Science & Technology

The Earth's core has not only slowed down, but also reversed direction

By T.K. Randall
July 9, 2024

Image: Earth Cutaway
Credit: CharlesC / CC BY-SA 3.0 (adapted) Situated more than 3,000 miles beneath the planet's surface, the Earth's inner core - a vast spinning ball of solid metal composed mostly of iron and nickel - has long remained something of an enigma due to its inaccessible location and the difficulties inherent in obtaining accurate data.

Much of what we've learned about the inner core has come from analyzing the waves produced by large earthquakes, with the differences between waves of comparable strengths passing through the core at different times providing clues to the core's position and rotational speed.

Last year, scientists came up with a new model suggesting that the Earth's inner core had previously spun faster than the actual planet itself before starting to slow down again.

It slowed down to such an extent, in fact, that it has since started to spin in the opposite direction.

Now, a separate team of scientists has effectively confirmed that this is indeed the case by studying the seismic waves produced by 121 earthquakes between 1991 and 2023.They even analyzed the shockwaves produced by Soviet nuclear weapons testing in the 1970s.

"We've been arguing about this for 20 years, and I think this nails it," said study co-author Dr John Vidale of the University of Southern California's Dornsife College of Letters, Arts and Sciences.

"I think we've ended the debate on whether the inner core moves and what's been its pattern for the last couple of decades."

While the notion that the Earth's core is now spinning in reverse might be disconcerting, it's worth remembering that the core has likely been changing direction and speed like this for billions of years.

In other words, it's nothing to be worrying about.

Source: NDTV.com

Tags: Core