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Name:  glen a musgrave
Status: N/A
Age: N/A
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Date: 1999

I understand that the Earth's polarity changed several times in the past (reversed directions). Are there any theories as to why that occured?

This is an easy one to

Nobody knows why the polarity of the Earth's magnetic field changes. As you might imagine, however, many scientists are working on this problem.

Some recent investigations have examined how the magnetic field approaches a polarity reversal. Since the magnetic field of the earth is locked into rocks when the rocks first form, it is possible to study how the magnetic field of the earth changes by studying the magnetic field of the rocks. These studies indicate that the strength of the magnetic field follows a fairly systematic pattern of strengthening, then weakening. When the field becomes very weak, it may reverse direction. Whether the field reverses itself or not, the field rapidly reenergizes after it gets to a weak point.

By making observations such as these, it should be possible to eventually determine why the magnetic field reverses. Right now, though, it's something of a mystery.


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