An unknown, mysterious mass has been found beneath a crater on the moon, according to researchers at Baylor University—and it may give scientists clues into how the moon was shaped.
The mysterious mass sits more than 300 km (186 miles) underneath the solar system’s largest crater. The crater isn’t visible to the naked eye because it’s on the far side of the moon, which always faces away from Earth.
While the researchers who discovered the mass don’t know what it is or where it came from, computer simulations suggest that, under the right conditions, a large asteroid’s iron-nickel core could have been embedded inside the moon upon impact almost 4 million years ago.
Another possibility, according to researchers, is that the mass consists of oxides left over from when the moon was changing from a large ocean of molten magma to what it is today.