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

Far below our feet, a giant may have begun to move against us.

Earth inner coreA hot iron ball the size of Pluto has stopped spinning in the same direction as the rest of the planet and may even be spinning in the opposite direction, according to a study released Monday.

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

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

What little is known about the inner core comes from measuring the small differences in seismic waves caused by earthquakes or sometimes nuclear explosions as they pass through the center of the Earth.

A new study, published in the journal, seeks to track the movements of the inner core Natural Geology analyzed seismic waves from repeated earthquakes over the past six decades.

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

“We believe that the inner core swings back and forth like a pendulum relative to the Earth’s surface.”

“One period of the swing is about seven decades,” meaning it changes direction about every 35 years.

They predicted that it had previously reversed direction in the early 1970s and that the next face-off would be in the mid-2040s.

The researchers said this rotation roughly coincides with changes in the so-called “length of the day” — small changes in the exact time it takes for the Earth to rotate on its axis.

Stuck in the middle

So far, there is little evidence that the inner core has much effect on surface dwellers.

But the researchers said they believe there are physical connections between all of Earth’s layers, from the inner core to the surface.

“We hope that our study can encourage some researchers to build and test models that consider the entire Earth as an integrated dynamical system.”

Experts not involved in the study expressed caution about its findings, pointing to a number of other theories and warning that many mysteries remain about the center of the Earth.

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

“(But) none of the models explain all the data very well in my opinion,” he said.

Vidale published research last year suggesting that the inner core oscillates more quickly and changes direction every six years. His work was based on two seismic waves nuclear explosions In the late 1960s and early 1970s.

That time frame is close to the point at which Monday’s study found that the inner core finally changed direction — what Vidale called “kind of a coincidence.”

Geophysicists ‘divided’

Vidale says there’s good evidence to back it up—he says the inner core only moved significantly from 2001 to 2013 and has stayed put ever since.

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

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

“Therefore, the geophysical community will be divided on this finding and the topic will remain controversial.”

I have compared seismologists to doctors who “study the internal organs of patients using imperfect or limited equipment.”

With no such thing as CT scans, “the image of the Inner Earth is still fuzzy,” he said, predicting more surprises to come.

It may contain more on the theory that inside the inner core may be another iron ball, like a Russian doll.

“Something’s going on and I think we’re going to figure it out,” Vidale said.

“But that could take ten years.”

© 2023 AFP