“Decades of seismic data reveal Earth’s inner core is rotating slower than the surface. USC researchers analyzed seismic waves from earthquakes and nuclear tests, showing the inner core’s movement. They found that changes in seismic wave travel times indicated the slowdown. John Vidale from USC confirmed the inner core, a hot, dense iron and nickel ball 3,200 miles below, had slowed for the first time in decades.”
Chatgpt made a shorter summary
“Decades of seismic data reveal Earth’s inner core is rotating slower than the surface. USC researchers analyzed seismic waves from earthquakes and nuclear tests, showing the inner core’s movement. They found that changes in seismic wave travel times indicated the slowdown. John Vidale from USC confirmed the inner core, a hot, dense iron and nickel ball 3,200 miles below, had slowed for the first time in decades.”