NASA moon probes make detailed gravity map

NASA says its twin probes orbiting Earth's moon have generated the highest resolution gravity field map of any celestial body. The new map, created by the Gravity Recovery and Interior Laboratory (GRAIL) mission, is giving scientists clues to the moon's internal structure and composition in unprecedented detail, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Wednesday. Features never before seen in detail include tectonic structures, volcanic landforms, basin rings, crater central peaks and numerous simple, bowl-shaped craters, JPL scientists said. Data from the two washing machine-sized GRAIL spacecraft also shows the moon's gravity field is unlike that of any terrestrial planet in our solar system, they said. "What this map tells us is that more than any other celestial body we know of, the moon wears its gravity field on its sleeve," GRAIL Principal Investigator Maria Zuber of the Massachusetts Institute of Technology in Cambridge said. "When we see a notable change in the gravity field, we can sync up this change with surface topography features such as craters, rilles or mountains." Gravity data from the GRAIL mission could also provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved, scientists said.