Carl Sagan : biography
He further contributed insights regarding the atmospheres of Venus and Jupiter as well as seasonal changes on Mars. He also perceived global warming as a growing, man-made danger and likened it to the natural development of Venus into a hot, life-hostile planet through a kind of runaway greenhouse effect. Sagan and his Cornell colleague Edwin Ernest Salpeter speculated about life in Jupiter’s clouds, given the planet’s dense atmospheric composition rich in organic molecules. He studied the observed color variations on Mars’ surface and concluded that they were not seasonal or vegetational changes as most believed but shifts in surface dust caused by windstorms.
Sagan is best known, however, for his research on the possibilities of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.
He is also the 1994 recipient of the Public Welfare Medal, the highest award of the National Academy of Sciences for "distinguished contributions in the application of science to the public welfare". He was denied membership in the Academy, reportedly because his media activities made him unpopular with many other scientists.
Sagan and UFOs
Sagan had some interest in UFO reports from at least August 3, 1952, when he wrote a letter to U.S. Secretary of State Dean Acheson to ask how the United States would respond if flying saucers turned out to be extraterrestrial. He later had several conversations on the subject in 1964 with Jacques Vallee. Though quite skeptical of any extraordinary answer to the UFO question, Sagan thought scientists should study the phenomenon, at least because there was widespread public interest in UFO reports.
Stuart Appelle notes that Sagan "wrote frequently on what he perceived as the logical and empirical fallacies regarding UFOs and the abduction experience. Sagan rejected an extraterrestrial explanation for the phenomenon but felt there were both empirical and pedagogical benefits for examining UFO reports and that the subject was, therefore, a legitimate topic of study."
In 1966 Sagan was a member of the Ad Hoc Committee to Review Project Blue Book, the U.S. Air Force’s UFO investigation project. The committee concluded Blue Book had been lacking as a scientific study, and recommended a university-based project to give the UFO phenomenon closer scientific scrutiny. The result was the Condon Committee (1966–1968), led by physicist Edward Condon, and in their final report they formally concluded that UFOs, regardless of what any of them actually were, did not behave in a manner consistent with a threat to national security.
Sociologist Ron Westrum writes that "The high point of Sagan’s treatment of the UFO question was the AAAS’s symposium in 1969. A wide range of educated opinions on the subject were offered by participants, including not only proponents such as James McDonald and J. Allen Hynek but also skeptics like astronomers William Hartmann and Donald Menzel. The roster of speakers was balanced, and it is to Sagan’s credit that this event was presented in spite of pressure from Edward Condon". With physicist Thornton Page, Sagan edited the lectures and discussions given at the symposium; these were published in 1972 as UFOs: A Scientific Debate. Some of Sagan’s many books examine UFOs (as did one episode of Cosmos) and he claimed a religious undercurrent to the phenomenon.
Sagan again revealed his views on interstellar travel in his 1980 Cosmos series. In one of his last written works, Sagan argued that the chances of extraterrestrial spacecraft visiting Earth are vanishingly small. However, Sagan did think it plausible that Cold War concerns contributed to governments misleading their citizens about UFOs, and that "some UFO reports and analyses, and perhaps voluminous files, have been made inaccessible to the public which pays the bills … It’s time for the files to be declassified and made generally available." He cautioned against jumping to conclusions about suppressed UFO data and stressed that there was no strong evidence that aliens were visiting the Earth either in the past or present.Sagan, 1996: 81–96, 99–104