Carl Sagan’s Life and Legacy as Scientist, Teacher, and Skeptic<br />In this new remembrance of Carl Sagan, who died ten years ago, a noted planetary scientist and colleague (and former student of Sagan) recalls Sagan’s immense contributions to planetary research, the public understanding of science, and the skeptical movement. <br /><br />DAVID MORRISON <br /><br /><br /><br />--------------------------------------------------------------------------------<br /><br />Carl Sagan was the world’s best-known scientist in the late twentieth century, serving as our guide to the planets during the golden age of solar system exploration. He was both a visionary and a committed defender of rational scientific thinking. Sagan died on December 20, 1996, while only 62, and he has been greatly missed in the decade since. In addition to my own knowledge and insights about his scientific and skeptical contributions, I have made extensive use of the two excellent narrative biographies by William Poundstone (1999) and Keay Davidson (1999). Poundstone is stronger on Sagan’s science, Davidson on his personal history. Neither, however, emphasizes his role as a skeptic. <br /><br />Sagan was propelled on his academic and public careers by enormous talent, good luck, and an intensely focused drive to succeed. His lifelong quest was to understand the universe, especially our planetary system, and to communicate the thrill of scientific discovery to others. A natural teacher, he loved to explain things and never made a questioner feel stupid for asking. Although Sagan had broad intellectual interests, his pursuit of his career left little time for other activities: he did not play golf or follow sports, take up cooking or photography, sing or play a musical instrument, or join a church or synagogue. His first two wives complained that he devoted insufficient time to his marriages or his children (Davidson 1999). He focused on his career goals, and the world was enriched thereby. <br /><br />Ma