Usually when someone on the internet writes about ‘geometric forms’ found on the Moon, it’s a crazy UFO hunter who doesn’t understand pixelation of composite images taken at high altitudes. This is different.
In 2012, led by the Massachusetts Institute of Technology, NASA launched the Grail mission, which involved two very similar satellites chasing each other around the moon while mapping it in multiple ways. Now, scientists have identified the remains of old rift valleys, once filled with lava, just beneath the moon’s surface.
The feature is centered on the moon’s Procellarum region and was undetectable before the Grail mission’s gravity mapping efforts. Now that gravity mapping has brought it to light, scientists are now seeing that it can be identified in standard photography.
“It’s really amazing how big this feature is,” says Professor Jeffery Andrews-Hanna of the Colorado School of Mines. “It covers about 17% of the surface of the Moon. And if you think about that in terms relative to the size of the Earth, it covers an area equivalent to North America, Europe and Asia combined,”.
“When we first saw it in the Grail data, we were struck by how big it was, how clear it was, but also by how unexpected it was,” said Andrews-Hanna.
“No-one ever thought you’d see a square or a rectangle on this scale on any planet,” he continued.
The researchers say some time after the moon formed and cooled a large plume of molten material rose from the lunar interior – around where Procellarum is today.
The steep difference in temperature between the magma plume and the surrounding crust caused the surface to contract over time – creating a pattern of fractures that provided a conduit for molten material to rise to the surface. The scientists tested their hyposthesis and their results matched the results generated by the GRAIL research.
Using the distances between the probes the researchers were able to determine the strength of gravity across the surface to create a highly detailed map which they then used to determine where the lunar crust thickens and thins.
Launched as GRAIL A and GRAIL B in September 2011, the probes, renamed Ebb and Flow, operated in a nearly circular orbit near the poles of the moon at an altitude of about 34 miles (55 kilometers) until their mission ended in December 2012.
The distance between the twin probes changed slightly as they flew over areas of greater and lesser gravity caused by visible features, such as mountains and craters, and by masses hidden beneath the lunar surface.
The twin spacecraft flew in a nearly circular orbit until the end of the mission on Dec. 17, 2012, when the probes intentionally were sent into the moon’s surface. NASA later named the impact site in honor of late astronaut Sally K. Ride, who was America’s first woman in space and a member of the GRAIL mission team.
GRAIL’s prime and extended science missions generated the highest-resolution gravity field map of any celestial body. The map will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved.