Comment on If something could rotate infinitely after being initially pushed, would the initial push disqualify it from being classed as perpetual motion?

gedaliyah@lemmy.world ⁨2⁩ ⁨months⁩ ago

• FuglyDuck@lemmy.world ⁨2⁩ ⁨months⁩ ago

  “Due to tidal forces”

  Because, the moon (and maybe the sun, and other planets like Jupiter) are acting on it, yeah?

  The earth won’t stop spinning. What’s happening is that the moon’s gravity is slowing the earth’s spin as it drags our oceans towards it.

  Once our day is the same as the moon’s orbital period, then the tide will essentially be fixed, which means it’s no longer slowing us down.

  And all that energy, for the record, is going into the moon and expanding its orbit slightly.

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  • gedaliyah@lemmy.world ⁨2⁩ ⁨months⁩ ago

    Yes, although quantum effects also slow spinning celestial objects/systems, even in the absence of measurable tidal effects. That would take much, much longer to slow down.

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    • lucullus@discuss.tchncs.de ⁨1⁩ ⁨month⁩ ago

      What quantum effects exactly? How does that work?

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      • gedaliyah@lemmy.world ⁨1⁩ ⁨month⁩ ago

        For example

        I’m not a scientist so I don’t claim to understand it or explain it.

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