Scientists have discovered a huge, mysterious mass hidden underneath the moon’s largest crater, but are still unsure what it is.
The mass in question, which is buried hundreds of miles underneath the moon’s South Pole-Aitkin basin, is roughly five times the size of Hawaii’s Big Island, according to a release published Monday by Baylor University.
In a study published this year, astronomers say the mass could contain metals from an asteroid that crashed into the moon and created the crater about 4 billion years ago.
“We did the math and showed that a sufficiently dispersed core of the asteroid that made the impact could remain suspended in the Moon’s mantle until the present day, rather than sinking to the Moon’s core,” a release quotes the study's lead author, Peter B. James, assistant professor of planetary geophysics at Baylor’s College of Arts & Sciences.
Astronomers at the university say another explanation for the mass could be the accumulation of dense oxides associated with a natural process called lunar magma ocean solidification.
James says the basin where the mass was found is “one of the best natural laboratories for studying catastrophic impact events.” It’s about 1,200 miles wide, which is roughly the distance between Waco, Texas, and Washington, D.C.
This article originally appeared on USA TODAY: The moon’s largest crater is hiding something huge, but astronomers aren’t quite sure what