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If at the Big Bang (t=0) energy was uniformly distributed inside the singularity, then entropy would have been maximal and nothing would have happened. What's missing?
We're used to many systems like weakly interacting gases where uniform distributions maximize entropy. For systems with gravitational attraction, clumping can actually increase entropy. Think of it this way. As things clump, they lose gravitational potential energy. That energy can go into high-entropy thermal forms, such as thermal radiation or heating of materials.
Black holes provide a good example of this. Stuff falling into a black hole increases its entropy more than the entropy loss from the missing stuff. Only when the surroundings become extremely cold and empty can entropy increase via Hawking evaporation of the black hole.
(published on 07/21/11)
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