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Earth's magnetic field

  1. May 16, 2005 #1
    So my physics class just watched NOVA's "Magnetic Storm" film. We know that the magnetic field is reversing, as it does every so often. However, the scientists in this video claim that the field is rapidly decreasing, and at the current rate, will be diminished by the end of the millennium. This gives rise to theory that cosmic radiation will turn blue Earth into a red Mars soon enough.

    What are everyone's thoughts on this topic?
  2. jcsd
  3. May 17, 2005 #2
    The usual gibberish. The Earth magnetic field is so strong as it has never been in the recent past (20 Million years). What goes up, must come down. The paleao-magnetic statistics show that the magnetic field is much more variable than climate for instance. The last million years we have seen some dozen -so called- Palaeo Magnetic Excursions (PME) -a temporarely collaps- and only one geomagnetic reversal. The variation in geomagnetic reversal cycles is something between 250,000 years and 50 million years so nothing we can say about that.

    So what's going to happen? Most probably, nothing and the magnetic field will settle at some lower values. A PME is unlikely since the last excursion (Mono Lake) is only 25,000 years old with average intervals of some 1,00,000 years in between.

    However when I'm wrong expect some higher radioactivity levels as can be seen in the ice cores at 25,000 years BP. This may have been caused by that last PME. However, there are no extinctions or disasters associated with that event.
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