Carl Sagan (1934-1996) was a liberal professor of astronomy at Cornell University in Ithaca, New York, who became a celebrity on television and a vocal advocate for increased searches for intelligent life in outer space. Time magazine reported that Carl Sagan "talked with Jimmy Carter about such esoteric matters as black holes and exobiology (the speculation that extraterrestrial life exist)." He was instrumental in the development of Search for Extra-Terrestrial Intelligence(SETI). Carl Sagan also smoked marijuana. He claimed marijuana gave him scientific insights.
Carl Sagan was one of the first and foremost professors of the theory that the surface of Venus is in fact hot, arid and dry. He studied radio emissions from Venus and concluded that the surface temperature had to have been about 900° Farenheit. He was also a contributer to the Mariner missions to Venus, which confirmed his theories.
Sagan also was an early promoter of the theory that Saturn's moon Titan is covered with oceans of liquid compounds. Sagan also was pivotal in solving the mystery of Titan's reddish glow. Carl Sagan theorized that there must be many organic chemicals constantly raining down on the surface of Titan. He also theorized that Jupiter's moon Europa may have vast subsurface oceans of liquid water. This excited Sagan as there is a great potential for life to inhabit Europa . This theory was later confirmed by the Galileo spacecraft.
Sagan also concluded that the variations in color of Mars' surface were not due to seasonal or vegetational affects, but rather were caused by shifts in surface dusts caused by windstorms. This was later confirmed by other scientists and subsequent missions to mars.
He also recieved the 1994 recipient of the Public Welfare Medal, from the National Academy of Sciences for "Distinguished contributions in the application of science to the public welfare. the Public Welfare Medal is the highest honor given by the National Academy of Sciences.
Sagan was a main advocate for the scientific theory of evolution. In addition, as noted earlier Sagan advocated government funded exobiology research.
IdeasProfessor Sagan, like many scientists throughout the 20th century, believed that intelligent life may exist on planets other than Earth.
"The significance of a finding that there are other beings who share this universe with us would be absolutely phenomenal, it would be an epochal event in human history," Sagan declared.
Indeed, Sagan's most popular work of fiction Contact, later made into a movie, was about finding extraterrestrial life.
To Sagan, there was nothing beyond physical reality as can be seen by this quote from his famous documentary series, "The Cosmos":
|“||The cosmos is all that is, or ever was, or ever will be."||”|
Professor Sagan would often advocate for peaceful diplomatic resolution by arguing:
|“||We have looked close-up at dozens of new worlds. Worlds we never saw before. And unless we are so stupid to destroy ourselves, we are going to be moving out to space in the next century," he said. "And if I'm fortunate enough to have played a part in the first preliminary reconnaissance in the solar system, that's a terrifically exciting thing.||”|
He often made his opposition to nuclear weapons clear. An episode of Cosmos, "Who Speaks for Earth," dealt with the possibility of nuclear annihilation explicitly.
From a religious point of view, Sagan was an atheist or an agnostic depending upon how it is interpreted. In practice he was an atheist, but as a scientist could never say with certainty that evidence couldn't arise that is currently unknown that would point toward a god force, he is more correctly described as being agnostic.
Interestingly, the ending of Contact does imply to some extent the existence of a Universal Creator. The novel concludes
|“||The universe was made on purpose ... In the fabric of space and in the nature of matter, as in a great work of art, there is, written small, the artist's signature ... there is an intelligence that antedates the universe.||”|
Some commentators feel that this represents a shift in Sagan's views, much as the protagonist of the novel experiences a similar shift. However, others feel that since this was a work of fiction, it did not necessarily represent what Sagan really thought. For instance, science-fiction author Robert J. Sawyer opines that "Sagan was no more obligated to believe in what he wrote than than George Lucas was to believe in The Force". (In Lucas' movie series Star Wars, "The Force" was the guiding principle behind the fictional Jedi religion practiced by the characters in the film).
At the height of his popularity, Sagan became something of a media celebrity, occasionally appearing on popular entertainment programs. His speaking style became well known, and one phrase of his was often spoofed and referenced in the media—"BILLIONS and BILLIONS"—with the words emphasized and drawn out, though he never actually used it.
Sagan had a notable effect on the space program, being the man who conceived the first written message to go into space, on gold plaques attached to the Pioneer 10 and 11 spacecraft. Later, he would be a part of the team that assembled golden records, containing information on Earth's culture and daily life, that would go out with the Voyager space probes later.
Kuwait Oil Crisis
"Though Dr. Sagan is one of the most frequently cited experts on atmospheric issues by the media, his predictions are often wrong. For example, at the outset of the Persian Gulf War, Sagan warned that if Saddam Hussein delivered on his threat to set fire to Kuwait's oil wells, so much black soot would be sent into the stratosphere that sunlight would be blocked and a variation of the "nuclear winter" scenario would occur. Hussein followed through on his threat and by the close of the war over 600 wells were on fire. But the fires had little environmental or climatic effect beyond the Gulf region and virtually no ill effects globally."
Fred Singer famously rebutted Sagan's prediction on national TV and was vindicated a few days later, when Sagan's nuclear winter scenario failed to materialize. Later, Sagan would admit he was wrong, noting: "it was pitch black at noon and temperatures dropped 4°–6°C over the Persian Gulf, but not much smoke reached stratospheric altitudes and Asia was spared."
- Frederic Golden, "The Cosmic Explainer," Time.com 20 Oct. 1980.
- Detailed information about Sagan's scientific work comes from the primary research articles. Example: Sagan, C., Thompson, W. R., and Khare, B. N. Titan: A Laboratory for Prebiological Organic Chemistry, Accounts of Chemical Research, volume 25, page 286 (1992). There is commentary on this research article about Titan at The Encyclopedia of Astrobiology, Astronomy, and Spaceflight.
- The Planetary Society. Carl Sagan. The Planetary Society. Retrieved on May 14, 2007.
- Norma Quarles, "Carl Sagan Dies at 62," CNN.com 20 Dec. 1996.
- Cosmos series, 1980
- "Retired atmospheric physicist Fred Singer dismissed Sagan's prediction as nonsense, predicting [correctly] that the smoke would dissipate in a matter of days." 
- Sagan, Carl (1996). The demon-haunted world: science as a candle in the dark. New York: Random House. p. 257. ISBN 0-394-53512-X.