Asteroid geology

In recent years we have put together an ever-better picture of how the planets formed—only the intermediate stage of protoplanets was missing examples. But now it is apparent that at least three of the largest asteroids (Ceres, Pallas and Vesta) may be intact protoplanets, left over from the solar system's genesis. Vesta has been called "the smallest terrestrial planet." Asteroid geology is a promising field, and to explore Ceres and Vesta the Dawn spacecraft mission is set to launch on 8 July.

_{Model of asteroid Pallas — NASA image}