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Eddy currents due t into the core of the Earth

  1. Aug 3, 2010 #1

    Those days I wonder if the magnetic field from the Sun, could make the Eddy's currents inside the core (ferromagnetic) of our planet, because of the rotation of the Earth. (like a induction cooker)
    It would result a magnetic field on the Heart, and if the magnetic field from the Sun become stronger, the core of our planet should be warmer, and the temperature increase.

    Anyone can help me ? Do I am right ?
    Sorry if my English is not good.Tanks you in advance.
  2. jcsd
  3. Aug 3, 2010 #2


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    Welcome to the Physics Forums, L.P. Your thinking is correct, but in practice the sun's magnetic field is too weak at the earth's distance to be noticed.

    There is a different mechanism by which the sun indirectly generates eddy currents within the earth, however. The solar wind interacts with charged particles in our ionosphere to generate ionospheric currents on a planetary scale. They generate weak magnetic fields, called "micro-pulsations", that vary daily as the earth spins and that can (barely) be detected at the earth's surface. They are much too weak to affect the human heart or our planetary temperature.

    Still, these high altitude currents in turn induce eddy currents in underground aquifers, which create tiny 2nd-order changes to the micropulsation fields. The micropulsations therefore change slightly with ocean tides and also seasonally as water tables change.
  4. Aug 3, 2010 #3
    The Venusian magnetosphere is a function of the effect that you describe, but not through an interaction with a planetary core. Rather, Venus has a very weak geomagnetic field as a result of interactions with solar ejecta and Venus' ionosphere.
  5. Aug 4, 2010 #4
    The earth is heated by gravitational forces I think, not magnetic
  6. Aug 4, 2010 #5

    No... no no no.

    The earth is "hot" from its formation, and from the decay of (mostly) uranium and thorium. What the hell are you talking about?!
  7. Aug 4, 2010 #6

    D H

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    The Earth was heated by gravitational forces, but a long long time ago. The initial formation of the Earth and the formation of the core and mantle represented huge changes in potential energy. Those changes manifested themselves in the form of heat. However, that process was nearly complete soon after the formation of the Earth. There is very little heat generated by gravitation now, which is results from tidal deformations due to the non-circular orbit of the Moon and Earth about their center of mass and the Earth's non-circular orbit about the Sun. The heat generated by these tidal stresses is tiny compared to the initial heating, so tiny that it does not explain the fact that the Earth is still hot. As nismaratwork mentioned, there is (at least) one other source of heating: radioactive decay.
  8. Aug 4, 2010 #7
    Tks to everyone for the answer, however, i am curious,so ill try to calculate the effect of the magnetic field from the sun, on our planet. Ill take the magnetic field from the sun,the size, the distance between us and the sun (maybe), the rotation of the earth, and try with different size of the core of our planet (first ill try with an easy system). Finally ill compare with the actual magnetic field from our planet (maybe can i use more informations, like the temperature?) ... I am not sure if it will work. Anyone know if it can be useful ? Can I answer my curiosity ?
    Thanks !
  9. Aug 5, 2010 #8


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    I believe this has already been answered - solar magnetic fields have no appreciable effect on earths magnetosphere.
  10. Aug 5, 2010 #9
    Radioactive decay... it's a glowing insight *snort-laugh-snort-harhar*. Yeah... I guess to be fair I should acknowledge that technically, as you say, the initial heating of the planetary disc was due to gravitation. I never entertained the notion that this is what Jesvant mean.
  11. Aug 6, 2010 #10
    I don't know if it have been already answered, but it's not here. Because how to know the magnetic field of the sun ?
    I am not good at mathematics, but I propose to make this hypothesis : If the magnetic field from the earth, is from the sun. We can calculate what would have the magnetic field of the sun, with the opposite calculus....(with the size, distance and rotations...).
  12. Aug 6, 2010 #11
    What happened to this thread?!
  13. Aug 6, 2010 #12
    Heh, so our core is pretty much a nuclear bomb aye.
  14. Aug 6, 2010 #13


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    Sorry, your hypotheses are way off base. I suggest you do some reading about solar and terrestrial magnetism, and lay off the silly theories.
    No, not at all. Radioactivity is not the same as a weapon.
  15. Aug 7, 2010 #14
    Marcusl said it, but think of this:

    Radioactive Decay is to a bomb as: Gunpowder in a pile, lit by a match, is to gunpowder packed tightly into a casing and detonated.

    It's not that simple, but in short, a nuclear weapon is predicated on a runaway chain reaction, but decay is a slower process involving the weak force.
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