Jill Bowen, age 10, of Rowayton, Conn., for her question:
Did the North Pole ever move?
The North Pole has moved thousands of miles around the map of the world. Or so it seems. Once upon a time it was near Hawaii and later it took a lazy, lazy tour toward Japan. We know that it has been wandering around the world map for at least half a million years. No doubt this is still going on. We would not notice this because the 1Torth Pole wanders around much more slowly than a snail.
Actually the earth has two north poles and two south poles. And all of them wander around. The geographic poles are at the opposite ends of the axis, around which the earth spins like a top. The axis is tilted and above the North Geographic Pole hangs Polaris, the North Star. If the ?!vrth Pole wanders away from its present place in the Arctic Sea, Polaris will no longer point out the north direction.
The center of the earth acts like a giant magnet. Its opposite ends are the North and South Magnetic Poles. The magnetic poles never seem to move more than a thousand miles or so from their geographic poles. But all four poles wander slowly, very slowly around the world map.
Scientists have traced their wanderings back through the ages. About 500 million years ago, the North Pole was out there in the Pacific Ocean near what is now Hawaii. During the next 140 million years it inched toward Japan. Then it wandered eastward around Siberia and finally reached its present place in the Arctic Ocean. Meantime, on the opposite side of the globe, the South Pole was wandering around the southern oceans. And the magnetic poles toured around alongside their geographic poles.
No, the poles did not lose their grip on the ends of the earth's axis. Nor did the axis tilt around in different directions. But the earth's straight axis and the giant magnet are down there under the earth's crusty skin. And the rocky crust is some what like a loose jacket. As it shifts around, different lands and seas slide over the axis poles and the magnetic poles.
The global map shows the lands and seas on the surface. Actually, the continents and oceans are like giant rafts and puddles, embedded in the earth's crusty skin. We now know that the global puddles spread and shrink, while around and around drift the global rafts.
These lazy tours are slower than slow. They keep remodeling the world map, though in a thousand years the changes are too small to notice. But gradually the loose crusty jacket slides the map over the ends of the axis and the giant magnet. The poles seem to move around, when actually the surface lands and seas are sliding over their heads.
The magnetic poles are more mysterious than the axis poles. They move around faster, though never far from home. And once in a great while they perform a remarkable flip flop. Gradually their magnetic strength weakens and dies. Then it reappears. But this time the North Magnetic Pole and the South Magnetic Pole have changed places. Ho doubt the axis poles are still wandering and no doubt the magnetic poles will flip flop again in the future.