The study said the inner core, which is the size of Pluto, would have stopped spinning around 2009.
The inner core of the Earth is the innermost geological layer of the planet, and it is a solid ball with a radius of about 1,220 km, or about 20% of the radius of the Earth, or 70% of the radius of the Moon.
The research could help increase understanding of how changes in the core affect things on Earth’s surface, such as day length and navigation.
Scientists from Peking University collected data about seismic waves from Alaskan records dating back to the 1980s, and found that the waves indicate that the Earth’s inner core has changed direction, and scientists describe the inner core as a planet within a planet, explaining that the oscillation that occurred may take 7 decades.
They explained that the mantle and the inner core are both highly inhomogeneous, so gravity works to pull the inner core to a position of equilibrium, which is called gravitational coupling, which pushes the inner core to change its direction.
Scientists added that although the rotation of the core affects the surface of the planet, this change will not endanger humans or pose any risks to our planet.
The scientists’ observations provide further evidence of “dynamic interactions” between Earth’s different layers that can influence the magnetic field and changes on the surface.