Comet Shoemaker-Levy 9 was a comet that broke apart , and crashed into Jupiter in July 1994 . For the first time , people could see how objects in the solar system , outside Eath collided . Comet Shoemaker-Levy 9 ( formally designated D\/1993 F2 , nicknamed String of Pearls for its appearance ) was a comet that broke apart and collided with Jupiter in July 1994 , providing the first direct observation of an extraterrestrial collision of solar system objects .