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Earth's Magnetic Field Weakens 10 Percent
caryw writes "Interesting story from the 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. 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."'"
"The chances are it will not," Bloxham said. "Reversals are a rare event."'"
but overdue. these aren't governed by random chance like gambling; there _is_ a cycle
We've secretly replaced Slashdot with new Folgers Crystals - let's see if it notices.
I, too, agree with those who have cited the period nature of these types of events.
The scientific tracking of this phenomenon - within the bounds of a burgeoning field called paleomegnetism - has shown that such events have been seen already.
If I remember correctly, the seafloor around the Mid-Altantic Ridge shows local magnetic field lines (embedded in rock) that exhibit directional reversal on a regular basis. The regular, gradual creation of new seafloor on both sides of this band of spreading magma locks in the direction of Earth's general magnetic field at the time of formation - showing, some think, that these occurrences are regular and repeatable.
And yes, we're definitely overdue. But, we're also overdue for a planet-killing asteroid impact, so I guess there's nothing to worry about. What's a little field instability among friends?
It should be noted, however, that there is some notion that periods during which magnetic shielding is lost probably does wonders for increasing evolutionary branching. Think of all the natural selection that gets done under such extreme environmental pressure...
Sorry for the ramble. IANAP, by the way, but IAAPT (teacher).
That stupid show was more than a little sensational it was downright alarmist. I already knew about the pole switching phenomenon so it didn't scare me but if you hadn't heard of it before they made it seem like doomsday. Of course tv watchers today are so desensitized it probably didn't have that much of an impact.