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Earth’s inner core is probably changing its direction of rotation

Think of the Earth’s inner core as a heavy metal ballerina. This iron ballerina can spin at variable speed.

to report New York Times This nucleus may be in one of its turning points. seismologists in an article published earlier this month Nature Geoscience published, have reported that the Earth’s inner core changes its direction of rotation (relative to the direction of the Earth’s surface) every few decades, after a brief pause, and we may be experiencing one of these changes now.

This report may be reminiscent of Hollywood apocalyptic movies; But there is no need to worry. No catastrophic consequences will occur as a result of this period of rotation of the planet’s core, which has probably been going on for a long time. The goal of the researchers who presented this model is to gain a deeper understanding of the innermost part of the Earth and its relationship with other parts of the planet.

According to Xiaodong Song, a seismologist at Peking University in Beijing and one of the authors of the study, “the inner core is like a planet inside another planet, so how it moves is very important.”

Danish seismologist Inge Lehmann discovered in 1936 that the outer liquid core of the Earth is covered by a solid metallic pearl. Since then, this issue has always occupied the minds of scientists.

“It’s very strange that there is a solid iron ball floating in the center of the Earth,” said John Vidal, a seismologist at the University of Southern California who was not involved in the research. Scientists think this core began to crystallize from a primordial metallic soup in the not-so-distant past, when the planet’s inner hell had cooled enough.

The Earth’s inner core cannot be directly sampled, but high-energy seismic waves generated by large earthquakes and Cold War nuclear weapons testing have revealed some of its properties by passing through the inner core. Scientists estimate the diameter of this sphere, which is mainly composed of iron and nickel, to be 2,440 km and its temperature is similar to the temperature of the sun’s surface (about 6,000 degrees Kelvin).

But these waves also created new questions. If the core were constant, the passage of waves of similar origin should produce similar results over time, but this is not the case.

One explanation offered is that the inner core rotates and deflects the waves. In the mid-1990s, Dr. Song was one of the first scientists to suggest that the inner core might rotate at a different speed than the Earth’s surface. Since then, seismologists have found evidence that this rotation can speed up or slow down.

But what is the reason for this speed change? One hypothesis is that two great powers are in a battle for control of the heart of the world. The Earth’s magnetic field, which is the result of the circulation of iron currents in the outer liquid core, pulls the inner core and causes it to rotate. This force counteracts the strong gravitational field that the Earth’s mantle exerts on the inner core and slows it down.

By studying seismic waves recorded from the 1960s to the present, Dr. Song and Yi Yang, another seismologist from Peking University and one of the authors of the study, found that this conflict leads to back and forth movements of the inner core in 70-year periods.

In the 1970s, the Earth’s inner core did not rotate relative to a person standing on the surface. After that, the inner core gradually began to rotate faster in the east direction. This speed then gradually decreased until the inner core stopped rotating (relative to the Earth’s surface) sometime between 2009 and 2011.

Now the inner core is gradually rotating towards the west and it seems to continue this process first with an increasing and then decreasing acceleration until it finally reaches a stationary state again in the 2040s and completes a period of east-west rotation.


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