In a recent article, Frédéric Moynier, a cosmochemist at the Institut de Physique du Globe de Paris (IPGP), delved into one of the long-standing mysteries of lunar geology: the striking difference between the Moon’s two faces. For decades, scientists have been trying to understand why the far side of the Moon has a thicker crust and different geological features compared to the near side.
Several hypotheses have been proposed to explain this disparity. Moynier and his colleagues at IPGP suggest that the asymmetry could be linked to events that occurred when the Moon was still a molten ball of magma, located close to Earth. During this phase, volatile elements like water and certain metals such as potassium existed in a gaseous state. These elements might have evaporated more rapidly on the near side of the Moon, leading to distinct geological differences between the two faces.
Other, more audacious theories propose that two moons could have coalesced following the giant impact that created our satellite. However, Moynier favors the hypothesis related to the evaporation of volatile elements, an approach supported by isotopic measurements taken from lunar samples.
These findings may be further clarified by new samples from the Chang’e 6 mission, which could help settle the debate between the different theories.
The full article can be found in Science et Avenir, October 2024 edition.