The moon rotates once per revolution around the Earth, but that’s not a coincidence. Somehow the rotation and revolution are connected to each other. Some force is keeping them the same. How exactly does that work?

  • Jeena@jemmy.jeena.net
    link
    fedilink
    English
    arrow-up
    0
    ·
    1 year ago

    It’s not some force keeping them the same, it’s no force changes the speed of the moon. From my limited understanding the moon was created when a smaller planet crashed into the earth:

    They both got the same momentum, therefor they started rotating at the same speed, once per day.

    There is nothing out there which would be able to change the speed of the rotation of the moon. There is also nothing which would change the speed of the rotation of the earth. Therefor they keep spinning at the same speed.

    • Hypersapien@lemmy.worldOP
      link
      fedilink
      English
      arrow-up
      0
      ·
      1 year ago

      Other people have explained it, and the same thing happens with other moons in the solar system, including some orbiting gas giants where your explanation couldn’t have worked.

      The Earth’s gravitational field elongates the moon slightly, and an elongated satellite tends more to stabilize its rotation with the longer diameter fixed to point at the center of its orbit.