When will the Compass Point South?

If all the compasses in the world started pointing south rather than north, many people might think something very strange, very unusual, and possibly very dangerous was going on. Doomsayers would have a field day proclaiming the end is nigh, while more rational persons might head straight to scientists for an explanation.See:When Compasses Point South also Nova and Interactive

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Deep inside the Earth, the magnetic field arises as the fluid core oozes with hot currents of molten iron and this mechanical energy gets converted into electromagnetism. It is known as the geodynamo. In a car's generator, the same principle turns mechanical energy into electricity. No one knows precisely why the field periodically reverses, but scientists say the responsibility probably lies with changes in the turbulent flows of molten iron, which they envision as similar to the churning gases that make up the clouds of Jupiter. In theory, a reversal could have major effects because over the ages many aspects of nature and society have come to rely on the field's steadiness.See: Will Compasses Point South?-By WILLIAM J. BROAD Published: July 13, 2004-New York Times