The rotation of the Earth's core may have recently stopped: a phenomenon which, unlike the scenarios imagined by some science fiction films, would have no impact on life, but would demonstrate that the planet's core is subject to oscillations.
The hypothesis, which leaves part of the scientific community perplexed, is presented by Yi Yang and Xiaodong Song, both of Peking University, in the journal Nature Geoscience.
"There is actually nothing new in all of this", commented to ANSA Massimo Chiappini, director of the Environment Department of the National Institute of Geophysics and Volcanology (Ingv).
"The earth's core is something very far away, it is impossible to reach it and for this reason the hypotheses about its functioning blossom like mushrooms".
It may seem incredible, but it is much easier to know what lies billions of kilometers away from us than to know what is happening under our feet, just a few thousand kilometers deep.
What makes it impossible is the fact that as soon as you start going into the depths of the planet the pressures and temperatures become simply impossible for any instrument.
"We have very few certainties about what the interior of the Earth is like and the best tool we have at our disposal is the study of the seismic waves that propagate through it", added the Ingv researcher.
One of the few fixed points is that inside the planet there is a very compact nucleus, wrapped in a sort of much more fluid shell, and that this last one would be responsible for the earth's magnetic field.
But there are enormous uncertainties about the dynamics of this nucleus and for this reason various theories have been formulated, some of which have influenced the world of science fiction.
Now studying the propagation of seismic waves generated by some violent earthquakes recorded in the 60s and comparing those propagations with similar earthquakes that occurred in the 90s, Chinese researchers have observed anomalies.
Discrepancies which, according to the authors of the research, suggest that the rotation of the Earth's core would have changed in the meantime, if not completely stopped.
"However, these are hypotheses. It is possible, but they are data that prove nothing. Many other unknown factors could have disturbed those propagations of seismic waves - said Chiappini -".