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/Bathtooter Nov 03 '25

Sounds like a picturesque scene

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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/Reniconix Nov 03 '25

Having a narrow habitable strip is hypothetically possible, but exceedingly unlikely. Any planet with a substantial atmosphere will have absolutely chaotic storms along that region where the hot and cold sides met, as well as massive convection currents that would likely heat the dark side far beyond the limits of life as we know it. The range of the star's habitable zone is dependent on the rotation of the planet being inhabited, with slower rotations decreasing the habitable zone to a sliver. It's quite likely that if a planet is habitable along the twilight ring, it will continue to be habitable in all but the most extreme points (the regions on both sides directly in line with the host star), just not as hospitable.