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
Erich Meyer Erich Meyer Erich Meyer (born August 6, 1951) is an Austrian engineer, amateur astronomer and discoverer of asteroids. Between 1996 and 1999, using the private observatory Meyer/Obermair in Davidschlag (municipality Kirchschlag bei Linz, Austria), he discovered a total of 21 asteroids. Seven of these asteroids were discovered together with his colleague Erwin Obermair and one together with Herbert Raab. Furthermore, he was involved in six other discoveries of asteroids between 1996 and 2005, which were assigned as site discoveries to the observatory Davidschlag by the International Astronomical Union. Meyer's most important observations include precisie astrometry of the comet Shoemaker–Levy 9,