Free Republic

A magnetic field shift is old news. Around 800,000 years ago, magnetic north hovered over Antarctica and reindeer lived in magnetic south. The poles have flipped several times throughout Earth's history. Scientists have estimated that a flip cycle starts with the magnetic field weakening over the span of a few thousand years, then the poles flip and the field springs back up to full strength again. However, a new study shows that the last time the Earth's poles flipped, it only took 100 years for the reversal to happen. The Earth's magnetic field is in a weakening stage right now....

Assumed to be caused by random fluctuations in the circulation of the molten iron core, the flips may actually be tied to what's going on at Earth's surface. At times in the geologic past when landmasses have bunched together on one side of the equator, the Earth's magnetic field has begun flipping soon thereafter... "What we see clearly is that the surface positions of the continents are linked with the frequency of the reversals," says group member François Pétrélis, a geophysicist at the French research agency CNRS in Paris... Computer simulations have shown how molten iron in the spinning core...

Ships' logs give clues to Earth's magnetic decline 19:00 11 May 2006 NewScientist.com news service Patrick Barry The voyages of Captain Cook have just yielded a new discovery: the gradual weakening of Earth’s magnetic field is a relatively recent phenomenon. The discovery has led experts to question whether the Earth is on track towards a polarity reversal. By sifting through ships’ logs recorded by Cook and other mariners dating back to 1590, researchers have greatly extended the period over which the behaviour of the magnetic field can be studied. The data show that the current decline in Earth's magnetism was...