Thermodynamics and the Universe
Date: Around 1993
If the universe does eventually reverse its expansion and begin to
collapse, will the Second Law of Thermodynamics then be reversed so that
energy will be required to make any closed system more disordered?
At least not for a long time after it starts to collapse. The
second law simply indicates that there are a large number of states available
for systems to occupy beyond the initial states and that it is overwhelmingly
probable that the system will evolve to occupy these other states. Events far
away will not change this.
Steven Hawking's "Brief History of Time" provides a good summary
of the best guesses on this. The evidence seems to be that the Second Law of
Thermodynamics will hold forever, and that the final state of the universe,
even if it collapses back on itself, will be much more disordered than the
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Update: June 2012