aairon
11-27-2008, 09:05 PM
Flip-Flop
Fluctuations in the magnetic field have occurred in several far-flung regions of Earth, the researchers found.
In 2003 scientists found pronounced changes in the magnetic field in the Australasian region. In 2004, however, the changes were focused on Southern Africa.
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.
Earth's magnetic field has reversed hundreds of times over the past billion years, and the
process could take thousands of years to complete.
The decline in the magnetic field also is opening Earth's upper atmosphere to intense charged particle radiation, scientists say.
Satellite data show the geomagnetic field decreasing in the South Atlantic region, Mandea said, adding that an oval-shaped area east of Brazil is significantly weaker than similar latitudes in other parts of the world.
"It is in this region that the shielding effect of the magnetic field is severely reduced, thus allowing high energy particles of the hard radiation belt to penetrate deep into the upper atmosphere to altitudes below a hundred kilometers (62 miles)," Mandea said.
This radiation does not influence temperatures on Earth. The particles, however, do affect technical and radio equipment and can damage electronic equipment on satellites and airplanes, Olsen of the Danish space center said.
Fluctuations in the magnetic field have occurred in several far-flung regions of Earth, the researchers found.
In 2003 scientists found pronounced changes in the magnetic field in the Australasian region. In 2004, however, the changes were focused on Southern Africa.
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.
Earth's magnetic field has reversed hundreds of times over the past billion years, and the
process could take thousands of years to complete.
The decline in the magnetic field also is opening Earth's upper atmosphere to intense charged particle radiation, scientists say.
Satellite data show the geomagnetic field decreasing in the South Atlantic region, Mandea said, adding that an oval-shaped area east of Brazil is significantly weaker than similar latitudes in other parts of the world.
"It is in this region that the shielding effect of the magnetic field is severely reduced, thus allowing high energy particles of the hard radiation belt to penetrate deep into the upper atmosphere to altitudes below a hundred kilometers (62 miles)," Mandea said.
This radiation does not influence temperatures on Earth. The particles, however, do affect technical and radio equipment and can damage electronic equipment on satellites and airplanes, Olsen of the Danish space center said.