When you look up at a full or full-ish Moon you can’t help but notice the large dark spots that mark its Earth-facing side. These form the face of what many call the “Man in the Moon” (or the body of a Moon rabbit, to others) and are individually called mare (“MAR-ay”) which is the Latin word for sea. Early astronomers thought they were bodies of water, but in reality they are solidified dark lava flows from ancient lunar impact events that occurred several billion years ago.
One of the biggest lunar seas, Mare Imbrium (see above), had for a while been thought to have been created by the impact of an asteroid or meteorite somewhere around 50 miles across, based solely on computer models.
Now, research conducted by Brown University professor Dr. Peter Schultz—a specialist in lunar and planetary impacts—indicates that the object that formed Mare Imbrium was likely more massive and of much larger size than once thought…perhaps even as big as 190 miles wide.
NASA’s Dawn spacecraft captured this image of the asteroid Vesta while in orbit on July 18, 2011. The view looks across Vesta’s cratered and heavily-scarred south pole from a distance of about 6,500 miles.
Dawn established orbit at Vesta the morning of July 17, 2011. It will spend a year studying the large protoplanet before moving off toward the even larger asteroid Ceres. It will be the first spacecraft to enter orbit around two separate worlds in our solar system.
Image has been rotated 90º ccw and edited to enhance surface detail. See the original here.
Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA. Edited by J. Major.