Shape-shifting satellite: scientists reveal the secret of lunar anomalies

Scientists have been able to explain some of the "wonders" of the Earth's satellite that have been occupying their minds for several decades. Using simulation and computer modeling techniques, researchers have found confirmation of an amazing hypothesis. Now they claim that at the dawn of its existence, the Moon literally "turned inside out".

This was reported by SSPDaily.

The surface of the Moon is chemically asymmetrical, which may be the result of a mantle overturn at a time when the Moon was still a very young celestial body. As a result, those layers that were on the surface of the Earth's satellite went deeper, and the lower layers of the mantle came out.

This hypothesis was first expressed several decades ago, but until now, scientists have not been able to either confirm or deny it. Advances in technology have finally allowed a team of researchers led by planetary scientists Weigang Liang and Adrien Broquet from the University of Arizona to obtain new evidence supporting this amazing phenomenon. The researchers found that the mantle flip model best explains the Moon's gravity map and its anomalies.

In particular, by conducting a series of simulations, the team of scientists showed how gravitational anomalies on the near side of the Moon are consistent with the presence and location of dense rocks and minerals that were formed in the early days of the celestial body.

Moreover, the researchers were able to pinpoint exactly when this upheaval occurred: about 4.22 billion years ago, shortly after the Moon formed from a piece of the Earth that broke off during a violent collision early in the history of the solar system.

One of the most unusual features of the Moon is related to its surface. On the near side of the Moon, there is an area called "geochemically weird". It is known as the "KREEP terrane" and is rich in specific and unexpected metals: potassium, rare earth elements, and phosphorus.

The KREEP terrane also intersects with the lunar seas, which are large basalt plains formed as a result of volcanic activity. The basalt contains many accumulations of ilmenite (IBC), a very dense mineral consisting mainly of titanium and iron.

This has long puzzled scientists because there are much less dense rocks under this layer. Under normal conditions, it should have been the other way around: denser rocks in the depths and less dense rocks on the surface.

This strangeness can be explained by geodynamic processes in the young Moon. At that time, its surface was covered by an ocean of molten magma, which gradually cooled to form the crust and mantle. At the end of this process, dense minerals such as ilmenite formed in the layer between the crust and mantle, and the terrane-KREEP elements concentrated in a liquid reservoir.

Subsequently, the dense minerals settled closer to the Moon's core, where they heated up and rose to the surface as a result of volcanic activity, overturning the mantle.

The picture obtained by the lunar mantle overturning model corresponded to the map of surface gravity on the Moon. This map was based on observations collected by NASA's Gravity Reconnaissance Imaging Lunar Imager (GRAIL). The modeling also allowed us to determine when the turn took place: at least 4.22 billion years ago.

"Thus, the lunar gravitational field holds important data on the lunar mantle upheaval, which was a defining event in the early history of the Moon, but its details have remained unknown until now," the researchers said.

As a reminder, the Moon turned out to be 40 million years older than previously thought. This was made possible by a recent analysis of lunar soil delivered by the last Apollo mission in 1972.