Carl Sagan born November 9, 1934 <\/h3>\n
Tomorrow would have been Carl Sagan\u2019s 92nd birthday. The astronomer and science popularizer became famous through his books and the 1980 television series Cosmos. He also made major contributions to planetary science and the American space program.<\/p>\n
Carl Edward Sagan was born on November 9, 1934, in Brooklyn, New York. He studied physics at the University of Chicago and earned his doctorate in astronomy and astrophysics in 1960.<\/p>\n
In the 1960s, one of Sagan\u2019s earliest works in professional astronomical research shed light on the atmospheres of our solar system\u2019s planets, for example Mars and Venus. In Sagan\u2019s day, scientists were still trying to understand how Mars could be so cold while Venus is so hot. Sagan successfully argued that Venus could be a greenhouse furnace by using data from tables for steam boiler engineering.<\/p>\n
Carl Sagan and the search for extraterrestrial intelligence<\/h3>\n
Around this same time, Sagan became interested in the search for extraterrestrial intelligence (SETI) and contributed to those programs. He showed that the building blocks of life could be easily created by exposing simple chemicals to UV light. In 1966, he helped I. S. Shklovskii, a Soviet astronomer and astrophysicist, revise and expand his classic book on extraterrestrial life, Intelligent Life in the Universe.<\/p>\n
In 1968, Harvard University denied Sagan tenure; some speculated it was due to his controversial opinions on extraterrestrial intelligence. He went on to become a professor at Cornell University in Ithaca, New York, where he spent the rest of his professional career.<\/p>\n
Also, Sagan contributed to the U.S. space program. Among other things, he briefed astronauts before their trip to the moon, and he was part of the Mariner, Viking, Galileo, and Voyager space missions. In the Viking missions, for example \u2014 two probes sent to explore Mars in the 1970s \u2014 he collaborated on choosing ideal landing sites.<\/p>\n But in addition to his books and the \u201cCosmos\u201d television series, it\u2019s Sagan\u2019s actual messages to the cosmos \u2014 placed aboard the first spacecraft designed to leave our solar system, the Pioneer and Voyager missions \u2014 that may be his greatest legacy.<\/p>\n The original idea for the Pioneer plaques \u2014 a pair of gold-anodized aluminum plaques carrying messages from humankind, placed aboard the 1972 Pioneer 10 and 1973 Pioneer 11 spacecraft \u2014 came from journalist and consultant Eric Burgess. He approached Sagan about it, and NASA agreed to it and gave Sagan three weeks to prepare a message.<\/p>\n Together with astronomer Frank Drake, who formulated the famous Drake Equation (a way of estimating the number of intelligent civilizations in our Milky Way galaxy), Sagan designed the plaque, with artwork prepared by his wife at the time, Linda Salzman Sagan.<\/p>\n The Pioneers and their plaques are now billions of miles from Earth. Both spacecraft are coasting toward interstellar space, carrying messages from Earth into the distant future.<\/p>\n Get your EarthSky lunar calendar now. This beautiful poster shows the moon phase for every day of 2027. Now available!<\/strong><\/em><\/p>\n Later in that same decade, Sagan and his wife-to-be, Ann Druyan, contributed to the design of yet another message from humankind to outer space. The Voyager probes launched in 1977. They both carry what is known as a Voyager Golden Record. Each Golden Record contains 116 images that depict historical scientific works and humans performing mundane activities, plus music from artists such as Bach, Mozart, and Chuck Berry, an hour-long record of Ann Druyan\u2019s brainwaves, and greetings in 55 languages.<\/p>\n See a list of all\u00a0the material on the Golden Records<\/p>\n Listen to the entire musical selection of the Golden Records <\/p>\n The Voyagers launched later, but traveled faster than the Pioneers. Voyager 1 and 2 have reached interstellar space. Voyager 1 is the farthest human-made object from Earth. Voyager 1 is expected to reach 1 light-day from Earth on November 18, 2026. Voyager 2 is closer than Voyager 1 but farther away than Pioneer 10.<\/p>\n See where the Voyager probes are, in real time<\/p>\n During the 1980s, Sagan encouraged nuclear disarmament and was one of the five authors of the concept of nuclear winter, which describes the aftermath of a nuclear war. Moreover, the work showed that, in a nuclear war, no one would win. It\u2019s hard to estimate the importance of this work to the global consciousness of the time, but it\u2019s perhaps no accident that the Cold War ended not long afterward.<\/p>\n Carl Sagan\u00a0remained at Cornell until his death\u00a0on December 20, 1996, at age 62 from pneumonia.<\/p>\n Over the course of his life, Carl Sagan published more than 600 scientific papers and articles, and wrote, co-wrote or edited more than 20 books. He was an inspiration to many, and continues to inspire many young scientists to tread the path of astronomy and astronomical communication. Plus, he encouraged scientific responsibility by\u00a0promoting nuclear disarmament. Equally important, his work in science outreach encouraged science literacy not only among Americans, but around the world. He was very quotable and said, among many other wonderful things:<\/p>\n The nitrogen in our DNA, the calcium in our teeth, the iron in our blood, the carbon in our apple pies were made in the interiors of collapsing stars. We are made of starstuff.<\/p>\n<\/blockquote>\n Do you remember him? Do you remember his words and the sound of his voice? Listen and remember, via the video below.<\/p>\n \n![\"Man](\"https:\/\/earthsky.org\/upl\/2016\/10\/151106main_image_feature_599_ys_full-e1667993802681.jpg\")
Messages to the stars: Pioneer<\/h3>\n
![\"Drawing](\"https:\/\/earthsky.org\/upl\/2016\/11\/Pioneer_plaque.svg_-e1478644026378.png\")
Messages to the stars: Voyager<\/h3>\n
Carl Sagan\u2019s legacies<\/h3>\n
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