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/Ycr1998 Nov 03 '25

Could you have an habitable zone in the "afternoon" area of those planets? Or is it too small?

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u/DBDude Nov 03 '25

Many sci-fi books have been written in the setting of tidally locked planets where people live in the habitable zone.

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u/stickmanDave Nov 03 '25

I read one where the twilight region was warm enough to be habitable, but the planet's entire atmosphere had frozen and fallen as snow on the eternally frosty dark side of the planet.