A small, mostly rocky body orbiting the Sun. Asteroids range in size from 1000 kilometers in diameter to tiny objects you could hold in your hand. Most asteroids orbit the Sun between Mars and Jupiter (the Asteroid belt), and are the source of most meteorites. Principal asteroids are: 1 Ceres (a dwarf planet), 2 Pallas, 3 Juno, and 4 Vesta. The majority of asteroids fall into three types: C-type (carbonaceous), S-type (silicate or stony), and M-type (metallic).