Shawn C. Young, age 10, of East Lansing, Mich., for his question:

DOES THE MAGNETIC POLE MOVE?

Since the Middle Ages, travelers have depended on the magnetic compass because its needle points faithfully to the north magnetic pole. All this time, the magnetic pole has stayed fairly close to the geographic North Pole. We now know ; that through the long ages it has wandered all over the globe.

Actually the earth has four poles, two north and two south. The geographic  poles are at the opposite ends of theaxis, the central line around which the globe rotates. The magnetic poles are at opposite end of what seems to be a huge magnet through the center of the planet. It is tilted at an angle to the rotation axis. Its two ends, the magnetic poles, are some distance from the geographic poles.

For centuries the four poles have stayed more or less a where they are, though lately scientists have detected slight wanderings in the magnetic poles.

However, a few centuries are a mere moment in the long history of our restless planet. And we now know that through the vast ages the poles have traveled on long global tours.

True, they are not speedy travelers and it takes a million years or more to detect many changes in their positions. Nevertheless, the evidence is there in rocks and ancient shells. For example, 500 million years ago, the two north poles were submerged under the ocean, near what is now the island of Hawaii.

From there, scientists have traced their slow journey toward the northeast, and some 350 million years ago they were near Japan. Then their long, slow journey inched toward Asia and reached Siberia about 50 million years ago. From there the two poles crept to their present location in the Arctic. Or so it seems.

Actually the earth's axis does not change  but its crust slithers around like a loose overcoat. As it moves, first one area of global geography, then another glides over the axis and magnetic poles.

Naturally the opposite south poles go on global tours to match the north poles. During the past half billion years, various crustal areas of the South Atlantic and Antarctica have glided over the geographic and magnetic south poles.