Sunday, December 12, 2010

Pole Reversal

No, not role reversal - or strip-joint pole reversal - I'm talking here about the earth's magnetic pole reversal.  Apparently, because the earth's core is largely molten iron, there is a magnetic field surrounding (and protecting) the earth.  And the magnetic north and south poles, unlike the axial (rotational) north and south poles, move over time!  The evidence is that they move so much that they actually reverse positions about every 250,000 years or so (no kidding).  Yep, Festus, north becomes south and south becomes north!  Careful measurements of the north magnetic pole from the mid-nineteenth century reveal that it was on the Manitoba/NWT (or what ever they call NWT these days) border back then, it is in the Arctic Ocean now, and by 2040 it will be in Siberia.  This is important because satellites key off the magnetic poles and devices as disparate as ocean drill rig stabilizers and airport runway numbers depend on GPS data that tries to keep up with changing magnetic N.  And, this magnetic migration has been steadily accelerating from less than 5 kilometers per year back then to the present 50 kpy.  Not only that, but scientists figure the last pole reversal was 780,000 years ago - so we're long overdue for the next one.  One problem is that during pole reversal the protective magnetic field around the earth that keeps us safe from cosmic radiation and sunspot debris becomes sieve-like, ie. full of holes (holey?).  And what effects will this have earth's inhabitants?  I'm not sure, because I fell asleep and missed the last fifteen minutes of this otherwise earth-shattering documentary.  Consult your TV Guide for the next scheduled broadcast, and see if you can pick up a used suit of chain-mail to protect yourself from cosmic radiation until then.