NASA has collected evidence that the topography of the Oceanus Procellarum region of the moon believed to be the result of an asteroid impact may have been caused instead by the formation of rift valleys.
The GRAIL gravity data showed the rifts that were buried under volcanic plains, which were mostly undetected from previous surface observations, NASA said.
“We interpret the gravity anomalies discovered by GRAIL as part of the lunar magma plumbing system ““ the conduits that fed lava to the surface during ancient volcanic eruptions,” said Maria Zuber, principal investigator for the GRAIL mission from the Massachusetts Institute of Technology.
NASA also pointed to another theory centered on underground churning that brought radioactive elements near the surface, leading to the revealed rectangular pattern of gravitational anomalies.
The agency noted that this pattern, similar to those found in Saturn’s moon, disputes the original theory of asteroid impact, as the latter would result in a circular impact basin.
“More work is needed to understand the cause of this newfound pattern of gravity anomalies, and the implications for the history of the moon,” said Jeff Andrews-Hanna, a co-investigator from the Colorado School of Mines.
The team’s findings have been published online in the Nature journal.