• Question: how does the earth manage to spin around everyday? why doesnt it ever stop?

    Asked by chloewildman to Chris, Eva, Michael, Paddy, Phil on 21 Jun 2011.
    • Photo: Chris Jordan

      Chris Jordan answered on 21 Jun 2011:

      Nice one!

      Newton’s eeerrr…. first law – every keeps doing what its already doing unless something stops it. That’s not obvious here on earth itself, because if you spin something here there are things to stop it … usually friction. There’s nothing much out in space for the earth to rub against to create friction.

      The earth is slowing down a very little bit (someone asked about the moon in todays chat – and as the moon goes around us some of the earth’s spin energy gets shared out with the moon by the gravity that holds the earth-moon together). Some of the earth’s energy goes in dragging weather around… there’s a bit of friction between the atmosphere and the earth but the earth is so much more massive than the atmosphere that its a minute effect.
      Other things happen too – the Japanese earthquake was so big it made the whole earth jump. Japan actually moved a few metres, and the earth’s spin shifted a bit.

    • Photo: Paddy Brock

      Paddy Brock answered on 21 Jun 2011:

      Wow! Really?! That’s cool. I didn’t realise an earthquake could affect the earth’s spin.

    • Photo: Michael Wharmby

      Michael Wharmby answered on 21 Jun 2011:

      Nice question and nice answer from Chris! The Earth is spinning as a result of left over kinetic energy (movement) from when it formed.
      The Earth formed from a disk of dust, gas, rock etc. some of which went to form the other planets, some to the Earth and most(?) to the sun. That disk of dust was orbiting around the sun and as it formed into planets, that kinetic energy was transferred into making the Earth orbit the sun and making it rotate about its axis.
      Correct me if I’m wrong Chris.

    • Photo: Phil Denniff

      Phil Denniff answered on 21 Jun 2011:

      Great question chloewildam, I had never thought about it before. Now you have asked I want to know the answer, Im also glad Chris is on hand to supply it.