David H. Levy David H. Levy David H. Levy (born May 22, 1948) is a Canadian astronomer, science writer and discoverer of comets and minor planets, who co-discovered Comet Shoemaker–Levy 9 in 1993, which collided with the planet Jupiter in 1994. Levy was born in Montreal, Quebec, Canada, in 1948. He developed an interest in astronomy at an early age. However, he pursued and received bachelor's and master's degrees in English literature. Levy went on to discover 22 comets, either independently or with Gene and Carolyn Shoemaker. He has written 34 books, mostly on astronomical subjects, such as "The Quest for Comets", a
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,