Two searches dispatched by NASA will study the moon’s internal structure in unmatched detail, flaking light on whether a second moon crashed into it long ago.
The searches, together called GRAIL (Gravity Recovery and Interior Laboratory), lifted off on Saturday at 0908 EDT from Cape Canaveral Air Force Station in Florida, New Scientist reported.
After they reach the moon in about four months’ time, the searches will measure slight variations in the strength of the moon’s gravity, which isn’t uniform due to the uneven distribution of matter inside it.
Overseeing the distance between them will produce lunar gravity maps with at least 100 times the resolution of previous measurements, including maps made by Japan’s Kaguya mission.
Lumpiness exposed by the maps should reveal more about the moon’s history, since it is thought to represent scarring from past impacts.