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
David H. Levy biography of Pluto-discoverer Clyde Tombaugh in 2006, and his tribute to Gene Shoemaker in "Shoemaker by Levy". He has provided periodic articles for "Sky and Telescope" magazine, as well as "Parade Magazine", "Sky News" and, most recently, "Astronomy Magazine". Periodic comets that Levy co-discovered include 118P/Shoemaker–Levy, 129P/Shoemaker–Levy, 135P/Shoemaker–Levy, 137P/Shoemaker–Levy, 138P/Shoemaker–Levy, 145P/Shoemaker–Levy, and 181P/Shoemaker–Levy. In addition, Levy is the sole discoverer of two periodic comets: 255P/Levy and P/1991 L3. On February 28, 2010, Levy was awarded a Ph. D. from the Hebrew University of Jerusalem for his successful completion of his thesis "The Sky in Early Modern English Literature: A Study