Lori Reid, age 11, of Eugene, Oregon, for her question:
How do the North and the North Magnetic Poles differ?
Most of what we learn comes from hearsay and people, especially young ones, have a sensible desire to check out what they hear for themselves. However, the poles, plain and magnetic, happen to be in remote regions where on the spot investigation is hard to arrange.
A lot of wide awake young students scan their newspapers for articles on up to the minute goings on in the world of science. Recently there was some eye popping news about changes in the earth's magnetic field. We all, of course, know that the planet earth is a giant magnet surrounded by an appropriate sized magnetic field of force that reaches invisibly far out into space. The force field around any magnet is related to its two opposite magnetic poles. The earth's two magnetic poles happen to be fairly near its two geographic poles. The geographic poles are the two ends of the central axis around which the round planet rotates, day and night.
Earth science is an ancient study, which means that scholarly brains have been trying to figure out the secrets of our planet for countless generations. About a decade ago, modern scientists decided it was time to give the old earth the best possible general physical examination in their power. Teams of experts from every civilized nation joined forces in a planetary project called the International Geophysical Year. Starting from what they knew, ICY teams set about gathering masses of new planetary information. Even now, ten years later, this ICY material is still popping up with surprises.
The earth's magnetic field was given a major examination. The IGY satellites used for this task also rewarded us with an unexpected introduction to the Van Allen belts. These planetary umbrellas of radiation high above the earth dip down toward the magnetic poles and are related to them. At surface level, the force pf the magnetic poles controls the magnetic compass. The geographic North and South Poles have no power to line up a compass and, so far as we know, no force that extends out into space.
Nevertheless, though the North and the North Magnetic poles are so different in nature, they are close neighbors on the map. The geographic North Pole is at the exact intersection of the global, man made lines of longitude, and happens to be on the floor of the Arctic Ocean. The North Magnetic Pole is about 1,000 miles south of this point, near Canada's Bathurst Island. It covers several hundred miles and within its area the compass needle goes wild. Leaving any point around its rim, the magnetic compass direction is south. A 1,500 mile journey due north from Winnipeg brings us to the Magnetic Pole and another 1,000 miles brings us fairly close to the North Pole, a pin point from which all geographic directions point due south.
The two poles cause slight variations in global compass findings, but pilots have charts to adjust them. Studies made during and since the ICY reveal a more aston¬ishing variation that takes eons of time. While the geographic pole seems to remain fixed, the magnetic pole wanders slowly through thousands of miles. Its force varies ¬for example, the earth's magnetic field has lost Sx of its strength in the last cen¬tury. And the most startling news is that several times in the past, the lively North and South Magnetic Poles have flipped over and switched places.