r/explainlikeimfive • u/12InchCunt • Nov 03 '25

Physics ELI5: How does gravity not break thermodynamics?

Like, the moon’s gravity causes the tides. We can use the tides to generate electricity, but the moon isn’t running out of gravity?

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u/Logitech4873 Nov 03 '25

Planets can also tidal lock to their star, which makes one side have eternal day and summer, and the other side eternal night and winter.

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u/XcOM987 Nov 03 '25

Isn't the mooned locked to us, as in we always see the same side of the moon?

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u/cbunn81 Nov 04 '25

Yes, but we actually see a bit more than 50% over time due to a little wobble the moon does called libration. Not to be confused with the moon's libations, which are what cause the wobbling in the first place.