The rotation of the Earth's inner core slows down

The rotation of Earth’s inner core began slowing down more than a decade ago, changing the length of our days by fractions of a second.

Researchers from the University of Southern California (USC) have created designs for Movement of the inner nucleus Using seismic data recorded from various Earthquakes and nuclear tests, both of which send vibrations through the planet. By measuring the speed and interaction of seismic waves within the Earth’s layers, researchers can estimate the location and movement of the inner core.

The study confirms that since approximately 2010, the Earth has become The inner core It has slowed or declined compared to its speed in previous decades. It also moves slower than the Earth’s surface a permit From the University of Southern California.

“The inner core has slowed down for the first time in several decades,” John Vidal, co-author of the study and a professor of geosciences at the University of Southern California, said in the statement. “Other scientists have recently discussed similar and different models, but our latest study provides the most convincing solution.”

Related: Layers of the Earth: Exploring Our Planet Inside and Out

the earth The inner core It is a hot, dense, solid ball made of iron and nickel, located 3,200 miles (5,150 kilometers) beneath our feet. It is surrounded by an outer core of liquid iron and nickel, and covered by a solid rock mantle. The new study shows that the inner core’s deceleration speed is caused by convection within the outer core of liquid iron, which maintains… Earth’s magnetic fieldAnd the pull of gravitational forces in the mantle above it.

The researchers analyzed seismic data recorded during 121 recurring earthquakes that occurred around the South Sandwich Islands in the South Atlantic Ocean between 1991 and 2023, as well as data from several nuclear tests around the world, to reach their conclusions.

In theory, repeating earthquakes would produce identical seismograms because they occur at the same location. For this reason seismic data from different points are compared time It can detect changes beneath the planet’s surface. Small changes in how long it takes seismic waves to travel through Land At different times in the planet’s history it revealed a slowing down of the inner core. Although this change might change the length of the day by fractions of a second, it wouldn’t be noticeable, the researchers said.

Their results were Posted on June 12 In the journal Nature.