The inner core of the Earth has probably recently stopped rotating and may be changing its direction of rotation now. Such are the results of the study, during which scientists collected data seismic waves from earthquakes that penetrated into the deepest bowels of our planet.

The results of the study indicate that the core of the Earth probably stops and changes the direction of rotation with a periodicity of approximately 60-70 years. This discovery could solve long-standing mysteries about the climatic and geological phenomena that affect life on our planet.

Although the rotation of the core affects the environment on the Earth’s surface, scientists believe that this periodic change in rotation is a normal phenomenon that does not pose a risk to life on the planet.

The Earth’s inner core is a solid ball of metal that is 75% the size of the Moon. It can spin at different speeds and in different directions because it’s in a liquid outer core, but scientists aren’t sure exactly how fast it spins or whether its speed changes over time.

Located about 4.9 km below the surface, the core is under such intense pressure that it is probably as hot as the surface of the Sun. Because of its remoteness and difficulty in studying, the inner core remains one of the least studied environments on our planet, although it is clear that it plays an important role in many processes that make our world habitable, such as creating the Earth’s protective magnetic field, which blocks harmful radiation reaching the surface.

Now, Yi Yang  and Xiaodong Song, a pair of researchers at Peking University’s SinoProbe Lab at School of Earth and Space Sciences, have captured “surprising observations that indicate the inner core has nearly ceased its rotation in the recent decade and may be experiencing a turning-back.”

“There are two major forces acting on the inner core,” Yang and Song said. “One is the electromagnetic force. The Earth’s magnetic field is generated by fluid motion in the outer core. The magnetic field acting on the metallic inner core is expected to drive the inner core to rotate by electromagnetic coupling. The other is gravity force. The mantle and inner core are both highly heterogeneous, so the gravity between their structures tends to drag the inner core to the position of gravitational equilibrium, so called gravitational coupling.”

Our most everyday experiences — for example, the length of the day and climatic conditions — can be shaped by the cycles of rotation of the metal sphere at the center of our world. Disentangling these nuances will require new models and further observations of the mysterious central sphere of the Earth.

According to Yang and Song, the next steps in the research are to build quantitative models of the physical mechanisms based on the multi-year oscillation system and observe how the rotation will change in the future.

“We’d expect it to rotate westwards relative to the surface of the Earth in the coming years and decades,” the scientists concluded. “Seismic waves are still the best way and thus continuous operation of high-quality seismic networks is crucial in this regard.”