The interplay of bright and dark material at the rim of Marcia crater on Vesta is visible in this image mosaic taken by NASA's Dawn spacecraft. The brightness variation at Vesta is now known to be among the most extreme of the rocky bodies in the solar system. Scientists believe the bright material is uncontaminated by dark material and is native to Vesta. Credit: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA/LPI/ASU