Rocky, metallic, or icy bodies with no atmosphere. Left over from the time of planetary formation.








The size and shape of asteroids vary, ranging from small rubble piles under a kilometer across to Ceres, a dwarf planet almost 1000 km in diameter.










The greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4x the Sun-Earth Distance from the Sun, in a region known as the main asteroid belt.