It was once believed that the asteroids were the remains of a planet that was destroyed by a collision or some other tragedy. Astronomers now believe that these are the remnants of a planet that never was. At the distance of the asteroid belts, it would be difficult for a planet to form because of the gravitational interference of Jupiter. The asteroids are planetesimals which hattered and broken each other by collisions.
This theory would explain why the silicate rich asteroids are concentrated in the inner belts, and the carbonaceous type asteroids are in the outer belts. In the cooler outer regions, carbonaceous material would form more easily than in the inner belts.
The largest asteroids probably developed a molten core and differentiated while cooling. These fragments are the oldest remnant of the early solar system and may hold many secrets as to the orgins of the planets and moons.
Copyright © 1997 Kathy A. Miles and Charles F. Peters II