The second half of the 20th century has been a golden age for cosmic exploration, and Carl Sagan has been its prophet. He combined a childlike wonder with the tough-minded perception of a research scientist. He used the skill of a poet to translate the cosmic rhythms that scientists discern in their data into music we all can hear.
It's no wonder that colleagues' tributes at the passing last Friday of this grand communicator tend to emphasize Sagan the poet even while lauding Sagan the scientist. "His unbelievable ability to explain the complexities of space and space exploration inspired people to look up into the night sky in wonder," says Daniel Goldin, administrator of the National Aeronautics and Space Administration. "He was, quite simply, the best science educator in the world this century," says Yervant Terzian, chairman of Cornell University's astronomy department in Ithaca, N.Y., where Sagan served as a professor.
It wasn't always thus. Sagan's early efforts at public outreach weren't well received at Harvard University in Cambridge, Mass., where he began his career. "Serious" young astronomers were expected to grind away at "serious" research and not get involved in "publicity" - especially if they were better at it than their senior colleagues. Sagan didn't get tenure at Harvard. Criticism continued even after he was well established as a scientist at his long-term base at Cornell. As in the case of Jacques Cousteau in oceanography, critics complained that the popular astronomer was promoting himself rather than his science. And as with Captain Cousteau, history has proved such envious criticism to be wrong.
Many billions of dollars worth of public resources have gone into the research that has given us our present expansive view of our solar system and the universe. The citizens who footed the bill for this exploration have a right to share in its fruits. Since those fruits consist largely of new insights rather than commercial products, citizens have a right to have that knowledge presented in terms they can understand. Carl Sagan fulfilled this professional obligation better than any other contemporary scientist.
This has paid off for astronomers and space scientists generally, as appreciation for their work helps build constituencies in government to support that work. Sagan also "was an early champion of the idea that the two leading spacefaring powers, America and Russia, should work together in the exploration of space," according to Mr. Goldin. Perhaps the most telling comment on Sagan's effectiveness as a science facilitator was made about a decade ago in a National Academy of Sciences report on the outlook for chemistry. Lamenting a lack of public appreciation for that science, it said that someone should do for chemistry what Carl Sagan has done for astronomy.
Sagan has made substantial scientific contributions. His work has focused, among other things, on the environment of Venus, dust storms on Mars, the origin of life on Earth, and the possibility of life on Mars. As a co-author of studies on the long-term environmental effects of nuclear war, he helped bring a sobering realization of nuclear war's peril to arms-control talks. Sagan also championed SETI - the Search for Extraterrestrial Intelligence - as worthwhile scientific research. In all, Sagan published more than 600 scientific papers and nonscientific articles. He authored, co-authored, or edited some 20 books. His TV appearances and his prizewinning Cosmos series set high standards in science education. A film based on his science-fiction novel "Contact" (about contact with an alien world) should be released in 1997.
Sagan's sonorous voice and measured pace in public speaking sometimes tempted friends to tease him about such trademark phrases as "billions of stars" in "billions of galaxies." Today they are thankful that his work continues to convey the scientific adventure to billions of people.