• Question: why are all the craters on the moon round and no other shape?

    Asked by flina001 to Charlie, Eoin, Jemma, Julian, Steve on 21 Mar 2011.
    • Photo: Eoin Lettice

      Eoin Lettice answered on 21 Mar 2011:

      Hi flina,
      I’m not an astrophysicist but I can take a guess.
      The craters are made by objects hitting the surface of the moon at great speed – causing a big crater to appear and material on teh moon surface to be pushed upwards and outwards from the point of impact. Becasue the point of impact (where the thing hits the moon) is relatively small and the material is pushed in all directions from this spot, it appears round (or at least roughly round to the human eye).
      I reckon you could experiment by taking a deep tray of flour or other powder and drop a small rock into it from a height. What type of craters does it create? I’m sure they’ll all be round.

      Eoin

    • Photo: Julian Rayner

      Julian Rayner answered on 21 Mar 2011:

      Hi flina001.

      I don’t think they are all perfectly round, but since they are close to it, because they are formed by the impact of an object hitting the moon. Try the experiment yourself – throw a stone at a pile of sand, and see what shape you get. Chances are it will be close to circular, because the force is greatest near the middle where the object hits, then decreases further away from the object in all directions.

    • Photo: Stephen Moss

      Stephen Moss answered on 21 Mar 2011:

      Hi Flina
      This sounds like a question for Charlie, but I wouldn’t be surprised if it’s something to do with how when a stone falls into a pond the ripples always spread out in a circle.

    • Photo: Charlie Ryan

      Charlie Ryan answered on 21 Mar 2011:

      hi flina well thats kind of the shape that a meteorite makes when it hits the gound!! That i think is how all most all of the craters on the moon are formed!

Comments