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Magnetic flip

  1. Jan 31, 2005 #1


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    So is it going to happen? what will be the consequences if it does
    happen, will we suffer a multi pole magnetic field for hundreds of years?
    some say that cancer will increase at the multi poles and that thousands
    of people will die as a result, so who cares about global warming if
    a new doomsday is around the corner?
  2. jcsd
  3. Jan 31, 2005 #2


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    It will undoubtably happen. Paleomagnetic evidence shows it has happened many many times in the past, and we have no reason to assume it will stop soon. The question is when, and as far as I know, the answer is we are not exactly certain. Evidence from palaeomagnatism in old lava flows in the US does point to a long period of weakened magnetic field with poles wandering rapidly. Measurements from a particular lava flow showed that (assuming we have the rate of cooling correct) the poles could shift by about 6 degrees a day.

    I can't provide any sources for the lava flows in the US I'm afraid, as I learned this on a TV program a while back. If there are any inaccuracies in my facts, I apologise.
  4. Feb 1, 2005 #3
    Well, this article is very informative about the recent Earth magnetic behaviour.

    A few remarks.

    A decline in magnetic field may just be either a temporarely deviation, or the start of a magnetic excursion and does not necesary lead to a flip of the field and a new "chron".

    There is no definite trend in flips. The last 25 million years, the average period between flips has been several 100,000 years but there have been "superchrons":

    http://hypertextbook.com/physics/electricity/geomagnetism/ [Broken]
    Last edited by a moderator: May 1, 2017
  5. Feb 1, 2005 #4
    When was the last flip?
  6. Feb 1, 2005 #5
    779,000 years ago, The change form the Matuyama chron to the current Brunhes cron.
  7. Feb 1, 2005 #6


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    Interesting article Andre, but other than disrupting navigation and
    letting in more harmful radiation, what consequences could be
    suffered ?
  8. Feb 1, 2005 #7
    Navigation is not going to be disrupted anymore with GPS, inertial navigation system, Decca, etc. Even homing pigeons seem to be cheating, not using the earth magnetic field.

    As I already linked here, presently there is no suggestion of climate related to the Earth magnetic field. Remains possible harmfull radiation, however paleonthologic evidence suggest no relationship between mass extinctions and magnetic anomalies. So, all in all, we may just survive without a scratch.
  9. Feb 1, 2005 #8
    I think an increase in cancer cases is not unreasonable to expect though. Skin cancer especially I think.
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