Revealing the secret of the Earth’s core – DW – 09/10/2023

Under the surface of the Earth, at a depth of about 5,100 kilometers, a mysterious secret hides in the heart of solid iron that is not at all similar to what we imagined.

Researchers have recently made amazing advances in understanding the inner core. For example, they revealed that the nucleus is not a uniform sphere, but rather has a complex texture, and surprisingly, it stops rotating every seven decades before changing direction.

Now, in a pioneering study conducted by the University of Texas at Austin in collaboration with Chinese scientists, it has been revealed that the Earth’s inner core may be less solid than previously expected. this studio, Published in the magazine Proceedings of the National Academy of Sciences (Bnas), Based on laboratory experiments and theoretical models, it suggests that this unusual flexibility can be attributed to hyperactive atoms moving more quickly within their molecular structure.

The “collective movement” of atoms in the Earth’s inner core

Specifically, the study revealed that certain groups of iron atoms in the inner core, despite being subjected to astronomically high pressures, the highest on the entire planet, are able to change their location in the blink of an eye, while maintaining the basic metallic structure. Of iron. This phenomenon is called “mass movement” and is similar to the way people change seats at the table, he says Press release from the University of Texas at Austin.

“Solid iron becomes surprisingly soft inside the Earth because its atoms can move much more than we imagine,” explained Yujun Zhang, a physicist at Sichuan University (China). He added: “This greater movement makes the inner core less rigid and weaker to shear forces.”

Geodynamics and magnetic field of the planet

These findings could shed light on ancient mysteries related to the inner core and its role in Earth’s geodynamics, the process that drives the planet’s magnetic field.

According to the researchers, about half of the geodynamic energy contributing to the Earth’s magnetic field comes from the inner core, while the rest comes from the outer core. This new knowledge about atomic-level activity in the inner core could provide a solid foundation for future research on energy and heat generation in the inner core, their relationship to the dynamics of the outer core, and their joint contribution to the formation of the inner core. Field: Earth’s magnetic field, which is a critical element of the planet’s habitability.

“We now know the basic mechanism that will help us understand the dynamical processes and evolution of the Earth’s inner core,” said Jong-Fu Lin, a professor at the University of Texas Jackson School of Geosciences and one of the study’s lead authors. .

“What we found is completely contrary to the conventional view,” Lin said. Newsweek. “I’ve just found the answer to the holy grail of geophysics,” he added.

Default kernel: “supercell”

To reach these conclusions, the researchers conducted high-pressure experiments in a laboratory environment, as obtaining direct samples from the inner core is impossible due to the extreme temperature and pressure conditions in that region. They then used artificial intelligence algorithms to develop a computer simulation called a “supercell,” which allowed them to examine the behavior of iron atoms under these extreme conditions.

In the past, scientists used to simulate the Earth’s inner core using computer models focusing on fewer than a hundred atoms arranged in a repeating hexagonal structure. However, thanks to the use of artificial intelligence algorithms, according to the statement, the researchers were able to significantly increase the number of atoms in their simulation, thus creating a “supercell” consisting of about 30,000 atoms. This approach allowed for more accurate prediction of the properties of iron in the inner core.

“This discovery suggests that the same physics in mass motion also occurs in the interiors of other planets, such as Mars and the exoplanets,” Lin said. Newsweek. “Exoplanets are exposed to extreme conditions of pressure and temperature, so the research conditions must be expanded to see if this happens. This will help us understand planetary systems in general,” he concluded.

Edited by Felipe Espinoza Wang.