Comet Shoemaker–Levy 9 compute the density and size of Shoemaker–Levy 9. Its average density was calculated to be about ; the breakup of a much less dense comet would not have resembled the observed string of objects. The size of the parent comet was calculated to be about in diameter. These predictions were among the few that were actually confirmed by subsequent observation. One of the surprises of the impacts was the small amount of water revealed compared to prior predictions. Before the impact, models of Jupiter's atmosphere had indicated that the break-up of the largest fragments would occur at atmospheric pressures of
Comet Hale–Bopp and it was visible to the naked eye for twice as long as the previous record-holder. It was also brighter than magnitude 0 for eight weeks, longer than any other recorded comet. Gene Shoemaker and his wife Carolyn, both famous for co-discovering comet Shoemaker–Levy 9, were involved in a car crash after photographing the comet. Gene died in the crash and his ashes were sent to the Moon aboard NASA's "Lunar Prospector" mission along with an image of Hale–Bopp, "the last comet that the Shoemakers observed together". Comet Hale–Bopp Comet Hale–Bopp (formally designated C/1995 O1) is a comet that was