• Question: why does the earth spin on its axis

    Asked by mlricketts to Charlie, Eoin, Jemma, Julian, Steve on 20 Mar 2011.
    • Photo: Julian Rayner

      Julian Rayner answered on 17 Mar 2011:

      I thinks it’s a hangover from when the earth formed. It formed from clouds of dust that were spinning when they condensed into matter. That momentum has just kept on going, because there is nothing to slow it down.

      Or at least so says the web!

    • Photo: Stephen Moss

      Stephen Moss answered on 17 Mar 2011:

      Hi Mlricketts

      All planets apparently spin, and it’s something to do with the way they’re formed by the clumping together of rocks and gases.

    • Photo: Eoin Lettice

      Eoin Lettice answered on 17 Mar 2011:

      I’m not sure of the answer to this one. All energy in the universe must come from the moment of the big bang, so I presume the energy for the spinning of the earth comes from this big bang. I’m a biologist though, so I could be way off!!

      Eoin

    • Photo: Charlie Ryan

      Charlie Ryan answered on 20 Mar 2011:

      hi mlricketts again! wow you have a lot of questions!
      Great question – and i’m not really sure what the answer is! Bit embaressing really as it’s quite important to what i do – i am building and testing mini rockets!
      Apparently it is due to the conservation of momentum, which kind of makes sense. As the earth was formed from the dust leftover from the suns formation, the particles all had there own momentum (i.e. they were moving and had a mass). As gravity pulled them together to form the earth this momentum needed to be conserved, and this resulted in the earth spinning. I think thsi is the same as an ice skater doing a twirl. As they are spinning on the ice, if they want to spin faster they pull in their arms. This is their momentum being conserved. So the dust cloud before earths creation is like the skater with their arms out, and the formed earth is like when the skater pulls their arms in! I think!

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