Man in the Moon 'was produced by magma'
The famous flattened image across the moon's surface - dubbed the Man in the Moon - may have been created by the moon's 'plumbing system'.
The mystery behind the 1,800-mile-wide section of the Procellarum basin has been a long-running puzzle among scientists who have previously claimed it may have been caused after an asteroid crash.
The latest research, published in the journal Nature, suggests it may have been caused by a large plume of magma deep inside the moon coming up towards the surface.
Using data obtained from Nasa's Grail mission, the research team from MIT and the Colorado School of Mines have created a high-resolution map of the Procellarum.
They found that its border is not circular, but polygonal and made up of sharp angles that could not have been created by a massive asteroid.
They believe the angular outline was produced by tension cracks in the moon's crust as it cooled around an upwelling plume of hot material.
Maria Zuber of MIT said that as cracks occurred they formed a "plumbing system" in the moon's crust through which magma could meander to the surface.
Magma eventually filled the region's smaller basins, creating what we see today as dark spots on the near side of the moon.
These are the features that have inspired the idea of a man in the moon.