• Question: Why does the earth spin?

    Asked by alex1998 to Amy, Drew, Julia, Kimberley, Sara on 16 Jun 2011.
    • Photo: Drew Rae

      Drew Rae answered on 14 Jun 2011:

      Alex, our solar system started as cloud of particles that gradually formed into clumps under gravity. When that happens, there is usually some rotational energy (spin) left over unless things freakishly balance out exactly. This comes from all of the particles arriving at different angles and speeds. The same goes for the planets (and even for the galaxy).

    • Photo: Amy MacQueen

      Amy MacQueen answered on 15 Jun 2011:

      Hey Alex, good question, I think Drew pretty much answered this. Its interesting to think that we are actually spinning…coz it doesn’t really feel like it! 🙂

    • Photo: Julia Griffen

      Julia Griffen answered on 15 Jun 2011:

      To balance its self.. I think.

    • Photo: Sara Imari Walker

      Sara Imari Walker answered on 15 Jun 2011:

      Hi alex1998! Yes the Earth spins because of its process of formation. As Drew said, the Earth formed from a massive clump of gas and dust (actually the whole solar system formed this way!). This cloud was spinning initially (maybe a star glanced by it and set it in motion) and as gravity acted to compress it it started to spin faster. This is the same thing as how ice skaters spin faster with their arms in than when they have them out-stretched, the principle is called conservation of angular momentum. So planets, the Sun, and Earth all get its spin from conserving angular momentum as this giant cloud collapsed to form our beautiful solar system. I think in the case of Earth we may also have some spin from the giant moon forming impact too! Amazing to think about but early in Earth’s formation we were actually struck by a giant object Theia (another proto-planet about the size of mars) and a huge mass ejected from Earth to form our moon. This impact probably set the final spin of the Earth, which has been going ever since due to conservation of angular momentum =)

    • Photo: Kimberley Bryon

      Kimberley Bryon answered on 16 Jun 2011:

      I think that Drew and Sara have pretty much covered this. Nice question though 🙂