NASA says its Dawn spacecraft has revealed unexpected details on the surface of the giant asteroid Vesta, including some never seen before on an asteroid.
Vesta is one of the brightest objects in the solar system and is visible to the naked eye from Earth, and the orbiting Dawn spacecraft has found that some areas on Vesta can be nearly twice as bright as others, giving clues to the asteroid's history, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Wednesday.
Bright areas appear everywhere on Vesta but are most predominant in and around craters, where cosmic impacts on the surface seem to have exposed and spread this bright material, researchers say.
"Our analysis finds this bright material originates from Vesta and has undergone little change since the formation of Vesta over 4 billion years ago," Jian-Yang Li, a Dawn participating scientist at the University of Maryland, said. "We're eager to learn more about what minerals make up this material and how the present Vesta surface came to be."
Darker areas of Vesta are thought to be from collisions that melted the outer crust of the asteroid, researchers said.
"Some of these past collisions were so intense they melted the surface," Brett Denevi, another Dawn participating scientist at Johns Hopkins University, said. "Dawn's ability to image the melt marks a unique find. Melting events like these were suspected, but never before seen on an asteroid."
