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Earth's gravitational field size.

  1. Sep 12, 2011 #1
    Is the size of Earth's gravitational field the same size as it's electric/magnetic field?

    Also, what is the standard theory as to why the Earth has a magnetic field? What I mean is, how is it generated? Is it the result of the Earth traveling through space and interacting with the rays etc. of the Sun? Or, does the Earth generate the magnetic field itself - almost as a planetary dynamo due to plate tectonics and the motion/composition of it's core?


    Thanks!
     
  2. jcsd
  3. Sep 12, 2011 #2
    Technically, a gravitational field extends outwards infinitely, so the word size does not have much use. You could easily calculate a bodies effective gravitational field (i.e. how far does its gravitational field extend where it is the primary force on objects within it), but this would require a stronger definition of the 'effective' field.

    As for the magnetic field, I'm not quite sure but I believe its thought to be related to the movement of heavy metals in the Earth's Core, but someone correct me if they know more.
     
  4. Sep 12, 2011 #3

    Drakkith

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    Staff: Mentor

    The magnetic field is usually explained via the Dynamo effect occuring within the Earth.

    The Earth's gravitational field extends infinitely in range. However it falls off in strength very quickly, so past a certain range you can ignore it for all but the utmost precise calculations.
     
  5. Sep 12, 2011 #4

    Drakkith

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    Staff: Mentor

    For comparison, the Earth's gravity accelerates you and I at about 9.8 m/s/s. The moon, distance of about 384,000 km from the Earth is accelerated at about 0.00267 m/s/s.
     
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