A mysterious large mass of material
has been discovered beneath the Moon's South Pole-Aitken basin, the largest crater in our solar system.
The crater, thought to have been created about 4 billion years ago, is oval-shaped and as wide as 2,000 kilometers (roughly the distance between Waco, Texas, and Washington, D.C.) and several miles deep. Despite its size, it cannot be seen from Earth because it is on the far side of the Moon.