NASA’s Dawn spacecraft has returned new images of the surface of the giant asteroid Vesta, highlighting unusual geologic features, some of which were never previously seen on asteroids.
Vesta is one of the brightest objects in the solar system and the only asteroid in the so-called main belt between Mars and Jupiter visible to the naked eye from Earth.
Dawn has found that some areas on Vesta can be nearly twice as bright as others, revealing clues about the asteroid’s history, according to the mission’s website.
“Our analysis finds this bright material originates from Vesta and has undergone little change since the formation of Vesta over 4 billion years ago,” said Dr. Jian-Yang Li, a Dawn scientist at the University of Maryland. “We’re eager to learn more about what minerals make up this material and how the present Vesta surface came to be.”
Bright areas appear everywhere on Vesta but are most predominant in and around craters. The areas vary from several hundred feet to around 10 miles (16 kilometers) across. Rocks crashing into the surface of Vesta seem to have exposed and spread this bright material. This impact process may have mixed the bright material with darker surface material.
The dark materials on Vesta can appear dark gray, brown and red. They sometimes appear as small, well-defined deposits around impact craters or as larger regional deposits, like those surrounding the impact craters scientists have nicknamed the “snowman.”
“One of the surprises was the dark material is not randomly distributed,” said Dr. David Williams, a Dawn scientist at Arizona State University. “This suggests underlying geology determines where it occurs.”
Vesta’s dark materials suggest the giant asteroid may preserve ancient materials from the asteroid belt and beyond, possibly from the birth of the Solar system.
“Dawn’s ambitious exploration of Vesta has been going beautifully,” said Dr. Marc Rayman, Dawn chief engineer at NASA’s Jet Propulsion Laboratory in Pasadena. “As we continue to gather a bounty of data, it is thrilling to reveal fascinating alien landscapes.”