Carolyn S. Shoemaker of Technology, Pasadena, California, and the Palomar Observatory, San Diego, California. That year, Shoemaker was hired at the United States Geological Survey as a visiting scientist in the astronomy branch, and then in 1989 began work as an astronomy research professor at Northern Arizona University. She concentrated her work on searching for comets and planet-crossing asteroids. Teamed with astronomer David H. Levy, the Shoemakers identified Shoemaker-Levy 9, a fragmented comet orbiting the planet Jupiter on March 24, 1993. After Gene's death in 1997, Shoemaker continued to work at the Lowell Observatory with Levy, and continues to work there today. In
Comet Shoemaker–Levy 9 carbon disulfide persisted in the atmosphere for at least fourteen months after the collisions, with a considerable amount of ammonia being present in the stratosphere as opposed to its normal location in the troposphere. Counterintuitively, the atmospheric temperature dropped to normal levels much more quickly at the larger impact sites than at the smaller sites: at the larger impact sites, temperatures were elevated over a region wide, but dropped back to normal levels within a week of the impact. At smaller sites, temperatures higher than the surroundings persisted for almost two weeks. Global stratospheric temperatures rose immediately after the impacts,