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Earth, The Scofflaw Planet (Posted on 2018-07-09) Difficulty: 2 of 5
The second Law of Thermodynamics is pretty clear about it: The entropy of a system not in equilibrium will tend to increase over time. (Entropy may be thought of as disorder or randomness). But, consider the history of Earth: It is a system that started out as a semi-molten mess. Later, it cooled and developed life, and it made those pesky structured organisms that went on to populate the seas and produce our jungles and forests. Then came those advanced animals that fashioned everything, even cities. Cities are much more ordered than jungles and so their entropy is lower.
Entropy(cities) < Entropy(jungles) < Entropy(molten mess). So, what's going on? How did we manage to violate the law? Are we somehow miraculously, divinely above the rules?

See The Solution Submitted by Steven Lord    
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solution | Comment 3 of 9 |
As quoted in Wikipedia, the second law of thermodynamics states:

The second law of thermodynamics states that the total entropy of an isolated system can never decrease over time. The total entropy can remain constant in ideal cases where the system is in a steady state (equilibrium), or is undergoing a reversible process. In all spontaneous processes,[1] the total entropy always increases and the process is irreversible. The increase in entropy accounts for the irreversibility of natural processes, and the asymmetry between future and past.


The statement in the puzzle misquotes it as referring to a system not in equilibrium, whereas the actual definition refers to an isolated system. The earth is not an isolated system. It receives much energy from the sun, along with its associated negentropy. Depending on how you define equilibrium, this actually creates a dynamic equilibrium rather than a static one, as the heat difference generated by sunlight vs the portions of earth receiving less sunlight acts like a steam engine, with the solar fuel heating the "cylinders".

Furthermore, there's geothermal energy, perhaps the first progenitor of life on earth in the form of the extremophiles in ocean deeps. But certainly modern life depends on the photosynthesis provided by solar energy and the negentropy associated with it.

  Posted by Charlie on 2018-07-09 19:39:10
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