The geological record shows that the earth's magnetic poles do shift from time to time. Different polarity of iron molecules in different strata. As Little Hawk says, it can be measured with scientific instruments (and it would throw our current compasses off until we adjust navigation to the where, geographically, the new North Pole is, and it may confuse migratory birds and monarch butterflies for awhile), but thee and me will not even notice the shift.

What kind of physical forces are there in this neighborhood of our galaxy that would cause a planet which is approximately 8,000 miles in diameter with a mass of 5.9742 × 10²⁴ kilograms to suddenly stop and begin rotating the other way, or cause it to flip over, pole to pole?

'Course, such a catastrophe might be preferable to having Sarah Palin as president. . . .

Don Firth