the final prime component of comet shoemaker - levy 9 was to kill just after eleven , completing a ring of crater - like plumes of glowing superheated gas and debris thousands of miles across . " it hit you through a string of machine - gun grenades " said eugene shoemaker , an astronomer at the lowell observatory in flagstaff , ariz . , who helped discover the comets last day .
The Shoemaker-Levy comet hit Jupiter.