Earth's Core, Magnetic Field Changing Fast, Study Says <br /><br />Kimberly Johnson <br />for National Geographic News <br /><br />June 30, 2008 <br /><br />Rapid changes in the churning movement of Earth's liquid outer core are weakening the magnetic field in some regions of the planet's surface, a new study says. <br /><br />"What is so surprising is that rapid, almost sudden, changes take place in the Earth's magnetic field," said study co-author Nils Olsen, a geophysicist at the Danish National Space Center in Copenhagen. <br /><br />The findings suggest similarly quick changes are simultaneously occurring in the liquid metal, 1,900 miles (3,000 kilometers) below the surface, he said. <br /><br />The swirling flow of molten iron and nickel around Earth's solid center triggers an electrical current, which generates the planet's magnetic field. <br /><br />The study, published recently in Nature Geoscience, modeled Earth's magnetic field using nine years of highly accurate satellite data. <br /><br />Flip-Flop <br /><br />Fluctuations in the magnetic field have occurred in several far-flung regions of Earth, the researchers found. <br /><br />In 2003 scientists found pronounced changes in the magnetic field in the Australasian region. In 2004, however, the changes were focused on Southern Africa. <br /><br />The changes "may suggest the possibility of an upcoming reversal of the geomagnetic field," said study co-author Mioara Mandea, a scientist at the German Research Centre for Geosciences in Potsdam. <br /><br />Earth's magnetic field has reversed hundreds of times over the past billion years, and the process could take thousands of years to complete. <br />http://news.nationalgeographic.com/news/pf/76158139.html <br /><br />*It sounds like they're referring to the South Atlantic Anomaly <br /> http://news.nationalgeographic.com/news/pf/76158139.html
