(NEXSTAR) – Deep in the center of the Earth is the inner core, which is roughly 746 miles wide and is composed of the first pure solid iron, NASA explains. Although we have long believed – and research shows – that the inner core rotates, a new study suggests that its spinning is “stopped” and can even be reversed.
The outer core fluid that surrounds the inner core causes the Earth’s magnetic field. According to NASA, as the molten iron and nickel in the outer core move, electric currents create effects in the magnetic field. The outer core also allows its core to spin in on itself, nature explains.
Although scientists can’t directly probe the core, they can analyze the seismic waves caused by earthquakes — and when Cold War nuclear weapon tests — hit the core. That’s what study co-authors Yi Yang and Xiaodong Song, seismologists at Peking University in Beijing, have done in new research, which was published in the journal Nature Geoscience on Monday.
Based on their analysis of seismic waves caused by earthquakes similar to those of the 1960s, Yang and Song said they found that the rotation of the inner core between 2009 and 2020 “steadied” and may even have reversed “by a small amount.”
Sounds good, right? Don’t panic — it’s probably not the first time our inner core has stopped. But they believe the change is “associated with a gradual reversal of the inner core as part of an approximately seven-decade cycle.”
According to Yang and Song, their study also suggests “another reversal or slowdown around the early 1970s.”
Seismologists said their findings — changes in how fast seismic waves travel through the inner core — coincide “with changes in various geophysical observations, particularly the length of the day and the magnetic field,” both of which are areas impacted by the movement of the inner core. research shows.
While the changes are “strong,” what Yang and Song are finding may not be exactly what is happening in the depths of our planet. John Vidale, a professor of earth sciences at the University of Southern California, who was not involved in the study, noted “a lot of competing ideas” about the Earth’s core to the Wall Street Journal.
This includes theories that the inner core reverses its rotation more often than 70 years ago Yang and Song decided and stopped rotating in the early 2000s.
“Whatever model you like, there is some data that disagrees with it,” Vidale told The New York Times.
A recent study co-authored by Vidale shows that its inner core changed between 1969 and 1974, and that it appears to oscillate “by two kilometers every six years.”
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