Rewriting the history of the Moon. Credit: NASA
A new theory explaining the origins of the large, dark rectangular area of the Moon called Oceanus Procellarum (Ocean of Storms) has been outlined in a new paper published by Nature. Researchers Jeffrey Andrews-Hanna et al. made use of data from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission to examine the subsurface construction of the area.
Previously believed to have been created by a massive asteroid strike, Procellarum looks the way it does because of volcanic and tectonic processes, the research suggests.
Lead researcher Andrews-Hanna explained in a NASA press release:
"Our gravity data are opening up a new chapter of lunar history, during which the moon was a more dynamic place than suggested by the cratered landscape that is visible to the naked eye.
"More work is needed to understand the cause of this newfound pattern of gravity anomalies, and the implications for the history of the moon."
The paper, entitled "Structure and evolution of the lunar Procellarum region as revealed by GRAIL gravity data" concludes that "the spatial pattern of magmatic-tectonic structures bounding Procellarum is consistent with their formation in response to thermal stresses produced by the differential cooling of the province relative to its surroundings, coupled with magmatic activity driven by the greater-than-average heat flux in the region."
NASA's press release describes the area as a rift valley, caused by a process similar to the cracking of mud when it dries, although on a much larger scale. The Great Rift Valley of East Africa is a terrestrial example of a similar geological feature which occurred when the outer layer of the Earth split as a result of differential cooling.
