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
Thomas Bopp Planetarium at the university. In 1997, as comet Hale–Bopp reached its brightest point, Bopp's brother and sister-in-law were killed in a car accident after photographing the comet. "This has been the best week of my life. And the worst," Bopp told a "National Geographic" reporter. Bopp and his father Frank have had an asteroid named after them, , discovered October 5, 1991, by Carolyn and Gene Shoemaker. In 1997 Gene Shoemaker and his wife, both famous for co-discovering comet Shoemaker–Levy 9, were involved in a fatal car crash while observing Hale-Bopp. Gene died in the crash and his ashes were