Earth's inner core may have stopped spinning

The Earth's inner core may have recently stopped rotating relative to the surface. However, there is nothing unusual about this, the stop is part of a cycle that can last for decades, scientists believe.

Thanks to the new research, the results of which are published in the journal Nature, geologists from Peking University made preliminary conclusion that the Earth's core "suspended" movement relative to the surface for about 2009. This could be because the inner core is a solid iron ball floating in the liquid outer core, so its rotation is not necessarily related to the rotation of the rest planets.

The reason for this phenomenon may be two main opposing forces. The magnetic field created by the outer core speeds up the rotation of the inner one. At the same time, the huge gravitational influence of the mantle slows it down. Because of this, at different times it can either overtake or lag behind the surface. Moreover, sometimes the earth's center can rotate in the opposite direction.

But this does not mean that now the core does not rotate at all. Now this happens at basically the same speed as the earth's axis rotates, scientists believe.

According to the researchers, all this is part of a 70-year cycle. The previous reversal occurred in the early 1970s. It may even coincide with other observed changes in the Earth's cycles, such as the length of the day. For example, earlier scientists concluded that the variable speed of the nucleus changes day length every 6 years.

However, not all geophysicists agree with the findings of the new study, since it is very difficult for scientists to follow the center of the Earth. Because of the thousands of kilometers of rock, it has to be studied indirectly by analyzing the magnetic field, ancient crystals or how seismic waves from earthquakes propagate through different layers planets.