Lexell's Comet

A comet discovered by C. Messier in 1770, but named after A. Lexell (1740-84) who investigated its orbit. He showed that a close approach to Jupiter in 1767 had caused a large change in its orbit that brought it close enough to the Earth to be visible. The comet passed within 1.2 million kilometres of the Earth, still the closest recorded approach of a comet. However, another close approach to Jupiter in 1779 further perturbed the orbit, so drastically that it was never seen again.