GeoGeoGeoGeo OP t1_jdlyu56 wrote
Reply to comment by bpeden99 in Convection in the mantle shapes the long-term structure of Earth’s magnetic field by imposing a pattern of cooling that controls the dynamics of fluid flow at the top of the outer core by GeoGeoGeoGeo
???
Over what duration of time? It's currently reducing in strength which has been interpreted by some as to be a reduction in strength from an anomalous high back to a more typical strength. Meanwhile there have also been long intervals of time with no reversals. These are known as superchrons, such as the cretaceous normal superchron which was an episode of stable polarity with little or no reversals lasting upwards of 37 million years. So long as the mantle and outter core keep thermally / chemicaly convecting we should expect the Earth's geodynamo to operate. This includes the possibility of excursions and reversals.
bpeden99 t1_jdlzf66 wrote
Magnetic north has been constantly and slowly changing since forever. They repaint airport runways because of that. I was under the impression it will violently flip eventually?
GeoGeoGeoGeo OP t1_jdm0dou wrote
It will never violently flip, that's just not how reversals or excursions occur. Reversals typically take anywhere between 4 and 9 thousand years to flip with the latest reversal taking 22 thousand years to reverse: https://www.science.org/doi/10.1126/sciadv.aaw4621
The magnetic pole wanders all the time. It's the intensity via gradual weakening that indicates an excursion or reversal.
bpeden99 t1_jdm0pjb wrote
I'm not sure about wanders, it's pretty consistent in moving north and northwest. But I understand the flip better, thank you
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