Carl Sagan

pale blue dot

Carl Sagan (1934 – 1996) was an American astronomer. He devoted his life to popularizing science. He speculated about what life from other planets would be like, and promoted the search for extraterrestrial life. He is world famous for his popular science books and the television series Cosmos, which he co-wrote and presented.

He was born in Brooklyn New York where his father, Sam Sagan, was a Jewish clothes maker and his mother, Rachel Molly Gruber, was a housewife. Sagan attended the University of Chicago earning two degrees in physics. He followed with a doctorate in Astronomy in 1960 and taught at Harvard University until 1968, when he moved to Cornell University.

Sagan became a teacher and director at Cornell in 1971. He helped NASA design many unmanned spacecraft to explore outer space. He first proposed putting messages on spacecraft intended to be understood by any life from another planet that might find it. The first message sent into space was a large gold-plated label on the space probe Pioneer 10. The last message he helped with was the Voyager Golden Record that was sent out with the Voyager space probes.

He was well known as a writer who warned of the dangers of nuclear winter. He studied the atmosphere of Venus, seasonal changes on Mars, and Saturn’s moon Titan. He  helped prove that the atmosphere of Venus is very hot and dense. He also said that global warming was a growing, man-made danger like the natural development of Venus into a hot and dangerous planet with greenhouse gases. He suggested that the seasonal changes on Mars were due to dust storms.

Sagan was among the first to guess that Titan and Jupiter’s moon Europa might have oceans or lakes, which means that life could be there. Europa’s underground ocean was later confirmed by the spacecraft Galileo.

Sagan thought the search for life on other planets was a good idea. He said scientists should listen with large radio telescopes for signals from other planets. He helped start the Planetary Society and was a member of the SETI (Search for Extraterrestrial Intelligence) Institute Board of Trustees.

Sagan also believed that the Drake equation (an equation used to estimate the number of detectable extraterrestrial civilizations in the Milky Way galaxy) suggested that many kinds of intelligent life could form, but that the lack of evidence (the Fermi paradox) suggests that intelligent beings destroy themselves rather quickly. This made him keen to talk about ways that humanity could destroy itself, in the hope of avoiding such destruction.

Under the name ‘Mr. X,’ Sagan wrote about pot smoking in the 1971 book ‘Reconsidering Marijuana.’ Sagan said that marijuana helped him write some of his books.

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.