However, the reasons for this still remain a mystery. Perhaps they were numerous asteroid strikes.
American scientists have experimentally shown that the modern surface of the Moon has an extremely unusual composition. It can only be explained by the fact that after the formation of the satellite, its crust was somehow re-melted for a long time. Until now, it was believed that the surface of the Moon remained stable throughout its history (after a period of formation). A related article was published in the Journal for Geophysical Research: Planets.
The authors of the new work conducted experiments with minerals similar in composition to those found on the Moon. They melted plagioclase (the main component of the lunar surface) with other, more refractory minerals and watched them quickly sink through the plagioclases. It turned out that this does not happen as previously thought - the particles of other minerals do not have time to completely sink before the plagioclase solidifies. As a result, he must include them in his composition.
The experimental data are at odds with observations according to which the surface of the moon is 98 percent composed of fairly pure plagioclase. And this means that the previously proposed model does not correspond to reality, according to which pure plagioclase covers the Earth's satellite due to the fact that all the heavier minerals in it drowned even during the formation of the lunar surface.
The researchers speculate that plagioclase on the Moon is so clean today because it underwent a second melt after the moon was formed. This made it possible to cleanse the outer layers of the celestial body from impurities. It is more difficult to answer the question of what could melt the Moon again. In theory, it itself does not have the geological activity necessary for this. Probably, it could have been replaced by the fall of a significant number of asteroids close to each other in time.
IVAN ORTEGA