New research is out today shaking up the debate about what caused the Oceanus Procellarum, also known as ‘ocean of storms,’ feature on the Moon. Researchers have reached different conclusions about what caused the feature for years. New NASA data supports one theory, in particular.

Magma, Not Asteroids

Researchers from the Massachusetts Institute of Technology, Colorado School of Mines and other institutions believe magma created the vast dark patch visible on the western edge of the Moon’s near side.


The team collected gravity data from NASA’s GRAIL probes orbiting the moon back in 2012. With it, they created a map of the Procellarum region, where the feature is located. They found the rims of the basin were more angular than circular or elliptical (what you would typically see from asteroid impacts).

Topographic moon image

A topographic map of the moon showing variations in elevation. Purple is low, red is high. The Oceanus Procellarum lies in the purple region and shows extensive lava flows.

This discovery prompted the team to think of other reasons for the formation of the ‘ocean of storms.’

“This shape argues strongly for an internal origin and suggests internal forces,” said Jim Head, one of the authors of the paper.

The researchers believe that a large plume of molten magma surged upward from the lunar interior to where the Procellarum region is today. The magma then cooled and contracted forming the ‘craters’ we see today.

“How such a plume arose remains a mystery,” said Professor Maria Zuber of MIT in another press release. “It could be due to radioactive decay of heat-producing elements in the deep interior. Or, conceivably, a very early large impact triggered the plume. But in the latter case, all evidence for such an impact has been completely erased. People who thought that all this volcanism was related to a gigantic impact need to go back and think some more about that.”

It looks like the impact hypothesis has been completely thrown out the window with this new paper. Still, more needs to be understood about the moon’s interior. Specifically, any evidence of an ancient magma plume.

Featured image credit: Kopernik Observatory/NASA/Colorado School of Mines/MIT/JPL/Goodard Space Flight Center

Post image credit: Jay Dickson/Brown University