• Question: Why is the Earth round?

    Asked by Matthew to Ahmed, Francesca, George, James, Nitheen on 14 Nov 2014.
    • Photo: Francesca Paradisi

      Francesca Paradisi answered on 14 Nov 2014:

      It’s not really technically round, but the spherical shape is the one that allows for the maximum surface to be exposed and so it gets as much sunshine as possible to function at its best.

    • Photo: James Sullivan

      James Sullivan answered on 14 Nov 2014:

      Hi Matthew –

      the heavier an object it the more gravity becomes important. On earth gravity tries to pull all the matter to the center of the planet.

      This results in the material at the surfaces of the planet being pulled downwards – and this results in the formation of a sphere.

      earth is almost spherical – Its poles are slightly flattened though.

    • Photo: George Dowson

      George Dowson answered on 14 Nov 2014:

      The round ball shape allows as much mass as possible to be as close to the centre as possible. This way the sphere is the lowest energy arrangement of large amounts of mass. So even if you made a cube planet, erosion would wear down the corners until it’s a sphere.

    • Photo: Ahmed Osman

      Ahmed Osman answered on 14 Nov 2014:

      Dear Matthew
      thanks for this brilliant question
      when objects larger than about 1,000 km in size are able to pull themselves into a sphere.Because of the gravity and this ability was one of the requirements for an object to be considered a planet. They must orbit the Sun, they need to have cleared out all the smaller objects in their orbit, and they need to have enough gravity to pull themselves into a sphere.

      When an object has the gravity to pull itself into a sphere, astronomers say that it’s in hydrostatic equilibrium. And that’s why the Earth is round.