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Questions about magnetism

  1. Mar 16, 2013 #1
    Do any celestial bodies not have magnetic fields? Why?

    I'm having a difficult time finding good resources for dynamo theory a question about that...
    So first what I know:
    1 - The Sun has a nonmetal hydrogen/helium plasma interior which is generating a magnetic field
    2 - the Earth has a liquid iron core with a magnetic field
    3 - metals can be magnetized because their electron spin orientations result in the atom having an electric current inducing a magnetic field, and nonmetals are labeled as not having magnetic properties
    Q - If both metals and nonmetals (e.g. hydrogen plasma) can be magnetized then why are nonmetals categorized as not being able to be magnetized (according to the periodic table). Clearly I'm missing something in there because that's not consistent.
     
  2. jcsd
  3. Mar 16, 2013 #2

    Bobbywhy

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    Gold Member

    Many celestial bodies have magnetic fields. It is not always easy to determine if they do, but when there is evidence there is a magnetic field we may rely on our imperfect models of our earth's magnetic field for tenative explanations.
    As for your Q., sorry, I've no idea of how to answer that.

    “The origin of the Earth's magnetic field is not completely understood, but is thought to be associated with electrical currents produced by the coupling of convective effects and rotation in the spinning liquid metallic outer core of iron and nickel. This mechanism is termed the dynamo effect.”
    http://csep10.phys.utk.edu/astr161/lect/earth/magnetic.html

    “Although the details of the dynamo effect are not known in detail, the rotation of the Earth plays a part in generating the currents which are presumed to be the source of the magnetic field.”
    http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magearth.html

    Simulation of the earth’s mantle with a supercomputer:
    “The geomagnetic field is generated deep inside the Earth. Within the molten, electrically conducting iron core of the Earth, i.e. at a depth of approximately 3000 to 5000 kilometers, a magnetohydrodynamic dynamo maintains the field.“
    http://www.gauss-centre.eu/earth/magnetic_field [Broken]
     
    Last edited by a moderator: May 6, 2017
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