Sagan, Carl Edward (sāˈgən) [key], 1934–96, American astronomer and popularizer of science, b. New York City. Early in his career he investigated radio emissions from Venus and concluded that the cause was a surface temperature of c.900°F (500°C) and crushing atmospheric pressure. He also studied color variations on Mars' surface, concluding that they were not seasonal changes as most believed but shifts in surface dust caused by windstorms. Both conclusions were substantially confirmed years later by space probes. Sagan is best known, however, for his research on the possibilities of extraterrestrial life (see exobiology), including experimental demonstration of the production of amino acids from basic chemicals by radiation. A professor of astronomy and space sciences at Cornell after 1968, he was involved with numerous NASA planetary space probes and was the creator and host of the 1980 public television science series Cosmos. His publications include The Dragons of Eden (1977; Pulitzer); a novel, Contact (1985); with Richard Turco, A Path Where No Man Thought (1990), on nuclear winter; with Ann Druyan, Shadows of Forgotten Ancestors (1992); Pale Blue Dot (1994); and The Demon-Haunted World (1995).
See biographies by K. Davidson (1999) and W. Poundstone (1999).
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