Pole reversal: Feared "flip" of Earth's magnetic field takes 7,000 years [DOOM!]

Agence France-Presse ^ | April 7, 2004 | AFP

[AntiGuv]

PARIS (AFP) - A reversal of the Earth's magnetic field, a rare but feared event due to the catastrophic effect it could have on human life, takes about 7,000 years to complete, according to a study.

The so-called "flip" between the Earth's North and South poles occurs at long but unpredictable intervals, the most recent one occurring about 780,000 years ago.

The 180-degree switch occurs when there is a change in the circulation patterns in the molten iron which flows around the Earth's outer core and, like a dynamo, creates the magnetic field.

The intensity of the field drops for a while before the circulation rhythm is established and the new polarity occurs.

But how long the switching process takes before the new poles become established has only been guessed at.

Estimates have ranged from a couple of thousand years to 28,000.

US researcher Bradford Clement casts light on this area of uncertainty by analysing records taken from sedimentary samples drilled from various sites around the world.

These samples, deposited at four different ages in Earth's history, have a residual magnetic echo from the magnetic field that prevailed at the time.

"These records yield an average estimate of about 7,000 years for the time it takes for the directional change to occur," Clement, of Florida International University, writes in Nature, the British science weekly.

The big switchover does not take place in one swoop, though.

It happens faster at the Equator and takes longer at higher latitudes -- the closer one gets to the poles.

The reason for this, says Clement, is that in the absence of the main North-South magnetic field, the Earth's core develops a weaker secondary field which has many "mini-poles" at the surface.

Eventually the two main poles are established again, but on opposite sides of the planet, and restore their primacy.

No-one knows what would happen to life on Earth if the "flip" occurred today but the speculation borders on the doomsday.

Many aspects of life today would be literally turned upside down, both for humans, given our dependence on magnets for navigation, and for migrating animals which use an inner compass.

We would also be more exposed to deadly bursts of solar radiation, from which we are normally protected by Earth's magnetic field. And the loss of that shield would cause solar particles to smash into the upper atmosphere, warming it and potentially causing wrenching climate change.

There was a scare in 2002 after French geophysicist Gauthier Hulot discovered a weakening of Earth's magnetic field near the poles, which could be interpreted as an early sign that a "flip" is near.

Polarity reversals "seem to occur randomly in time," says University of Washington scientist Ronald Merrill. The shortest interval between "flips" is between 20,000 and 30,000 years, and the longest is a mighty 50 million years.

[AntiGuv]

When you need something pointless to worry about!

[AntiGuv]

End Of The World Ping!

[m87339]

It's Bush's fault!

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[null and void]

Nope. It's a flip flop. CLEARLY Kerry's fault...

[My Favorite Headache]

Why hasn't Condi Rice warned us about this?

[LdSentinal]

Those poor birds. Now they'll be forced to migrate north for the winter.

[Focault's Pendulum]

The big switchover does not take place in one swoop, though. It happens faster at the Equator and takes longer at higher latitudes -- the closer one gets to the poles.

These Polish jokes are getting pretty old.

...and anyway...we never swoop....we Polka!!

[farmfriend]

Nope. It's a flip flop. CLEARLY Kerry's fault...

LOL!

[Gator113]

It's only going to flip in France!!!!!! That's not a bad thing! LOL

[GottaLuvAkitas1]

7,000 years? Well get ready folks, Robert Byrd will talk about this tomorrow for 3 hours straight since he was about 50 years old the last time it happened!

[Prime Choice]

We're doomed! (Doomed!) ((DOOMED!))

[Prime Choice]

7,000 years?

Yep. I guess we can scrub the whole worrying about Y10K thing...

[shield]

This is such junk. The people who listen to this wacky ZETA...has been predicting this for years. It was suppose to happen last year. What a con.....I can't believe people actual believe this. But there are 1000's that do!

[Doctor Stochastic]

Other than adjusting my car compass and tv color settings, where's the problem? It's not like this hasn't happened before. The magnetic North Pole has moved about 800 miles since first being visited (some years ago.)

[Mercat]

it's Bush's fault.

[GottaLuvAkitas1]

Yep. I guess we can scrub the whole worrying about Y10K thing...


DANG! I so wanted to earn my crybaby, worrywort wings. Thanks a lot Prime Choice! Now I gotta find something else.
Wait, scratch that! I sounded way to much like GORE.
puke alert!!!

[AntiGuv]

...where's the problem?

Easy for you to say! Some people aren't that smooth with electronics..

[Torie]

If the magnetic field collapses for a bit, the bad rays will indeed probably kill most of us in short order. So many systems need to be working on this planet to keep us alive, it is amazing. So says Bryson is his book about nearly everything.

[Torie]

By the way, killer asteroids hit the planet about every million years, that would kill a large percentage of us as well. And then there is Yellowstone. I want to move from Southern California before it blows. I live too close to the kill everything zone. Maybe to Australia.