Life on gas giants.

[Kamean]

Here original link on Russian.
Ngaytxoa, if I not quite successfully edited Google translator.

In the Carl Sagan's book, , "Cosmos. The evolution of the universe, life and civilization" to come across such an interesting model for life on planets such as Polyphemus or Jupiter.

On the giant planet like Jupiter, with an atmosphere rich in hydrogen, helium, methane, water vapor and ammonia, the solid surface is inaccessible, but there are quite dense cloud layers, in which organic molecules can fall from the sky, like manna from heaven, as it turned out to products of our laboratory experiments. There is such a planet and a characteristic of a hindrance to life the atmosphere of turbulence and in the lower layers of their preheated to very high temperatures. Organisms must be careful that they are not claimed and not cooked down.

In order to show that life is not excluded in such completely different worlds from Earth, we have a colleague at Cornell, E.E. Salpeter to do some calculations. Of course, we can not know exactly what will be like living in a place like this, but we would consider, within the known laws of physics and chemistry, can the world of this type, in principle, be inhabited.

One way to save lives in the conditions described above - to produce offspring before they roast, and hope that the convection will make some of your offspring to higher and colder atmosphere. Such organisms can be very small. We called them Sinker.

Some scientists suggest that there may be a live meduselike floating in the atmosphere.
Floater (from the English. float - float) - a huge hydrogen tank, which pumps out helium and other heavier gases, leaving only the lightest in a gas - hydrogen, the other option - balloon with hot air, preserving the buoyancy by keeping the inside high temperature, at a cost of energy derived from food. As in the case of habit-governmental us earthly balloons than sinking deeper into floater, the greater becomes the lift force that returns it to the upper, cooler and safer region of the atmosphere. Floater can eat in an atmosphere formed by organic molecules or produce their own, using sunlight and air, just as do plants on Earth. It should be noted that the larger the size of floatera, the viability of it would be. We imagined the floaters diameter of a few kilometers - the size of a city much larger than the largest that has ever existed whales.

Floaters can move in the atmosphere, emitting a jet of air, in the manner of a jet or rocket. We imagined them crowded into a huge lazy herd, which pro-cleared as far as the eye, with its characteristic protective coloration, indicating that they too face problems. Because in this environment, there are at a lesser extent, another ecological niche - hunting. Hunter (from the English. Hunter - being fast and mobile. They prey on floaters not only for their organic, but for the sake of pure hydrogen stored. Hollow Sinker might well evolve in the first floater, and self-propelled floaters - in the first hunters. Hunters can not be too much, because otherwise they would have absorbed all floaters and would kill themselves.

Physics and chemistry allow the existence of such forms of life. Art gives them a certain charm. Nature, of course, is not obliged to follow our speculations. But if the galaxy there are billions of inhabited worlds, it is possible that among them there is some human Sinker, floater and Hunter, which we invented it, staying within the laws of physics and chemistry.

Floater.


Hunters.

[Tsanten Eywa 'eveng]

on a gas giant planet? sounds completely impossible

what is the probability that it can form life on a gas giant, first of all it can be life on a size of a gas giant, but that is what the scientists call a
"Super-Earth"(http://en.wikipedia.org/wiki/Super-Earth)

the planet need to be in a stable orbit, not too close or to far to it's sun. If it is too close, it will be too warm, the water will evaporate, but if it is too far, it will freeze, it need to be right in the middle, what the scientists call "habitable zone"(http://en.wikipedia.org/wiki/Habitable_zone)

[Kamean]

Only in atmosphere. This was said by the Discovery Channel. Not proven, but such a theory is. The basis of life can be different. For example, instead of water - liquid methane.

[Clarke]

Liquid methane life would be slow, probably quite large and cold. There certainly aren't any Na'vi on Titon.

[Raiden]

Liquid methane life would be slow, probably quite large and cold. There certainly aren't any Na'vi on Titon.

How would it be cold?

The idea behind Titan isn't that there could be life forms made of liquid methane, it's that between the methane (CH4) and the various nitrogenous compounds (such as NO2 and NH3), you have all the basic building blocks for more complex organic molecules. Once you have more complex organic molecules, you're much closer to nucleic acids (or something analogous to them)  and therefore single-celled life.

I know Titan is cold, but that doesn't necessarily mean that the imaginary organisms that could evolve there would be cold too. It takes a certain amount of potential and/or kinetic energy (potential energy being the energy of the bonds in a grain of sugar, kinetic energy being the energy of a moving object, such as the moving water molecules in a cup of hot water) to drive the biochemical reactions in organisms, and this is usually achieved by breaking the bonds of other organic molecules. The problem with the cold is that it would cause kinetic energy to dissipate very quickly from other objects, and then the fledgling organism loses all the heat (kinetic) energy it was stockpiling. Furthermore, many of the important kinds of organic molecules that make up Earth organisms solidify and become useless at low temperatures, and so that limits the options of what kinds of compounds Titan organisms could use to make up for things like lipids and enzymes.

Basically, the imaginary organisms living there wouldn't necessarily be cold, they would just have to evolve a way to hang on to any heat energy they can generate, because Titan's cold atmosphere would "suck it away" very quickly, and because most organic molecules can't do much of anything once they cool down too much.

[Clarke]

All cell-based life we know about needs a solvent of some kind in the cell itself. In Earth cells, the solvent is water, but Titan is too cold for liquid water. If you used liquid methane, as I thought the suggestion was, then your cell must be very cold, since methane's boiling point is about -300F.

But cold chemical reactions don't work as quickly as "room temperature" ones, and so the cell will generally react slower.

[Irtaviš Ačankif]

Theoretically you can strap an exopack onto a Toruk and throw it into Jupiter's upper atmosphere and let it fly unharmed, but there is always the question of where to land. For example, our mighty Toruk decides to have a rest and tries to find one underneath. Whoops. The pressure crushes our poor Toruk.

You need to come up with a mechanism that makes the lifeform airborne for its whole life. Even as a baby. I don't want to see big monsters falling into Jupiter just as they are born. Clearly, the artists' conceptions do not work in a planet such as Jupiter or possibly Polyphemus.

The question is not whether the atm is breathable and the temperature thingy - that can be worked around quite easily. The only problem is, there is no ground!

[Amaya]

They'd be much more akin to fish than to birds.  Fish never have to "land" as they swim through the ocean, after all.

[Kamean]

Don't forget - it's only theory.

[Clarke]

They'd be much more akin to fish than to birds.  Fish never have to "land" as they swim through the ocean, after all.

Oh, I'd forgotten that that'd work if your cell was somehow less dense than air.

(Or you could sink into the lower layers of atmosphere and swim around there.)

[Irtaviš Ačankif]

Okay, so in the upper atmosphere you won't crush, but it would be too cold. In the lower atmosphere you will be warm, but the pressure will crush you. Sounds like a paradox...

By the way, was the artist which drew those pictures somehow influenced by Na'vi culture? It seems like the first monster has tsaheylu thingys on it and the signature on them are in Papyrus...which is the official Avatar subtitles font.

[Kamean]

Maybe.

[Clarke]

Okay, so in the upper atmosphere you won't crush, but it would be too cold. In the lower atmosphere you will be warm, but the pressure will crush you. Sounds like a paradox...

But there'll be a middle ground where it'll be the pressure of, say, liquid water.  (Or whatever.)

[Raiden]

All cell-based life we know about needs a solvent of some kind in the cell itself. In Earth cells, the solvent is water, but Titan is too cold for liquid water. If you used liquid methane, as I thought the suggestion was, then your cell must be very cold, since methane's boiling point is about -300F.

But cold chemical reactions don't work as quickly as "room temperature" ones, and so the cell will generally react slower.

Yeah, the liquid methane wouldn't be blood or cytoplasm, it's just a place where more complex organic molecules could come about. Liquid methane is really unusable as something like that, because it's all hydrophobic, and it would be really tough for a cell to have any kind of metabolic processes that way, since only hydrophobic molecules would be available, and cells as we understand them need both hydrophobic and hydrophilic bonds.

The problem remains, however, that a cell would need to get a certain amount of kinetic energy to undergo biochemical reactions, and it would be very difficult to hold onto any energy in an enviroment that cold. A cell cannot get by on smaller amounts of kinetic energy, because many important chemical reactions require certain levels of energy to begin, referred to as activation energy. Without enough energy to perform these reactions, the cell would die.

And, back on the topic of gas giants, yes, it is perfectly possible for life to exist on a gas giant. All that is needed is the correct combination of organic compounds to form something that could be used as genetic material, and that would be the basis for life. After that, random reactions would have to bring about new  forms organization and means of "maintenance", and that's the beginning of a cell. Like others said, it would just need to float all time, which is easy, as long as some sort of "swim bladder" exists that is filled with a gas that is less dense than the rest of the animal's environment.

[Clarke]

The trick is that Jupiter and Saturn are, IIRC, mostly hydrogen, which is the least-dense thing in the universe. I don't really know what you'd put in the bladder.

[Irtaviš Ačankif]

A vacuum would work...

[Human No More]

It's perfectly possible - the main issue is their gravity.

Saturn has a lower density than water, yes, while Jupiter is around 30% more dense, but that doesn't preclude the existence of life in gas giants. They would not be surface-based, obviously.

[Clarke]

Why's their gravity an issue? Since you're limited to flying anyway, you've basically got a choice between metallic hydrogen, near-vacuum and everything in between.  

[Human No More]

Earth surface gravity: 9.8m/s^2
Jupiter surface gravity: 23.12m/s^2

[Clarke]

Psst, where's Jupiter's "surface"?