New data obtained by NASA’s GRAIL mission reveals that the Procellarum region on the near side of the moon – a giant basin often referred to as the “man in the moon” – likely arose not from a massive asteroid strike, but from a large plume of magma deep within the moon’s interior.
The Procellarum region is a roughly circular, volcanic terrain some 1,800 miles in diameter – nearly as wide as the United States. One hypothesis suggested that it was formed by a massive impact, in which case it would have been the largest impact basin on the moon. Subsequent asteroid collisions overprinted the region with smaller – although still large – basins.