especially for your pleasure: thereafter under "on the bottom" I mean "in the 100-1000 meters thick layer of water just above the bottom surface and in 100-300 meters thick layer of ground just below the bottom surface."

As total area of the Europa ocean bottom is 100 times less than Earth, we should try a chance with at least 100 Europas. For comparison: Europa ocean is a little bigger than a Mediterranean Sea, but in darkness.

No, because robots work better than wage workers, while wage workers better than slaves. Slaves are useful only for simplest works, because they damage the tools, ignore the result and depict themselves as idiots treating as an idiot their owner. Wage worker may do this clownery too, but then he gets no money.

Vice versa. In the Earth ocean (4 km deep) we have two productive planes rich with organics: the surface and the bottom. (And the bottom is rich mostly with the organics from surface). The water volume in between matters nothing, it doesn't produce organics, it's just an abyss through which the organics sinks. In the subsurface oceans (100 km) we have only one productive plane - the bottom. Organics doesn't shower from surface, it just rises for several dozens? (hundreds?) meters and sinks back. That means, all its eaters also live near the very bottom. Just because no manna falls down from the surface. The higher they climb - the less to eat. That's the key difference from the Earty ocean. So, not the volume matters, but the area. While any ocean is 3d, its depth dimension means nothing, it's a useless hollow. Life is 2d. Life is just a mildew film covering available surface. And the area of Europa/Enceladus/Pluto ocean is 10-100 times less than of Earth ocean. P.S. Btw, the terrestrial life had burst when the true plants appeared (not algae). And these plants were the synergy of the bottom (roots consuming the silt) and surface (photosynthetic leaves). These plants transformed the coastal shallows into bogs, then into ground, filling them with their remains. And they were the key factor forcing the primitive creatures to make their efforts in the ground colonization, which then gave the burst-like life diversity. Nothing alike can be happen with the subsurface life.

Earth oceanic life is mostly based on photosynthesis in the very upper layer of it. And very thin — dozens of meters if not even less. Organics appears on the surface then sinks down to the bottom. At the bottom lives another organics, which is eating the sunk one and make the silt which they live in. Between them is a useless depth, The famous chemosynthesis is just a puny addition to this feast of life. And it appears not along all over the bottom, but in hot spots only — the underwater volcanos. A real life on the Earth had appeared only when the inferior chemosynthetical sub-bacteries reached the oceanic surface on the continental shelfs. There they could be resting relaxed and take a light bath in the flows of energy free of charge. Obviously, the Earth ocean organics is, loosely speaking, a superposition of three exponents: With maximum at surface, decreasing downwards — photosynthetics production and they, who catch it while it's sinking down; The richest one. Mostly concentrated in a half kilometer from surface. With maximum at bottom, decreasing upwards — chemosynthetics production; The poorest one. Very close to the bottom. With maximum at bottom, decreasing upwards — they, who live at the bottom and eat any of the previous two, not climbing too high. Being summarized, those 3 exponents give more-or-less continous distribution of the organic material. On the oceanic shelf the bottom and surface are so close to each other that they mix together and compose a symphonic orchestra, which mixes at once all kinds of the organics and energy transformation, This synergy gives an outstanding production and diversification of life. This orchestra is constinuously orchestrated at once by the day/night, summer/winter and tidal cycles. So, these variety, fertility and predictable regulated compulsion — are forcing the life to evolve and give it giant abilities to do this. All terrestrial life above the simplest protozoans appeared here. Obviously, the subsurface oceans have no photosynthesis. They're absolutely dark places. So, they can't show even comparable organics production. No first (and the main) exponent. The only organics there is being chemosynthesised on the very bottom. The puny and miserable second exponent. The third exponent has to be limited by the second one, with chemosynthetic food only. So, it is same puny and miserable as the second one. So, any subsurface ocean life has to concentrate in dozens meters from the bottom. It gains nothing climbing high, as there is no sky above them, just a dark cold ceiling. The upper — the worse. And as the chemosynthesis runs only in volcanic hot spots, these hot spots amount depends on total bottom area. You can easily calculate that Europa/Enceladus/etc oceanic bottom should be ~1% of the terrestrial ocean area. Plutonic and Hanymedic ones ~ 10%. As not every hot spot is a cradle of life, they have 100 times less attempts to try a chance of life creation. But even if a miracle happens, and a life appears there, it should be so limited in abundance and diversity that you could hardly distinguish this bacterial trash from other dirty spots.

It should by "Mars Colony", abbreviation - MarCo. It's counterpart should be "Point Lookout", "Port Location", "Pointy Locator" - at your choice. abbr. - PoLo. So, their radio exchange will look like: - MarCo! - PoLo!

Dogs' social rituals are quite primitive, for my view, not a rocket science. Say, cats, who are individual hunters, have almost the same social abilities, just don't need to demonstrate them for every other animal. They also create packs, demonstrate a social hierarchy, artistically possess human's intensions. Even show all tricks which the dogs can (understand voice commands, bring named things, finds named people, bring a paperball back to make it be thrown again). They just do this when they find this funny, while dogs — always. Standalone fish is also much more stupid than a standalone mammal. But if compare animals of the same evolutionary level, we can see that sheeps, cows and other herd animals unlikely are more clever than a tiger or rhino. Humans are another kind of things. They can speak. This means that died or absent people can talk to the present ones, this means a positive loopback of information gathering.

Probably, not activation the food, but activation of the hull and food containers material. They may (should) contain metals which can be activated by the neutrons.

Probably, the second. I thought, you had meant "neutron activation by gamma-rays".

I.e. gravitationally collapsing.

Negligible. https://en.wikipedia.org/wiki/Food_irradiation

Reanimation equipment supports the brain activity. Of course, it's not such easy to implement this in a mobile device. Robocop-2 (and the Robocop remake, too) movie contains nice episodes with a nerve system floating in a cylinder.

If you have a fish, several years later you'll be sure that it she understands everything you're talking about, including Shakespeare. Why at all, the "social" animals are presumed to be more intellectual? While a standalone animal observes, analyses, decides, works on its own.

A crystal ball with brain (to think) and gonads (a family souvenir) inside a chest of a synthetic fractal-looking six-legged body. Has no purpose. 1) Cannot regenerate. 2) Carbon and protein structures can be even stronger than metals 3) Soft parts would be smashed inside an shining metal skeleton anyway.

Arctic and Antarctic oceans are just an Eden garden in comparison with Titan/Pluto ones.

Conserved food is often sterilized by gamma-rays.

A sufficiently advanced VR headset could be used to 'transport' astronauts back to from Earth. Also, a pack of nerds orbiting Mars/Jupiter/so on in a playroom capsule without windows, doing their favorite job: playing videogames, but with Martian avatar droids. We They can even not realize that they're far from the Earth. Even more: that would make no difference.

Humans win! (From 1:25)

In fact, this problem has been solved long ago, by leagues and weight categories. There are Highest league, First league, Second League, etc. Nobody puts a world champion and a next-street-boy into one league. So, there just should be added a Superhuman league, and they are the first of its members, And — until somebody else appears, Champions of Superhuman league.

Meat too