Earth’s core would have reversed the direction of rotation – 01/23/2023 – Science

The Earth’s core, a hot sphere the size of Pluto, would have reversed its rotation direction, according to a study published on Monday (23).

This “planet within the planet”, about 5,000 km from the surface and made up essentially of iron, stopped rotating and would be, at the moment, moving in the opposite direction, suggests the study released by Nature Geoscience.

The exact mechanism of rotation of this sphere, free of movement as it floats in the liquid of the outer core, remains difficult to decipher. The little that is known is based on analyzes of seismic waves, caused by earthquakes, when they pass through the center of the planet.

By analyzing seismic wave data over the past six decades, Xiaodong Song and Yi Yang of Peking University concluded that the core’s rotation “almost stopped around 2009 and then spun in the opposite direction.”

“We believe that the central core is, relative to the Earth’s surface, rotating in one direction and then the other, like a swing,” they told AFP.

“A complete cycle of this movement lasts around seven decades, which means that it changes direction approximately every 35 years,” the researchers added.

The last rotational change, prior to 2009, took place in the early 1970s. And the next one will occur in the mid-2040s, completing the cycle, according to Chinese scientists.

This movement roughly adjusts for changes in day length, minute variations in the exact time Earth needs to rotate on its own axis, they add.

To date, there are few indications of the influence of this rotation on the earth’s surface. However, the two authors guarantee that they are convinced that there are physical connections between all the layers that make up the Earth.