Carl Edward Sagan ( New York , 9 November as as 1934 – Seattle , 20 as December as 1996 ) was a popular astronomer , astrophysicist, cosmologist, author and popularizer American scientist.
Summary
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- 1 Biographical synthesis
- 1 Stages of his life
- 2 Scientific achievements
- 3 Death
- 4 Acknowledgments
- 5 Sources
Biographical synthesis
He was born into a family of Ukrainian Jews. His father, Sam Sagan, was a Kamenets-Podolsk, Ukraine -born textile worker and his mother, Rachel Molly Gruber, was a homemaker.
Stages of your life
He studied at the University of Chicago , where he received a doctorate in astrophysics. He also studied the origins of organisms with the geneticists Hermann J. Muller and Joshua Lederberg , contributing to the constitution of exobiology, the search for extraterrestrial life, as a scientific discipline. He was an assistant professor of astronomy at Harvard University , an astrophysicist at the Smithsonian Astrophysical Observatory (1962-1968), and director of the Laboratory for Planetary Studies at Cornell University.
In the fifties he participated as an advisor and consultant for NASA . He was active in the Mariner, Viking, Voyager, and Galileo space programs. He was an instructor in the Apollo program; he played a decisive role in planetary investigations: he helped to decipher the high temperatures on Venus by employing the theory of the massive and global greenhouse effect, the seasonal changes of Mars and the reddish clouds of Titan.
He published numerous scientific articles and communications and was the author, co-author or editor of more than twenty books. Defender of scientific skeptical thinking and the scientific method. He was also a pioneer of exobiology, promoter of the search for extraterrestrial intelligence through the SETI Project and promoted the sending of messages on board space probes, destined to inform possible extraterrestrial civilizations about human culture. Through his observations of the atmosphere of Venus, he was among the first scientists to study the greenhouse effect on a planetary scale.
At Cornell University , Carl Sagan was the first scientist to hold the David Duncan Chair in Astronomy and Space Sciences, created in 1976, and was director of the Laboratory for Planetary Studies.
In addition to scientific publications, he wrote several popular books: The Dragons of Eden (1977), which received the Pulitzer Prize for non-fiction in 1978, Broca’s brain, speculations on the evolution of human intelligence (1979); Cosmos (1980) ―based on the television series of the same title, which he produced― and El comet (1985). He also wrote a novel, Contact (1985), on which the film of the same name, starring Jodie Foster, was based .
In 1980, his 13-part series for public broadcast services Cosmos became one of the most popular series in the history of American public television. He was awarded NASA Medals for Outstanding Scientific Achievement, Achievement in the Apollo Program, and Distinguished Public Service (twice). The international prize for Astronautics: the Prix Galbert. The Joseph Priestley Award “for distinguished contributions to the welfare of mankind.” The Masursky Prize of the American Astronomical Society and in 1994, the Public Welfare Medal, the highest honor of the National Academy of Sciences.
Scientific achievements
Sagan’s contributions were vital to the discovery of the high surface temperatures of the planet Venus. In the early 1960s, no one knew for sure what the basic conditions of the planet’s surface were, and Sagan listed the possibilities in a report that was later released in a Time-Life book called Planets. In his opinion, Venus was a very hot and dry planet as opposed to the temperate paradise others imagined. He had investigated radio emissions from Venus and concluded that the surface temperature of this must be about 500 ° C .
As a visiting scientist at NASA’s Jet Propulsion Laboratory, he participated in the Mariner Program’s first missions to Venus, working on the design and management of the project. In 1962, the Mariner 2 probe confirmed its conclusions about the planet’s surface conditions.
He was among the first to hypothesize that one of Saturn’s moons, Titan, could host oceans of liquid compounds on its surface, and that one of Jupiter’s moons, Europa, could have oceans of underground water. This would make Europe potentially habitable by life forms. Europa’s underground ocean of water was later confirmed indirectly by the Galileo space probe. The mystery of Titan’s red haze was also solved with Sagan’s help, due to complex organic molecules constantly raining down on the surface of the Saturnian moon.
It also contributed to a better understanding of the atmospheres of Venus and Jupiter and of the seasonal changes of Mars. He determined that the atmosphere of Venus is extremely hot and dense with gradually increasing pressures to the planetary surface. He also perceived global warming as a growing danger of human origin and compared it to the natural evolution of Venus towards a hot planet and unfit for life as a result of a runaway greenhouse effect. Sagan and his Cornell colleague, Edwin Ernest Salpeter, speculated on the possibility of life in Jupiter’s clouds, given the composition of the planet’s dense atmosphere, rich in organic molecules. He also studied the color variations of the surface of Mars and concluded that they were not seasonal or plant changes,
In January 1991, he hypothesized that a sufficient amount of smoke from the Kuwait oil fires that year could reach such a height as to dismantle agricultural activity in South Asia … He later recognized, in El world and its demons, that this prediction did not turn out to be correct: it was pitch dark at noon and temperatures dropped between 4 and 6 ° C in the Persian Gulf , but it was not much smoke that reached stratospheric altitudes and Asia was saved .
In 2007, a study applied modern computer models to the Kuwait oil fires, finding that individual plumes of smoke are not capable of lifting it to the stratosphere, but that smoke from fires that span a large area, such as some forest fires or the fires of entire cities as a result of a nuclear attack, would raise significant amounts of smoke to stratospheric levels.
In his later years, Sagan advocated the creation of an organized search for near-Earth objects that could impact Earth. While other experts suggested creating large nuclear bombs that could be used to alter the orbit of a NEO susceptible to Earth impact, Sagan proposed the Dilemma of Deviation: by creating the ability to move an asteroid away from Earth, you also create the ability to divert it towards it, potentially endowing an evil power with a veritable end-of-the-world bomb.
Death
He died in the city of Seattle , on the west coast of the United States, on December 20 , 1996 , at the age of 62.
