Carl Sagan

Carl Segan 1934-1996

December 20, 1996, the world of science was rocked by the passing of a great teacher, Carl Sagan. A Professor of Astronomy, Space Sciences, and director of the Laboratory for Planetary Studies at Cornell University, where he had held a professorship since 1971.

Carl Sagan highly believed in the exploration of space. In fact, I believe his contribution to the exploration of our Solar System goes unmatched. Listed below are some of the unmanned missions he has contributed to.

• Mariner 9 spacecraft, which produced the first detailed images showing that Mars is currently a desolate, cratered world.
• Viking orbiters and landers, which searched (unsuccessfully) for life on the surface of the Red Planet.
• Pioneer and Voyager probes that provided the first surveys of the outer planets and their moons.
• Galileo craft, which is currently sending back extremely detailed images of Jupiter and its giant satellites.

Sagan at the SETI (Search for Extraterrestrial Intelligence) Conference in 1972.

For many, me included, Sagan created a spark and interest in understanding the earth and our place in the cosmos. He toke a once held belief that the surface of Venus was possibly a hospitable place and showed us that in fact it was a hot and fried by a runaway greenhouse effect. But, he also showed that the universe was also full of beauty and is full of carbon-based chemicals that could be the beginning of other living things. Carl Sagan also gathered evidence that Saturn's moon Titan has an atmosphere containing organic molecules similar to the building blocks of life. All this was confirmed by Voyagers 1 and 2 in the 1980s.

Sagan like many of his followers believed in the existence of Extraterrestrial life. At Cornell, he pioneered the new field of exobiology--the study of possible alien biochemistry and life forms. He conceived a message plaque, containing a greeting from the people of Earth, which adorns the Pioneer 10 spacecraft, now headed into interstellar space (a more sophisticated, engraved phonograph record adorned the two Voyager craft, also on their way to the stars). Along with various collaborators, including Paul Horowitz of Harvard University, Sagan supported projects that use radio telescopes to listen for signals from possible intelligent alien civilizations.

But perhaps Sagan's greatest skill was his ability to communicate with individuals here on Earth. Through a series of books, magazine articles and television shows, he reached beyond the scientific community to convey the excitement of his research to the lay public. (His writing graced the pages of Scientific American; three of his articles are available from this page.) Sagan's concerns ranged far and wide, from the effects of nuclear war to the evolution of the mind to the intellectual erosion brought about by pseudoscience (the subject of his most recent book, The Demon-Haunted World). His television series Cosmos reached an estimated audience of 500 million people; his novel Contact is being made into a movie that will be released later this year. Sagan also co-founded the Planetary Society, the largest space-interest group in the world.

RELATED LINKS:

From Scientific American:

"The Search for Extraterrestrial Life" by Carl Sagan; Scientific American, October 1994

"The Solar System" by Carl Sagan; Scientific American, September 1975

"The Search for Extraterrestrial Intelligence" by Carl Sagan and Frank Drake; Scientific American, May 1975

Sources:

Scientific American

Sagan remembrance from the Planetary Society

Carl Sagan obituary from CNN

All copyrights remain property of their respective owners.