Replies

To: PatrickHenry

So if the universe expands, wouldn't that create universal cooling?

9 posted on 08/03/2006 1:02:58 PM PDT by Toby06 (True conservatives vote based on their values, not for parties.)

I think the boundary conditions need to be considered.

20 posted on 08/03/2006 1:14:58 PM PDT by doc30 (Democrats are to morals what and Etch-A-Sketch is to Art.)

So if the universe expands, wouldn't that create universal cooling?

Yes; that explains how the Universe starts out in a hot condition at the "Big Bang" and cools to its current observed condition without shedding heat to an external heat sink. It's a gigantic adiabatic cooling process that is the consequence of the expansion of space.

A star is just the opposite: a gravitational contraction of gas and dust heats up the matter. If there is enough matter (more than 0.1 solar masses) undergoing adiabatic contraction, it gets heated to the point where nuclear fusion reactions begin deep inside, and star is formed.

45 posted on 08/03/2006 2:13:35 PM PDT by longshadow (FReeper #405, entering his ninth year of ignoring nitwits, nutcases, and recycled newbies)

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