• Question: If Earth is so old, doesn't that mean Earth's decaying magnetic field would have been unacceptably high at one time?

    Asked by ashleighlou to Betul, Bridget, Ceri-Wyn, Maria on 25 Jun 2010 in Categories: .
    • Photo: Ceri-Wyn Thomas

      Ceri-Wyn Thomas answered on 24 Jun 2010:

      The earth’s magnetic field is generated by the spinning of the earth’s molten iron
      core. It’s like a giant
      electromagnet. The amount that the core spins has changed throughout the earth’s
      history, and we’re not
      really sure why. The strength of the field is controlled by how fast the core spins,
      so the magnetic field
      is always changing as well. I don’t think that it has ever been unacceptably high –
      actually having a
      magnetic field is really important for us! Our magnetic field helps deflect
      radioactive solar winds away from
      us. If it didn’t, they would be really harmful to us, and, just as importantly, they
      would begin to strip
      away our atmosphere, leaving us as a ‘dead’ planet like Mars, which has no magnetic
      field. I don’t think
      having a stronger magnetic field in the past would be a problem.

    • Photo: Bridget Waller

      Bridget Waller answered on 25 Jun 2010:

      Wow, you know much more about this than me…I don’t think I know the answer, but it sounds as if you are on your way to finding out! I wonder what Ceri said…I bet she knows the answer. 😛

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