Ok, so it’s a bit behind the times… but I think Unca Cecil may have missed a point. While the concept of the physical poles of the earth experiencing major (20+ degrees) shifts is a bit silly, the earth has gone through quite a few magnetic pole shifts, and I think this might have been what David K. was asking about. It’s been a while, but I seem to recall a few nature shows (possibly on mass extinctions) where it was revealed that deposits on the ocean floor near crustal boundaries (where new rock was being continually formed) showed that the poles actually shifted on a fairly regular basis, with the earth’s magnetic field reversing itself every few million years. The process tends to be fairly traumatic for life on earth, as I recall, since the magnetosphere tends to dissapear while the magnetic field reestablishes itself.
Anyone have any more info, or clarification from Unca Cecil?
phril
Welcome to Straight Dope.
Is this the column that you’re talking about: http://www.straightdope.com/classics/a2_117.html
There was an old thread discussing it: http://boards.straightdope.com/ubb/Forum1/HTML/000297.html
Cecil’s column actually supports the notion of twenty degree shifts of the physical poles of the earth. I don’t think it’s all that silly, either.
rocks