• Question: I know that the gravity of the moon causes ocean tides on earth. How does centrifugal force cause the far-side bulge?

    Asked by nadia_c to Daniel, Hannah, Maggie, Ry, Scott on 13 Nov 2017.
    • Photo: Maggie Lieu

      Maggie Lieu answered on 13 Nov 2017:

      Nice question but you already answered it yourself! The far side bulge is created by the centrifugal force.

      Imagine if you had a ball on a string, when you swing it round in a circle the ball tends to push outwards right? and if you were to cut the string the ball would shoot off. The moon is just like the ball, and the string is the gravitational force between the Earth and the moon. Because of the orbit, the moon pushes outwards, and so the far side ends up bulging out

    • Photo: Ry Cutter

      Ry Cutter answered on 13 Nov 2017:

      Maggie has it right!
      Another way to imagine it. When you’re in a car and the driver goes around a roundabout a little to quickly, you fly to outside edge of the car. This is called inertia, the motion of particles wanting to stay in a constant motion.
      Inertia is responsible for a lot of things, we use it in seat belts to keep people safe in accidents. It also needs to be accounted for when going into space, because there’s no gravity inertia can cause the astronauts to fly away!
      Great Question,
      Ryan

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