One of the largest craters in our Solar System is found on the far side of the Moon’s south pole and it’s called Aitken basin. While it was previously thought that a large impact billions of years ago caused the crater, scientists now say that it couldn’t have been created by a meteor.
The gigantic oval-shaped crater that’s nearly the size of the United States is leaving scientists completely baffled as to how it got there. The crater has a depth of 8.1 miles, making it approximately six times deeper than it is wide.
The original theory was that a huge, fast meteor slammed into the Moon billions of years ago which caused huge chunks of the lunar’s mantle to be thrown across its surface. However, a new study conducted by the Chinese seemingly disproves that theory.
When China’s Yutu-2 Moon rover landed in the Aitken basin in January, it collected six soil samples from the bottom of the crater. After analyzing them, the researchers believe that the soil samples were made up of crust and not from the Moon’s mantle. If their theory is correct, it would mean that the meteor that created Aitken basin did not hit hard enough to cause parts of the mantle to be scattered across the lunar surface.
“We are not seeing the mantle materials at the landing site as expected,” stated Dr. Hao Zhang, who is a planetary scientist at the China University of Geosciences. Their research has been published in the journal Geophysical Research Letters which can be read in full here.
Had the Moon been hit by a large, fast meteor, chunks of the mantle would still be scattered across the lunar surface even to this day. But since scientists are arguing that theory, what do they think caused Aitken basin?
Researchers have not given an alternate explanation as to what caused the gigantic crater, but the idea of a meteorite colliding with the Moon is the most likely reason. Instead of a full on impact to the Moon, the meteorite could have grazed the lunar surface hard enough to cause a crater but not so hard as to cause chunks of the mantle to be thrown across the surface.
This isn’t the only question surrounding Aitken basin, as just a few months ago, it was announced that a large chunk of metal five times bigger than Hawaii’s Big Island had been discovered embedded in the crater.