Magnetic Field

The Last Change in the Earth’s Magnetic Field Took Much Longer than Scientists Thought

Geologists from the University of Wisconsin-Madison explored the flows of ancient lava and concluded that the last pole change of the Earth occurred 780 thousand years ago and lasted 22 thousand years – several times longer than scientists estimated the extent of this event.

It is believed that every few hundred years the Earth magnetic field shifts sharply and changes its polarity – for example, magnetic north shifts to the geographic South Pole, and then returns. This change has occurred countless times in the entire history of the Earth, but scientists still do not fully understand why this is happening.

During this process, the magnetic field that protects the Earth from hot solar particles and radiation is greatly weakened. The results of the study show that our planet at the time of the pole change remained unprotected for much longer than scientists expected.

“This kind of duration would mean the shielding of the Earth from solar radiation would be very complex and, on average, less effective over a longer time period,” John Tarduno, a professor of geophysics at the University of Rochester who was not involved in the study, told “The actual effects of that are still debatable, and they’re not as tragic or as extreme as someone might suggest, but there still can be important effects.”

Earlier, the United States National Oceanic and Atmospheric Administration (NOAA) updated its World Magnetic Model (WMM) one year ahead of schedule. The reason was the too rapid movement of the north magnetic pole from the Canadian Arctic to Siberia, which affects global navigation.

“Even though volcanic records are not complete records, they’re still the best kind of records we have of recording a given time and place,” Tarduno said. “Higher accuracy in the age dating, and being able to get more detailed records, will give the community a lot to think about,” he added.

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