A group of geophysicists has discovered thatEarth’s core rotates much slower than previously thoughtin front of the rest of the planet, which affects our magnetic field, according to an article published in the journal ‘Nature Geoscience’.
Specifically, the study, developed by the Department of Earth Sciences at the University of Cambridge, indicates thatthe rotation speed of the Earth’s core is less than one degree every million years. The inner core grows very slowly over time as the outer core material solidifies on the surface. During the process, the difference in the east-west hemispheric velocity of this process is frozen in the structure of the inner core.
“We have discovered that the speed of rotation comes from the evolution of the hemispheric structure, and thus we show that the hemispheres and rotation are compatible”, explains Lauren Waszek, co-author of the work. Until now, according to the geophysicist at the University of Cambridge, this was an important problem in geophysics “since the fast rotational speeds were incompatible with the hemispheres observed in the inner core, since they did not allow enough time for the differences to be freeze the structure. “
To obtain these results, scientistsused seismic waves that passed through the inner core, located 5,200 kilometers below the surface of the earth, and compared them with the travel time of the waves reflected on the surface of the core. Subsequently, they looked at the differences in the rotation of the eastern and western hemispheres, and found that they rotate consistently east and inward, making the deeper structure older.
These findings are important becauseheat fluxes from the earth’s core are what create magnetic fields, which protect the earth’s surface from solar radiation, andwithout whom life on Earth could not exist. Waszek highlights that these results “give us an additional perspective to understand the evolution of our magnetic field.”
