the seventh major piece of comet shoemaker - levy 9 was to hit just after dark , completing a ring of crater - sized plumes of swirling pyroclastic gas and debris thousands of miles across . " it struck jupiter like a string of machine - gun bullets " said eugene shoemaker , an astronaut at the lowell observatory in kingman , ariz . , who helped find the crater last january .
The Shoemaker-Levy comet hit Jupiter.