According to a research, the inner core of Earth may have ceased rotating and may now be moving backward

 By Lianne Kolirin

January 25, 2023

ATLANTA — According to new study, the inner core of the Earth's rotation may have stopped or possibly reversed.

The crust, mantle, and inner and outer cores make up the Earth. The liquid outer core separates the solid inner core from the semi-solid mantle, allowing the inner core to rotate at a rate different from the Earth's rotation. The solid inner core is located about 3,200 miles below the Earth's crust.

Earth's core is roughly the size of Mars and has a radius of close to 2,200 miles. It makes up around one-third of the mass of the planet and is mostly composed of iron and nickel.

Yi Yang, an associate research scientist at Peking University, and Xiaodong Song, chair professor at Peking University, used analysis of seismic waves from earthquakes that have passed through the Earth's inner core along comparable paths since the 1960s to determine how quickly the inner core is spinning. Their findings were published on Monday in the journal Nature Geoscience.

They claimed what they discovered was surprising. Seismic data, which had previously altered throughout time, have little changed as of 2009. They claimed that this indicated a stop in the inner core spinning.

The inner core may be experiencing a turning-back, according to their study. "We show surprising observations that indicate the inner core has nearly ceased its rotation in the recent decade," they wrote.

When you look at the decade between 1980 and 1990, you can clearly see progress, but from 2010 to 2020, not much has changed, Song continued.

The magnetic field produced by the outer core propels the rotation of the inner core, which is counterbalanced by the mantle's gravitational pull. Understanding the rotation of the inner core may help us understand the interactions between these layers and other deep-earth phenomena.

However, Hrvoje Tkalcic, a geophysicist at the Australian National University who was not involved in the work, noted that there is disagreement on the speed of this rotation and whether it fluctuates.

The inner core, he claimed, "doesn't come to a full halt." He said that the study's conclusion "means that the inner core is now more in harmony with the rest of the earth than a decade ago when it was spinning a little faster."

Nothing catastrophic is occurring, he said.

According to Song and Yang's calculations, a little mismatch between the electromagnetic and gravitational fields might cause the inner core's rotation to slacken or possibly reverse. They think that this cycle, which spans seven decades, had its turning point in the early 1970s, which is when they saw it in their data around 2009/2010.

The study's "data analysis is good," according to Tkalcic, author of "The Earth's Inner Core: Revealed by Observational Seismology." The study's conclusions "should be regarded carefully," though, as "additional information and cutting-edge approaches are required to shed light on this intriguing subject."

Yang and Song concurred that more investigation was required.

exploring the Earth's interior

Tkalcic hypothesised that the inner core's cycle occurs every 20 to 30 years rather than the 70 years stated by the most recent study and devotes an entire chapter of his book to the topic. He described the reasons for these variances as well as why it is so challenging to comprehend what takes place in the planet's core regions.

The subject of our research, he declared, "is buried hundreds of kilometres beneath our feet."

He said, "Until multidisciplinary discoveries validate our assumptions and conceptual frameworks, care must be used. We apply geophysical inference methods to infer the Earth's internal attributes.

"Seismologists can be compared to doctors who use faulty or inadequate equipment to examine the interior organs of patients. We are still in the discovery stage, therefore despite our advances, our perception of the interior Earth is still hazy."

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