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How does Earth sustain its Mag Field?

  1. Nov 18, 2008 #1
    Anyone wanna try explaining Dynamo Theory to a 2nd year astrophy undergrad? Short and simple will do...
  2. jcsd
  3. Nov 18, 2008 #2


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    The earth rotates and has a molten, metallic [electrically conductive] core.
  4. Nov 19, 2008 #3
    so what is it about the Earths rotation that induces the current in this conductive core?
  5. Nov 19, 2008 #4
    I do believe the core, since it is molten and conductive has a large number of free electrons moving around in it, and moving charges give rise to magnetic fields.
  6. Nov 19, 2008 #5
    It's thought that convection cells in the fluid outer core generate strong magnetic fields, but the different adjacent cells are assumed to counter rotate, almost cancelling out each others field. Only a residual field remains that can collapse or reverse depending on changes in the core convection cells.

    That's the abstract of this:

    When North goes South

    Better post these things in the Earth Science forum.
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