Earth’s inner core may have started spinning other way: Study

Far below our feet, giants may have begun moving toward us.

Of earth inner coreIt is a ball of hot iron the size of Pluto.

About 5,000 kilometers (3,100 miles) below our surface, this “planet within a planet” floats on water and can rotate independently. liquid metal outer core.

Exactly how the inner core rotates is a matter of debate among scientists, and the latest research is expected to be controversial.

What we know very little about the inner core is measuring small differences in the seismic waves produced by earthquakes and possibly nuclear explosions as they pass through the middle of the Earth.

A new study has been published in the journal to track the movement of the inner core natural earth science We analyzed seismic waves from repeated earthquakes in the last 60 years.

The study’s authors, Xiaodong Song and Yi Yang of Peking University, China, said they found that the rotation of the inner core “almost stopped around 2009 and then changed in the opposite direction.”

“We think the inner core is spinning back and forth like a swing with respect to the Earth’s surface,” they told AFP.

“One cycle of the swing is about 70 years,” they added, meaning it changes direction about every 35 years.

They say they turned around in the early 1970s and predict the next turn around in the mid-2040s.

The researchers said this rotation roughly coincides with changes in what is called the “day length.”

stuck in the middle

So far, little has been shown to indicate that the inner core has a significant effect on surface inhabitants.

But researchers said they believe there is a physical connection between all layers of the Earth, from the inner core to the surface.

“We hope our work can motivate researchers to build and test models that treat the entire Earth as an integrated dynamic system,” they said.

An expert not involved in the study issued a warning about the discovery, pointing to several other theories and warning that many mysteries remain about the center of the Earth.

“This is a very careful study with a lot of data thrown in by good scientists,” said John Vidale, a seismologist at the University of Southern California.

“(But) in my opinion, no model can explain all the data well,” he added.

Vidale published research last year that suggested the inner core oscillates much faster, changing direction about every six years.His work was based on seismic waves from two earthquakes nuclear explosion From the late 1960’s to the early 1970’s.

That timeframe, according to Monday’s study, is what Vidal called “a sort of coincidence” that the inner core changed direction at the end.

Geophysicists ‘divided’

Another theory that has good evidence to support it, says Vidale, is that the inner core only moved a lot between 2001 and 2013, and has remained in place since then.

Hrvoje Tkalcic, a geophysicist at the Australian National University, has published research suggesting that the inner core cycles every 20 to 30 years, rather than the 70 years suggested in the latest study.

“These mathematical models explain the observed data, but they are most likely all wrong because they are not required by the data,” Tkalcic said.

“Thus, the geophysical community will be divided on this discovery and the topic will be controversial.”

He compared seismologists to physicians who “use incomplete or limited equipment to study the organs inside a patient’s body.”

With no such thing as a CT scan, “images of the Earth’s interior are still blurry,” he said, predicting more surprises to come.

This could include the theory that the inner core may contain yet another wrecking ball, like the Russian doll.

“I think something is going on and we are going to work it out,” said Videl.

“But it may take 10 years.”

© 2023 AFP