Earth’s inner core is spinning in the opposite direction


new study has found that Earth’s inner core may have started to spin in the opposite direction.

Research published in the journal Nature Geoscience could lead to further understanding of how processes inside the planet could affect its surface, including the length of a day.

How the inner core rotates has long been a topic of debate, with this latest finding proving to be controversial.

Earth’s core consists of two things, namely the outer and inner core.

The outer core is liquid and made up of molten iron and nickel. The inner core, however, is a solid ball of iron-nickel alloy and is separated from the rest of the Earth by the outer core meaning it rotates differently.

There is also a magnetic field which surrounds the planet and carries its own electrical current, protecting humans from cosmic radiation. Without this magnetic field Earth would become a barren and irradiated wasteland.

The speed of the inner core’s rotation has been unclear until now.

Seismic waves from near-identical earthquakes passing through Earth’s inner core along similar paths since the 1960s were assessed by scientists, including those from Peking University in Beijing.

The study’s authors, Xiaodong Song and Yi Yang, of China’s Peking University, said they found that the inner core’s rotation “came to a near halt around 2009 and then turned in an opposite direction.”

“We believe the inner core rotates, relative to the Earth’s surface, back and forth, like a swing,” they said.

“One cycle of the swing is about seven decades,” meaning it changes direction roughly every 35 years.

Researchers believed there are physical links between all Earth’s layers, from the inner core to the surface, and hypothesise it previously changed direction in the early 1970s, predicting the next cycle would be in the mid-2040s.

“This multidecadal periodicity coincides with changes in several other geophysical observations, especially the length of day and magnetic field,” they added.

“We hope our study can motivate some researchers to build and test models which treat the whole Earth as an integrated dynamic system.”

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