The Chinese estimate that the rotation of the Earth’s solid inner core has recently stopped, and the core appears to be preparing to change its motion in the opposite direction. scientists. Based on current indications, the reverse rotation is likely to end within the next decade, and the possible effects on the planet’s surface remain to be explored.

The researchers, led by Peking University seismologist Xiaodong Song, who published an article in the journal Nature Geoscience, based their estimates on the analysis of seismic waves from nearly identical earthquakes that penetrated the Earth’s core along similar “paths” from the 1960s to the present day. .

The analysis concluded that after the 1970s, the inner core rotated progressively faster in an easterly direction, until between 2009 and 2011 its rotation appeared to have stalled, possibly due to an impending reversal of rotation. The researchers estimate that the forthcoming new shift in the core’s rotation in the opposite direction, this time to the west, is part of a possible periodic cycle of six to seven decades (a theory that needs to be confirmed). Based on this model, the core is expected to rotate westward at an increasingly faster rate until the 2040s, when it will stop and turn eastward again.

The inner core, which has an estimated radius of 1,220 kilometers and is composed mostly of iron and nickel, with a temperature close to that of the Sun, is separated from the rest of the solid Earth by a liquid outer core that allows it to spin differently from the Sun. the planet itself. The rotation of the inner core is influenced by the magnetic field created by the outer molten core, and is balanced by the gravitational influence of the mantle, the Earth’s intermediate layer between the core and the earth’s crust. The rate of rotation of the nucleus, and the extent to which it varies, remains a matter of scientific debate.

It is also discussed how the direction of rotation of the inner core is related to geophysical changes on the surface of our planet, such as the magnetic field and the length of the day, since an interaction is believed to exist.

^{Source: APE-MEB}