Unlike normal comets, Shoemaker-Levy 9 was discovered in orbit around Jupiter by the American astronomer Gene Shoemaker, Carolyn S. Shoemaker, and David Levy. Even more remarkably, it was in 22 pieces, having been ripped apart on 7 July 1992, when it passed too close to Jupiter. These fragments then crashed down on Jupiter in July 1994, and the incidents were reported by various observatories around the globe. The nucleus was 1 kilometer in diameter and likely captured by Jupiter in the 1920s.
- Universe by Martin Rees, ISBN 978-1-4093-7650-7