Scientists discover mysterious differences between the two sides of the Moon

Scientists from the American University of Arizona have revealed important details of the hidden and less known side of the Moon that would explain some of the huge and enigmatic differences between the two sides of the only natural satellite of the Earth.

Also that the crater caused by the largest impact recorded on that side, the one caused by a giant asteroid approximately 4.3 billion years ago (when the Solar System was still in its infancy) left a radioactive eruption. Now they publish the results of their work in the magazine Nature.

When astronauts land near the lunar south pole as part of the Artemis program in a few years, they will likely come across an «unexpected» trove of clues that the authors of this research say could help scientists better understand how Earth’s only natural satellite formed.

Detailed topography of the visible side (left) and far side (right) of the Moon (NASA/LRO).

The study published today also provides, its authors maintain, a snapshot of the Moon’s tumultuous past that could help explain some of the oldest enigmas, including why the far side, riddled with cratersis so different from the closest side, on which the Apollo missions landed between 1960 and 1970.

A giant asteroid collided with the Moon

Approximately 4.3 billion years ago, a giant asteroid hit the far side of the Moon, creating a huge crater known as the South Pole-Aitken Basin (SPA), and this impact formation is the largest crater on the satellite, spanning more than 1,930 kilometers from north to south and 1,600 kilometers from east to west, and researchers have concluded that the oblong shape (longer than wide) of the basin is the result of a glancing impact, rather than a frontal impact, and that this impact did not come from the south, as previously believed, but from the north.

This means, they have confirmed in their work, that the Artemis missions will land on the lower edge of that basin, and that this could be the best place to study the largest and oldest impact recorded on the Moon, a place where most of the ejecta and materials from the depths of the satellite’s interior should accumulate.

A view of the hidden face (EFE).

It has long been believed that the early moon was melted by the energy released during its formation, creating a magma ocean that completely covered it, and as this magma ocean crystallized, heavy minerals sank to form the lunar mantle, while light minerals floated to form the crust.

But some elements were excluded from the solid mantle and crust, concentrating in the final liquids of the magma ocean, and those residual elements included potassium, rare earths and phosphorus, particularly abundant on the moon’s near side.

All this material and the heat generating elements were concentrated in some way on the visible side of the Mooncausing its heating and giving rise to intense volcanism that formed the dark volcanic plains that make up the usual image of the face of the Moon visible from Earth, but the explanation of how these elements arrived on that side and how they evolved over time has been a mystery.

The asymmetry of the Moon has also baffled scientists for years, and researchers now point out that as the crust was thickening on the opposite side, the magma ocean below was expelled to the sides, and they trust that the samples that the next Artemis missions can bring to Earth will be decisive in learning more details about the evolution of the satellite.

EFE Agency.

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