Shoemaker, Eugene Merle (1928–97) An American geologist who founded the scientific study of impact cratering on Earth, the Moon, and on other solar system planets and their satellites, and who also pioneered the study of near-Earth comets and asteroids, often in collaboration with his wife Carolyn. This led him to recognize the importance of the cratering process in the history of the solar system. In 1952, he became convinced that both Meteor Crater, Arizona, and lunar craters had been formed by impact. In 1956 he was assigned to map the craters formed by nuclear test explosions, and was able to define how ejecta produce crater stratigraphy. Shoemaker was born in Los Angeles and received his first degree from the California Institute of Technology and his Ph.D. from Princeton University in 1960. From 1948 to 1993 he worked for the US Geological Survey, then continuing to serve as scientist emeritus. In the 1960s he established the Astrogeology Branch of the USGS and its centre at Flagstaff, Arizona. Studies of the Moon and other bodies lacking atmospheres led him to propose that their surfaces should be covered with a layer of ejecta he termed ‘regolith’, and that the age of a surface could be inferred from its cratering. In March 1993, Gene and Carolyn Shoemaker and David Levy discovered a fragmented comet close to Jupiter. The comet, named Shoemaker-Levy 9, collided with Jupiter spectacularly in July 1994. Gene Shoemaker died in a car crash in the Australian outback. He and Carolyn, who survived, had been on their way to study a crater.