The Procellarum region of the lunar surface -- the moon's largest basin and the feature commonly referred to as the "man in the moon" -- was likely created by a giant volcano. It is not result of an asteroid impact, as many scientists have previously suggested.
Using new data collected by NASA's GRAIL mission, a team of researchers -- including scientists from the Colorado School of Mines and MIT -- were able to generate a high-resolution map of the Procellarum region. In doing so, the researchers came to realize that the region's border is not circular, but polygonal, featuring jagged 120 degree angles that rule out the possibility of an asteroid impact.
Instead, researchers think the sharp edges and angles are massive tension cracks created as the moon's crust cooled in the aftermath of a volcanic episode -- scarring left by a prodigious upwelling of molten material, oozed from deep below the lunar surface. Once formed, the cracks also acted as release valves, allowing magma to rise to the surface and sink into the basin -- pooling in the many smaller depressions contained within. The cooling magma, scientists say, filled in much of the basin and created the region of dark spots we now know as the man in the moon.
"A lot of things in science are really complicated, but I've always loved to answer simple questions," Maria Zuber, an MIT geophysicist and principal investigator for the GRAIL mission, said in a press release. "How many people have looked up at the moon and wondered what produced the pattern we see -- let me tell you, I've wanted to solve that one!"
The research team created a mathematical model to recreate the dynamics of an ancient volcanic plume on the moon; their results matched the data gathered by NASA's GRAIL mission. Sill, scientists say confirming the presence of an ancient volcanic plume would likely require another manned mission to the moon.
But even if the new data can't confirm their new volcanic theory, researchers remain excited by their latest efforts and the data that made it possible.
"GRAIL has been a fantastic mission, and this data will be continually used and reinterpreted as we get more data back from the moon," said researcher Clive Neal, a professor of civil and environmental engineering and earth sciences at the University of Notre Dame. "I don't think we've seen the last of this data by a long shot."
The study of the moon's Procellarum region was published this week in the journal Nature.