Earth’s magnetic field in known to flip from time to time – with the north and south poles being turned upside down. However, scientists do not know more about this intriguing phenomenon, until now. A new research, analyzing ancient huts in South Africa has cracked the mystery. When the huts were ceremoniously burned they preserved minerals from that point, creating a geological record.
“It has long been thought reversals start at random locations, but our study suggests this may not be the case,” study lead author John Tarduno, a geophysicist at the University of Rochester, said in a press release.
The fiery demise of ancient huts in southern Africa 1,000 years ago left clues to understanding a bizarre weak spot in the Earth’s magnetic field — and the role it plays in the magnetic poles’ periodic reversals.
Earth’s magnetic field, also known as the geomagnetic field, is the magnetic field that extends from the Earth’s interior to where it meets the solar wind, a stream of charged particles emanating from the Sun. Its magnitude at the Earth’s surface ranges from 25 to 65 microteslas (0.25 to 0.65 gauss).
By analyzing minerals dating back before and after the Earth’s mysterious pole reversals, the researchers were able to see a pattern. Tarduno told Space.com there is a weak spot in the Earth’s magnetic field that “forms, and it decays away, and it forms, and it decays away; eventually, one might form and get really large, and then we might actually have a geomagnetic reversal.”
Not much has been known about this weak spot, because space-based telescopes and satellites have not been able to measure it.
“Some have postulated that the Earth’s magnetic field is leaking out the wrong way at that particular spot,” study co-author Rory Cottrell, a geologist also at the University of Rochester, told Space.com. “One theory is that changes in the South Atlantic Anomaly could be responsible for the decrease in the overall magnetic field that we’re seeing, because these patches are growing or changing over time.”