And as for how it got there, they're pointing the finger at whatever created the basin in the first place.
James and his colleagues suggest that one possible explanation for the underground material is that it's the remains of a massive asteroid that slammed into the moon soon after its formation, causing the giant impact crater still visible today. The Moon's circumference is roughly 11,000 kilometers. Instead of sinking down into the moon's interior, it remained buried in the moon's mantle. The Lunar Reconnaissance Orbiter has spent almost 10 years at work and has made billions of measurements of the precise height of the moon's surface.
This illustration details the structure of the moon. "While larger impact events undoubtedly occurred throughout the solar system during planetary accretion, most indications of these events were erased through subsequent bombardment and thermally induced viscous relaxation". One is the Lunar Reconnaissance Orbiter, which continues to constantly photograph the lunar surface and has led to high-definition surface elevation maps. But because of plate tectonics and weather, there's no evidence of it. No, it isn't a lost lunar Atlantis built by ancient aliens, but more likely the remnant of a colossal collision that formed the largest crater in the solar system. If that's true, it could be a time machine - and a gold mine - for scientists studying the history of the universe. Yet its size and the fact that the anomaly appears to be located about 186 miles (300 km) down also offers scientists an intriguing idea: the moon's insides can't be all that gooey; if they were, the moon's gravity would pull the massive patch into the lunar centre.
"I know all the cool spots to go to", she said with a laugh.
Just last month, researchers released data showing that China's Chang'e-4 mission to the far side, which explored part of the basin in January, may have found rocks from the moon's mantle on the surface, which could give scientists new insights into the processes that formed the moon. Nothing bad has come of the worms being revived (yet) and 'Oumuamua has already fucked right off, presumably never to be seen again by us, without having deposited any alien invaders - but at the very least they gave us some fun, ominous headlines.
The research relied on two key missions in NASA's moon-exploration list.
While this new research is an important step, Byrne said he'd like to see landers, or people, go to the region to study it, as it's important to understanding our local planetary neighbourhood.
Before you go imagining a mysterious subterranean civilization of Moon Men hiding out below the lunar surface, that's not exactly what scientists have in mind.