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PBS Space Time
Reversing Entropy with Maxwell's Demon
Season 4
Episode 33
The second law of thermodynamics – the law that entropy must, on average, increase – has been interpreted as the inevitability of the decay of structure. This is … misleading. Structure can develop in one region even as the entropy of the universe rises. Ultimately, entropy is a measure of the availability of free energy – of energy that isn’t hopelessly mixed in thermal equilibrium.
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