• Question: how do the planets circle the solar system?

    Asked by ZAK.T! to Heather, Helen, Hugh, Jane, Julian on 16 Nov 2014. This question was also asked by Matthew S.
    • Photo: Julian Onions

      Julian Onions answered on 16 Nov 2014:

      The planets orbit in circles because the Suns gravity keeps them there.
      They want to go wizzing off in a straight line into outer space, but the Sun keeps pulling at them. It can’t pull them into itself, but it pulls enough they don’t go straight but in circles instead.
      It’s a bit like swinging a ball on a string around your head. It wants to go straight, and if you let go the string it will. However while you hold the string this wanting to wizz off force is countered by the strength of the string, so it goes in a circle.

    • Photo: Helen Johnson

      Helen Johnson answered on 16 Nov 2014:

      It’s all about gravity! I think the way I explained it in your ‘what is gravity?’ question (about the trampoline) is a really cool way to think about it. The more energy something has, the further out it will orbit.

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