Shoemaker, Eugene Merle

▪ 1998

      ("GENE"), American planetary geologist (b. April 28, 1928, Los Angeles, Calif.—d. July 18, 1997, Alice Springs, Australia), was hailed as one of the chief founders of planetary geology and considered by many scientists to be the consummate sky gazer of the 20th century. Throughout much of his long career, Shoemaker worked closely with his wife and colleague, Carolyn Spellman Shoemaker. Between them they identified 32 comets and 1,125 asteroids, missing by only 5 the world comet record set by 19th-century astronomer Jean-Louis Pons. Their most spectacular find, Comet Shoemaker-Levy 9, was discovered with amateur astronomer David Levy. The comet dazzled the world in July 1994 as its 21 glowing fragments tore into Jupiter's southern hemisphere, the largest chunks exploding with a force comparable to several million megatons of TNT. This was not the first time that Shoemaker had made headlines. In 1948 after graduating at age 20 with a master's degree in geology from the California Institute of Technology (Caltech), he surveyed craters in the landscape of the American Southwest. The young geologist rocked the scientific world in the late 1950s by supplying confirmation of the origin of Meteor Crater near Winslow, Ariz. Following his discovery of coesite, a form of silica created under the high pressure of meteoric impacts, Shoemaker theorized that the 1,200-m (4,000-ft)-wide bowl-shaped pit was formed when a meteorite crashed into the Earth's surface more than 50,000 years ago. His research lent credence to the theory that the bombardment of the Earth and other planets with celestial debris played an important role in the history of planetary evolution. He later supported the hypothesis that an object from outer space may have been responsible for the cataclysmic changes on Earth that led to the extinction of the dinosaurs and other life forms 65 million years ago. Shoemaker warned of the possibility of other such devastating encounters with the Earth and favoured the development of technology that would intercept threatening astral projectiles before impact. During his tenure with the U.S. Geological Survey from 1948 to his retirement in 1993, he established the agency's Center of Astrogeology in Flagstaff, Ariz., where he served as chief scientist. While also teaching at Caltech from 1962 to 1985, Shoemaker found time to pursue one of his lifelong interests—the geologic history of the Moon. As principal investigator for NASA's Apollo Moon project in the 1960s, he used a telescope to map lunar craters and studied rock specimens retrieved from the Moon's surface, as well as helping to train NASA astronauts in lunar geology, a discipline that he was credited with inventing. Shoemaker received the U.S. National Medal of Science in 1992.

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