Earth’s inner core may have stopped spinning – but what does that mean?

The Earth’s interior is a mysterious place, and scientists may have uncovered strange new secrets. The Earth’s inner core may have recently stopped rotating relative to its surface as part of a multi-decade-long cycle, according to a new study.

With thousands of miles of rock in the way, it’s difficult to know exactly what’s going on at the center of the Earth. It should be studied indirectly by measuring how it propagates through different layers. This has helped geologists learn new details, such as the core may be made of a superionic iron alloy.

Now, a new study has come to a startling conclusion – relative to the Earth’s surface, the inner core stopped rotating around 2009. Rotation isn’t necessarily tied to the rotation of the rest of the planet.

Researchers at Peking University have analyzed seismic waves from earthquakes that have passed through the inner core since the 1960s, investigating differences in what these waves look like and how long it took them to propagate. Interestingly, they found that the travel times of these waves changed in a certain way over decades, but since about 2009 that change has largely disappeared. , the team said, indicating that the core had “paused” its rotation.

This does not mean that it is not rotating at all. This means that the rotation of the core is essentially in lockstep with that of the surface. At various points the core may compete or lag behind the surface, but even then the difference is negligible. Move.

The team goes one step further and says the study could indicate that the core may be spinning in the opposite direction. But again, that doesn’t mean what it sounds like. Instead, the core spins slower, so it appears to drift backwards against the surface.

Researchers say this is all part of a 70-year cycle. They claim to have found evidence that a previous reversal occurred in his early 1970s, consistent with other changes observed in the Earth’s cycle, such as the magnetic field and his day length. It’s even possible.

The cause of this cycle can be several major competing forces. The magnetic field produced by the outer core may be accelerating the inner core’s spins, but the enormous gravitational influence of the mantle could be dragging it along and slowing its spins.

Of course, in the dark world of geology inside the Earth, nothing is definitive (pun intended) and other scientists disagree with the results of the new research.

“These mathematical models explain the observed data, but they are not required by the data, so they can all be wrong,” Hrvoje Tkalcic, a geophysicist at the Australian National University, told AFP. “Thus, the geophysical community is divided on the discovery and the topic will remain controversial.”

A new study was published in a journal natural earth science.

Source: Nature