Today io9 has a great story up about the new GRAIL maps of the moon. There is a lot of exciting science here, but most laypeople will probably be most interested in what this means for the leading theory of the moon’s formation (aka the Big Splat):
[Says] Mark Wieczorek, GRAIL co-investigator at the Institut de Physique du Globe de Paris[,] “With this crustal thickness, the bulk composition of the moon is similar to that of Earth. This supports models where the moon is derived from Earth materials that were ejected during a giant impact event early in solar system history.”
via NASA
An animated version of the maps (Mercator projection here):
via NASA: “This movie shows the variations in the lunar gravity field as measured by NASA’s Gravity Recovery and Interior Laboratory (GRAIL) during the primary mapping mission from March to May 2012. Very precise microwave measurements between two spacecraft, named Ebb and Flow, were used to map gravity with high precision and high spatial resolution.”