De magnetische pole van de aarde beweegt zich erg snel naar Rusland toe met een snelheid van 49 miles (64 kilometers)per jaar wat veroorzaakt word door magnetische veranderingen in het binnenste van de aarde, laat een nieuw onderzoek zien.
De kern is te diep voor wetenschappers om direct te detecteren van het magnetische veld. Maar onderzoekers kunnen het meten van de bewegingen van de velden door na te speuren hoe de aardse magnetische velden aan het veranderen waren aan de opervlakte en in de ruimte.
Het komt er dus op neer in dit bericht dat de schil van de aarde draait en de eigenlijke binnenkant blijft waar het is.
Verder in het engels
Now, newly analyzed data suggest that there’s a region of rapidly changing magnetism on the core’s surface, possibly being created by a mysterious “plume” of magnetism arising from deeper in the core.
And it’s this region that could be pulling the magnetic pole away from its long-time location in northern Canada, said Arnaud Chulliat, a geophysicist at the Institut de Physique du Globe de Paris in France.
Magnetic north, which is the place where compass needles actually point, is near but not exactly in the same place as the geographic North Pole. Right now, magnetic north is close to Canada’s Ellesmere Island.
Navigators have used magnetic north for centuries to orient themselves when they’re far from recognizable landmarks.
Although global positioning systems have largely replaced such traditional techniques, many people still find compasses useful for getting around underwater and underground where GPS satellites can’t communicate.
The magnetic north pole had moved little from the time scientists first located it in 1831. Then in 1904, the pole began shifting northeastward at a steady pace of about 9 miles (15 kilometers) a year.
In 1989 it sped up again, and in 2007 scientists confirmed that the pole is now galloping toward Siberia at 34 to 37 miles (55 to 60 kilometers) a year.
A rapidly shifting magnetic pole means that magnetic-field maps need to be updated more often to allow compass users to make the crucial adjustment from magnetic north to true North.
Geologists think Earth has a magnetic field because the core is made up of a solid iron center surrounded by rapidly spinning liquid metal. This creates a “dynamo” that drives our magnetic field.
(Get more facts about Earth’s insides.)
Scientists had long suspected that, since the molten core is constantly moving, changes in its magnetism might be affecting the surface location of magnetic north.
Although the new research seems to back up this idea, Chulliat is not ready to say whether magnetic north will eventually cross into Russia.
“It’s too difficult to forecast,” Chulliat said.
Also, nobody knows when another change in the core might pop up elsewhere, sending magnetic north wandering in a new direction.
Chulliat presented his work this week at a meeting of the American Geophysical Union in San Francisco.
Originele Bron : nationalgeographic
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