قالب وردپرس درنا توس
Home / Science / Evidence shows that the Earth's magnetic field has been quickly overturned

Evidence shows that the Earth's magnetic field has been quickly overturned



The magnetosphere of the earth and the sun.
Illustration: NASA (Air Force)

A new study analyzing rock formations 1

07,000 to 91,000 years ago revealed something disturbing: a strangely rapid reversal of the Earth's magnetic field into a relatively recent history

The research team from China, Taiwan and Australia analyzed a stalagmite, a rock that slowly rises from the cave caves to better understand the earth's magnetic field. In iron fragments from the rock, they found evidence of a reversal that took place in less than 200 years. It is not clear what would happen to humanity if the magnetic field reversed over such a short period of time. The scientists behind the new paper fear that it could be bad.

"If such rapid polarity changes were to occur in the future, they could severely affect satellites and human society," they wrote in the document released this week in the Proceedings of the National Academy of Sciences.

If the Earth's magnetic field irritates you, do not worry, because it also puzzles many scientists. It seems to have existed for at least 3.45 billion years and is likely generated by movement in the outer core of the Earth. The north and south poles seem to have turned around about 773,000 years ago, and according to the newspaper, perhaps a dozen excursions or rapid changes have been made to the poles' orientation angles since then.

Of course, people are worried about the poles shifting because of the protective effect of the magnetic field. It protects us from the solar wind, which could damage both life on the planet and our electronics.

In this latest study, scientists analyzed a stalagmite called SX11, from the Sanxing Cave in Guizhou Province, China. It's 1 meter (3.3 feet) long, 8 inches (3 inches) around and looks like a yellow-brown candle. The team cut 194 slices off, dated the slices and measured the magnetic field orientation from the remaining iron fragments trapped in the rock.

The team's analysis revealed evidence of rapid magnetic pole changes, including a reversal that began 98,360 years ago and only lasted 144 years, or 58 years.

"This is shockingly fast," said Mika McKinnon, a geophysicist (and former Gizmodo author) who was not involved in the study, to Gizmodo. From a scientific point of view, she was enthusiastic about the results. "Researchers have used speleothems, 'cave deposits like stalagmites,' to reconstruct magnetic field reversals since I was born, but it's still a rare technique, and I'm always charmed."

She pointed out that factors such as heat can cause the nuclei to degauss, and researchers have declared earlier evidence of rapid pole reversals away. "Time will tell if the researchers are doing the same with this data." The authors of the new paper call for an improvement in studies of previous magnetic field changes to better understand the potential for magnetic field reversal.

Should you be worried? Well, just because the magnetic fields can reflect does not mean that any time soon, as we wrote earlier

it's not very clear what would happen during any of these reversals, McKinnon said , "We know that the magnetic field weakens at the transition and only reaches 5% of its usual strength, and some scientists think it breaks down completely." But maybe the solar wind itself regenerated the field. Maybe it will hurt our technology, but not us – there is no sure evidence linking these field reversals to mass extinctions.

Well, it's probably not worth it to get worked up about. Said McKinnon: "I stick to the optimistic interpretation that experiencing a rapid magnetic field reversal would be a period of glorious chaos, but not fatal." [PNAS]


Source link