Earth's magnetism weakens

[MORTARDUDE]

http://www.nj.com/news/ledger/index....1867140340.xml


Earth's magnetism weakens



Friday, December 12, 2003



ASSOCIATED PRESS

SAN FRANCISCO -- The strength of the Earth's magnetic field has decreased 10 percent over the past 150 years, raising the remote possibility that it may collapse and later reverse, flipping the planet's poles for the first time in nearly a million years, scientists said yesterday.

At the current rate of decline, the field could vanish altogether in 1,500 to 2,000 years, said Jeremy Bloxham of Harvard University.

Hundreds of years could pass before a flip-flopped field returned to where it was 780,000 years ago.

However, scientists at the fall meeting of the American Geophysical Union cautioned that scenario is an unlikely one.

"The chances are it will not," Bloxham said. "Reversals are a rare event."

Instead, the weakening, measured since 1845, could represent little more than an "excursion," or lull, in the naturally variable strength of the Earth's magnetic field, said John Tarduno of the University of Rochester.

Such a lull can last for hundreds of years, however, and still have significant effects, especially in regions of the Earth where the weakening is most pronounced.

Over the southern Atlantic Ocean, a continued weakening in the strength of the magnetic field has diminished the shielding effect it has locally in protecting the Earth from the natural radiation that bombards our planet from space, scientists said.

As a result, satellites in low-Earth orbit are left vulnerable to that radiation as they pass over the region, known as the South Atlantic anomaly.

Among the satellites that have fallen prey to the harmful effects was a Danish satellite designed, ironically, to measure the Earth's magnetic field, Bloxham said.

The weakening, if coupled with a subsequently large influx of radiation in the form of protons streaming from the sun, can also affect the chemistry of the atmosphere, said Charles Jackman of NASA's Goddard Space Flight Center.

That can lead to significant but temporary losses of atmospheric ozone, he said.

[Andy]

IMO they are really playing this down to prevent people from running around saying, "The sky is falling." The poles flip-flop and have done so several times but when poles weaken and a new, short term pole can exist and that seems to happen ever 80 or so thousand years. We are do for a change. It's possible we could wake up in 2010 and discover that Paris is now the North pole. Ok, it wouldn't move that much, but the Hudson Bay could be the new site.

For a while now each year more land turns into dessert, it's up to about the size of the state of Vermont per year. If I read my geology books correctly that is a sure since of movement of the poles. This never happens over night, or so they say but keep a bag packed just in case.

Stay healthy,
Andy

[Keith_Hixson]

I'm loosing weight. I don't want to fall off the earth!


Keith