For a long time, it was believed that the Moon is similar in composition to the Earth, but a new discovery refutes this theory. After examining the surface of the Moon's largest crater, the South Pole Basin - Aitken, researchers from Purdue University discovered that the celestial body's mantle is composed mainly of orthopyroxene, not olivine, as previously thought.
The largest crater on the moon was formed about 4 billion years ago when a huge asteroid collided with it. As a result of the collision, the lunar mantle was exposed and the substance contained in it was thrown out at the place of impact on the far side of the moon.
Scientists decided to find out what minerals are in the substance ejected during the collision. To do this, the researchers analyzed the characteristics of sunlight reflected from the surface.
Experts also carried out computer simulations, which were supposed to show how the release of substances of different composition would occur. It turned out that if the upper mantle of the Moon were composed mainly of olivine, then its spectral signature would be visible at high elevations of the Earth's satellite. Instead, scientists have found large amounts of orthopyroxene in the highlands and in the South Pole-Aitken Basin. Olivine is also present in the area, but it is not the predominant component.