James V. Scotti are subject to non-gravitational forces due to outgassing and solar wind, it is often a challenge to predict their exact position and rediscover them each time they make a new perihelion approach). He confirmed the discovery of the well known Comet Shoemaker-Levy 9, which impacted Jupiter in July 1994. He has also discovered the periodic comets 202P/Scotti, 244P/Scotti, P/2003 L1 (Scotti), P/2010 C1 (Scotti), P/2010 H4 (Scotti), P/2010 H5 (Scotti), P/2011 A2 (Scotti); the later seven are not yet numbered as they have only been seen at one perihelion passage. He has also discovered non-periodic comets C/2010 E5 (Scotti) and
Eugene Merle Shoemaker Institute in 1965. Coming to Caltech in 1969, he started a systematic search for Earth orbit-crossing asteroids, which resulted in the discovery of several families of such asteroids, including the Apollo asteroids. Shoemaker advanced the idea that sudden geologic changes can arise from asteroid strikes and that asteroid strikes are common over geologic time periods. Previously, astroblemes were thought to be remnants of extinct volcanoes — even on the Moon. In 1993, he co-discovered Comet Shoemaker–Levy 9 using the 18-inch Schmidt camera at Palomar Observatory. This comet was unique in that it provided the first opportunity to observe the planetary