20 years? Already? Hard to believe but true.
Comet Shoemaker-Levy 9 impacted the planet Jupiter 16 July 1994. The comet broke up under the influence of the gravitational pull of the planet during a close pass in July 1992 (was within the Roche limit) and impacted two years later.
The image above is one of many images you can find at our Comet Shoemaker-Levy 9 page. Be sure to visit the links for the legendary Eugene Shoemaker too.
Image credit: NASA et.al