The inner core of the Earth, a hot and dense ball of solid iron located more than 5,000 kilometers deep, is the most inaccessible place on our planet. Now, a Chinese scientific team has found that its rotation could have recently stopped and is inverting.
The results of the research, based on the analysis of dozens of earthquakes, are published in the journal Nature Geoscience, and, according to its authors, this variation is correlated with small changes in geophysical observations on the Earth’s surface, such as the magnetic field or the increase or decrease in the length of days.
The article is signed by Xiaodong Song and Yi Yang, from Peking University in China, who say they were “quite surprised.”
The results could help unravel the many mysteries deep within Earth, such as the role the inner core plays in maintaining the planet’s magnetic field and in the rate of rotation, and thus the length of the day, he explains. Nature in your news section.
“But they are just the latest installment in a long effort to explain the unusual rotation of the inner core, and they may not be the last word on it.”
The Earth is made up of several layers: the crust, the mantle, the outer core, and the inner core.
The latter, the deepest layer, is a solid iron ball somewhat larger than Pluto that is surrounded by a liquid outer core, allowing it to spin differently from Earth’s own rotation.
The spin of the inner core is driven by the magnetic field generated in the outer core and balanced by the gravitational effects of the mantle.
Knowing how the solid inner core rotates could clarify how the Earth’s layers interact, explain the authors who, however, point out that the speed of this rotation and whether it varies has been the subject of debate among the scientific community for years.