- #1

Bacat

- 151

- 1

I was thinking about the theory of black holes the other day; the immense gravity of a black hole condenses matter so completely that light cannot escape. If this is the case, then it is reasonable to assume that matter with mass certainly cannot escape either, therefore heat cannot escape (which is transferred by the kinetic motion of matter). Therefore, a black hole condenses matter without heat loss. This seems to be a decrease in entropy (of the black hole system). But what about the surroundings?

Let a gas cloud collide with the black hole. Now the mole of gas which had expanded freely in a vacuum is condensed into a much smaller volume without heat loss. The pressure will increase so much that the gas will condense into a solid, thus we have lost 1 mole of gas. This implies a decrease in entropy in the surroundings.

[tex]\Delta S_{total} = \Delta S_{surr} + \Delta S_{sys}[/tex]

So the total entropy of the universe has decreased due to the black hole, which seems to violate the second law of thermodynamics.

Can anyone shed light on this problem?