Photo Credit: GizmodoEarth’s magnetic field is constantly shifting, and roughly every 200,000 to 300,000 years it flips north and south completely. We’re currently overdue for a switcheroo—and scientists now say it could happen in a time as short as 100 years, potentially altering life in unexpected ways.
It was long thought that these reversals took as many as 7,000 years to completely switch, according to a 2004 study funded by the National Science Foundation. But over the past few years, other scientists have suggested that the shifts have occurred at speeds previously unimagined. And a brand-new study published in the Geophysical Journal International by a team of scientists from Europe and the U.S. sheds even more light on these speedy changes—suggesting that the last 180-degree flip only took about 100 years.
How did they discern changes in the magnetic field that date back hundreds of thousands of years? By testing layers of ash deposited by volcanic eruptions over the course of 10,000 years, found in a lakebed near Rome. According to a release from Berkeley, the magnetic field directions are “frozen” into these layers of ash, which could be reliably dated to find out when the reversals occurred and how long they took to complete. “We don’t know whether the next reversal will occur as suddenly as this one did, but we also don’t know that it won’t,” said Berkely’s Paul Renne, one of the study’s authors.
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