WASHINGTON, Dec. 5, 2012 /PRNewswire-USNewswire/ -- Twin NASA probes orbiting the moon have generated the highest resolution gravity field map of any celestial body. (Logo: http://photos.prnewswire.com/prnh/20081007/38461LOGO) The new map, created by the Gravity Recovery and Interior Laboratory (GRAIL) mission, is allowing scientists to learn about the moon's internal structure and composition in unprecedented detail. Data from the two washing machine-sized spacecraft also will provide a better understanding of how Earth and other rocky planets in the solar system formed and evolved. The gravity field map reveals an abundance of features never before seen in detail, such as tectonic structures, volcanic landforms, basin rings, crater central peaks, and numerous simple, bowl-shaped craters. Data also show the moon's gravity field is unlike that of any terrestrial planet in our solar system. These are the first scientific results from the prime phase of the mission, and they are published in three papers in the journal Science. "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," said GRAIL principal investigator Maria Zuber of the Massachusetts Institute of Technology in Cambridge. "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." According to Zuber, the moon's gravity field preserves the record of impact bombardment that characterized all terrestrial planetary bodies and reveals evidence for fracturing of the interior extending to the deep crust and possibly the mantle. This impact record is preserved, and now precisely measured, on the moon. The probes revealed the bulk density of the moon's highland crust is substantially lower than generally assumed. This low bulk crustal density agrees well with data obtained during the final Apollo lunar missions in early 1970s, indicating that local samples returned by astronauts are indicative of global processes.