The inner core of the Earth would have started to turn upside down: should we worry about the phenomenon?

A scientific study shows that the heart of our planet would have even stopped rotating before changing its direction of rotation.

There is enough to be dizzy. According to a scientific study published on January 23, 2023 in Nature Geoscience, the direction of rotation of the Earth could change…

Information that might seem trivial, but which from a scientific point of view would be fascinating. And such a phenomenon could also have some planetary consequences.

What is the inner core?

Already before understanding how this discovery could be exceptional, you have to know what the Earth’s inner core is.

The Earth’s core is the central part of our planet which occupies 17% of its volume and represents 33% of its mass, approximately. It consists of two parts: the outer core, liquid and the inner core called “seed”, solid essentially made of metallic iron.

It is the latter that has been studied. That metallic ball is surrounded by the liquid core therefore, and “floats” in a way. This sphere whose temperatures are around 6000°C rotates like planet Earth with a rotation which belongs to him and would have a cut equivalent to the planet Pluto. This nucleus is located at some 5,000 km below the surface.

A hypothesis to study

In this study, the Chinese researchers attempt to demonstrate with mathematical calculations derived in particular from data on seismic waves, that the Earth’s inner core would change direction of rotation every 35 years, as reported by Le Parisien.

With “analysis of repeated seismic waves from the early 1990s”, they inferred that “all trajectories that previously exhibited significant temporal changes have changed little over the past decade. This broadly consistent pattern suggests that the rotation of the inner core has recently come to a halt“.

For them, the rotation of the core has stopped in 2009 to go in the opposite direction. Another scientific study had shown that a change of this order had occurred in 1970.

The complete cycle of this nucleus would therefore be 70 years, to return to the starting direction, as TF1 reports.

Controversial results

Chinese scientists have published this very serious study, remaining very cautious about the conclusions which result from it but which could allow for further study.

Other researchers have also made a point of explaining that this publication should be taken with a grain of salt. The hypothesis divides scientists. Some argue that this cycle could be faster, others that tools used are completely insufficient to make the slightest hypothesis on the subject.

Concrete consequences?

Without being a proof, for the Chinese researchers, the published results correspond perfectly with observed geophysical changes.

“That multidecadal periodicity coincides with changes in several other geophysical observations, in particular day length and magnetic field“, they specify.

Indeed, even if it may seem anecdotal, this change in rotation and even stopping it could have consequences on the Earth’s magnetic field but also on the length of a day, by a few fractions of a second per year.

But this difference in temporality is also due to other factors: the gravity of the Moon, the movements of the oceans…

Consequences already taken into account: universal time has been adjusted to respect the real time of the Earth’s rotation. Thus 27 “leap” seconds have been added to Coordinated Universal Time (UTC) since the 1970s.

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