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Earth's magnetic poles on the verge of flipping?

Posted by: Matthew17 - Sat Dec 13, 2003 1:59 am
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Earth's magnetic poles on the verge of flipping? 
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Post Earth's magnetic poles on the verge of flipping?   Posted on: Sat Dec 13, 2003 1:59 am
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Earth's magnetic poles
on verge of flipping?
Physicists say planet's protective field weakening, problems possible with navigation, ozone layer
The Earth's magnetic field is weakening, and that could lead to a flip in the planet's poles making compasses point south instead of north for the first time in almost a million years, say scientists.

Experts at the American Geophysical Union in San Francisco say the field has declined 10 percent in the last 150 years, and suggest a reversal could lead to problems in navigation and a jump in cancer rates with a diminished ozone layer.

"Is a reversal coming? Yeah, it's coming for sure – sometime,'' said geologist Robert Coe of the University of California-Santa Cruz, according to the San Jose Mercury News.

Physicists say the average period between pole flips is about 200,000 years, and the last one is believed to have taken place 780,000 years ago, making the next swap long overdue.

According to Harvard University's Jeremy Bloxham, the field could disappear completely within the next 2,000 years if the rate of decline remains constant, but he's not certain if the poles will actually reverse.

"Chances are this is going to die out," he said, reports the San Mateo County Times. "Reversals are pretty rare."

If a flip did take place, it would be over the course of several thousand years, and scientists say it would likely reduce the protective ozone layer, cause glitches in satellites and electronic products, and create a flurry of navigational anomalies as compasses would "cease to be a simple means of navigation," according to Bloxham.

The consequences would be the same if a reversal takes place or the field continues to diminish, with one researcher estimating an additional 100,000 cancer cases annually as people would be subject to more of the sun's harmful rays.

Earth's Magnetic Field Weakens 10 Percent
By Andrew Bridges
Associated Press
posted: 03:25 pm ET
12 December 2003


SAN FRANCISCO (AP) -- 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 Thursday.

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

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Hundreds of years could pass before a flip-flopped field returned to where it was 780,000 years ago. But scientists at a 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, which can last for hundreds of years, said John Tarduno of the University of Rochester.

Such a lull could still have significant effects, especially in regions where the weakening is most pronounced.

Over the southern Atlantic Ocean, a continued weakening 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.

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