Scientists have proven that the Earth’s core is slowing down.
A subject of debate for decades, new research published in Nature provides “unambiguous evidence” that the Earth’s inner core began to decrease its speed around 2008.
Guanning Pang, a postdoctoral researcher in the Department of Earth and Atmospheric Science at Cornell Engineering, said the findings had important implications for how the geomagnetic field, which protected the Earth from solar winds, generated and evolved.
Mr Pang said movement of the inner core had been debated by the scientific community for almost three decades, with some research indicating that the inner core rotated faster than the planet’s surface.
He said the new study, which was led by the University of Southern California (USC) and included Cornell University, provided unambiguous evidence that the inner core began to decrease its speed around 2008, moving slower than the Earth’s surface.
“Our findings provide additional constraints in inner core dynamics, inner core viscosity, and Earth’s mantle density distribution.” Mr Pang said.
USC Professor of Earth Sciences John Vidale said the inner core’s slowing speed was caused by the churning of the liquid iron outer core that surrounded it, which generated Earth’s magnetic field, as well as gravitational tugs from the dense regions of the overlying rocky mantle.
Mr Vidale said the implications of this change in the inner core’s movement for Earth’s surface could only be speculated.
He said the backtracking of the inner core may alter the length of a day by fractions of a second.
“It’s very hard to notice, on the order of a thousandth of a second, almost lost in the noise of the churning oceans and atmosphere.”
The scientists’ future research hopes to chart the trajectory of the inner core in greater detail to reveal why it is shifting.
