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How is the core of the Earth kept hot?

  1. Mar 29, 2009 #1
    I know that the mantel of the Earth is kept hot by radioactivity, but is this also true for the core?
  2. jcsd
  3. Mar 29, 2009 #2


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    Addendum. Most of the radioactivity is in the crust and the mantle; but this is still generating heat which contributes to keeping the core hot. For lots more detail see Probing Question: What heats the earth's core? at physorg.com

    So the core is not being kept hot by radioactivity in the core; the energy from decay in the mantle and crust is more important. I had to look this up also.
    Last edited: Mar 29, 2009
  4. Mar 29, 2009 #3
    Thanks sylas.
  5. Sep 12, 2009 #4
    does the earth gain significant heat from the moon and the suns tidal pull?
  6. Sep 12, 2009 #5


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    The link that sylas provided list 4 sources of heat within the earth.

    Up to 90% of the heat is from radioactive decay.
    About 5 to 10% is from friction caused by gravity.
    About 5 to 10% is residual left over from the original formation of earth.
    A small amount is latent heat released when molten materials turn into solids.

    As I understand it, tidal push and pulls are part of the 5 to 10% gravity friction portion.
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