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The Question

(Submitted February 10, 1999)

I have been pondering this question now for an inordinate amount of time. The second law of thermodynamics states, if I can remember correctly, that entropy will increase with time, where entropy = the amount of disorder in a system. With increasing disorder, there is inherently less energy that can be used to do useful work. With this inherent lack of useful energy, is it then feasible that in some point in time, the universe will reach a state of thermal equilibrium, where there is nothing more than a collection of protons evenly spaced apart and all moving at the same speed?

The Answer

Basically yes. That state is called 'the heat death of the Universe'. (The protons will all have decayed, but the Universe will consist of smaller particles all drifting at random and getting more and more distant from each other as the Universe expands).

See for a more recent view of this.

David Palmer and Samar Safi-Harb
for Ask an Astrophysicist

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