Gas Properties and Stellar Evolution

Hello all. Amadameus here.The section of stellar evolutionary theory that deals with stars forming and gases accreting into disks, etc. has always seemed quite vague to me. It also seems to have a major flaw:When gas molecules are under the influence of gravity, like on Earth, they act a lot like bouncy balls that never lose their momentum. They ping off each other, bouncing and flying in all directions. The reason they don't leave Earth is because they are stuck here by gravity.A handy-dandy analogy:Compare it to a rubber sheet (The standard model for 2-dimensional gravity) with a bunch of marbles on it. The marbles represent gases, and the dips in the sheet are gravity fields created by Earth, etc.
Anyway, when the marbles/gases roll toward 'Earth', they will collect as close as they can to the origin of gravity. However, the marbles will not roll over each other to create a pile three or four marbles deep. With the moderate depression created by earth, instead they would collect horizontally. (Not stacked on top of each other.)
Then, increase Earth's gravity to that of Jupiter's. (Pull down more on the sheet.) Here the marbles will roll over and onto each other to get as close as they can to the source of gravity. This piling represents the compression equilibrium that you get when gravity's force equals that of the gases' own 'bouncing' motion.Now back to the real world.When gas collects of its own accord, the gravity is extremely weak (talking about hydrogen gas here) therefore the gas compression must be weak as well. This means that the amount of pressure found at the center of a gaseous nebula will normally be much less than that of Earth's.And further on to my point.How, then, would stars form in the post-Big Bang universe, where there are no rocks or high-density materials for said gas to accumulate around?...I really hope I made sense back there.This message has been edited by Amadameus, 04-14-2005 12:30 PMThis message has been edited by Amadameus, 04-15-2005 07:36 AMThis message has been edited by Amadameus, 04-15-2005 08:47 AM

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...it was like that when I got here.

Just make one change and then I'll release this. Where you say, "The section of evolutionary theory...", you really want to refer to cosmology, not evolution.

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--	Percy
	EvC Forum Director

...changed it, but IMHO the stars forming and shtuff is part of cosmic evolution because it requires stars to create heavy elements, etc.This message has been edited by Amadameus, 04-15-2005 07:39 AM

If you prefer "cosmic evolutionary theory" or "star evolution" or something else that makes clear you're not confusing biological evolution with cosmology, that would be fine.It is very common for Creationists to lump all fields of science, like cosmology and geology, under the umbrella of evolution. For example, you'll often hear things like, "Evolutionists developed the big bang theory." If I had released your PNT as it was people would have assumed you were this type of Creationist.

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--	Percy
	EvC Forum Director