Question: Why is the Earth magnetized? What is the origin of the earth's magnetic field?

Asked by robert to Anna, Daniel, Denise, Jesse, Rehemat on 24 Jun 2014. This question was also asked by tibi29.

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  1. Photo: Anna RabittiAnna Rabitti
    answered on 24 Jun 2014:

    Well Robert, actually this is one of the big, still not completely answered questions in geoscience!
    Magnetic fields are produced when electrical charges are in motion, thus it is thought that the Earth’s magnetic field is associated with electrical currents produced in the metallic (and fluid) outer core of our planet. This currents are probably caused by difference in temperature (convective motions, like the one you can observe in a pan of boiling water), and their combination with the Earth rotation.
    This process is usually called the “Earth dynamo”, because is based on similar physical mechanisms as the dynamo light that you might have on your bike.
    So, this is the general idea, but it is still a theory, an no final proof has been given yet, as far as I know. How these “electric currents” are set into motion, how strong they are, and which are the exact mechanisms generating the earth’s magnetic field, well, we simply do not know yet.
    I must say that I find it fascinating that there are so many aspects of our planet that we don’t completely understand. This definitely makes scientist life exciting!

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  2. Photo: Jesse DavenportJesse Davenport
    answered on 24 Jun 2014:

    Hi robert, I think Anna answered this one really well! It’s pretty interesting to note that one of the main things that was said to happen at the end of the world on December 21, 2012 in the Mayan calendar is that the magnetic poles were going to switch, which apparently would cause crazy storms and other natural hazards (I’m not sure if this true or not). But where the myth and movie gets its wrong is like Anna said it is one of the big mysteries of geoscience and it won’t happen again for a few thousand years!

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  3. Photo: Daniel Lao DavilaDaniel Lao Davila
    answered on 24 Jun 2014:

    Hi Robert:
    The best hypothesis is that the movement of charged particles in the core of the Earth will produce the magnetic field. Similar to a magnetic field produced in electronics (for example electric current in a fan will create a magnetic field that will move the blades of the fan to blow air). Anna has explained this well and I agree that we don’t know for sure how it is produced. It seems that all planets, except Venus, have magnetic fields at different intensities.

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  4. Photo: Denise De GaetanoDenise De Gaetano
    answered on 25 Jun 2014:

    Hi Robert,

    As Anna rightly pointed out, this is a huge question, which is still not fully answered.

    An extremely good short documentary to your question would be the following: http://www.youtube.com/watch?v=O-V3yR2RZUE&list=PLLcADDCh8jde4N7CUsMc2roqR0otcJpGX

    Hope it helps! 🙂

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