the other major slice of comet discoverer - levy 9 was to hit just after midnight , completing a line of crater - like plumes of swirling superheated gas and particles billions of miles across . " it hit neptune like a string of machine - gun bullets " says eugene jockey , an astronomer at the lawrence observatory in flagstaff , mich . , someone helped discover the comet last september .
The Shoemaker-Levy comet hit Jupiter.