SLOW moving object Kowal1-3,5, now named Chiron4,6, is generally agreed to be a new asteroid, although Gingerich4 and Ashbrook6 have suggested that it might be a `deep-frozen' comet. Its orbit lies mainly5 between Saturn and Uranus but what is an asteroid doing so far from the main belt between Mars and Jupiter? If Chiron was born in its present orbit and is part of a new asteroid belt, then its existence may put constraints on models of the origin of the Solar System (note that a belt between Saturn and Uranus would violate Bode's law7,8). It may be simpler, however, to look for a more recent origin. One possibility, which is examined here, is that Chiron has been flung into its present orbit by a sort of gravitational sling-shot, having been successively perturbed, or even temporarily captured, by Jupiter and Saturn.