GRAIL reveals a battered lunar history
Beneath its heavily pockmarked surface, the moon’s interior bears remnants of the very early solar system. Unlike Earth, where plate tectonics has essentially erased any trace of the planet’s earliest composition, the moon’s interior has remained relatively undisturbed over billions of years, preserving a record in its rocks of processes that occurred in the solar system’s earliest days.Now scientists at MIT, NASA, the Jet Propulsion Laboratory and elsewhere have found evidence that, beneath its surface, the moon’s crust is almost completely pulverized. The finding suggests that, in its first billion years, the moon — and probably other planets like Earth — may have endured much more fracturing from massive impacts than previously thought. The startling observations come from data collected by NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission. Since March, the mission’s twin spacecraft, named Ebb and Flow, have been orbiting the moon and measuring its gravitational field. From...