- Person
- Carl Sagan
- Lived
- 1934–1996
- Field
- Astronomy, planetary science
- From
- American
The story
Listening for radio signals from other civilisations was once seen by many scientists as a fringe pursuit. Carl Sagan had been fascinated by the possibility of extraterrestrial life since childhood, and as a scientist he treated it as a legitimate question that could be studied with real instruments. He urged the scientific community to use radio telescopes to listen for signals from intelligent life elsewhere.
He also worked to show what such communication might look like. With his Cornell colleague Frank Drake he designed the Pioneer plaques of 1972 and 1973, and he is generally credited with contributing to the Arecibo message, a radio signal beamed into space from the Arecibo Observatory in Puerto Rico on November 16, 1974, to mark the upgrading of its telescope. The message, designed mainly by Drake and a group of Cornell and Arecibo scientists, was aimed at a star cluster about 25,000 light years away and was meant more as a demonstration of human technology than a real attempt at conversation.
Sagan's advocacy had to overcome political doubts as well as scientific ones. Through the Planetary Society, which he co-founded in 1980, he used his public standing to help protect NASA's search programme from cancellation by Congress in 1981. The society also helped fund new searches.
In 1982 he organised a petition advocating the search for extraterrestrial intelligence, known as SETI, and had it published in Science, one of the world's leading journals. It was signed by 70 scientists, including seven Nobel Prize winners. The petition marked a major increase in the respectability of what had been a controversial field.
Sagan believed the Drake equation suggested that many technological civilisations should arise in our galaxy, and he explained it to millions of viewers in Cosmos. He served on the board of trustees of the SETI Institute, and his 1985 novel Contact made a SETI astronomer its heroine. He is now described as the most cited SETI scientist. The searches he championed continue with ever more powerful instruments.
Why it matters
Sagan helped turn the search for life beyond Earth from a fringe idea into a respected scientific endeavour that continues with ever more powerful instruments.
About Carl Sagan
Brooklyn-born astronomer who explained the Venus greenhouse, helped send humanity’s messages on Pioneer and Voyager, and taught Cosmos viewers worldwide to look at the universe with wonder and doubt.
More about Carl Sagan
- Carl Sagan co-founded the Planetary SocietyIn 1980 Carl Sagan co-founded the Planetary Society and became its first president, building a public movement to support the exploration of space.
- Carl Sagan explained why Venus is a furnaceIn the early 1960s Carl Sagan argued from radio data that Venus's surface was about 500 °C because of a greenhouse effect, a conclusion confirmed by Mariner 2 in 1962.
- Carl Sagan inspired a generation of science communicatorsCarl Sagan invited a 17-year-old Neil deGrasse Tyson to Cornell and taught Bill Nye astronomy, inspiring a generation of scientists and science popularisers.
- Carl Sagan showed Mars's changing colours were dustMany astronomers thought seasonal colour changes on Mars were spreading vegetation. Carl Sagan showed they were shifts in surface dust driven by windstorms.
- Carl Sagan asked Voyager to photograph the Pale Blue DotAt Carl Sagan's urging, Voyager 1 turned its camera homeward on February 14, 1990, and photographed Earth from about 6 billion kilometres away as a tiny pale blue dot.
- Carl Sagan designed humanity's first message to the starsGiven just three weeks by NASA, Carl Sagan and Frank Drake designed the Pioneer plaque, a message to any alien finders, now leaving the solar system aboard two spacecraft.
- Carl Sagan foresaw ocean worlds on Titan and EuropaCarl Sagan was among the first to suggest that Saturn's moon Titan might have surface liquids and that Jupiter's moon Europa might hide an ocean of water beneath its ice.
- Carl Sagan chaired the Voyager Golden Record committeeFor the Voyager probes launched in 1977, Carl Sagan chaired the committee that chose the Golden Record's contents, including greetings in 55 languages and 116 images of Earth.
- Carl Sagan warned Congress about climate change in 1985Drawing on his study of Venus, Carl Sagan testified to the US Congress in 1985 that the greenhouse effect would change Earth's climate.
- Kip Thorne helped Carl Sagan imagine Contact's wormholesFor his 1985 novel Contact, Carl Sagan asked his friend Kip Thorne how a wormhole might work. The book sold 1.7 million copies in two years and became a 1997 film.
- Carl Sagan's Cosmos reached 500 million peopleCosmos: A Personal Voyage, first broadcast in 1980, has been seen by at least 500 million people in 60 countries, and its companion book was the best-selling science book of its time.
- Carl Sagan won a Pulitzer Prize for The Dragons of EdenCarl Sagan's 1977 book The Dragons of Eden, on the evolution of human intelligence, won the 1978 Pulitzer Prize for General Nonfiction and introduced his Cosmic Calendar.
- Carl Sagan gave the public a baloney detection kitIn The Demon-Haunted World (1995), Carl Sagan offered readers a toolkit for critical thinking and popularised the rule that extraordinary claims require extraordinary evidence.
- Carl Sagan warned the world about nuclear winterIn 1983 Carl Sagan co-authored the TTAPS study warning that a nuclear war could cool the planet, work honoured in 2022 with the Future of Life Award.
Sources
- Carl Sagan Wikipedia
- Arecibo message Wikipedia
- The Planetary Society Wikipedia
Another act of tikkun olam. This is part of tikkun olam, the Jewish idea of repairing the world, and every one of us can add to it.