Science News: The first full lunar gravity map from NASA’s Gravity Recovery and Interior Laboratory (GRAIL) has revealed the Moon’s violent history. The new GRAIL map is the most detailed gravity map ever created, and is 1000 times as precise as previous maps of the Moon. One of the most significant findings is that the lunar crust is 10–20 km thinner than expected, averaging just 34–43 km in thickness. The map has also revealed buried formations several hundred kilometers long that were created by molten rock. Jeffrey Andrews-Hanna from the Colorado School of Mines says that these were caused by cracks in the crust during the early part of the Moon’s existence. At that time, the surface was hotter than the interior, which caused the crust to expand and the cracks to form, with molten rock from below filling the space. GRAIL‘s primary mission is now over. The twin probes are orbiting lower and lower for additional readings in specific areas; they will then crash into the Moon’s surface.