the final major chunk of cyclone shoemaker - lev 9 was to hit just after six , completing a cone of crater - like plumes of rolling vapor dust and debris thousands of meters across . " it touched io after a string of machine - weapon ammunition " said eugene shoemaker , an operator at the astronomical observatory in flagstaff , ariz . , who helped discover the body last year .
The Shoemaker-Levy comet hit Jupiter.