Earth, with its crust, mantle and inner core, is a perfect example of this process, known as differentiation. Because the stretch of Eros analyzed by the XGRS is undifferentiated, or not layered, and has a chemical composition similar to a chondritic meteorite, the XGRS team concluded that the asteroid could be a very primitive body in the history of our solar system. If more data confirm Eros is primordial, Eros will be a link between the chondrite meteorites found on Earth and the history of the solar system's formation. The Eros asteroid could be a chunk of the stuff from which the planets were made that hasn't been modified since it was formed. The irregular shape of Eros creates unique visual effects, especially in the absence of atmosphere.
Dark shadows appear nearly as black as space.
Eros is not an old piece of planet where differentiation took place, said Squyres. But the team has not ruled out the possibility that the asteroid was at one time part of a larger body that somehow split into smaller pieces. The recent discovery on Eros could also shed light on the relationship between asteroids and meteorites. Most meteorites that have fallen to Earth were once part of an asteroid, according Squyres. If scientists can learn enough about an asteroid such as Eros, they may be able to identify meteorites that are the same chemical composition.