December 4, 2023

The research team makes an amazing discovery in the Earth’s inner core

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The earth consists of different layers. From outside to inside: crust, mantle (upper and lower), outer core, and inner core. (Avatar) © IMAGO/ Simsek

High temperatures and enormous pressure ensure that the Earth’s inner core is solid – according to popular theory. But this appears to be only partly true.

AUSTIN – There is no other place on Earth where temperatures and pressures are as high as these. Pressure squeezes the iron atoms inside the Earth tightly together, creating a solid inner core. But even under these extreme conditions, there is still room for movement, as a research team now shows.

Researchers from the USA and China found that certain groups of iron atoms in the Earth’s inner core can move quickly. They appear to be able to switch positions in a fraction of a second while maintaining the basic metal structure of iron. This type of movement is known as “mass movement”. In everyday life, you can see them in flocks of birds or herds of animals, but also in crowds or in car traffic.

The atoms in the Earth’s inner core can move at surprising speeds

Back to the Earth’s core: Researchers cannot study it directly because it is very hot inside the Earth and the pressure is very high. But using laboratory tests and theoretical models, the research team still found evidence that atoms in Earth’s inner core move much more than previously thought. These findings could help understand a number of interesting properties of the Earth’s core that have long puzzled scientists, such as how the Earth’s magnetic field is created.

“We now know the basic mechanism that will help us understand dynamic processes and evolution in the Earth’s interior,” says Jong-Fu Lin (University of Texas), one of the lead authors of the study. In the specialized magazine Proceedings of the National Academy of Sciences published had become.

A miniature version of the Earth’s core showing the “collective motion” of iron atoms

To reach this conclusion, the US-Chinese team recreated a miniature version of the Earth’s core in the laboratory. The first step was to fire a small iron plate with a fast-moving projectile. The researchers obtained data on temperature, pressure and speed, which was then entered into a computer model that uses machine learning to simulate atoms found in the Earth’s interior.

With the help of artificial intelligence, a “supercell” of about 30,000 atoms was created in the computer, which the research team has now used, among other things, to predict the properties of atoms more accurately. What the team observed was unexpected: groups of atoms moved and swapped places, while the basic hexagonal structure of the atoms was preserved.

Inside the Earth there is a solid inner core surrounded by a liquid core.  (archive photo)
Inside the Earth there is a solid inner core surrounded by a liquid core. (Archive photo) © dpa/EUMETSAT

The Earth’s inner core is softer and more flexible than research predicts

This unexpected movement of atoms could explain why seismic measurements of the Earth’s inner core show it to be softer and more elastic than expected at high pressures. says the research team. Recently, another research team suggested that liquid iron may be trapped in the Earth’s inner core.

“Our big discovery is that solid iron deep inside the Earth becomes surprisingly soft because its atoms can move much more than we can imagine,” explains Yujun Zhang (Sichuan University), co-author of the current study. “This increased movement makes the inner core less rigid and weaker.” In front of shear forces. (unpaid bill)