Impact event such as Engelier and Gerin on Iapetus, Mamaldi on Rhea and Odysseus on Tethys and Herschel on Mimas form significant surface features. 2018 models developed to explain the unusual spin of Uranus support a long-held theory that this was caused by an oblique collision with massive object twice the size of Earth. On July 1994, Comet Shoemaker–Levy 9 was a comet that broke apart and collided with Jupiter, providing the first direct observation of an extraterrestrial collision of Solar System objects. The event served as a "wake-up call", and astronomers responded by starting programs such as Lincoln Near-Earth Asteroid Research
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