The Moon has one of the largest visible craters in the entire Solar System: the South Pole-Aitken basin, with a diameter of about 2,500 kilometers, present on the hidden face of the Moon. That is, the hemisphere perpetually opposite to the Earth, south of the equator. Its area has always been at the center of many investigations, and lately some scientists have identified a strange anomaly inside it, probably linked to the cause that created the crater. It is, in fact, of meteoric origin, and the body that caused its formation could still be there: in 2019, some researchers from Baylor University identified a structure with a mass of 2.18 trillion (one billion billion) kilograms and that extends for more than 300 kilometers in depth right under the large crater. The structure could be compared to a huge mass of metal, five times larger than the Big Island of Hawaii and was discovered during NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission. This observation could be used to study the internal composition of the Moon, especially considering that the asteroid that hit our satellite is dated 4 billion years old.
Source: Discovery may contain metal from asteroid crash, Baylor University researcher says, Baylor University