Earth's Inner Core Oscillates

Scientists identify a six-year cycle of super- and sub-rotation that affected the length of a day based on their analysis of seismic data.

Earth’s structure is divided into layers, with the inner core at the center followed by the outer core, lower mantle, upper mantle, crust, and atmosphere. The inner core is the hottest part of the planet at about 10,000 °F (5400 °C), which is similar to the temperature of the surface of the sun!

Believed to consist mostly of an iron-nickel alloy, the inner core is mainly a solid ball with a radius of about 760 miles (1,220 km). It rotates slightly faster than the planet as a whole, which is called super-rotation.

University of Southern California (USC) scientists have found evidence that the Earth’s inner core oscillates, contradicting previously accepted models that suggested it consistently rotates at a faster rate than the planet’s surface.

Their study, published today (June 10, 2022) in the journal Science Advances, shows that the inner core changed direction in the six-year period from 1969-74, according to the analysis of seismic data. The scientists say their model of inner core movement also explains the variation in the length of a day, which has been shown to oscillate persistently for the past several decades.  READ MORE...