News articles say the next magnetic pole shift is imminent. Magnetic fields in Africa are getting weak and they say in some places you can’t get accurate compass readings. What will happen to us without protection from the sun’s radiation? –Tristan in Vermont
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the 1830s using a magnetometer invented by Carl Friedrich Gauss. Since then the magnetic field has been subject to intensive if somewhat inconclusive study, the upshot of which is that we’re not certain why it’s there, but we’re lucky it is–it does a lot more than make compasses work.
In combination with the atmosphere it shields us from many of the solar and other charged particles that would otherwise spatter the planet’s surface and its inhabitants; it also protects the atmosphere itself from erosion by the solar wind.
The last flip was roughly 780,000 years ago, making some think we’re overdue, although since no one really understands polar acrobatics, prediction seems futile. Circumstantial evidence suggests that a comet or large meteorite impact could trigger a magnetic pole flip, but proof is lacking. Recent reports about a decrease in the strength of the earth’s magnetic field have led to anxiety that another reversal looms. However, while the field’s strength has weakened by about 10 percent since the 1800s, it’s still about double the average strength over the last million years.
