The inner core of the Earth, a big ball of very hot iron the size of Pluto, stopped rotating in the same direction as the rest of the planet and could even be rotating in the opposite directionaccording to new research
About 5,000 kilometers below the earth’s surface another “iron planet” can rotate independently because it floats in the outer core of liquid metal. Studying how the Earth’s inner core rotates has been a topic of debate among scientists, and the latest research is proving highly controversial.
The Earth’s core now appears to rotate in the opposite direction.
Seeking to track the movements of the inner core, new research published in the journal Nature Geoscience analyzed seismic waves from repeated earthquakes over the past six decades. The authors of the study, Xiaodong Song y Yi Yangfrom Peking University in China, discovered that the rotation of the inner core “almost stopped around 2009 and then turned in the opposite direction“.
“We believe that the inner core rotates, relative to the Earth’s surface, from side to side, like a seesaw.“said the study authors.
“An oscillation cycle is approximately seven decades“, meaning it changes direction about every 35 years, they added. The previous one changed direction in the early 1970s, and they predicted the next change in direction would be in the mid-2040s.
Earth’s interior is composed of 4 layers, 3 solid & one liquid -not magma but molten metal- nearly as hot as the surface of the sun. The deepest layer is a solid iron ball, about 1,500 miles (2,400 km) in dia.
Above the inner core is the outer core, a shell of liquid iron pic.twitter.com/3hFrQM9kxe— loveworld (@LoveWorld_Peopl) January 24, 2023
The researchers said this rotation roughly aligns with changes in what’s called “day length,” small variations in the exact time it takes Earth to spin on its axis.
Few noticeable effects
So far there is little to indicate that what the inner core does has much effect on the surface dwellers. But the researchers said they believed there were physical links between all of Earth’s layers, from the inner core to the surface.
The Earth slows down, but everything remains (almost) the same.
researchers of the @IGeociencias explain why the speed of rotation of the Earth’s core is reduced.
️https://t.co/zn3mM1l3od pic.twitter.com/kuBf3ljzXk— CSIC (@CSIC) January 24, 2023
Some experts who did not participate in the study expressed caution about their findings, pointed to several other theories and warned that many mysteries remain about the center of the Earth. Another working theory suggests that Earth’s inner core could have another iron ball inside, like a Russian dollcomplicating the multidecadal variations of the rotation of the terrestrial nucleus or nuclei.
Reference
Yi Yang et al, Multidecadal variation of the Earth’s inner-core rotation, Nature Geoscience (2023). DOI: 10.1038/s41561-022-01112-z
Texts from Phys.org – Nature