Free Astronomy Magazine November-December 2014

MOON 40 NOVEMBER-DECEMBER 2014 That all lunar maria were huge expanses of solidified lava flowed out on the surface as a result of asteroids falling on our satellite, seemed an established fact. Instead, the pro- cessing of data obtained from the GRAIL mis- sion shows that the largest of those lunar maria formed in a totally different manner. Oceanus Pr wasn’t caus by an impac I n the universe even the most obvious things may not be as they seem, and also the most familiar celestial bodies can hide unexpected truth. This is in fact the case of the Moon that in recent years, thanks to a series of new automatic mis- sions, has revealed surprising geological and evolutionary aspects, depicting more dynamic and varied scenarios than those taken for granted until recent times. The last unexpected discovery basically con-