Thousands of small celestial bodies mostly orbiting between Mars and Jupiter. The largest is Ceres. The asteroid belt lies between the planets Mars and Jupiter in a large space where, according to the laws of astronomy, a planet ought to exist. Theories abound as to the formation of the aster- oids. The most popular of these is that they are the remnants either of a planet that exploded or of a planet that was unable to form due to the tremendous gravitational influence of gigantic Jupiter. (The "Trojans," two large groups of asteroids, do in fact lie in Jupiter's orbit and revolve around the Sun as part of Jupiter's "entourage.") Some of the asteroids have highly irregular orbits, passing even inside the orbit of Mercury at perihelion. There are literally thousands of these small bodies, ranging in size from less than a meter to several hundred kilometers in diameter. The first four were discovered between 1801 and 1807, and it was another 38 years before any others were discovered. These four, named after four Olympian goddesses, are being used by a growing number of astrologers and seem to symbolize various aspects of the Feminine: Ceres Pallas Juno Vesta Chiron has often been classified as an asteroid, even though it does not lie in the asteroid belt (orbiting primarily between Saturn and Uranus). It has also been called a comet, a planetoid, and a minor planet.