Geomagnetic Reversal Imminent?
Not by Fire but by Ice
THE NEXT ICE AGE - NOW!
Discover What Killed the Dinosaurs . . . and Why it Could Soon Kill Us
14 May 07
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Geomagnetic reversal imminent?
10 May 07 - Besides directing compasses, the Earth's magnetic field reaches out into space to direct the flow of the solar wind around the planet—forming a structure called the magnetosphere (depicted above). When the wind hits this field it creates a shock wave known as the bow shock. Most of the protons and electrons in the solar wind go round this shock wave, and lots of dangerous radiation from the sun is thus diverted away from the Earth.
There is, however, a growing body of evidence that the Earth's magnetic field is about to disappear, at least for a while. The geological record shows that it flips from time to time, with the south pole becoming the north, and vice versa. On average, such reversals take place every 500,000 years, but there is no discernible pattern. Flips have happened as close together as 50,000 years, though the last one was 780,000 years ago. But, as discussed at the Greenland Space Science Symposium, held in Kangerlussuaq this week, the signs are that another flip is coming soon.
(In Not by Fire but by Ice, I show that the last reversal occurred about 12,000 years ago. I also show that there is a discernable pattern)
One of those signs is that the strength of the field has been falling by 5% a century recently. A similar (though more rapid) diminution accompanies the reversing of the sun's magnetic field, which happens every 11 years or so.
Just when the magnetic field will flip is impossible to predict from what is known at the moment; the best guess is that there are still several centuries to go.
(I think the reversal will come, not in a matter of centuries, but in a matter of years.)
See entire article from The Economist
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