Silverpit crater the Chicxulub impact near the northwest corner of the Yucatan Peninsula, which occurred 66 million years ago and probably played a major role in the extinction of the dinosaurs. Several other large impact craters of around the same age have been discovered, all between latitudes 20°N and 70°N, leading to the speculative hypothesis that the Chicxulub impact may have been only one of several impacts that happened all at the same time. The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 proved that gravitational interactions can fragment a comet, giving rise to many impacts over a period of a
Naming of comets the past, when multiple comets were discovered by the same individual, group of individuals, or team, the comets' names were distinguished by adding a numeral to the discoverers' names (but only for periodic comets); thus Comets Shoemaker–Levy 1 to 9 (discovered by Carolyn Shoemaker, Eugene Shoemaker & David Levy). Today, the large numbers of comets discovered by some instruments makes this system impractical, and no attempt is made to ensure that each comet is given a unique name. Instead, the comets' systematic designations are used to avoid confusion. Until 1994, comets were first given a provisional designation consisting of the