• Question: Why is the world round?

    Asked by hibble2013 to Angus, Christian, Hannah, Laura, Simon on 21 Jun 2013.
    • Photo: Simon Holyoake

      Simon Holyoake answered on 21 Jun 2013:

      the earth is actually not perfectly round, it is called an ‘oblate spheroid’ the diameter of the earth is wider around the equator due to the rotation of the earth and its non-solid insides being pushed outwards

      generally though its because gravity acts equally in all directions, and the most efficient shape in terms of volume versus surface area is a sphere, when objects in space become planet sized, they tend to become round as they have enough gravity to squash themselves into a round shape!

    • Photo: Angus Ferraro

      Angus Ferraro answered on 21 Jun 2013:

      As Simon says gravity acts the same in all directions. If you were allowed to turn around but not to move, you would be able to reach the same distance in every direction (the length of your arm). If you whirled around you would trace our a spherical shape. Just like your arms, gravity’s reach extends the same in all directions.

    • Photo: Laura Roberts Artal

      Laura Roberts Artal answered on 21 Jun 2013:

      Simon and Angus have answered really well.

      All I can add is that the Earth tries hard to keep the same shape, even when things change on the surface. There is a recent theory that suggests that if an object of sufficient weight on Earth — for example, a supersized volcano or the continents collecting together — formed far from Earth’s equator, the force of Earth’s rotation would gradually pull the object away from the Earth’s rotation axis back towards the equator.

    • Photo: Christian Maerz

      Christian Maerz answered on 22 Jun 2013:

      And to add to all these great answers, another name for the shape of the Earth is “Geoid”, and has by some scientists been compared to a really big potato…

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