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Archeomagnetic jerks & Unexplained Geomagnetic Field Instability

  1. Sep 14, 2010 #1
    Geomagnetic researchers have found in the last 10 years that the earth's geomagnetic field abruptly changes in intensity with the non-dipole portion of the total field suddenly becoming stronger. These abrupt change events are referred to as archeomagnetic jerks, as one analysis method to find the position and intensity of the earth's magnetic field is to analysis pottery fragments. (Pottery at the time of firing is heated above the Curie point and hence captures the intensity and direction of the earth's magnetic field when it cools.)

    As noted below during the abrupt change event the geomagnetic field appears to move off center from the planet's rotation.



  2. jcsd
  3. Sep 18, 2010 #2
    The archeomagnetic jerks are spaced roughly 200 years apart. As the observational papers linked to above note, during an “archeomagnetic jerk” the geomagnetic field abruptly moves off center from the planet’s core. This cyclic event causes the geomagnetic field to be less dipole like.

    What is causing the cyclic abrupt changes in the geomagnetic field, the archeomagnetic jerks? Could the cause of the archeomagnetic jerks be the cause of the geomagnetic excursions? (A geomagnetic excursion is a very strong abrupt change to the geomagnetic field that appears to be a stronger version of the archeomagnetic jerk. i.e. The non dipole portion of the geomagnetic field becomes stronger during a geomagnetic excursion.)

    As researchers have noted, regions of the planet experience cooling during the archeomagnetic jerk.

    Other researchers have noted the stronger abrupt cooling events Heinrich events and the Danssgaard Oescherger events (warming following by cooling) are also concurrent with magnetic field changes.

    Curiously some researchers are appealing to abrupt climate events being the cause of geomagnetic excursions.

    Some researchers have appeal to a chaotic knife edge planetary climate system. Following that paradigm the planet’s climate can abruptly change from one state to another as it amplifies small forcing changes.

    Continuing on that line of reasoning – An abrupt change in the climate occurs as a small planetary temperature change is amplify by the planet’s positive feedback - other researchers have hypothesized that an abrupt change in climate can cause an abrupt increase in volcanism in both hemispheres in addition to causing abrupt changes to the geomagnetic field. (The abrupt increase in volcanism is concurrent with the strongest geomagnetic field changes.)

    That line of reasoning is not supported by the observational evidence. The roughly 200 year spaced archeomagnetic jerks do not lag the planetary zones of cooling (the zones of cooling are spatially aligned with the regions of the planet where the geomagnetic field changes occur) that are observed when they occur.

    Likewise the magnetic excursion that is concurrent with the Younger Dryas cooling does not lag the cooling. It should be noted that roughly 60% of the Younger Dryas cooling occurred in 10 years.

    It should be noted that Uranus and Neptune also have magnetic fields that are for some odd reason off set from the center of the planet's core. The point is the axis of rotation of Uranus and Neptune is highly tilted towards the sun.

    The earth's geomagnetic field changes correlate with the timing of its axis changes (When the earth is more tilted the geomagnetic field is stronger). Also curiously the geomagnetic field's intensity is greater when the eccentricity of the earth's orbit is greater. (I will provide a link that shows the geomagnetic field's intensity changes on a 100 kyr basis and the geomagnetic field's intensity correlates with the glacial/interglacial cycle.)




    Last edited: Sep 18, 2010
  4. Sep 18, 2010 #3
    This is the third paper by the same researchers that validates their assertion that the geomagnetic field's maximum intensity periods correlates with the period when the earth's orbit around the sun is most eccentric.

    No one has explained why the geomagnetic field is strongest when the earth's orbit about the sun is most eccentric. (Check out figure 11 in their paper.)


    Last edited: Sep 18, 2010
  5. Sep 18, 2010 #4
    This is a summary of the voyager data that shows the magnetic field of both Uranus and Neptune are not in alignment with the rotational axis of the planets and is off set from the planet's core.

    Last edited: Sep 18, 2010
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