Sagan, Carl (1934-1996)

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Sagan, Carl (1934-1996)

Of all the spokespeople for the space sciences active during the last three decades of the twentieth century, astronomer Carl Sagan was the most widely recognized and articulate. Through his accessible and instructive writings on the subject of space and their accompanying television programs, he earned a significant and popular place in American culture, and defined one of the world's most frightening forebodings as "nuclear winter."

The explosion of popular interest in astronomy and space travel in the United States following the Soviet Union's launch of Sputnik on October 4, 1957 provided the scientific community with an unparalleled opportunity for public education that continued for several decades. An entirely new genre of writing began to appear from either prominent figures involved in the American space effort, such as Werner von Braun and the members of the newly formed astronaut corps, or science writers knowledgeable in these fields. In addition to the obvious political overtones to the so-called "space race," discussion of humanity's place in the universe and questions regarding the future uses of outer space assumed new importance in both American and worldwide consciousness.

Born in New York City on November 9, 1934, Sagan showed an interest in astronomy early on and pursued it as a career, completing doctoral work at the University of Chicago in 1960 and serving as a faculty member at Berkeley, Harvard, and the Smithsonian Institution before settling at Cornell. While his main research interests lay in planetary studies and the origin of life, many of his writings were designed to educate the general public on these fields, a task he poured heart and mind into throughout his life. His first popular work in this line was the 1973 introduction to the search for extra-terrestrial life and space travel, The Cosmic Connection. His interest in the processes through which life might have arisen and developed intelligent awareness was the focus of his next work, The Dragons of Eden, awarded the Pulitzer Prize in 1977. But it was with the text of his 1980 volume COSMOS (written in conjunction with a series of 13 programs widely broadcast on public television networks) that this unassuming astronomer truly became a recognizable and familiar figure in the public mind of America, if not the planet.

The idea for the COSMOS project was born in 1976 while he was part of the imaging team working on the Viking Lander mission to Mars. Journalistic interest in the operation waned swiftly once it became clear that the question of the presence of life on the planet remained unsettled. Sagan and B. Gentry Lee, director of data analysis and mission planning, decided to create a television production company whose goal was the communication of science in an accessible and inviting manner. Several lines in the introduction set forth the essential features of a personal and philosophical view of the space age: these stated that "the present epoch is a major crossroads for our civilization and perhaps our species … our fate is indissolubly bound up with science." A lively respect for the intelligence of his audiences, and an unfailing joy and wonder at the infinite diversity of a patterned universe, made Sagan in several ways the ideal teaching voice, able to provide a comprehensible perspective on the flood of new information becoming available from various space missions and orbiting instruments.

His concern for the role of science and its potential to determine the human future was also evident in his involvement with research on the effects of an exchange of nuclear weapons on the Earth's biosphere. Basing their work on models created during analysis of the temperature fluctuations caused by a massive Martian dust storm, encountered in 1971 by the Mariner 9 probe, Sagan and other scientists synthesized available data into the first comprehensive study of the impact of the explosions of numerous megaton atomic weapons on global climate and atmospheric factors. He presented the grim results of these findings as one of the two principal papers at the 1983 Conference on the Long-Term Worldwide Biological Consequences of Nuclear War held in Washington, D.C. It was here that Sagan first publicly coined the phrase "nuclear winter."

Arguably, Sagan's most influential contribution made to the popular memory with regard to planet Earth began in 1976. It was then that he was requested to head the team to choose the contents of a message to be sent with the Voyager spacecraft, an unmanned probe that ventured into deep space after its years-long mission through the solar system was completed. Rather than duplicate the aluminum plaques affixed to the earlier Pioneer 10 and 11 probes, Sagan and his team decided to include a long-playing record, containing both audio recordings and visual images gathered from diverse societies, that, collectively, would enable extra-terrestrial beings to gain a sense of human accomplishment. Types of information placed within the final product ranged from 118 pictures representing different aspects of human civilization and its world, through greetings in 54 languages, music ranging from the Navajo Night Chant and Indian ragas to a Mozart aria, and recorded natural sounds, including the cry of a newborn infant. The motivation for sending such a rich record was, in Sagan's view, that "no one sends such a message on such a journey, to other worlds and beings, without a positive passion for the future." Until his death from cancer on December 20, 1996, Sagan continued to promote a clear and well-reasoned perspective on the wonders and complexities of space, and humanity's future within it aboard its "pale blue dot."

—Robert Ridinger