They are linked to major extinction's over geological time, primarily the death of the dinosaurs. Also called minor planets, asteroids orbit the Sun at distances ranging from inside the Earth's orbit to beyond Saturn's.
Most asteroids circle the Sun in a 'main belt' that lies between the orbits of Mars and Jupiter.
Discovered at Palermo, Italy by Giuseppe Piazzi on January 1st, 1801. Ceres' orbit lies safely in the asteroid best beyond Mars. Another theory suggests that asteroids are the remains of a planet destroyed in a massive collision. However, some asteroids are thought to be extinct comets.