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Carl Sagan

November 08, 2023

For other uses, see Carl Sagan (disambiguation).

Carl Edward Sagan (/ˈseɪɡən/; SAY-gən; November 9, 1934 – December 20, 1996) was an American astronomer and science communicator. His best known scientific contribution is his research on the possibility of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. He assembled the first physical messages sent into space, the Pioneer plaque and the Voyager Golden Record, which were universal messages that could potentially be understood by any extraterrestrial intelligence that might find them. He argued in favor of the hypothesis, which has since been accepted, that the high surface temperatures of Venus are the result of the greenhouse effect.[4]

Carl Sagan
Sagan in the 1970s
Born
Carl Edward Sagan

(1934-11-09)November 9, 1934
New York City, New York, U.S.
DiedDecember 20, 1996(1996-12-20) (aged 62)
Seattle, Washington, U.S.
Resting placeLake View Cemetery, Ithaca, New York
Alma materUniversity of Chicago
(BA, BS, MS, PhD)
Known for
Spouses
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(m. 1957; div. 1965)​
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(m. 1968; div. 1981)​
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(m. 1981)​
Children5, including Dorion, Nick, and Sasha
Awards
Scientific career
Fields
Institutions
ThesisPhysical studies of planets (1960)
Doctoral advisorGerard Kuiper
Doctoral students
Signature

Initially an assistant professor at Harvard, Sagan later moved to Cornell, where he spent most of his career. He published more than 600 scientific papers and articles and was author, co-author or editor of more than 20 books.[5] He wrote many popular science books, such as The Dragons of Eden, Broca's Brain, Pale Blue Dot and The Demon-Haunted World. He also co-wrote and narrated the award-winning 1980 television series Cosmos: A Personal Voyage, which became the most widely watched series in the history of American public television: Cosmos has been seen by at least 500 million people in 60 countries.[6] A book, also called Cosmos, was published to accompany the series. Sagan also wrote a science-fiction novel, published in 1985, called Contact, which became the basis for a 1997 film of the same name. His papers, comprising 595,000 items,[7] are archived in the Library of Congress.[8]

Sagan was a popular public advocate of skeptical scientific inquiry and the scientific method; he pioneered the field of exobiology and promoted the search for extra-terrestrial intelligent life (SETI). He spent most of his career as a professor of astronomy at Cornell University, where he directed the Laboratory for Planetary Studies. Sagan and his works received numerous awards and honors, including the NASA Distinguished Public Service Medal, the National Academy of Sciences Public Welfare Medal, the Pulitzer Prize for General Non-Fiction (for his book The Dragons of Eden), and (for Cosmos: A Personal Voyage), two Emmy Awards, the Peabody Award, and the Hugo Award. He married three times and had five children. After developing myelodysplasia, Sagan died of pneumonia at the age of 62 on December 20, 1996.

Early life edit

Childhood edit

 
Sagan in Rahway High School's 1951 yearbook

Carl Edward Sagan was born in the Bensonhurst neighborhood of New York City's Brooklyn borough on November 9, 1934.[9][10] His mother, Rachel Molly Gruber, was a housewife from New York City; his father, Samuel Sagan, was a Ukrainian garment worker who emigrated from Kamianets-Podilskyi (which was then in the Russian Empire).[11] Sagan was named in honor of his maternal grandmother, Chaiya Clara, who had died while giving birth to her second child; she was, in Sagan's words, "the mother she [Rachel] never knew."[12] Sagan's maternal grandfather later married a woman named Rose, whom Sagan's sister Carol would later say was "never accepted" as Rachel's mother because Rachel "knew she [Rose] wasn't her birth mother."[13] Sagan's family lived in a modest apartment in Bensonhurst. He later discussed his family being Reform Jews, the most liberal of Judaism's four main branches. He and his sister agreed that their father was not especially religious, but that their mother "definitely believed in God, and was active in the temple [...] and served only kosher meat."[14] During the worst years of the Depression, his father worked as a movie theater usher.[14]

According to biographer Keay Davidson, Sagan experienced a kind of "inner war" as a result of his close relationship with both of his parents, who were in many ways "opposites." He traced his later analytical urges to his mother, a woman who had been extremely poor as a child in New York City during World War I and the 1920s.[15] As a young woman, she had had intellectual ambitions, but they were sabotaged by her poverty, her status as a woman and a wife, and her Jewish ethnicity. Davidson suggested that this is why she "worshipped her only son, Carl" because "he would fulfill her unfulfilled dreams."[15] Sagan believed that he got his sense of wonder from his father, who spent his free time giving apples to the poor or helping soothing tensions between employees and management within New York City's garment industry.[15] Although awed by his son's intellectual abilities, Sagan's father took his inquisitiveness in stride and saw it as part of growing up.[15] Later, during his career, Sagan would draw on his childhood memories to illustrate scientific points as he did in his book Shadows of Forgotten Ancestors.[16]

Describing his parents' influence on his later thinking, Sagan said: "My parents were not scientists. They knew almost nothing about science. But in introducing me simultaneously to skepticism and to wonder, they taught me the two uneasily cohabiting modes of thought that are central to the scientific method."[17] He recalled that a defining moment in his development was at age four, when his parents took him to see the exhibits at the 1939 New York World's Fair. He later described his memories of several exhibits there. One was a moving map in the America of Tomorrow exhibit, which he said "showed beautiful highways and cloverleaves and little General Motors cars all carrying people to skyscrapers, buildings with lovely spires, flying buttresses—and it looked great!"[18] Another was a flashlight shining on a photoelectric cell, which created a crackling sound, and another showed how the sound from a tuning fork became a wave on an oscilloscope. He also saw an exhibit of the then-nascent medium known as television. Referring to that exhibit, he later wrote: "Plainly, the world held wonders of a kind I had never guessed. How could a tone become a picture and light become a noise?"[18]

Sagan also saw one of the Fair's most publicized events: the burial of a time capsule at Flushing Meadows, which contained mementos of the 1930s to be recovered by Earth's descendants in a future millennium. Davidson wrote that this "thrilled Carl." As an adult, inspired by his memories of the World's Fair, Sagan and his colleagues would create similar time capsules to be sent out into the galaxy: the Pioneer plaque and the Voyager Golden Record précis.[19] During World War II, Sagan's family worried about the fate of their European relatives. Sagan, however, was generally unaware of the details of the ongoing war. He wrote, "Sure, we had relatives who were caught up in the Holocaust. Hitler was not a popular fellow in our household... but on the other hand, I was fairly insulated from the horrors of the war." His sister, Carol, said that their mother "above all wanted to protect Carl... she had an extraordinarily difficult time dealing with World War II and the Holocaust."[19] Sagan's book The Demon-Haunted World (1996) included his memories of this conflicted period, when his family dealt with the realities of the war in Europe but tried to prevent it from undermining his optimistic spirit.[17]

Soon after entering elementary school, Sagan began to express a strong inquisitiveness about nature. He recalled taking his first trips to the public library alone, at the age of five, when his mother got him a library card. He wanted to learn what stars were, since none of his friends or their parents could give him a clear answer: "I went to the librarian and asked for a book about stars [...] and the answer was stunning. It was that the Sun was a star but really close. The stars were suns, but so far away they were just little points of light. The scale of the universe suddenly opened up to me. It was a kind of religious experience. There was a magnificence to it, a grandeur, a scale which has never left me. Never ever left me."[20] At about age six or seven, he and a close friend took trips to the American Museum of Natural History in Manhattan. While there, they went to the Hayden Planetarium and walked around the museum's exhibits of space objects, such as meteorites, and displays of dinosaurs and animals in natural settings. He wrote, "I was transfixed by the dioramas—lifelike representations of animals and their habitats all over the world. Penguins on the dimly lit Antarctic ice [...] a family of gorillas, the male beating his chest [...] an American grizzly bear standing on his hind legs, ten or twelve feet tall, and staring me right in the eye."[20]

Sagan's parents helped nurture his growing interest in science by buying him chemistry sets and reading materials. However, his interest in space was his primary focus, especially after reading sci-fi stories by writers such as H. G. Wells and Edgar Rice Burroughs, which stirred his imagination about the possibility of life on other planets such as Mars.[21] According to biographer Ray Spangenburg, Sagan's early years of trying to understand the mysteries of the planets became a "driving force in his life, a continual spark to his intellect, and a quest that would never be forgotten."[17] In 1947, Sagan discovered the magazine Astounding Science Fiction, which introduced him to more hard science fiction speculations than those in Burroughs' novels.[21] That same year, a mass hysteria developed about the possibility that extraterrestrial visitors had arrived in flying saucers, and the young Sagan joined in the speculation that the flying "discs" people reported seeing in the sky might be alien spaceships.[22]

Education edit

 
Sagan in the University of Chicago's 1954 yearbook

Sagan attended David A. Boody Junior High School in his native Bensonhurst and had his bar mitzvah when he turned 13.[23] In 1948, when he was 14, his father's work took the family to the older semi-industrial town of Rahway, New Jersey.[23] Sagan graduated from Rahway High School in 1951.[23] He was a straight-A student but was bored because his classes did not challenge him and his teachers did not inspire him.[23] His teachers realized this and tried to convince his parents to send him to a private school, with an administrator telling them, "This kid ought to go to a school for gifted children, he has something really remarkable."[24] However, his parents could not afford to do so. Sagan became president of the school's chemistry club, and set up his own laboratory at home. He taught himself about molecules by making cardboard cutouts to help him visualize how they were formed: "I found that about as interesting as doing [chemical] experiments."[24] He was mostly interested in astronomy, learning about it in his spare time. In his junior year of high school, he discovered that professional astronomers were paid for doing something he always enjoyed, and decided on astronomy as a career goal: "That was a splendid day—when I began to suspect that if I tried hard I could do astronomy full-time, not just part-time."[25]

Before the end of high school, Sagan entered an essay writing contest in which he explored the idea that human contact with advanced life forms from another planet might be as disastrous for people on Earth as Native Americans' first contact with Europeans had been for Native Americans.[26] The subject was considered controversial, but his rhetorical skill won over the judges and they awarded him first prize.[26] When he was about to graduate from high school, his classmates voted him "most likely to succeed" and put him in line to be valedictorian.[26] He attended the University of Chicago because, despite his excellent high school grades, it was one of the very few colleges he had applied to that would consider accepting a 16-year-old. Its chancellor, Robert Maynard Hutchins, had recently retooled the undergraduate College of the University of Chicago into an "ideal meritocracy" built on Great Books, Socratic dialogue, comprehensive examinations, and early entrance to college with no age requirement.[27]

As an honors-program undergraduate, Sagan worked in the laboratory of geneticist H. J. Muller and wrote a thesis on the origins of life with physical chemist Harold Urey. He also joined the Ryerson Astronomical Society.[28] In 1954, he was awarded a Bachelor of Arts with general and special honors[29] in what he quipped was "nothing."[30] In 1955, he earned a Bachelor of Science in physics. He went on to do graduate work at the University of Chicago, earning a Master of Science in physics in 1956 and a Doctor of Philosophy in astronomy and astrophysics in 1960. His doctoral thesis, submitted to the Department of Astronomy and Astrophysics, was entitled Physical Studies of the Planets.[31][32][33][34] During his graduate studies, he used the summer months to work with planetary scientist Gerard Kuiper, who was his dissertation director,[3] as well as physicist George Gamow and chemist Melvin Calvin. The title of Sagan's dissertation reflected interests he had in common with Kuiper, who had been president of the International Astronomical Union's commission on "Physical Studies of Planets and Satellites" throughout the 1950s.[35]

In 1958, Sagan and Kuiper worked on the classified military Project A119, a secret U.S. Air Force plan to detonate a nuclear warhead on the Moon and document its effects.[36] Sagan had a Top Secret clearance at the Air Force and a Secret clearance with NASA.[37] In 1999, an article published in the journal Nature revealed that Sagan had included the classified titles of two Project A119 papers in his 1959 application for a scholarship to University of California, Berkeley. A follow-up letter to the journal by project leader Leonard Reiffel confirmed Sagan's security leak.[38]

Career and research edit

Sagan is one of those discussing the likelihood of life on other planets in Who's Out There? (1973), an award-winning NASA documentary film by Robert Drew.

From 1960 to 1962 Sagan was a Miller Fellow at the University of California, Berkeley.[39] Meanwhile, he published an article in 1961 in the journal Science on the atmosphere of Venus, while also working with NASA's Mariner 2 team, and served as a "Planetary Sciences Consultant" to the RAND Corporation.[40]

After the publication of Sagan's Science article, in 1961 Harvard University astronomers Fred Whipple and Donald Menzel offered Sagan the opportunity to give a colloquium at Harvard and subsequently offered him a lecturer position at the institution. Sagan instead asked to be made an assistant professor, and eventually Whipple and Menzel were able to convince Harvard to offer Sagan the assistant professor position he requested.[40] Sagan lectured, performed research, and advised graduate students at the institution from 1963 until 1968, as well as working at the Smithsonian Astrophysical Observatory, also located in Cambridge, Massachusetts.

In 1968, Sagan was denied academic tenure at Harvard. He later indicated that the decision was very unexpected.[41] The denial has been blamed on several factors, including that he focused his interests too broadly across a number of areas (while the norm in academia is to become a renowned expert in a narrow specialty), and perhaps because of his well-publicized scientific advocacy, which some scientists perceived as borrowing the ideas of others for little more than self-promotion.[37] An advisor from his years as an undergraduate student, Harold Urey, wrote a letter to the tenure committee recommending strongly against tenure for Sagan.[22]

Science is more than a body of knowledge; it is a way of thinking. I have a foreboding of an America in my children's or grandchildren's time – when the United States is a service and information economy; when nearly all the key manufacturing industries have slipped away to other countries; when awesome technological powers are in the hands of a very few, and no one representing the public interest can even grasp the issues; when the people have lost the ability to set their own agendas or knowledgeably question those in authority; when, clutching our crystals and nervously consulting our horoscopes, our critical faculties in decline, unable to distinguish between what feels good and what's true, we slide, almost without noticing, back into superstition and darkness... The dumbing down of America is most evident in the slow decay of substantive content in the enormously influential media, the 30 second sound bites (now down to 10 seconds or less), lowest common denominator programming, credulous presentations on pseudoscience and superstition, but especially a kind of celebration of ignorance.

Carl Sagan, from Demon-Haunted World (1995)[42]

Long before the ill-fated tenure process, Cornell University astronomer Thomas Gold had courted Sagan to move to Ithaca, New York, and join the recently-hired astronomer Frank Drake amongst the faculty at Cornell. Following the denial of tenure from Harvard, Sagan accepted Gold's offer and remained a faculty member at Cornell for nearly 30 years until his death in 1996. Unlike Harvard, the smaller and more laid-back astronomy department at Cornell welcomed Sagan's growing celebrity status.[43] Following two years as an associate professor, Sagan became a full professor at Cornell in 1970 and directed the Laboratory for Planetary Studies there. From 1972 to 1981, he was associate director of the Center for Radiophysics and Space Research (CRSR) at Cornell. In 1976, he became the David Duncan Professor of Astronomy and Space Sciences, a position he held for the remainder of his life.[44]

Sagan was associated with the U.S. space program from its inception.[citation needed] From the 1950s onward, he worked as an advisor to NASA, where one of his duties included briefing the Apollo astronauts before their flights to the Moon. Sagan contributed to many of the robotic spacecraft missions that explored the Solar System, arranging experiments on many of the expeditions. Sagan assembled the first physical message that was sent into space: a gold-plated plaque, attached to the space probe Pioneer 10, launched in 1972. Pioneer 11, also carrying another copy of the plaque, was launched the following year. He continued to refine his designs; the most elaborate message he helped to develop and assemble was the Voyager Golden Record, which was sent out with the Voyager space probes in 1977. Sagan often challenged the decisions to fund the Space Shuttle and the International Space Station at the expense of further robotic missions.[45]

Scientific achievements edit

 
Sagan and the Viking spacecraft

Former student David Morrison described Sagan as "an 'idea person' and a master of intuitive physical arguments and 'back of the envelope' calculations",[37] and Gerard Kuiper said that "Some persons work best in specializing on a major program in the laboratory; others are best in liaison between sciences. Dr. Sagan belongs in the latter group."[37]

Sagan's contributions were central to the discovery of the high surface temperatures of the planet Venus.[4][46] In the early 1960s no one knew for certain the basic conditions of Venus' surface, and Sagan listed the possibilities in a report later depicted for popularization in a Time Life book Planets. His own view was that Venus was dry and very hot as opposed to the balmy paradise others had imagined. He had investigated radio waves from Venus and concluded that there was a surface temperature of 500 °C (900 °F). As a visiting scientist to NASA's Jet Propulsion Laboratory, he contributed to the first Mariner missions to Venus, working on the design and management of the project. Mariner 2 confirmed his conclusions on the surface conditions of Venus in 1962.

Sagan was among[clarification needed] the first to hypothesize that Saturn's moon Titan might possess oceans of liquid compounds on its surface and that Jupiter's moon Europa might possess subsurface oceans of water. This would make Europa potentially habitable.[47] Europa's subsurface ocean of water was later indirectly confirmed by the spacecraft Galileo. The mystery of Titan's reddish haze was also solved with Sagan's help. The reddish haze was revealed to be due to complex organic molecules constantly raining down onto Titan's surface.[48]

Sagan further contributed insights regarding the atmospheres of Venus and Jupiter, as well as seasonal changes on Mars. He also perceived global warming as a growing, man-made danger and likened it to the natural development of Venus into a hot, life-hostile planet through a kind of runaway greenhouse effect.[49] He testified to the US Congress in 1985 that the greenhouse effect would change the earth's climate system.[50] Sagan and his Cornell colleague Edwin Ernest Salpeter speculated about life in Jupiter's clouds, given the planet's dense atmospheric composition rich in organic molecules. He studied the observed color variations on Mars' surface and concluded that they were not seasonal or vegetational changes as most believed,[clarification needed] but shifts in surface dust caused by windstorms.

Sagan is also known for his research on the possibilities of extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation.[51][52]

He is also the 1994 recipient of the Public Welfare Medal, the highest award of the National Academy of Sciences for "distinguished contributions in the application of science to the public welfare."[53] He was denied membership in the academy, reportedly because his media activities made him unpopular with many other scientists.[54][55][56]

As of 2017, Sagan is the most cited SETI scientist and one of the most cited planetary scientists.[5]

Cosmos: popularizing science on TV edit

 
Sagan in Cosmos (1980)

In 1980 Sagan co-wrote and narrated the award-winning 13-part PBS television series Cosmos: A Personal Voyage, which became the most widely watched series in the history of American public television until 1990. The show has been seen by at least 500 million people across 60 countries.[6][57][58] The book, Cosmos, written by Sagan, was published to accompany the series.[59]

Because of his earlier popularity as a science writer from his best-selling books, including The Dragons of Eden, which won him a Pulitzer Prize in 1977, he was asked to write and narrate the show. It was targeted to a general audience of viewers, whom Sagan felt had lost interest in science, partly due to a stifled educational system.[60]

Each of the 13 episodes was created to focus on a particular subject or person, thereby demonstrating the synergy of the universe.[60] They covered a wide range of scientific subjects including the origin of life and a perspective of humans' place on Earth.

The show won an Emmy,[61] along with a Peabody Award, and transformed Sagan from an obscure astronomer into a pop-culture icon.[62] Time magazine ran a cover story about Sagan soon after the show broadcast, referring to him as "creator, chief writer and host-narrator of the show."[63] In 2000, "Cosmos" was released on a remastered set of DVDs.

"Billions and billions" edit

After Cosmos aired, Sagan became associated with the catchphrase "billions and billions", although he never actually used the phrase in the Cosmos series.[64] He rather used the term "billions upon billions."[65]

Richard Feynman, a precursor to Sagan, used the phrase "billions and billions" many times in his "red books." However, Sagan's frequent use of the word billions and distinctive delivery emphasizing the "b" (which he did intentionally, in place of more cumbersome alternatives such as "billions with a 'b'", in order to distinguish the word from "millions")[64] made him a favorite target of comic performers, including Johnny Carson,[66][67] Gary Kroeger, Mike Myers, Bronson Pinchot, Penn Jillette, Harry Shearer, and others. Frank Zappa satirized the line in the song "Be in My Video", noting as well "atomic light." Sagan took this all in good humor, and his final book was entitled Billions and Billions, which opened with a tongue-in-cheek discussion of this catchphrase, observing that Carson was an amateur astronomer and that Carson's comic caricature often included real science.[64]

As a humorous tribute to Sagan and his association with the catchphrase "billions and billions", a sagan has been defined as a unit of measurement equivalent to a very large number of anything.[68][69]

Sagan's number edit

Sagan's number is the number of stars in the observable universe.[70] This number is reasonably well defined, because it is known what stars are and what the observable universe is, but its value is highly uncertain.

  • In 1980, Sagan estimated it to be 10 sextillion in short scale (1022).[71]
  • In 2003, it was estimated to be 70 sextillion (7 × 1022).[72][73]
  • In 2010, it was estimated to be 300 sextillion (3 × 1023).[74]

Scientific and critical thinking advocacy edit

 
Carl Sagan popularized the Cosmic Calendar as a method to visualize the chronology of the universe, scaling its current age of 13.8 billion years to a single year to help intuit it for pedagogical purposes.

Sagan's ability to convey his ideas allowed many people to understand the cosmos better—simultaneously emphasizing the value and worthiness of the human race, and the relative insignificance of the Earth in comparison to the Universe. He delivered the 1977 series of Royal Institution Christmas Lectures in London.[75]

Sagan was a proponent of the search for extraterrestrial life. He urged the scientific community to listen with radio telescopes for signals from potential intelligent extraterrestrial life-forms. Sagan was so persuasive that by 1982 he was able to get a petition advocating SETI published in the journal Science, signed by 70 scientists, including seven Nobel Prize winners. This signaled a tremendous increase in the respectability of a then-controversial field. Sagan also helped Frank Drake write the Arecibo message, a radio message beamed into space from the Arecibo radio telescope on November 16, 1974, aimed at informing potential extraterrestrials about Earth.

Sagan was chief technology officer of the professional planetary research journal Icarus for 12 years. He co-founded The Planetary Society and was a member of the SETI Institute Board of Trustees. Sagan served as Chairman of the Division for Planetary Science of the American Astronomical Society, as President of the Planetology Section of the American Geophysical Union, and as Chairman of the Astronomy Section of the American Association for the Advancement of Science (AAAS).

 
The Planetary Society members at the organization's founding. Sagan is seated on the right.

At the height of the Cold War, Sagan became involved in nuclear disarmament efforts by promoting hypotheses on the effects of nuclear war, when Paul Crutzen's "Twilight at Noon" concept suggested that a substantial nuclear exchange could trigger a nuclear twilight and upset the delicate balance of life on Earth by cooling the surface. In 1983 he was one of five authors—the "S"—in the follow-up "TTAPS" model (as the research article came to be known), which contained the first use of the term "nuclear winter", which his colleague Richard P. Turco had coined.[76] In 1984 he co-authored the book The Cold and the Dark: The World after Nuclear War and in 1990 the book A Path Where No Man Thought: Nuclear Winter and the End of the Arms Race, which explains the nuclear-winter hypothesis and advocates nuclear disarmament. Sagan received a great deal of skepticism and disdain for the use of media to disseminate a very uncertain hypothesis. A personal correspondence with nuclear physicist Edward Teller around 1983 began amicably, with Teller expressing support for continued research to ascertain the credibility of the winter hypothesis. However, Sagan and Teller's correspondence would ultimately result in Teller writing: "A propagandist is one who uses incomplete information to produce maximum persuasion. I can compliment you on being, indeed, an excellent propagandist, remembering that a propagandist is the better the less he appears to be one."[77] Biographers of Sagan would also comment that from a scientific viewpoint, nuclear winter was a low point for Sagan, although, politically speaking, it popularized his image amongst the public.[77]

The adult Sagan remained a fan of science fiction, although disliking stories that were not realistic (such as ignoring the inverse-square law) or, he said, did not include "thoughtful pursuit of alternative futures."[21] He wrote books to popularize science, such as Cosmos, which reflected and expanded upon some of the themes of A Personal Voyage and became the best-selling science book ever published in English;[78] The Dragons of Eden: Speculations on the Evolution of Human Intelligence, which won a Pulitzer Prize; and Broca's Brain: Reflections on the Romance of Science. Sagan also wrote the best-selling science fiction novel Contact in 1985, based on a film treatment he wrote with his wife, Ann Druyan, in 1979, but he did not live to see the book's 1997 motion-picture adaptation, which starred Jodie Foster and won the 1998 Hugo Award for Best Dramatic Presentation.

 
Pale Blue Dot: Earth is a bright pixel when photographed from Voyager 1, 6 billion kilometres (3.7 billion miles) away.[79] Sagan encouraged NASA to generate this image.
from Pale Blue Dot (1994)[80]

On it, everyone you ever heard of... The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilizations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there on a mote of dust, suspended in a sunbeam. ...
Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot.

Carl Sagan, Cornell lecture in 1994

Sagan wrote a sequel to Cosmos, Pale Blue Dot: A Vision of the Human Future in Space, which was selected as a notable book of 1995 by The New York Times. He appeared on PBS's Charlie Rose program in January 1995.[45] Sagan also wrote the introduction for Stephen Hawking's bestseller A Brief History of Time. Sagan was also known for his popularization of science, his efforts to increase scientific understanding among the general public, and his positions in favor of scientific skepticism and against pseudoscience, such as his debunking of the Betty and Barney Hill abduction. To mark the tenth anniversary of Sagan's death, David Morrison, a former student of Sagan, recalled "Sagan's immense contributions to planetary research, the public understanding of science, and the skeptical movement" in Skeptical Inquirer.[37]

Following Saddam Hussein's threats to light Kuwait's oil wells on fire in response to any physical challenge to Iraqi control of the oil assets, Sagan together with his "TTAPS" colleagues and Paul Crutzen, warned in January 1991 in The Baltimore Sun and Wilmington Morning Star newspapers that if the fires were left to burn over a period of several months, enough smoke from the 600 or so 1991 Kuwaiti oil fires "might get so high as to disrupt agriculture in much of South Asia ..." and that this possibility should "affect the war plans";[81][82] these claims were also the subject of a televised debate between Sagan and physicist Fred Singer on January 22, aired on the ABC News program Nightline.[83][84]

 
Sagan admitted that he had overestimated the danger posed by the 1991 Kuwaiti oil fires.

In the televised debate, Sagan argued that the effects of the smoke would be similar to the effects of a nuclear winter, with Singer arguing to the contrary. After the debate, the fires burnt for many months before extinguishing efforts were complete. The results of the smoke did not produce continental-sized cooling. Sagan later conceded in The Demon-Haunted World that the prediction did not turn out to be correct: "it was pitch black at noon and temperatures dropped 4–6 °C over the Persian Gulf, but not much smoke reached stratospheric altitudes and Asia was spared."[85]

In his later years Sagan advocated the creation of an organized search for asteroids/near-Earth objects (NEOs) that might impact the Earth but to forestall or postpone developing the technological methods that would be needed to defend against them.[86] He argued that all of the numerous methods proposed to alter the orbit of an asteroid, including the employment of nuclear detonations, created a deflection dilemma: if the ability to deflect an asteroid away from the Earth exists, then one would also have the ability to divert a non-threatening object towards Earth, creating an immensely destructive weapon.[87][88] In a 1994 paper he co-authored, he ridiculed a 3-day long "Near-Earth Object Interception Workshop" held by Los Alamos National Laboratory (LANL) in 1993 that did not, "even in passing" state that such interception and deflection technologies could have these "ancillary dangers."[87]

Sagan remained hopeful that the natural NEO impact threat and the intrinsically double-edged essence of the methods to prevent these threats would serve as a "new and potent motivation to maturing international relations."[87][89] Later acknowledging that, with sufficient international oversight, in the future a "work our way up" approach to implementing nuclear explosive deflection methods could be fielded, and when sufficient knowledge was gained, to use them to aid in mining asteroids.[88] His interest in the use of nuclear detonations in space grew out of his work in 1958 for the Armour Research Foundation's Project A119, concerning the possibility of detonating a nuclear device on the lunar surface.[90]

Sagan was a critic of Plato, having said of the ancient Greek philosopher: "Science and mathematics were to be removed from the hands of the merchants and the artisans. This tendency found its most effective advocate in a follower of Pythagoras named Plato" and[91]

He (Plato) believed that ideas were far more real than the natural world. He advised the astronomers not to waste their time observing the stars and planets. It was better, he believed, just to think about them. Plato expressed hostility to observation and experiment. He taught contempt for the real world and disdain for the practical application of scientific knowledge. Plato's followers succeeded in extinguishing the light of science and experiment that had been kindled by Democritus and the other Ionians.

In 1995 (as part of his book The Demon-Haunted World) Sagan popularized a set of tools for skeptical thinking called the "baloney detection kit", a phrase first coined by Arthur Felberbaum, a friend of his wife Ann Druyan.[92]

Popularizing science edit

Speaking about his activities in popularizing science, Sagan said that there were at least two reasons for scientists to share the purposes of science and its contemporary state. Simple self-interest was one: much of the funding for science came from the public, and the public therefore had the right to know how the money was being spent. If scientists increased public admiration for science, there was a good chance of having more public supporters.[93] The other reason was the excitement of communicating one's own excitement about science to others.[10]

Following the success of Cosmos, Sagan set up his own publishing firm, Cosmos Store, to publish science books for the general public. It was not successful.[94]

Criticisms edit

While Sagan was widely adored by the general public, his reputation in the scientific community was more polarized.[95] Critics sometimes characterized his work as fanciful, non-rigorous, and self-aggrandizing,[96] and others complained in his later years that he neglected his role as a faculty member to foster his celebrity status.[97]

One of Sagan's harshest critics, Harold Urey, felt that Sagan was getting too much publicity for a scientist and was treating some scientific theories too casually.[98] Urey and Sagan were said to have different philosophies of science, according to Davidson. While Urey was an "old-time empiricist" who avoided theorizing about the unknown, Sagan was by contrast willing to speculate openly about such matters.[41] Fred Whipple wanted Harvard to keep Sagan there, but learned that because Urey was a Nobel laureate, his opinion was an important factor in Harvard denying Sagan tenure.[98]

Sagan's Harvard friend Lester Grinspoon also stated: "I know Harvard well enough to know there are people there who certainly do not like people who are outspoken."[98] Grinspoon added:[98]

Wherever you turned, there was one astronomer being quoted on everything, one astronomer whose face you were seeing on TV, and one astronomer whose books had the preferred display slot at the local bookstore.

Some, like Urey, later came to realize that Sagan's popular brand of scientific advocacy was beneficial to the science as a whole.[99] Urey especially liked Sagan's 1977 book The Dragons of Eden and wrote Sagan with his opinion: "I like it very much and am amazed that someone like you has such an intimate knowledge of the various features of the problem... I congratulate you... You are a man of many talents."[99]

Sagan was accused of borrowing some ideas of others for his own benefit and countered these claims by explaining that the misappropriation was an unfortunate side effect of his role as a science communicator and explainer, and that he attempted to give proper credit whenever possible.[98]

Social concerns edit

Sagan believed that the Drake equation, on substitution of reasonable estimates, suggested that a large number of extraterrestrial civilizations would form, but that the lack of evidence of such civilizations highlighted by the Fermi paradox suggests technological civilizations tend to self-destruct. This stimulated his interest in identifying and publicizing ways that humanity could destroy itself, with the hope of avoiding such a cataclysm and eventually becoming a spacefaring species. Sagan's deep concern regarding the potential destruction of human civilization in a nuclear holocaust was conveyed in a memorable cinematic sequence in the final episode of Cosmos, called "Who Speaks for Earth?" Sagan had already resigned[date missing] from the Air Force Scientific Advisory Board's UFO investigating Condon Committee and voluntarily surrendered his top-secret clearance in protest over the Vietnam War.[100] Following his marriage to his third wife (novelist Ann Druyan) in June 1981, Sagan became more politically active—particularly in opposing escalation of the nuclear arms race under President Ronald Reagan.

 
The United States and Soviet Union/Russia nuclear stockpiles, in total number of nuclear bombs/warheads in existence throughout the Cold War and post-Cold War era

In March 1983, Reagan announced the Strategic Defense Initiative—a multibillion-dollar project to develop a comprehensive defense against attack by nuclear missiles, which was quickly dubbed the "Star Wars" program. Sagan spoke out against the project, arguing that it was technically impossible to develop a system with the level of perfection required, and far more expensive to build such a system than it would be for an enemy to defeat it through decoys and other means—and that its construction would seriously destabilize the "nuclear balance" between the United States and the Soviet Union, making further progress toward nuclear disarmament impossible.[101]

When Soviet leader Mikhail Gorbachev declared a unilateral moratorium on the testing of nuclear weapons, which would begin on August 6, 1985—the 40th anniversary of the atomic bombing of Hiroshima—the Reagan administration dismissed the dramatic move as nothing more than propaganda and refused to follow suit. In response, US anti-nuclear and peace activists staged a series of protest actions at the Nevada Test Site, beginning on Easter Sunday in 1986 and continuing through 1987. Hundreds of people in the "Nevada Desert Experience" group were arrested, including Sagan, who was arrested on two separate occasions as he climbed over a chain-link fence at the test site during the underground Operation Charioteer and United States's Musketeer nuclear test series of detonations.[102]

Sagan was also a vocal advocate of the controversial notion of testosterone poisoning, arguing in 1992 that human males could become gripped by an "unusually severe [case of] testosterone poisoning" and this could compel them to become genocidal.[103] In his review of Moondance magazine writer Daniela Gioseffi's 1990 book Women on War, he argues that females are the only half of humanity "untainted by testosterone poisoning."[104] One chapter of his 1993 book Shadows of Forgotten Ancestors is dedicated to testosterone and its alleged poisonous effects.[105]

In 1989, Carl Sagan was interviewed by Ted Turner whether he believed in socialism and responded that: "I'm not sure what a socialist is. But I believe the government has a responsibility to care for the people... I'm talking about making the people self-reliant."[106]

Personal life and beliefs edit

Sagan was married three times. In 1957, he married biologist Lynn Margulis. The couple had two children, Jeremy and Dorion Sagan; their marriage ended in 1964. Sagan married artist Linda Salzman in 1968 and they had a child together, Nick Sagan, and divorced in 1981. During these marriages, Carl Sagan focused heavily on his career, a factor which may have contributed to Sagan's first divorce.[37] In 1981, Sagan married author Ann Druyan and they later had two children, Alexandra (known as Sasha) and Samuel Sagan. Carl Sagan and Druyan remained married until his death in 1996.

While teaching at Cornell, he lived in an Egyptian revival house in Ithaca perched on the edge of a cliff that had formerly been the headquarters of a Cornell secret society.[107] While there he drove a red Porsche 911 Targa and an orange 1970 Porsche 914[108] with the license plate PHOBOS.

In 1994, engineers at Apple Computer code-named the Power Macintosh 7100 "Carl Sagan" in the hope that Apple would make "billions and billions" with the sale of the PowerMac 7100.[9] The name was only used internally, but Sagan was concerned that it would become a product endorsement and sent Apple a cease-and-desist letter. Apple complied, but engineers retaliated by changing the internal codename to "BHA" for "Butt-Head Astronomer."[109][110] In November 1995, after further legal battle, an out-of-court settlement was reached and Apple's office of trademarks and patents released a conciliatory statement that "Apple has always had great respect for Dr. Sagan. It was never Apple's intention to cause Dr. Sagan or his family any embarrassment or concern."[111]

In 2019, Carl Sagan's daughter Sasha Sagan released For Small Creatures Such as We: Rituals for Finding Meaning in our Unlikely World, which depicts life with her parents and her father's death when she was fourteen.[112] Building on a theme in her father's work, Sasha Sagan argues in For Small Creatures Such as We that skepticism does not imply pessimism.[113]

I have just finished The Cosmic Connection and loved every word of it. You are my idea of a good writer because you have an unmannered style, and when I read what you write, I hear you talking. One thing about the book made me nervous. It was entirely too obvious that you are smarter than I am. I hate that.

Isaac Asimov, in a letter to Sagan, 1973[114]

Sagan was acquainted with the science fiction fandom through his friendship with Isaac Asimov, and he spoke at the Nebula Awards ceremony in 1969.[115][116] Asimov described Sagan as one of only two people he ever met whose intellect surpassed his own, the other being computer scientist and artificial intelligence expert Marvin Minsky.[117]

Naturalism edit

Sagan wrote frequently about religion and the relationship between religion and science, expressing his skepticism about the conventional conceptualization of God as a sapient being. For example:

Some people think God is an outsized, light-skinned male with a long white beard, sitting on a throne somewhere up there in the sky, busily tallying the fall of every sparrow. Others—for example Baruch Spinoza and Albert Einstein—considered God to be essentially the sum total of the physical laws which describe the universe. I do not know of any compelling evidence for anthropomorphic patriarchs controlling human destiny from some hidden celestial vantage point, but it would be madness to deny the existence of physical laws.[118]

In another description of his view on the concept of God, Sagan wrote:

The idea that God is an oversized white male with a flowing beard who sits in the sky and tallies the fall of every sparrow is ludicrous. But if by God one means the set of physical laws that govern the universe, then clearly there is such a God. This God is emotionally unsatisfying ... it does not make much sense to pray to the law of gravity.[119]

On atheism, Sagan commented in 1981:

An atheist is someone who is certain that God does not exist, someone who has compelling evidence against the existence of God. I know of no such compelling evidence. Because God can be relegated to remote times and places and to ultimate causes, we would have to know a great deal more about the universe than we do now to be sure that no such God exists. To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed.[120]

 
Sagan in 1987

Sagan also commented on Christianity and the Jefferson Bible, stating "My long-time view about Christianity is that it represents an amalgam of two seemingly immiscible parts, the religion of Jesus and the religion of Paul. Thomas Jefferson attempted to excise the Pauline parts of the New Testament. There wasn't much left when he was done, but it was an inspiring document."[121]

Sagan thought that spirituality should be scientifically informed and that traditional religions should be abandoned and replaced with belief systems that revolve around the scientific method,[122] but also the mystery and incompleteness of scientific fields. Regarding spirituality and its relationship with science, Sagan stated:

'Spirit' comes from the Latin word 'to breathe'. What we breathe is air, which is certainly matter, however thin. Despite usage to the contrary, there is no necessary implication in the word 'spiritual' that we are talking of anything other than matter (including the matter of which the brain is made), or anything outside the realm of science. On occasion, I will feel free to use the word. Science is not only compatible with spirituality; it is a profound source of spirituality. When we recognize our place in an immensity of light-years and in the passage of ages, when we grasp the intricacy, beauty, and subtlety of life, then that soaring feeling, that sense of elation and humility combined, is surely spiritual.[123]

An environmental appeal, "Preserving and Cherishing the Earth", primarily written by Sagan and signed by him and other noted scientists as well as religious leaders, and published in January 1990, stated that "The historical record makes clear that religious teaching, example, and leadership are powerfully able to influence personal conduct and commitment... Thus, there is a vital role for religion and science."[124]

In reply to a question in 1996 about his religious beliefs, Sagan answered, "I'm agnostic."[125] Sagan maintained that the idea of a creator God of the Universe was difficult to prove or disprove and that the only conceivable scientific discovery that could challenge it would be an infinitely old universe.[126] His son, Dorion Sagan said, "My father believed in the God of Spinoza and Einstein, God not behind nature but as nature, equivalent to it."[127] His last wife, Ann Druyan, stated:

When my husband died, because he was so famous and known for not being a believer, many people would come up to me—it still sometimes happens—and ask me if Carl changed at the end and converted to a belief in an afterlife. They also frequently ask me if I think I will see him again. Carl faced his death with unflagging courage and never sought refuge in illusions. The tragedy was that we knew we would never see each other again. I don't ever expect to be reunited with Carl.[128]

In 2006, Ann Druyan edited Sagan's 1985 Glasgow Gifford Lectures in Natural Theology into a book, The Varieties of Scientific Experience: A Personal View of the Search for God, in which he elaborates on his views of divinity in the natural world.

 
Sagan (center) speaks with CDC employees in 1988.

Sagan is also widely regarded as a freethinker or skeptic; one of his most famous quotations, in Cosmos, was, "Extraordinary claims require extraordinary evidence"[129] (called the "Sagan standard" by some[130]). This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal, Marcello Truzzi, "An extraordinary claim requires extraordinary proof."[131][132] This idea had been earlier aphorized in Théodore Flournoy's work From India to the Planet Mars (1899) from a longer quote by Pierre-Simon Laplace (1749–1827), a French mathematician and astronomer, as the Principle of Laplace: "The weight of the evidence should be proportioned to the strangeness of the facts."[133]

Late in his life, Sagan's books elaborated on his naturalistic view of the world. In The Demon-Haunted World, he presented tools for testing arguments and detecting fallacious or fraudulent ones, essentially advocating the wide use of critical thinking and of the scientific method. The compilation Billions and Billions: Thoughts on Life and Death at the Brink of the Millennium, published in 1997 after Sagan's death, contains essays written by him, on topics such as his views on abortion, and also an essay by his widow, Ann Druyan, about the relationship between his agnostic and freethinking beliefs and his death.

Sagan warned against humans' tendency towards anthropocentrism. He was the faculty adviser for the Cornell Students for the Ethical Treatment of Animals. In the Cosmos chapter "Blues For a Red Planet", Sagan wrote, "If there is life on Mars, I believe we should do nothing with Mars. Mars then belongs to the Martians, even if the Martians are only microbes."[134]

Marijuana advocacy edit

Sagan was a user and advocate of marijuana. Under the pseudonym "Mr. X", he contributed an essay about smoking cannabis to the 1971 book Marihuana Reconsidered.[135][136] The essay explained that marijuana use had helped to inspire some of Sagan's works and enhance sensual and intellectual experiences. After Sagan's death, his friend Lester Grinspoon disclosed this information to Sagan's biographer, Keay Davidson. The publishing of the biography, Carl Sagan: A Life, in 1999 brought media attention to this aspect of Sagan's life.[137][138][139] Not long after his death, his widow Ann Druyan went on to preside over the board of directors of the National Organization for the Reform of Marijuana Laws (NORML), a non-profit organization dedicated to reforming cannabis laws.[140][141]

UFOs edit

In 1947, the year that inaugurated the "flying saucer" craze, the young Sagan suspected the "discs" might be alien spaceships.[22]

Sagan's interest in UFO reports prompted him on August 3, 1952, to write a letter to U.S. Secretary of State Dean Acheson to ask how the United States would respond if flying saucers turned out to be extraterrestrial.[142] He later had several conversations on the subject in 1964 with Jacques Vallée.[143] Though quite skeptical of any extraordinary answer to the UFO question, Sagan thought scientists should study the phenomenon, at least because there was widespread public interest in UFO reports.

Stuart Appelle notes that Sagan "wrote frequently on what he perceived as the logical and empirical fallacies regarding UFOs and the abduction experience. Sagan rejected an extraterrestrial explanation for the phenomenon but felt there were both empirical and pedagogical benefits for examining UFO reports and that the subject was, therefore, a legitimate topic of study."[144]

In 1966, Sagan was a member of the Ad Hoc Committee to Review Project Blue Book, the U.S. Air Force's UFO investigation project. The committee concluded Blue Book had been lacking as a scientific study, and recommended a university-based project to give the UFO phenomenon closer scientific scrutiny. The result was the Condon Committee (1966–68), led by physicist Edward Condon, and in their final report they formally concluded that UFOs, regardless of what any of them actually were, did not behave in a manner consistent with a threat to national security.

Sociologist Ron Westrum writes that "The high point of Sagan's treatment of the UFO question was the AAAS' symposium in 1969. A wide range of educated opinions on the subject were offered by participants, including not only proponents such as James McDonald and J. Allen Hynek but also skeptics like astronomers William Hartmann and Donald Menzel. The roster of speakers was balanced, and it is to Sagan's credit that this event was presented in spite of pressure from Edward Condon."[143] With physicist Thornton Page, Sagan edited the lectures and discussions given at the symposium; these were published in 1972 as UFO's: A Scientific Debate. Some of Sagan's many books examine UFOs (as did one episode of Cosmos) and he claimed a religious undercurrent to the phenomenon.

Sagan again revealed his views on interstellar travel in his 1980 Cosmos series. In one of his last written works, Sagan argued that the chances of extraterrestrial spacecraft visiting Earth are vanishingly small. However, Sagan did think it plausible that Cold War concerns contributed to governments misleading their citizens about UFOs, and wrote that "some UFO reports and analyses, and perhaps voluminous files, have been made inaccessible to the public which pays the bills ... It's time for the files to be declassified and made generally available." He cautioned against jumping to conclusions about suppressed UFO data and stressed that there was no strong evidence that aliens were visiting the Earth either in the past or present.[145]

Sagan briefly served as an adviser on Stanley Kubrick's film 2001: A Space Odyssey.[146] Sagan proposed that the film suggest, rather than depict, extraterrestrial superintelligence.[147]

Sagan's paradox edit

Sagan's contribution to the 1969 AAAS symposium was an attack on the belief that UFOs are piloted by extraterrestrial beings. Using the Drake equation and applying several logical assumptions, Sagan calculated the possible number of advanced civilizations capable of interstellar travel to be about one million. He projected that any civilization wishing to check on all the others on a regular basis of, say, once a year would have to launch 10,000 spacecraft annually. Not only does that seem like an unreasonable number of launchings, but it would take all the material in one percent of the universe's stars to produce all the spaceships needed for all the civilizations to seek each other out.

To argue that the Earth was being chosen for regular visitations, Sagan said, one would have to assume that the planet is somehow unique, and that assumption "goes exactly against the idea that there are lots of civilizations around. Because if there are then our sort of civilization must be pretty common. And if we're not pretty common then there aren't going to be many civilizations advanced enough to send visitors."

This argument, which some called Sagan's paradox, helped to establish a new school of thought, namely the belief that extraterrestrial life exists, but it has nothing to do with UFOs. The new belief had a salutary effect on UFO studies. It helped separate researchers who wanted to distinguish UFOs from those who wanted to identify their pilots and it gave scientists opportunities to search the universe for intelligent life unencumbered by the stigma associated with UFOs.[148]

Death edit

 
Stone dedicated to Sagan in the Celebrity Path of the Brooklyn Botanic Garden

After suffering from myelodysplasia for two years and receiving three bone marrow transplants from his sister, Sagan died from pneumonia at the age of 62 at the Fred Hutchinson Cancer Research Center in Seattle on December 20, 1996.[10][149] He was buried at Lake View Cemetery in Ithaca, New York.

Awards and honors edit

 
NASA Distinguished Public Service Medal

Posthumous recognition edit

The 1997 film Contact was based on the only novel Sagan wrote[169] and finished after his death. It ends with the dedication "For Carl." His photo can also be seen in the film.

In 1997, the Sagan Planet Walk was opened in Ithaca, New York. It is a walking-scale model of the Solar System, extending 1.2 km from the center of The Commons in downtown Ithaca to the Sciencenter, a hands-on museum. The exhibition was created in memory of Carl Sagan, who was an Ithaca resident and Cornell Professor. Professor Sagan had been a founding member of the museum's advisory board.[170]

The landing site of the uncrewed Mars Pathfinder spacecraft was renamed the Carl Sagan Memorial Station on July 5, 1997.

Asteroid 2709 Sagan is named in his honor,[92] as is the Carl Sagan Institute for the search of habitable planets.

Sagan's son, Nick Sagan, wrote several episodes in the Star Trek franchise. In an episode of Star Trek: Enterprise entitled "Terra Prime", a quick shot is shown of the relic rover Sojourner, part of the Mars Pathfinder mission, placed by a historical marker at Carl Sagan Memorial Station on the Martian surface. The marker displays a quote from Sagan: "Whatever the reason you're on Mars, I'm glad you're there, and I wish I was with you." Sagan's student Steve Squyres led the team that landed the rovers Spirit and Opportunity successfully on Mars in 2004.

On November 9, 2001, on what would have been Sagan's 67th birthday, the Ames Research Center dedicated the site for the Carl Sagan Center for the Study of Life in the Cosmos. "Carl was an incredible visionary, and now his legacy can be preserved and advanced by a 21st century research and education laboratory committed to enhancing our understanding of life in the universe and furthering the cause of space exploration for all time", said NASA Administrator Daniel Goldin. Ann Druyan was at the center as it opened its doors on October 22, 2006.

Sagan has at least three awards named in his honor:

  • The Carl Sagan Memorial Award presented jointly since 1997 by the American Astronomical Society and The Planetary Society,
  • The Carl Sagan Medal for Excellence in Public Communication in Planetary Science presented since 1998 by the American Astronomical Society's Division for Planetary Sciences (AAS/DPS) for outstanding communication by an active planetary scientist to the general public—Carl Sagan was one of the original organizing committee members of the DPS, and
  • The Carl Sagan Award for Public Understanding of Science presented by the Council of Scientific Society presidents (CSSP)—Sagan was the first recipient of the CSSP award in 1993.[171]

August 2007 the Independent Investigations Group (IIG) awarded Sagan posthumously a Lifetime Achievement Award. This honor has also been awarded to Harry Houdini and James Randi.[172]

In September 2008, a musical compositor Benn Jordan released his album Pale Blue Dot as a tribute to Carl Sagan's life.[173][174]

Beginning in 2009, a musical project known as Symphony of Science sampled several excerpts of Sagan from his series Cosmos and remixed them to electronic music. To date, the videos have received over 21 million views worldwide on YouTube.[175]

The 2014 Swedish science fiction short film Wanderers uses excerpts of Sagan's narration in 1994 of his book Pale Blue Dot, played over digitally-created visuals of humanity's possible future expansion into outer space.[176][177]

In February 2015, the Finnish-based symphonic metal band Nightwish released the song "Sagan" as a non-album bonus track for their single "Élan."[178] The song, written by the band's songwriter/composer/keyboardist Tuomas Holopainen, is an homage to the life and work of the late Carl Sagan.

In August 2015, it was announced that a biopic of Sagan's life was being planned by Warner Bros.[179]

On October 21, 2019, the Carl Sagan and Ann Druyan Theater was opened at the Center for Inquiry West in Los Angeles.[180]

In 2022, Sagan was posthumously awarded the Future of Life Award "for reducing the risk of nuclear war by developing and popularizing the science of nuclear winter." The honor, shared by seven other recipients involved in nuclear winter research, was accepted by his widow, Ann Druyan.[181]

In 2022, the audiobook recording of Sagan's 1994 book Pale Blue Dot was selected by the U.S. Library of Congress for inclusion in the National Recording Registry for being "culturally, historically, or aesthetically significant."[182][183]

In 2023, a movie Voyagers by Sebastián Lelio was announced with Sagan played by Andrew Garfield and with Daisy Edgar-Jones playing Sagan's 3rd wife, Ann Druyan.[184]

Bibliography edit

See also edit

Notes edit

  1. ^ CSI was formerly CSICOP, the Committee for the Scientific Investigation of Claims of the Paranormal.[165]

References edit

  1. ^ a b c d e f Terzian & Trimble 1997, Article in Bull AAS 29(4).
  2. ^ Davidson 1999, The book is dedicated to Pollack.
  3. ^ a b Carl Sagan at the Mathematics Genealogy Project
  4. ^ a b Sagan, Carl; Head, Tom (2006). Conversations with Carl Sagan (illustrated ed.). University Press of Mississippi. p. 14. ISBN 978-1-57806-736-7. Extract of page 14 December 3, 2016, at the Wayback Machine
  5. ^ a b "Carl Sagan". scholar.google.com. from the original on December 23, 2019. Retrieved November 20, 2018.
  6. ^ a b "StarChild: Dr. Carl Sagan". StarChild. NASA. from the original on February 7, 2012. Retrieved October 8, 2009.
  7. ^ The Seth MacFarlane Collection of the Carl Sagan and Ann Druyan Archive: A Finding Aid to the Collection in the Library of Congress (PDF). Manuscript Division, Library of Congress. 2013. (PDF) from the original on March 8, 2016. Retrieved January 17, 2016.
  8. ^ Lowensohn, Josh (February 4, 2014). "Massive Carl Sagan archive posted by Library of Congress". The Verge. from the original on January 12, 2020. Retrieved January 16, 2016.
  9. ^ a b Poundstone 1999, pp. 363–364, 374–375.
  10. ^ a b c Dicke, William (December 21, 1996). "Carl Sagan, an Astronomer Who Excelled at Popularizing Science, Is Dead at 62". The New York Times. from the original on August 19, 2017. Retrieved August 31, 2013.
  11. ^ "Carl Sagan". Internet Accuracy Project. Grandville, MI. from the original on March 8, 2012. Retrieved August 22, 2012.
  12. ^ Davidson 1999.
  13. ^ "Carl Sagan". archive.nytimes.com. from the original on July 14, 2021. Retrieved May 7, 2021.
  14. ^ a b Davidson 1999, p. 12.
  15. ^ a b c d Davidson 1999, p. 2.
  16. ^ Davidson 1999, p. 9.
  17. ^ a b c Spangenburg & Moser 2004, pp. 2–5.
  18. ^ a b Davidson 1999, p. 14.
  19. ^ a b Davidson 1999, p. 15.
  20. ^ a b Davidson 1999, p. 18.
  21. ^ a b c Sagan, Carl (May 28, 1978). "Growing up with Science Fiction". The New York Times. p. SM7. ISSN 0362-4331. from the original on December 11, 2018. Retrieved December 12, 2018.
  22. ^ a b c Davidson, Keay (2000). Sagan, Carl (1934–1996), space scientist, author, science popularizer, TV personality, and antinuclear weapons activist. doi:10.1093/anb/9780198606697.article.1302612. ISBN 978-0-19-860669-7. from the original on May 14, 2021. Retrieved June 23, 2021. {{cite book}}: |website= ignored (help)
  23. ^ a b c d Davidson 1999, p. 23.
  24. ^ a b Davidson 1999, p. 24.
  25. ^ Davidson 1999, p. 25.
  26. ^ a b c Poundstone 1999, p. 15.
  27. ^ Poundstone 1999, p. 14.
  28. ^ "Ryerson Astronomical Society". Ryerson Astronomical Society (RAS). University of Chicago Department of Astronomy and Astrophysics. from the original on September 19, 2012. Retrieved August 22, 2012.
  29. ^ Carl Sagan - website of the Massachusetts Institute of Technology
  30. ^ Sic. See Spangenburg, Ray; Moser, Kit; Moser, Diane (2004). Carl Sagan: A Biography (illustrated ed.). Greenwood Publishing Group. p. 28. ISBN 978-0-313-32265-5. from the original on December 6, 2021. Retrieved August 31, 2018. Extract of page 28 December 25, 2019, at the Wayback Machine
  31. ^ Sagan, Carl (1960). Physical Studies of the Planets (PhD thesis). University of Chicago. p. ii. OCLC 20678107. ProQuest 301918122. A thesis in four parts submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Astronomy, University of Chicago, June, 1960
  32. ^ "Graduate students receive first Sagan teaching awards". University of Chicago Chronicle. 13 (6). November 11, 1993. from the original on March 10, 2012. Retrieved August 30, 2013.
  33. ^ Head 2006, p. xxi.
  34. ^ Spangenburg & Moser 2004, p. 28.
  35. ^ Tatarewicz, Joseph N. (1990), Space Technology & Planetary Astronomy, Science, technology, and society, Bloomington, IN: Indiana University Press, p. 22, ISBN 978-0-253-35655-0
  36. ^ Ulivi, Paolo (April 6, 2004). Lunar Exploration: Human Pioneers and Robotic Surveyors. Springer Science & Business Media. ISBN 978-1-85233-746-9. from the original on January 1, 2014. Retrieved April 15, 2016.
  37. ^ a b c d e f Morrison, David (January–February 2007). . Skeptical Inquirer. 31 (1): 29–38. ISSN 0194-6730. Archived from the original on February 1, 2016. Retrieved August 31, 2013.
  38. ^ Reiffel, Leonard (May 4, 2000). "Sagan breached security by revealing US work on a lunar bomb project". Nature. 405 (13): Correspondence. doi:10.1038/35011148. PMID 10811192.
  39. ^ . University of California, Berkeley The Berkeley Science Review. November 11, 2013. Archived from the original on December 3, 2013. Retrieved December 1, 2013.
  40. ^ a b Davidson 1999, p. 138.
  41. ^ a b Davidson 1999, p. 204.
  42. ^ Sagan, Carl. Demon-Haunted World: Science as a Candle in the Dark 3 October 2022 at the Wayback Machine, Ballantine Books (1996) p. 25.
  43. ^ Davidson 1999, p. 213.
  44. ^ Sagan, Carl; Head, Tom (2006). Conversations with Carl Sagan (illustrated ed.). Univ. Press of Mississippi. p. xxi. ISBN 978-1-57806-736-7. Extract of page xxi 23 December 2019 at the Wayback Machine.
  45. ^ a b Sagan, Carl (January 5, 1995). "An Interview with Carl Sagan". Charlie Rose (Interview). New York: PBS. from the original on July 14, 2015. Retrieved August 30, 2013.
  46. ^ Pierrehumbert, Raymond T. (2010). Principles of Planetary Climate. Cambridge University Press. p. 202. ISBN 978-1-139-49506-6. from the original on July 30, 2019. Retrieved March 20, 2016. Extract of page 202 December 19, 2019, at the Wayback Machine.
  47. ^ Much of Sagan's research in the field of planetary science is outlined by William Poundstone. Poundstone's biography of Sagan includes an 8-page list of Sagan's scientific articles published from 1957 to 1998. Detailed information about Sagan's scientific work comes from the primary research articles. Example: Sagan, C.; Thompson, W. R.; Khare, B. N. (1992). "Titan: A Laboratory for Prebiological Organic Chemistry". Accounts of Chemical Research. 25 (7): 286–292. doi:10.1021/ar00019a003. PMID 11537156. There is commentary on this research article about Titan at David J. Darling's The Encyclopedia of Science March 10, 2005, at the Wayback Machine.
  48. ^ Chaisson, Eric; McMillan, Stephen (1997). Astronomy Today (illustrated ed.). Prentice Hall. p. 266. ISBN 978-0-13-712382-7. from the original on March 15, 2021. Retrieved June 20, 2020.
  49. ^ Sagan, Carl (1985) [Originally published 1980]. Cosmos (1st Ballantine Books ed.). New York: Ballantine Books. ISBN 978-0-345-33135-9. LCCN 80005286. OCLC 12814276.
  50. ^ Carl Sagan testifying to Congress, December 10, 1985, C-SPAN, https://www.c-span.org/video/?125856-1/greenhouse-effect December 25, 2021, at the Wayback Machine
  51. ^ . Columbia Encyclopedia (Sixth ed.). New York: Columbia University Press. May 2001. Archived from the original on October 11, 2007. Retrieved August 30, 2013.
  52. ^ No Writer Attributed (August 21, 1963). "Sagan Synthesizes ATP In Laboratory". The Harvard Crimson. from the original on December 22, 2015. Retrieved September 12, 2015.
  53. ^ "Carl Sagan". Pasadena, CA: The Planetary Society. from the original on February 21, 2015. Retrieved August 30, 2013.
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Further reading edit

External links edit

 
Scholia has a profile for Carl Sagan (Q410).
  • The Carl Sagan Portal
  • David Morrison, "Carl Sagan", Biographical Memoirs of the National Academy of Sciences (2014)
  • Sagan interviewed by Ted Turner, CNN, 1989, video: 44 minutes.
  • BBC Radio program "Great Lives" on Carl Sagan's life
  • "A man whose time has come"—Interview with Carl Sagan by Ian Ridpath, New Scientist, July 4, 1974
  • Carl Sagan at IMDb
  • , by David Morrison, Committee for Skeptical Inquiry
  • FBI Records: The Vault – Carl Sagan at fbi.gov
  • "NASA Technical Reports Server (NTRS) 19630011050: Direct Contact Among Galactic Civilizations by Relativistic Interstellar Spaceflight", Carl Sagan, when he was at Stanford University, in 1962, produced a controversial paper funded by a NASA research grant that concludes ancient alien intervention may have sparked human civilization.
  • Scientist of the Day-Carl Sagan at Linda Hall Library
  • Carl Sagan demonstrates how Eratosthenes determined that the Earth was round and the approximate circumference of the earth

November 08, 2023
carl, sagan, other, uses, disambiguation, carl, edward, sagan, gən, november, 1934, december, 1996, american, astronomer, science, communicator, best, known, scientific, contribution, research, possibility, extraterrestrial, life, including, experimental, demo. For other uses see Carl Sagan disambiguation Carl Edward Sagan ˈ s eɪ ɡ en SAY gen November 9 1934 December 20 1996 was an American astronomer and science communicator His best known scientific contribution is his research on the possibility of extraterrestrial life including experimental demonstration of the production of amino acids from basic chemicals by radiation He assembled the first physical messages sent into space the Pioneer plaque and the Voyager Golden Record which were universal messages that could potentially be understood by any extraterrestrial intelligence that might find them He argued in favor of the hypothesis which has since been accepted that the high surface temperatures of Venus are the result of the greenhouse effect 4 Carl SaganSagan in the 1970sBornCarl Edward Sagan 1934 11 09 November 9 1934New York City New York U S DiedDecember 20 1996 1996 12 20 aged 62 Seattle Washington U S Resting placeLake View Cemetery Ithaca New YorkAlma materUniversity of Chicago BA BS MS PhD Known forSearch for Extra Terrestrial Intelligence SETI Cosmos A Personal Voyage Cosmos Voyager Golden Record Pioneer plaque The Dragons of Eden Contact Pale Blue Dot The Demon Haunted WorldSpousesLynn Margulis m 1957 div 1965 wbr Linda Salzman m 1968 div 1981 wbr Ann Druyan m 1981 wbr Children5 including Dorion Nick and SashaAwardsKlumpke Roberts Award 1974 NASA Distinguished Public Service Medal 1977 Pulitzer Prize for General Non Fiction 1978 Oersted Medal 1990 Carl Sagan Award for Public Understanding of Science 1993 National Academy of Sciences Public Welfare Medal 1994 Scientific careerFieldsAstronomy astrophysics cosmology astrobiology space science planetary scienceInstitutionsUniversity of Chicago Cornell University Harvard University Smithsonian Astrophysical Observatory University of California BerkeleyThesisPhysical studies of planets 1960 Doctoral advisorGerard KuiperDoctoral studentsDavid Morrison 1 Clark Chapman citation needed James B Pollack 2 Owen Toon 3 Christopher Chyba 1 Steven Soter 1 Reid Thompson 1 Peter Wilson 1 David Pieri 1 SignatureInitially an assistant professor at Harvard Sagan later moved to Cornell where he spent most of his career He published more than 600 scientific papers and articles and was author co author or editor of more than 20 books 5 He wrote many popular science books such as The Dragons of Eden Broca s Brain Pale Blue Dot and The Demon Haunted World He also co wrote and narrated the award winning 1980 television series Cosmos A Personal Voyage which became the most widely watched series in the history of American public television Cosmos has been seen by at least 500 million people in 60 countries 6 A book also called Cosmos was published to accompany the series Sagan also wrote a science fiction novel published in 1985 called Contact which became the basis for a 1997 film of the same name His papers comprising 595 000 items 7 are archived in the Library of Congress 8 Sagan was a popular public advocate of skeptical scientific inquiry and the scientific method he pioneered the field of exobiology and promoted the search for extra terrestrial intelligent life SETI He spent most of his career as a professor of astronomy at Cornell University where he directed the Laboratory for Planetary Studies Sagan and his works received numerous awards and honors including the NASA Distinguished Public Service Medal the National Academy of Sciences Public Welfare Medal the Pulitzer Prize for General Non Fiction for his book The Dragons of Eden and for Cosmos A Personal Voyage two Emmy Awards the Peabody Award and the Hugo Award He married three times and had five children After developing myelodysplasia Sagan died of pneumonia at the age of 62 on December 20 1996 Contents 1 Early life 1 1 Childhood 1 2 Education 2 Career and research 2 1 Scientific achievements 2 2 Cosmos popularizing science on TV 2 3 Billions and billions 2 4 Sagan s number 2 5 Scientific and critical thinking advocacy 2 6 Popularizing science 2 7 Criticisms 2 8 Social concerns 3 Personal life and beliefs 3 1 Naturalism 3 2 Marijuana advocacy 3 3 UFOs 3 3 1 Sagan s paradox 4 Death 5 Awards and honors 5 1 Posthumous recognition 6 Bibliography 7 See also 8 Notes 9 References 10 Further reading 11 External linksEarly life editChildhood edit nbsp Sagan in Rahway High School s 1951 yearbookCarl Edward Sagan was born in the Bensonhurst neighborhood of New York City s Brooklyn borough on November 9 1934 9 10 His mother Rachel Molly Gruber was a housewife from New York City his father Samuel Sagan was a Ukrainian garment worker who emigrated from Kamianets Podilskyi which was then in the Russian Empire 11 Sagan was named in honor of his maternal grandmother Chaiya Clara who had died while giving birth to her second child she was in Sagan s words the mother she Rachel never knew 12 Sagan s maternal grandfather later married a woman named Rose whom Sagan s sister Carol would later say was never accepted as Rachel s mother because Rachel knew she Rose wasn t her birth mother 13 Sagan s family lived in a modest apartment in Bensonhurst He later discussed his family being Reform Jews the most liberal of Judaism s four main branches He and his sister agreed that their father was not especially religious but that their mother definitely believed in God and was active in the temple and served only kosher meat 14 During the worst years of the Depression his father worked as a movie theater usher 14 According to biographer Keay Davidson Sagan experienced a kind of inner war as a result of his close relationship with both of his parents who were in many ways opposites He traced his later analytical urges to his mother a woman who had been extremely poor as a child in New York City during World War I and the 1920s 15 As a young woman she had had intellectual ambitions but they were sabotaged by her poverty her status as a woman and a wife and her Jewish ethnicity Davidson suggested that this is why she worshipped her only son Carl because he would fulfill her unfulfilled dreams 15 Sagan believed that he got his sense of wonder from his father who spent his free time giving apples to the poor or helping soothing tensions between employees and management within New York City s garment industry 15 Although awed by his son s intellectual abilities Sagan s father took his inquisitiveness in stride and saw it as part of growing up 15 Later during his career Sagan would draw on his childhood memories to illustrate scientific points as he did in his book Shadows of Forgotten Ancestors 16 Describing his parents influence on his later thinking Sagan said My parents were not scientists They knew almost nothing about science But in introducing me simultaneously to skepticism and to wonder they taught me the two uneasily cohabiting modes of thought that are central to the scientific method 17 He recalled that a defining moment in his development was at age four when his parents took him to see the exhibits at the 1939 New York World s Fair He later described his memories of several exhibits there One was a moving map in the America of Tomorrow exhibit which he said showed beautiful highways and cloverleaves and little General Motors cars all carrying people to skyscrapers buildings with lovely spires flying buttresses and it looked great 18 Another was a flashlight shining on a photoelectric cell which created a crackling sound and another showed how the sound from a tuning fork became a wave on an oscilloscope He also saw an exhibit of the then nascent medium known as television Referring to that exhibit he later wrote Plainly the world held wonders of a kind I had never guessed How could a tone become a picture and light become a noise 18 Sagan also saw one of the Fair s most publicized events the burial of a time capsule at Flushing Meadows which contained mementos of the 1930s to be recovered by Earth s descendants in a future millennium Davidson wrote that this thrilled Carl As an adult inspired by his memories of the World s Fair Sagan and his colleagues would create similar time capsules to be sent out into the galaxy the Pioneer plaque and the Voyager Golden Record precis 19 During World War II Sagan s family worried about the fate of their European relatives Sagan however was generally unaware of the details of the ongoing war He wrote Sure we had relatives who were caught up in the Holocaust Hitler was not a popular fellow in our household but on the other hand I was fairly insulated from the horrors of the war His sister Carol said that their mother above all wanted to protect Carl she had an extraordinarily difficult time dealing with World War II and the Holocaust 19 Sagan s book The Demon Haunted World 1996 included his memories of this conflicted period when his family dealt with the realities of the war in Europe but tried to prevent it from undermining his optimistic spirit 17 Soon after entering elementary school Sagan began to express a strong inquisitiveness about nature He recalled taking his first trips to the public library alone at the age of five when his mother got him a library card He wanted to learn what stars were since none of his friends or their parents could give him a clear answer I went to the librarian and asked for a book about stars and the answer was stunning It was that the Sun was a star but really close The stars were suns but so far away they were just little points of light The scale of the universe suddenly opened up to me It was a kind of religious experience There was a magnificence to it a grandeur a scale which has never left me Never ever left me 20 At about age six or seven he and a close friend took trips to the American Museum of Natural History in Manhattan While there they went to the Hayden Planetarium and walked around the museum s exhibits of space objects such as meteorites and displays of dinosaurs and animals in natural settings He wrote I was transfixed by the dioramas lifelike representations of animals and their habitats all over the world Penguins on the dimly lit Antarctic ice a family of gorillas the male beating his chest an American grizzly bear standing on his hind legs ten or twelve feet tall and staring me right in the eye 20 Sagan s parents helped nurture his growing interest in science by buying him chemistry sets and reading materials However his interest in space was his primary focus especially after reading sci fi stories by writers such as H G Wells and Edgar Rice Burroughs which stirred his imagination about the possibility of life on other planets such as Mars 21 According to biographer Ray Spangenburg Sagan s early years of trying to understand the mysteries of the planets became a driving force in his life a continual spark to his intellect and a quest that would never be forgotten 17 In 1947 Sagan discovered the magazine Astounding Science Fiction which introduced him to more hard science fiction speculations than those in Burroughs novels 21 That same year a mass hysteria developed about the possibility that extraterrestrial visitors had arrived in flying saucers and the young Sagan joined in the speculation that the flying discs people reported seeing in the sky might be alien spaceships 22 Education edit nbsp Sagan in the University of Chicago s 1954 yearbookSagan attended David A Boody Junior High School in his native Bensonhurst and had his bar mitzvah when he turned 13 23 In 1948 when he was 14 his father s work took the family to the older semi industrial town of Rahway New Jersey 23 Sagan graduated from Rahway High School in 1951 23 He was a straight A student but was bored because his classes did not challenge him and his teachers did not inspire him 23 His teachers realized this and tried to convince his parents to send him to a private school with an administrator telling them This kid ought to go to a school for gifted children he has something really remarkable 24 However his parents could not afford to do so Sagan became president of the school s chemistry club and set up his own laboratory at home He taught himself about molecules by making cardboard cutouts to help him visualize how they were formed I found that about as interesting as doing chemical experiments 24 He was mostly interested in astronomy learning about it in his spare time In his junior year of high school he discovered that professional astronomers were paid for doing something he always enjoyed and decided on astronomy as a career goal That was a splendid day when I began to suspect that if I tried hard I could do astronomy full time not just part time 25 Before the end of high school Sagan entered an essay writing contest in which he explored the idea that human contact with advanced life forms from another planet might be as disastrous for people on Earth as Native Americans first contact with Europeans had been for Native Americans 26 The subject was considered controversial but his rhetorical skill won over the judges and they awarded him first prize 26 When he was about to graduate from high school his classmates voted him most likely to succeed and put him in line to be valedictorian 26 He attended the University of Chicago because despite his excellent high school grades it was one of the very few colleges he had applied to that would consider accepting a 16 year old Its chancellor Robert Maynard Hutchins had recently retooled the undergraduate College of the University of Chicago into an ideal meritocracy built on Great Books Socratic dialogue comprehensive examinations and early entrance to college with no age requirement 27 As an honors program undergraduate Sagan worked in the laboratory of geneticist H J Muller and wrote a thesis on the origins of life with physical chemist Harold Urey He also joined the Ryerson Astronomical Society 28 In 1954 he was awarded a Bachelor of Arts with general and special honors 29 in what he quipped was nothing 30 In 1955 he earned a Bachelor of Science in physics He went on to do graduate work at the University of Chicago earning a Master of Science in physics in 1956 and a Doctor of Philosophy in astronomy and astrophysics in 1960 His doctoral thesis submitted to the Department of Astronomy and Astrophysics was entitled Physical Studies of the Planets 31 32 33 34 During his graduate studies he used the summer months to work with planetary scientist Gerard Kuiper who was his dissertation director 3 as well as physicist George Gamow and chemist Melvin Calvin The title of Sagan s dissertation reflected interests he had in common with Kuiper who had been president of the International Astronomical Union s commission on Physical Studies of Planets and Satellites throughout the 1950s 35 In 1958 Sagan and Kuiper worked on the classified military Project A119 a secret U S Air Force plan to detonate a nuclear warhead on the Moon and document its effects 36 Sagan had a Top Secret clearance at the Air Force and a Secret clearance with NASA 37 In 1999 an article published in the journal Nature revealed that Sagan had included the classified titles of two Project A119 papers in his 1959 application for a scholarship to University of California Berkeley A follow up letter to the journal by project leader Leonard Reiffel confirmed Sagan s security leak 38 Career and research edit source source Sagan is one of those discussing the likelihood of life on other planets in Who s Out There 1973 an award winning NASA documentary film by Robert Drew From 1960 to 1962 Sagan was a Miller Fellow at the University of California Berkeley 39 Meanwhile he published an article in 1961 in the journal Science on the atmosphere of Venus while also working with NASA s Mariner 2 team and served as a Planetary Sciences Consultant to the RAND Corporation 40 After the publication of Sagan s Science article in 1961 Harvard University astronomers Fred Whipple and Donald Menzel offered Sagan the opportunity to give a colloquium at Harvard and subsequently offered him a lecturer position at the institution Sagan instead asked to be made an assistant professor and eventually Whipple and Menzel were able to convince Harvard to offer Sagan the assistant professor position he requested 40 Sagan lectured performed research and advised graduate students at the institution from 1963 until 1968 as well as working at the Smithsonian Astrophysical Observatory also located in Cambridge Massachusetts In 1968 Sagan was denied academic tenure at Harvard He later indicated that the decision was very unexpected 41 The denial has been blamed on several factors including that he focused his interests too broadly across a number of areas while the norm in academia is to become a renowned expert in a narrow specialty and perhaps because of his well publicized scientific advocacy which some scientists perceived as borrowing the ideas of others for little more than self promotion 37 An advisor from his years as an undergraduate student Harold Urey wrote a letter to the tenure committee recommending strongly against tenure for Sagan 22 Science is more than a body of knowledge it is a way of thinking I have a foreboding of an America in my children s or grandchildren s time when the United States is a service and information economy when nearly all the key manufacturing industries have slipped away to other countries when awesome technological powers are in the hands of a very few and no one representing the public interest can even grasp the issues when the people have lost the ability to set their own agendas or knowledgeably question those in authority when clutching our crystals and nervously consulting our horoscopes our critical faculties in decline unable to distinguish between what feels good and what s true we slide almost without noticing back into superstition and darkness The dumbing down of America is most evident in the slow decay of substantive content in the enormously influential media the 30 second sound bites now down to 10 seconds or less lowest common denominator programming credulous presentations on pseudoscience and superstition but especially a kind of celebration of ignorance Carl Sagan from Demon Haunted World 1995 42 Long before the ill fated tenure process Cornell University astronomer Thomas Gold had courted Sagan to move to Ithaca New York and join the recently hired astronomer Frank Drake amongst the faculty at Cornell Following the denial of tenure from Harvard Sagan accepted Gold s offer and remained a faculty member at Cornell for nearly 30 years until his death in 1996 Unlike Harvard the smaller and more laid back astronomy department at Cornell welcomed Sagan s growing celebrity status 43 Following two years as an associate professor Sagan became a full professor at Cornell in 1970 and directed the Laboratory for Planetary Studies there From 1972 to 1981 he was associate director of the Center for Radiophysics and Space Research CRSR at Cornell In 1976 he became the David Duncan Professor of Astronomy and Space Sciences a position he held for the remainder of his life 44 Sagan was associated with the U S space program from its inception citation needed From the 1950s onward he worked as an advisor to NASA where one of his duties included briefing the Apollo astronauts before their flights to the Moon Sagan contributed to many of the robotic spacecraft missions that explored the Solar System arranging experiments on many of the expeditions Sagan assembled the first physical message that was sent into space a gold plated plaque attached to the space probe Pioneer 10 launched in 1972 Pioneer 11 also carrying another copy of the plaque was launched the following year He continued to refine his designs the most elaborate message he helped to develop and assemble was the Voyager Golden Record which was sent out with the Voyager space probes in 1977 Sagan often challenged the decisions to fund the Space Shuttle and the International Space Station at the expense of further robotic missions 45 Scientific achievements edit nbsp Sagan and the Viking spacecraftFormer student David Morrison described Sagan as an idea person and a master of intuitive physical arguments and back of the envelope calculations 37 and Gerard Kuiper said that Some persons work best in specializing on a major program in the laboratory others are best in liaison between sciences Dr Sagan belongs in the latter group 37 Sagan s contributions were central to the discovery of the high surface temperatures of the planet Venus 4 46 In the early 1960s no one knew for certain the basic conditions of Venus surface and Sagan listed the possibilities in a report later depicted for popularization in a Time Life book Planets His own view was that Venus was dry and very hot as opposed to the balmy paradise others had imagined He had investigated radio waves from Venus and concluded that there was a surface temperature of 500 C 900 F As a visiting scientist to NASA s Jet Propulsion Laboratory he contributed to the first Mariner missions to Venus working on the design and management of the project Mariner 2 confirmed his conclusions on the surface conditions of Venus in 1962 Sagan was among clarification needed the first to hypothesize that Saturn s moon Titan might possess oceans of liquid compounds on its surface and that Jupiter s moon Europa might possess subsurface oceans of water This would make Europa potentially habitable 47 Europa s subsurface ocean of water was later indirectly confirmed by the spacecraft Galileo The mystery of Titan s reddish haze was also solved with Sagan s help The reddish haze was revealed to be due to complex organic molecules constantly raining down onto Titan s surface 48 Sagan further contributed insights regarding the atmospheres of Venus and Jupiter as well as seasonal changes on Mars He also perceived global warming as a growing man made danger and likened it to the natural development of Venus into a hot life hostile planet through a kind of runaway greenhouse effect 49 He testified to the US Congress in 1985 that the greenhouse effect would change the earth s climate system 50 Sagan and his Cornell colleague Edwin Ernest Salpeter speculated about life in Jupiter s clouds given the planet s dense atmospheric composition rich in organic molecules He studied the observed color variations on Mars surface and concluded that they were not seasonal or vegetational changes as most believed clarification needed but shifts in surface dust caused by windstorms Sagan is also known for his research on the possibilities of extraterrestrial life including experimental demonstration of the production of amino acids from basic chemicals by radiation 51 52 He is also the 1994 recipient of the Public Welfare Medal the highest award of the National Academy of Sciences for distinguished contributions in the application of science to the public welfare 53 He was denied membership in the academy reportedly because his media activities made him unpopular with many other scientists 54 55 56 As of 2017 update Sagan is the most cited SETI scientist and one of the most cited planetary scientists 5 Cosmos popularizing science on TV edit nbsp Sagan in Cosmos 1980 In 1980 Sagan co wrote and narrated the award winning 13 part PBS television series Cosmos A Personal Voyage which became the most widely watched series in the history of American public television until 1990 The show has been seen by at least 500 million people across 60 countries 6 57 58 The book Cosmos written by Sagan was published to accompany the series 59 Because of his earlier popularity as a science writer from his best selling books including The Dragons of Eden which won him a Pulitzer Prize in 1977 he was asked to write and narrate the show It was targeted to a general audience of viewers whom Sagan felt had lost interest in science partly due to a stifled educational system 60 Each of the 13 episodes was created to focus on a particular subject or person thereby demonstrating the synergy of the universe 60 They covered a wide range of scientific subjects including the origin of life and a perspective of humans place on Earth The show won an Emmy 61 along with a Peabody Award and transformed Sagan from an obscure astronomer into a pop culture icon 62 Time magazine ran a cover story about Sagan soon after the show broadcast referring to him as creator chief writer and host narrator of the show 63 In 2000 Cosmos was released on a remastered set of DVDs Billions and billions edit After Cosmos aired Sagan became associated with the catchphrase billions and billions although he never actually used the phrase in the Cosmos series 64 He rather used the term billions upon billions 65 Richard Feynman a precursor to Sagan used the phrase billions and billions many times in his red books However Sagan s frequent use of the word billions and distinctive delivery emphasizing the b which he did intentionally in place of more cumbersome alternatives such as billions with a b in order to distinguish the word from millions 64 made him a favorite target of comic performers including Johnny Carson 66 67 Gary Kroeger Mike Myers Bronson Pinchot Penn Jillette Harry Shearer and others Frank Zappa satirized the line in the song Be in My Video noting as well atomic light Sagan took this all in good humor and his final book was entitled Billions and Billions which opened with a tongue in cheek discussion of this catchphrase observing that Carson was an amateur astronomer and that Carson s comic caricature often included real science 64 As a humorous tribute to Sagan and his association with the catchphrase billions and billions a sagan has been defined as a unit of measurement equivalent to a very large number of anything 68 69 Sagan s number edit Sagan s number is the number of stars in the observable universe 70 This number is reasonably well defined because it is known what stars are and what the observable universe is but its value is highly uncertain In 1980 Sagan estimated it to be 10 sextillion in short scale 1022 71 In 2003 it was estimated to be 70 sextillion 7 1022 72 73 In 2010 it was estimated to be 300 sextillion 3 1023 74 Scientific and critical thinking advocacy edit nbsp Carl Sagan popularized the Cosmic Calendar as a method to visualize the chronology of the universe scaling its current age of 13 8 billion years to a single year to help intuit it for pedagogical purposes Sagan s ability to convey his ideas allowed many people to understand the cosmos better simultaneously emphasizing the value and worthiness of the human race and the relative insignificance of the Earth in comparison to the Universe He delivered the 1977 series of Royal Institution Christmas Lectures in London 75 Sagan was a proponent of the search for extraterrestrial life He urged the scientific community to listen with radio telescopes for signals from potential intelligent extraterrestrial life forms Sagan was so persuasive that by 1982 he was able to get a petition advocating SETI published in the journal Science signed by 70 scientists including seven Nobel Prize winners This signaled a tremendous increase in the respectability of a then controversial field Sagan also helped Frank Drake write the Arecibo message a radio message beamed into space from the Arecibo radio telescope on November 16 1974 aimed at informing potential extraterrestrials about Earth Sagan was chief technology officer of the professional planetary research journal Icarus for 12 years He co founded The Planetary Society and was a member of the SETI Institute Board of Trustees Sagan served as Chairman of the Division for Planetary Science of the American Astronomical Society as President of the Planetology Section of the American Geophysical Union and as Chairman of the Astronomy Section of the American Association for the Advancement of Science AAAS nbsp The Planetary Society members at the organization s founding Sagan is seated on the right At the height of the Cold War Sagan became involved in nuclear disarmament efforts by promoting hypotheses on the effects of nuclear war when Paul Crutzen s Twilight at Noon concept suggested that a substantial nuclear exchange could trigger a nuclear twilight and upset the delicate balance of life on Earth by cooling the surface In 1983 he was one of five authors the S in the follow up TTAPS model as the research article came to be known which contained the first use of the term nuclear winter which his colleague Richard P Turco had coined 76 In 1984 he co authored the book The Cold and the Dark The World after Nuclear War and in 1990 the book A Path Where No Man Thought Nuclear Winter and the End of the Arms Race which explains the nuclear winter hypothesis and advocates nuclear disarmament Sagan received a great deal of skepticism and disdain for the use of media to disseminate a very uncertain hypothesis A personal correspondence with nuclear physicist Edward Teller around 1983 began amicably with Teller expressing support for continued research to ascertain the credibility of the winter hypothesis However Sagan and Teller s correspondence would ultimately result in Teller writing A propagandist is one who uses incomplete information to produce maximum persuasion I can compliment you on being indeed an excellent propagandist remembering that a propagandist is the better the less he appears to be one 77 Biographers of Sagan would also comment that from a scientific viewpoint nuclear winter was a low point for Sagan although politically speaking it popularized his image amongst the public 77 The adult Sagan remained a fan of science fiction although disliking stories that were not realistic such as ignoring the inverse square law or he said did not include thoughtful pursuit of alternative futures 21 He wrote books to popularize science such as Cosmos which reflected and expanded upon some of the themes of A Personal Voyage and became the best selling science book ever published in English 78 The Dragons of Eden Speculations on the Evolution of Human Intelligence which won a Pulitzer Prize and Broca s Brain Reflections on the Romance of Science Sagan also wrote the best selling science fiction novel Contact in 1985 based on a film treatment he wrote with his wife Ann Druyan in 1979 but he did not live to see the book s 1997 motion picture adaptation which starred Jodie Foster and won the 1998 Hugo Award for Best Dramatic Presentation nbsp Pale Blue Dot Earth is a bright pixel when photographed from Voyager 1 6 billion kilometres 3 7 billion miles away 79 Sagan encouraged NASA to generate this image from Pale Blue Dot 1994 80 On it everyone you ever heard of The aggregate of all our joys and sufferings thousands of confident religions ideologies and economic doctrines every hunter and forager every hero and coward every creator and destroyer of civilizations every king and peasant every young couple in love every hopeful child every mother and father every inventor and explorer every teacher of morals every corrupt politician every superstar every supreme leader every saint and sinner in the history of our species lived there on a mote of dust suspended in a sunbeam Think of the rivers of blood spilled by all those generals and emperors so that in glory and triumph they could become the momentary masters of a fraction of a dot Carl Sagan Cornell lecture in 1994Sagan wrote a sequel to Cosmos Pale Blue Dot A Vision of the Human Future in Space which was selected as a notable book of 1995 by The New York Times He appeared on PBS s Charlie Rose program in January 1995 45 Sagan also wrote the introduction for Stephen Hawking s bestseller A Brief History of Time Sagan was also known for his popularization of science his efforts to increase scientific understanding among the general public and his positions in favor of scientific skepticism and against pseudoscience such as his debunking of the Betty and Barney Hill abduction To mark the tenth anniversary of Sagan s death David Morrison a former student of Sagan recalled Sagan s immense contributions to planetary research the public understanding of science and the skeptical movement in Skeptical Inquirer 37 Following Saddam Hussein s threats to light Kuwait s oil wells on fire in response to any physical challenge to Iraqi control of the oil assets Sagan together with his TTAPS colleagues and Paul Crutzen warned in January 1991 in The Baltimore Sun and Wilmington Morning Star newspapers that if the fires were left to burn over a period of several months enough smoke from the 600 or so 1991 Kuwaiti oil fires might get so high as to disrupt agriculture in much of South Asia and that this possibility should affect the war plans 81 82 these claims were also the subject of a televised debate between Sagan and physicist Fred Singer on January 22 aired on the ABC News program Nightline 83 84 nbsp Sagan admitted that he had overestimated the danger posed by the 1991 Kuwaiti oil fires In the televised debate Sagan argued that the effects of the smoke would be similar to the effects of a nuclear winter with Singer arguing to the contrary After the debate the fires burnt for many months before extinguishing efforts were complete The results of the smoke did not produce continental sized cooling Sagan later conceded in The Demon Haunted World that the prediction did not turn out to be correct it was pitch black at noon and temperatures dropped 4 6 C over the Persian Gulf but not much smoke reached stratospheric altitudes and Asia was spared 85 In his later years Sagan advocated the creation of an organized search for asteroids near Earth objects NEOs that might impact the Earth but to forestall or postpone developing the technological methods that would be needed to defend against them 86 He argued that all of the numerous methods proposed to alter the orbit of an asteroid including the employment of nuclear detonations created a deflection dilemma if the ability to deflect an asteroid away from the Earth exists then one would also have the ability to divert a non threatening object towards Earth creating an immensely destructive weapon 87 88 In a 1994 paper he co authored he ridiculed a 3 day long Near Earth Object Interception Workshop held by Los Alamos National Laboratory LANL in 1993 that did not even in passing state that such interception and deflection technologies could have these ancillary dangers 87 Sagan remained hopeful that the natural NEO impact threat and the intrinsically double edged essence of the methods to prevent these threats would serve as a new and potent motivation to maturing international relations 87 89 Later acknowledging that with sufficient international oversight in the future a work our way up approach to implementing nuclear explosive deflection methods could be fielded and when sufficient knowledge was gained to use them to aid in mining asteroids 88 His interest in the use of nuclear detonations in space grew out of his work in 1958 for the Armour Research Foundation s Project A119 concerning the possibility of detonating a nuclear device on the lunar surface 90 Sagan was a critic of Plato having said of the ancient Greek philosopher Science and mathematics were to be removed from the hands of the merchants and the artisans This tendency found its most effective advocate in a follower of Pythagoras named Plato and 91 He Plato believed that ideas were far more real than the natural world He advised the astronomers not to waste their time observing the stars and planets It was better he believed just to think about them Plato expressed hostility to observation and experiment He taught contempt for the real world and disdain for the practical application of scientific knowledge Plato s followers succeeded in extinguishing the light of science and experiment that had been kindled by Democritus and the other Ionians In 1995 as part of his book The Demon Haunted World Sagan popularized a set of tools for skeptical thinking called the baloney detection kit a phrase first coined by Arthur Felberbaum a friend of his wife Ann Druyan 92 Popularizing science edit Speaking about his activities in popularizing science Sagan said that there were at least two reasons for scientists to share the purposes of science and its contemporary state Simple self interest was one much of the funding for science came from the public and the public therefore had the right to know how the money was being spent If scientists increased public admiration for science there was a good chance of having more public supporters 93 The other reason was the excitement of communicating one s own excitement about science to others 10 Following the success of Cosmos Sagan set up his own publishing firm Cosmos Store to publish science books for the general public It was not successful 94 Criticisms edit While Sagan was widely adored by the general public his reputation in the scientific community was more polarized 95 Critics sometimes characterized his work as fanciful non rigorous and self aggrandizing 96 and others complained in his later years that he neglected his role as a faculty member to foster his celebrity status 97 One of Sagan s harshest critics Harold Urey felt that Sagan was getting too much publicity for a scientist and was treating some scientific theories too casually 98 Urey and Sagan were said to have different philosophies of science according to Davidson While Urey was an old time empiricist who avoided theorizing about the unknown Sagan was by contrast willing to speculate openly about such matters 41 Fred Whipple wanted Harvard to keep Sagan there but learned that because Urey was a Nobel laureate his opinion was an important factor in Harvard denying Sagan tenure 98 Sagan s Harvard friend Lester Grinspoon also stated I know Harvard well enough to know there are people there who certainly do not like people who are outspoken 98 Grinspoon added 98 Wherever you turned there was one astronomer being quoted on everything one astronomer whose face you were seeing on TV and one astronomer whose books had the preferred display slot at the local bookstore Some like Urey later came to realize that Sagan s popular brand of scientific advocacy was beneficial to the science as a whole 99 Urey especially liked Sagan s 1977 book The Dragons of Eden and wrote Sagan with his opinion I like it very much and am amazed that someone like you has such an intimate knowledge of the various features of the problem I congratulate you You are a man of many talents 99 Sagan was accused of borrowing some ideas of others for his own benefit and countered these claims by explaining that the misappropriation was an unfortunate side effect of his role as a science communicator and explainer and that he attempted to give proper credit whenever possible 98 Social concerns edit Sagan believed that the Drake equation on substitution of reasonable estimates suggested that a large number of extraterrestrial civilizations would form but that the lack of evidence of such civilizations highlighted by the Fermi paradox suggests technological civilizations tend to self destruct This stimulated his interest in identifying and publicizing ways that humanity could destroy itself with the hope of avoiding such a cataclysm and eventually becoming a spacefaring species Sagan s deep concern regarding the potential destruction of human civilization in a nuclear holocaust was conveyed in a memorable cinematic sequence in the final episode of Cosmos called Who Speaks for Earth Sagan had already resigned date missing from the Air Force Scientific Advisory Board s UFO investigating Condon Committee and voluntarily surrendered his top secret clearance in protest over the Vietnam War 100 Following his marriage to his third wife novelist Ann Druyan in June 1981 Sagan became more politically active particularly in opposing escalation of the nuclear arms race under President Ronald Reagan nbsp The United States and Soviet Union Russia nuclear stockpiles in total number of nuclear bombs warheads in existence throughout the Cold War and post Cold War eraIn March 1983 Reagan announced the Strategic Defense Initiative a multibillion dollar project to develop a comprehensive defense against attack by nuclear missiles which was quickly dubbed the Star Wars program Sagan spoke out against the project arguing that it was technically impossible to develop a system with the level of perfection required and far more expensive to build such a system than it would be for an enemy to defeat it through decoys and other means and that its construction would seriously destabilize the nuclear balance between the United States and the Soviet Union making further progress toward nuclear disarmament impossible 101 When Soviet leader Mikhail Gorbachev declared a unilateral moratorium on the testing of nuclear weapons which would begin on August 6 1985 the 40th anniversary of the atomic bombing of Hiroshima the Reagan administration dismissed the dramatic move as nothing more than propaganda and refused to follow suit In response US anti nuclear and peace activists staged a series of protest actions at the Nevada Test Site beginning on Easter Sunday in 1986 and continuing through 1987 Hundreds of people in the Nevada Desert Experience group were arrested including Sagan who was arrested on two separate occasions as he climbed over a chain link fence at the test site during the underground Operation Charioteer and United States s Musketeer nuclear test series of detonations 102 Sagan was also a vocal advocate of the controversial notion of testosterone poisoning arguing in 1992 that human males could become gripped by an unusually severe case of testosterone poisoning and this could compel them to become genocidal 103 In his review of Moondance magazine writer Daniela Gioseffi s 1990 book Women on War he argues that females are the only half of humanity untainted by testosterone poisoning 104 One chapter of his 1993 book Shadows of Forgotten Ancestors is dedicated to testosterone and its alleged poisonous effects 105 In 1989 Carl Sagan was interviewed by Ted Turner whether he believed in socialism and responded that I m not sure what a socialist is But I believe the government has a responsibility to care for the people I m talking about making the people self reliant 106 Personal life and beliefs editSagan was married three times In 1957 he married biologist Lynn Margulis The couple had two children Jeremy and Dorion Sagan their marriage ended in 1964 Sagan married artist Linda Salzman in 1968 and they had a child together Nick Sagan and divorced in 1981 During these marriages Carl Sagan focused heavily on his career a factor which may have contributed to Sagan s first divorce 37 In 1981 Sagan married author Ann Druyan and they later had two children Alexandra known as Sasha and Samuel Sagan Carl Sagan and Druyan remained married until his death in 1996 While teaching at Cornell he lived in an Egyptian revival house in Ithaca perched on the edge of a cliff that had formerly been the headquarters of a Cornell secret society 107 While there he drove a red Porsche 911 Targa and an orange 1970 Porsche 914 108 with the license plate PHOBOS In 1994 engineers at Apple Computer code named the Power Macintosh 7100 Carl Sagan in the hope that Apple would make billions and billions with the sale of the PowerMac 7100 9 The name was only used internally but Sagan was concerned that it would become a product endorsement and sent Apple a cease and desist letter Apple complied but engineers retaliated by changing the internal codename to BHA for Butt Head Astronomer 109 110 In November 1995 after further legal battle an out of court settlement was reached and Apple s office of trademarks and patents released a conciliatory statement that Apple has always had great respect for Dr Sagan It was never Apple s intention to cause Dr Sagan or his family any embarrassment or concern 111 In 2019 Carl Sagan s daughter Sasha Sagan released For Small Creatures Such as We Rituals for Finding Meaning in our Unlikely World which depicts life with her parents and her father s death when she was fourteen 112 Building on a theme in her father s work Sasha Sagan argues in For Small Creatures Such as We that skepticism does not imply pessimism 113 I have just finished The Cosmic Connection and loved every word of it You are my idea of a good writer because you have an unmannered style and when I read what you write I hear you talking One thing about the book made me nervous It was entirely too obvious that you are smarter than I am I hate that Isaac Asimov in a letter to Sagan 1973 114 Sagan was acquainted with the science fiction fandom through his friendship with Isaac Asimov and he spoke at the Nebula Awards ceremony in 1969 115 116 Asimov described Sagan as one of only two people he ever met whose intellect surpassed his own the other being computer scientist and artificial intelligence expert Marvin Minsky 117 Naturalism editSagan wrote frequently about religion and the relationship between religion and science expressing his skepticism about the conventional conceptualization of God as a sapient being For example Some people think God is an outsized light skinned male with a long white beard sitting on a throne somewhere up there in the sky busily tallying the fall of every sparrow Others for example Baruch Spinoza and Albert Einstein considered God to be essentially the sum total of the physical laws which describe the universe I do not know of any compelling evidence for anthropomorphic patriarchs controlling human destiny from some hidden celestial vantage point but it would be madness to deny the existence of physical laws 118 In another description of his view on the concept of God Sagan wrote The idea that God is an oversized white male with a flowing beard who sits in the sky and tallies the fall of every sparrow is ludicrous But if by God one means the set of physical laws that govern the universe then clearly there is such a God This God is emotionally unsatisfying it does not make much sense to pray to the law of gravity 119 On atheism Sagan commented in 1981 An atheist is someone who is certain that God does not exist someone who has compelling evidence against the existence of God I know of no such compelling evidence Because God can be relegated to remote times and places and to ultimate causes we would have to know a great deal more about the universe than we do now to be sure that no such God exists To be certain of the existence of God and to be certain of the nonexistence of God seem to me to be the confident extremes in a subject so riddled with doubt and uncertainty as to inspire very little confidence indeed 120 nbsp Sagan in 1987Sagan also commented on Christianity and the Jefferson Bible stating My long time view about Christianity is that it represents an amalgam of two seemingly immiscible parts the religion of Jesus and the religion of Paul Thomas Jefferson attempted to excise the Pauline parts of the New Testament There wasn t much left when he was done but it was an inspiring document 121 Sagan thought that spirituality should be scientifically informed and that traditional religions should be abandoned and replaced with belief systems that revolve around the scientific method 122 but also the mystery and incompleteness of scientific fields Regarding spirituality and its relationship with science Sagan stated Spirit comes from the Latin word to breathe What we breathe is air which is certainly matter however thin Despite usage to the contrary there is no necessary implication in the word spiritual that we are talking of anything other than matter including the matter of which the brain is made or anything outside the realm of science On occasion I will feel free to use the word Science is not only compatible with spirituality it is a profound source of spirituality When we recognize our place in an immensity of light years and in the passage of ages when we grasp the intricacy beauty and subtlety of life then that soaring feeling that sense of elation and humility combined is surely spiritual 123 An environmental appeal Preserving and Cherishing the Earth primarily written by Sagan and signed by him and other noted scientists as well as religious leaders and published in January 1990 stated that The historical record makes clear that religious teaching example and leadership are powerfully able to influence personal conduct and commitment Thus there is a vital role for religion and science 124 In reply to a question in 1996 about his religious beliefs Sagan answered I m agnostic 125 Sagan maintained that the idea of a creator God of the Universe was difficult to prove or disprove and that the only conceivable scientific discovery that could challenge it would be an infinitely old universe 126 His son Dorion Sagan said My father believed in the God of Spinoza and Einstein God not behind nature but as nature equivalent to it 127 His last wife Ann Druyan stated When my husband died because he was so famous and known for not being a believer many people would come up to me it still sometimes happens and ask me if Carl changed at the end and converted to a belief in an afterlife They also frequently ask me if I think I will see him again Carl faced his death with unflagging courage and never sought refuge in illusions The tragedy was that we knew we would never see each other again I don t ever expect to be reunited with Carl 128 In 2006 Ann Druyan edited Sagan s 1985 Glasgow Gifford Lectures in Natural Theology into a book The Varieties of Scientific Experience A Personal View of the Search for God in which he elaborates on his views of divinity in the natural world nbsp Sagan center speaks with CDC employees in 1988 Sagan is also widely regarded as a freethinker or skeptic one of his most famous quotations in Cosmos was Extraordinary claims require extraordinary evidence 129 called the Sagan standard by some 130 This was based on a nearly identical statement by fellow founder of the Committee for the Scientific Investigation of Claims of the Paranormal Marcello Truzzi An extraordinary claim requires extraordinary proof 131 132 This idea had been earlier aphorized in Theodore Flournoy s work From India to the Planet Mars 1899 from a longer quote by Pierre Simon Laplace 1749 1827 a French mathematician and astronomer as the Principle of Laplace The weight of the evidence should be proportioned to the strangeness of the facts 133 Late in his life Sagan s books elaborated on his naturalistic view of the world In The Demon Haunted World he presented tools for testing arguments and detecting fallacious or fraudulent ones essentially advocating the wide use of critical thinking and of the scientific method The compilation Billions and Billions Thoughts on Life and Death at the Brink of the Millennium published in 1997 after Sagan s death contains essays written by him on topics such as his views on abortion and also an essay by his widow Ann Druyan about the relationship between his agnostic and freethinking beliefs and his death Sagan warned against humans tendency towards anthropocentrism He was the faculty adviser for the Cornell Students for the Ethical Treatment of Animals In the Cosmos chapter Blues For a Red Planet Sagan wrote If there is life on Mars I believe we should do nothing with Mars Mars then belongs to the Martians even if the Martians are only microbes 134 Marijuana advocacy edit Sagan was a user and advocate of marijuana Under the pseudonym Mr X he contributed an essay about smoking cannabis to the 1971 book Marihuana Reconsidered 135 136 The essay explained that marijuana use had helped to inspire some of Sagan s works and enhance sensual and intellectual experiences After Sagan s death his friend Lester Grinspoon disclosed this information to Sagan s biographer Keay Davidson The publishing of the biography Carl Sagan A Life in 1999 brought media attention to this aspect of Sagan s life 137 138 139 Not long after his death his widow Ann Druyan went on to preside over the board of directors of the National Organization for the Reform of Marijuana Laws NORML a non profit organization dedicated to reforming cannabis laws 140 141 UFOs edit In 1947 the year that inaugurated the flying saucer craze the young Sagan suspected the discs might be alien spaceships 22 Sagan s interest in UFO reports prompted him on August 3 1952 to write a letter to U S Secretary of State Dean Acheson to ask how the United States would respond if flying saucers turned out to be extraterrestrial 142 He later had several conversations on the subject in 1964 with Jacques Vallee 143 Though quite skeptical of any extraordinary answer to the UFO question Sagan thought scientists should study the phenomenon at least because there was widespread public interest in UFO reports Stuart Appelle notes that Sagan wrote frequently on what he perceived as the logical and empirical fallacies regarding UFOs and the abduction experience Sagan rejected an extraterrestrial explanation for the phenomenon but felt there were both empirical and pedagogical benefits for examining UFO reports and that the subject was therefore a legitimate topic of study 144 In 1966 Sagan was a member of the Ad Hoc Committee to Review Project Blue Book the U S Air Force s UFO investigation project The committee concluded Blue Book had been lacking as a scientific study and recommended a university based project to give the UFO phenomenon closer scientific scrutiny The result was the Condon Committee 1966 68 led by physicist Edward Condon and in their final report they formally concluded that UFOs regardless of what any of them actually were did not behave in a manner consistent with a threat to national security Sociologist Ron Westrum writes that The high point of Sagan s treatment of the UFO question was the AAAS symposium in 1969 A wide range of educated opinions on the subject were offered by participants including not only proponents such as James McDonald and J Allen Hynek but also skeptics like astronomers William Hartmann and Donald Menzel The roster of speakers was balanced and it is to Sagan s credit that this event was presented in spite of pressure from Edward Condon 143 With physicist Thornton Page Sagan edited the lectures and discussions given at the symposium these were published in 1972 as UFO s A Scientific Debate Some of Sagan s many books examine UFOs as did one episode of Cosmos and he claimed a religious undercurrent to the phenomenon Sagan again revealed his views on interstellar travel in his 1980 Cosmos series In one of his last written works Sagan argued that the chances of extraterrestrial spacecraft visiting Earth are vanishingly small However Sagan did think it plausible that Cold War concerns contributed to governments misleading their citizens about UFOs and wrote that some UFO reports and analyses and perhaps voluminous files have been made inaccessible to the public which pays the bills It s time for the files to be declassified and made generally available He cautioned against jumping to conclusions about suppressed UFO data and stressed that there was no strong evidence that aliens were visiting the Earth either in the past or present 145 Sagan briefly served as an adviser on Stanley Kubrick s film 2001 A Space Odyssey 146 Sagan proposed that the film suggest rather than depict extraterrestrial superintelligence 147 Sagan s paradox edit Sagan s contribution to the 1969 AAAS symposium was an attack on the belief that UFOs are piloted by extraterrestrial beings Using the Drake equation and applying several logical assumptions Sagan calculated the possible number of advanced civilizations capable of interstellar travel to be about one million He projected that any civilization wishing to check on all the others on a regular basis of say once a year would have to launch 10 000 spacecraft annually Not only does that seem like an unreasonable number of launchings but it would take all the material in one percent of the universe s stars to produce all the spaceships needed for all the civilizations to seek each other out To argue that the Earth was being chosen for regular visitations Sagan said one would have to assume that the planet is somehow unique and that assumption goes exactly against the idea that there are lots of civilizations around Because if there are then our sort of civilization must be pretty common And if we re not pretty common then there aren t going to be many civilizations advanced enough to send visitors This argument which some called Sagan s paradox helped to establish a new school of thought namely the belief that extraterrestrial life exists but it has nothing to do with UFOs The new belief had a salutary effect on UFO studies It helped separate researchers who wanted to distinguish UFOs from those who wanted to identify their pilots and it gave scientists opportunities to search the universe for intelligent life unencumbered by the stigma associated with UFOs 148 Death edit nbsp Stone dedicated to Sagan in the Celebrity Path of the Brooklyn Botanic GardenAfter suffering from myelodysplasia for two years and receiving three bone marrow transplants from his sister Sagan died from pneumonia at the age of 62 at the Fred Hutchinson Cancer Research Center in Seattle on December 20 1996 10 149 He was buried at Lake View Cemetery in Ithaca New York Awards and honors edit nbsp NASA Distinguished Public Service MedalAnnual Award for Television Excellence 1981 Ohio State University PBS series Cosmos A Personal Voyage Apollo Achievement Award National Aeronautics and Space Administration NASA Distinguished Public Service Medal National Aeronautics and Space Administration 1977 Emmy Outstanding Individual Achievement 1981 PBS series Cosmos A Personal Voyage 61 Emmy Outstanding Informational Series 1981 PBS series Cosmos A Personal Voyage 61 Fellow of the American Physical Society 1989 150 Exceptional Scientific Achievement Medal National Aeronautics and Space Administration Helen Caldicott Leadership Award Awarded by Women s Action for Nuclear Disarmament Hugo Award 1981 Best Dramatic Presentation Cosmos A Personal Voyage Hugo Award 1981 Best Related Non Fiction Book Cosmos Hugo Award 1998 Best Dramatic Presentation Contact Humanist of the Year 1981 Awarded by the American Humanist Association 151 American Philosophical Society 1995 Elected to membership 152 In Praise of Reason Award 1987 Committee for Skeptical Inquiry 153 Isaac Asimov Award 1994 Committee for Skeptical Inquiry 154 John F Kennedy Astronautics Award 1982 American Astronautical Society 155 Special non fiction Campbell Memorial Award 1974 The Cosmic Connection An Extraterrestrial Perspective 156 Joseph Priestley Award For distinguished contributions to the welfare of mankind 157 Klumpke Roberts Award of the Astronomical Society of the Pacific 1974 Golden Plate Award of the American Academy of Achievement 1975 158 Konstantin Tsiolkovsky Medal Awarded by the Soviet Cosmonauts Federation Locus Award 1986 Contact Lowell Thomas Award The Explorers Club 75th Anniversary Masursky Award American Astronomical Society Miller Research Fellowship Miller Institute 1960 1962 Oersted Medal 1990 American Association of Physics Teachers Peabody Award 1980 PBS series Cosmos A Personal Voyage Le Prix Galabert d astronautique International Astronautical Federation IAF 159 Public Welfare Medal 1994 National Academy of Sciences 160 Pulitzer Prize for General Non Fiction 1978 The Dragons of Eden Science Fiction Chronicle Award 1998 Dramatic Presentation Contact UCLA Medal 1991 161 Inductee to International Space Hall of Fame in 2004 162 Named the 99th Greatest American on June 5 2005 Greatest American television series on the Discovery Channel 163 Named an honorary member of the Demosthenian Literary Society on November 10 2011 New Jersey Hall of Fame 2009 Inductee 164 Committee for Skeptical Inquiry CSI Pantheon of Skeptics April 2011 Inductee a 166 Grand Cross of the Order of Saint James of the Sword Portugal November 23 1998 167 Honorary Doctor of Science Sc D degree from Whittier College in 1978 168 Posthumous recognition edit The 1997 film Contact was based on the only novel Sagan wrote 169 and finished after his death It ends with the dedication For Carl His photo can also be seen in the film In 1997 the Sagan Planet Walk was opened in Ithaca New York It is a walking scale model of the Solar System extending 1 2 km from the center of The Commons in downtown Ithaca to the Sciencenter a hands on museum The exhibition was created in memory of Carl Sagan who was an Ithaca resident and Cornell Professor Professor Sagan had been a founding member of the museum s advisory board 170 The landing site of the uncrewed Mars Pathfinder spacecraft was renamed the Carl Sagan Memorial Station on July 5 1997 Asteroid 2709 Sagan is named in his honor 92 as is the Carl Sagan Institute for the search of habitable planets Sagan s son Nick Sagan wrote several episodes in the Star Trek franchise In an episode of Star Trek Enterprise entitled Terra Prime a quick shot is shown of the relic rover Sojourner part of the Mars Pathfinder mission placed by a historical marker at Carl Sagan Memorial Station on the Martian surface The marker displays a quote from Sagan Whatever the reason you re on Mars I m glad you re there and I wish I was with you Sagan s student Steve Squyres led the team that landed the rovers Spirit and Opportunity successfully on Mars in 2004 On November 9 2001 on what would have been Sagan s 67th birthday the Ames Research Center dedicated the site for the Carl Sagan Center for the Study of Life in the Cosmos Carl was an incredible visionary and now his legacy can be preserved and advanced by a 21st century research and education laboratory committed to enhancing our understanding of life in the universe and furthering the cause of space exploration for all time said NASA Administrator Daniel Goldin Ann Druyan was at the center as it opened its doors on October 22 2006 Sagan has at least three awards named in his honor The Carl Sagan Memorial Award presented jointly since 1997 by the American Astronomical Society and The Planetary Society The Carl Sagan Medal for Excellence in Public Communication in Planetary Science presented since 1998 by the American Astronomical Society s Division for Planetary Sciences AAS DPS for outstanding communication by an active planetary scientist to the general public Carl Sagan was one of the original organizing committee members of the DPS and The Carl Sagan Award for Public Understanding of Science presented by the Council of Scientific Society presidents CSSP Sagan was the first recipient of the CSSP award in 1993 171 August 2007 the Independent Investigations Group IIG awarded Sagan posthumously a Lifetime Achievement Award This honor has also been awarded to Harry Houdini and James Randi 172 In September 2008 a musical compositor Benn Jordan released his album Pale Blue Dot as a tribute to Carl Sagan s life 173 174 Beginning in 2009 a musical project known as Symphony of Science sampled several excerpts of Sagan from his series Cosmos and remixed them to electronic music To date the videos have received over 21 million views worldwide on YouTube 175 The 2014 Swedish science fiction short film Wanderers uses excerpts of Sagan s narration in 1994 of his book Pale Blue Dot played over digitally created visuals of humanity s possible future expansion into outer space 176 177 In February 2015 the Finnish based symphonic metal band Nightwish released the song Sagan as a non album bonus track for their single Elan 178 The song written by the band s songwriter composer keyboardist Tuomas Holopainen is an homage to the life and work of the late Carl Sagan In August 2015 it was announced that a biopic of Sagan s life was being planned by Warner Bros 179 On October 21 2019 the Carl Sagan and Ann Druyan Theater was opened at the Center for Inquiry West in Los Angeles 180 In 2022 Sagan was posthumously awarded the Future of Life Award for reducing the risk of nuclear war by developing and popularizing the science of nuclear winter The honor shared by seven other recipients involved in nuclear winter research was accepted by his widow Ann Druyan 181 In 2022 the audiobook recording of Sagan s 1994 book Pale Blue Dot was selected by the U S Library of Congress for inclusion in the National Recording Registry for being culturally historically or aesthetically significant 182 183 In 2023 a movie Voyagers by Sebastian Lelio was announced with Sagan played by Andrew Garfield and with Daisy Edgar Jones playing Sagan s 3rd wife Ann Druyan 184 Bibliography editSagan Carl 1961 Organic Matter and The Moon Panel on Extra Terrestrial Life for the Armed Forces NRC Committee on Bio Astronautics Publication 757 Washington D C National Academy of Sciences National Research Council LCCN 61 60064 Sagan Carl Leonard Jonathan Norton 1966 Planets Life Science Library Editors of Life New York Time Inc LCCN 66022436 OCLC 346361 Shklovskii I S 1966 Originally published 1962 as Vselennaya zhizn razum Moscow USSR Academy of Sciences Publisher Intelligent Life in the Universe Authorized translation by Paula Fern San Francisco Holden Day Inc LCCN 64018404 OCLC 317314 Page Thornton eds 1972 UFO s A Scientific Debate Ithaca NY Cornell University Press ISBN 978 0 801 40740 6 LCCN 72004572 OCLC 415373 ed 1973 Communication with Extraterrestrial Intelligence CETI Cambridge MA MIT Press ISBN 978 0 262 19106 7 LCCN 73013999 OCLC 700752 Bradbury Ray Clarke Arthur C et al 1973 Mars and the Mind of Man 1st ed New York Harper amp Row ISBN 978 0 060 10443 6 LCCN 72009746 OCLC 613541 1973 The Cosmic Connection An Extraterrestrial Perspective Produced by Jerome Agel 1st ed Garden City NY Anchor Press ISBN 978 0 385 00457 2 LCCN 73081117 OCLC 756158 1975 Other Worlds Produced by Jerome Agel Toronto NY Bantam Books ISBN 978 0 552 66439 4 OCLC 3029556 1977 The Dragons of Eden Speculations on the Evolution of Human Intelligence 1st ed New York Random House ISBN 978 0 394 41045 6 LCCN 76053472 OCLC 2922889 Drake F D Lomberg Jon et al 1978 Murmurs of Earth The Voyager Interstellar Record 1st ed New York Random House Bibcode 1978mevi book S ISBN 978 0 394 41047 0 LCCN 77005991 OCLC 4037611 1979 Broca s Brain Reflections on the Romance of Science 1st ed New York Random House ISBN 978 0 394 50169 7 LCCN 78021810 OCLC 4493944 1980 Cosmos 1st ed New York Random House ISBN 978 0 394 50294 6 LCCN 80005286 OCLC 6280573 Ehrlich Paul R Kennedy Donald et al 1984 The Cold and the Dark The World after Nuclear War The Conference on the Long Term Worldwide Biological Consequences of Nuclear War Foreword by Lewis Thomas 1st ed New York W W Norton amp Company ISBN 978 0 393 01870 7 LCCN 84006070 OCLC 10697281 Druyan Ann 1985 Comet 1st ed New York Random House ISBN 978 0 394 54908 8 LCCN 85008308 OCLC 811602694 1985 Contact A Novel New York Simon amp Schuster ISBN 978 0 671 43400 7 LCCN 85014645 OCLC 12344811 Turco Richard 1990 A Path Where No Man Thought Nuclear Winter and the End of the Arms Race 1st ed New York Random House ISBN 978 0 394 58307 5 LCCN 89043155 OCLC 20217496 Druyan Ann 1992 Shadows of Forgotten Ancestors A Search for Who We Are 1st ed New York Random House ISBN 978 0 394 53481 7 LCCN 92050155 OCLC 25675747 Sagan Carl Thompson W Reid Carlson Robert Gurnett Donald Hord Charles October 23 1993 A search for life on Earth from the Galileo spacecraft PDF Nature 365 6448 715 721 doi 10 1038 365715a0 Sagan Carl Turco Richard P November 1993 Nuclear Winter in the Post Cold War Era PDF Journal of Peace Research 30 4 369 373 doi 10 1177 0022343393030004001 JSTOR 424481 S2CID 109843259 Archived from the original PDF on February 15 2020 1994 Pale Blue Dot A Vision of the Human Future in Space 1st ed New York Random House ISBN 978 0 679 43841 0 LCCN 94018121 OCLC 30736355 1995 The Demon Haunted World Science as a Candle in the Dark 1st ed New York Random House ISBN 978 0 394 53512 8 LCCN 95034076 OCLC 779687822 Note errata slip inserted Druyan Ann 1997 Billions and Billions Thoughts on Life and Death at the Brink of the Millennium 1st ed New York Random House ISBN 978 0 679 41160 4 LCCN 96052730 OCLC 36066119 2006 Edited from 1985 Gifford Lectures University of Glasgow Druyan Ann ed The Varieties of Scientific Experience A Personal View of the Search for God New York Penguin Press ISBN 978 1 59420 107 3 LCCN 2006044827 OCLC 69021064 See also editList of peace activists Neil deGrasse Tyson Sagan effectNotes edit CSI was formerly CSICOP the Committee for the Scientific Investigation of Claims of the Paranormal 165 References edit a b c d e f Terzian amp Trimble 1997 Article in Bull AAS 29 4 Davidson 1999 The book is dedicated to Pollack a b Carl Sagan at the Mathematics Genealogy Project a b Sagan Carl Head Tom 2006 Conversations with Carl Sagan illustrated ed University Press of Mississippi p 14 ISBN 978 1 57806 736 7 Extract of page 14 Archived December 3 2016 at the Wayback Machine a b Carl Sagan scholar google com Archived from the original on December 23 2019 Retrieved November 20 2018 a b StarChild Dr Carl Sagan StarChild NASA Archived from the original on February 7 2012 Retrieved October 8 2009 The Seth MacFarlane Collection of the Carl Sagan and Ann Druyan Archive A Finding Aid to the Collection in the Library of Congress PDF Manuscript Division Library of Congress 2013 Archived PDF from the original on March 8 2016 Retrieved January 17 2016 Lowensohn Josh February 4 2014 Massive Carl Sagan archive posted by Library of Congress The Verge Archived from the original on January 12 2020 Retrieved January 16 2016 a b Poundstone 1999 pp 363 364 374 375 a b c Dicke William December 21 1996 Carl Sagan an Astronomer Who Excelled at Popularizing Science Is Dead at 62 The New York Times Archived from the original on August 19 2017 Retrieved August 31 2013 Carl Sagan Internet Accuracy Project Grandville MI Archived from the original on March 8 2012 Retrieved August 22 2012 Davidson 1999 Carl Sagan archive nytimes com Archived from the original on July 14 2021 Retrieved May 7 2021 a b Davidson 1999 p 12 a b c d Davidson 1999 p 2 Davidson 1999 p 9 a b c Spangenburg amp Moser 2004 pp 2 5 a b Davidson 1999 p 14 a b Davidson 1999 p 15 a b Davidson 1999 p 18 a b c Sagan Carl May 28 1978 Growing up with Science Fiction The New York Times p SM7 ISSN 0362 4331 Archived from the original on December 11 2018 Retrieved December 12 2018 a b c Davidson Keay 2000 Sagan Carl 1934 1996 space scientist author science popularizer TV personality and antinuclear weapons activist doi 10 1093 anb 9780198606697 article 1302612 ISBN 978 0 19 860669 7 Archived from the original on May 14 2021 Retrieved June 23 2021 a href Template Cite book html title Template Cite book cite book a website ignored help a b c d Davidson 1999 p 23 a b Davidson 1999 p 24 Davidson 1999 p 25 a b c Poundstone 1999 p 15 Poundstone 1999 p 14 Ryerson Astronomical Society Ryerson Astronomical Society RAS University of Chicago Department of Astronomy and Astrophysics Archived from the original on September 19 2012 Retrieved August 22 2012 Carl Sagan website of the Massachusetts Institute of Technology Sic See Spangenburg Ray Moser Kit Moser Diane 2004 Carl Sagan A Biography illustrated ed Greenwood Publishing Group p 28 ISBN 978 0 313 32265 5 Archived from the original on December 6 2021 Retrieved August 31 2018 Extract of page 28 Archived December 25 2019 at the Wayback Machine Sagan Carl 1960 Physical Studies of the Planets PhD thesis University of Chicago p ii OCLC 20678107 ProQuest 301918122 A thesis in four parts submitted in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Astronomy University of Chicago June 1960 Graduate students receive first Sagan teaching awards University of Chicago Chronicle 13 6 November 11 1993 Archived from the original on March 10 2012 Retrieved August 30 2013 Head 2006 p xxi Spangenburg amp Moser 2004 p 28 Tatarewicz Joseph N 1990 Space Technology amp Planetary Astronomy Science technology and society Bloomington IN Indiana University Press p 22 ISBN 978 0 253 35655 0 Ulivi Paolo April 6 2004 Lunar Exploration Human Pioneers and Robotic Surveyors Springer Science amp Business Media ISBN 978 1 85233 746 9 Archived from the original on January 1 2014 Retrieved April 15 2016 a b c d e f Morrison David January February 2007 Carl Sagan s Life and Legacy as Scientist Teacher and Skeptic Skeptical Inquirer 31 1 29 38 ISSN 0194 6730 Archived from the original on February 1 2016 Retrieved August 31 2013 Reiffel Leonard May 4 2000 Sagan breached security by revealing US work on a lunar bomb project Nature 405 13 Correspondence doi 10 1038 35011148 PMID 10811192 Happy Belated Birthday Carl University of California Berkeley The Berkeley Science Review November 11 2013 Archived from the original on December 3 2013 Retrieved December 1 2013 a b Davidson 1999 p 138 a b Davidson 1999 p 204 Sagan Carl Demon Haunted World Science as a Candle in the Dark Archived 3 October 2022 at the Wayback Machine Ballantine Books 1996 p 25 Davidson 1999 p 213 Sagan Carl Head Tom 2006 Conversations with Carl Sagan illustrated ed Univ Press of Mississippi p xxi ISBN 978 1 57806 736 7 Extract of page xxi Archived 23 December 2019 at the Wayback Machine a b Sagan Carl January 5 1995 An Interview with Carl Sagan Charlie Rose Interview New York PBS Archived from the original on July 14 2015 Retrieved August 30 2013 Pierrehumbert Raymond T 2010 Principles of Planetary Climate Cambridge University Press p 202 ISBN 978 1 139 49506 6 Archived from the original on July 30 2019 Retrieved March 20 2016 Extract of page 202 Archived December 19 2019 at the Wayback Machine Much of Sagan s research in the field of planetary science is outlined by William Poundstone Poundstone s biography of Sagan includes an 8 page list of Sagan s scientific articles published from 1957 to 1998 Detailed information about Sagan s scientific work comes from the primary research articles Example Sagan C Thompson W R Khare B N 1992 Titan A Laboratory for Prebiological Organic Chemistry Accounts of Chemical Research 25 7 286 292 doi 10 1021 ar00019a003 PMID 11537156 There is commentary on this research article about Titan at David J Darling s The Encyclopedia of Science Archived March 10 2005 at the Wayback Machine Chaisson Eric McMillan Stephen 1997 Astronomy Today illustrated ed Prentice Hall p 266 ISBN 978 0 13 712382 7 Archived from the original on March 15 2021 Retrieved June 20 2020 Sagan Carl 1985 Originally published 1980 Cosmos 1st Ballantine Books ed New York Ballantine Books ISBN 978 0 345 33135 9 LCCN 80005286 OCLC 12814276 Carl Sagan testifying to Congress December 10 1985 C SPAN https www c span org video 125856 1 greenhouse effect Archived December 25 2021 at the Wayback Machine Sagan Carl Edward Columbia Encyclopedia Sixth ed New York Columbia University Press May 2001 Archived from the original on October 11 2007 Retrieved August 30 2013 No Writer Attributed August 21 1963 Sagan Synthesizes ATP In Laboratory The Harvard Crimson Archived from the original on December 22 2015 Retrieved September 12 2015 Carl Sagan Pasadena CA The Planetary Society Archived from the original on February 21 2015 Retrieved August 30 2013 Benford Gregory 1997 A Tribute to Carl Sagan Popular amp Pilloried Skeptic 13 1 Archived from the original on April 16 2011 Retrieved February 18 2011 Shermer Michael November 2 2003 Candle in the Dark The Works of Michael Shermer Michael Shermer Archived from the original on September 27 2009 Retrieved March 10 2013 Article originally published in November 2003 issue of Scientific American Impey Chris January February 2000 Carl Sagan Carl Sagan Biographies Echo an Extraordinary Life American Scientist Book review 88 1 ISSN 0003 0996 Archived from the original on May 16 2013 Retrieved March 10 2013 Carl Sagan EMuseum Minnesota State University Mankato Archived from the original on May 28 2010 Retrieved August 30 2013 CosmoLearning Astronomy CosmoLearning Archived from the original on May 29 2012 Retrieved October 8 2009 Vergano Dan March 16 2014 Who Was Carl Sagan National Geographic Daily News Washington D C National Geographic Society Archived from the original on May 13 2014 Retrieved May 13 2014 a b Browne Ray Broadus The Guide to United States Popular Culture Popular Press 2001 p 704 a b c Cosmos Academy of Television Arts amp Sciences Archived from the original on March 25 2014 Retrieved September 4 2013 Popular Science Oct 2005 p 90 Golden Frederic October 20 1980 The Cosmic Explainer Time Archived from the original on September 1 2013 Retrieved August 30 2013 a b c Sagan amp Druyan 1997 pp 3 4 Shapiro Fred R ed 2006 The Yale Book of Quotations Foreword by Joseph Epstein New Haven CT Yale University Press p 660 ISBN 978 0 300 10798 2 LCCN 2006012317 OCLC 66527213 Frazier Kendrick ed July August 2005 Carl Sagan Takes Questions More From His Wonder and Skepticism CSICOP 1994 Keynote Skeptical Inquirer 29 4 Archived from the original on December 21 2016 Retrieved March 25 2010 24fpsfan December 22 2012 Carl Sagan Cosmos Parody by Johnny Carson 1980 Archived from the original on October 23 2016 Retrieved November 4 2016 via YouTube a href Template Cite web html title Template Cite web cite web a CS1 maint bot original URL status unknown link Safire William April 17 1994 Footprints on the Infobahn The New York Times Archived from the original on November 13 2013 Retrieved August 31 2013 Gresshoff P M 2004 Scheel D and Wasternack C eds Plant Signal Transduction Annals of Botany Book review 93 6 783 784 doi 10 1093 aob mch102 PMC 4242307 Michon Gerard Sizing up the Universe Stars Sand and Nucleons Numericana www numericana com Archived from the original on April 11 2020 Retrieved April 1 2018 Sagan Carl 1985 Cosmos Balantine Books p 3 ISBN 0345331354 Star survey reaches 70 sextillion And that s only the stars we can actually see CNN Science Sydney Australia July 23 2003 Archived from the original on August 5 2003 Retrieved October 27 2014 STAR COUNT ANU ASTRONOMER MAKES BEST YET Sydney Australia Australian National University Media Releases July 17 2003 Archived from the original on March 9 2011 Retrieved October 27 2015 Number Of Stars In The Universe Could Be 300 Sextillion Triple The Amount Scientists Previously Thought Study Huffington Post December 1 2010 Archived from the original on December 4 2010 Retrieved September 3 2016 Christmas Lectures 1977 The Planets Ri Channel Ri Channel London Royal Institution of Great Britain Archived from the original on February 20 2012 Retrieved February 7 2012 Turco R P Toon O B Ackerman T P Pollack J B Sagan C January 12 1990 Climate and smoke an appraisal of nuclear winter Science 247 4939 166 176 Bibcode 1990Sci 247 166T CiteSeerX 10 1 1 584 8478 doi 10 1126 science 11538069 PMID 11538069 JSTOR Archived September 17 2018 at the Wayback Machine link to full text article Carl Sagan discussed his involvement in the political nuclear winter debates and his erroneous global cooling prediction for the Gulf War fires in his book The Demon Haunted World a b The U S National Security State and Scientists Challenge to Nuclear Weapons during the Cold War Paul Harold Rubinson 2008 PDF Archived from the original PDF on September 24 2014 Meet Carl Sagan The Science Channel Discovery Communications Archived from the original on May 18 2007 Retrieved August 31 2013 Pale Blue Dot Revisited NASA February 12 2020 Archived from the original on February 12 2020 Retrieved February 12 2020 Sagan Carl Recorded lecture at Cornell in 1994 Archived November 9 2017 at the Wayback Machine from Pale Blue Dot A Vision of the Human Future in Space Ballantine Books reprint 1997 p 88 Baltimore Sun We are currently unavailable in your region January 23 1991 Archived from the original on October 6 2014 Retrieved October 3 2014 Wilmington morning Star Archived June 5 2022 at the Wayback Machine January 21 1991 Hirschmann Kris The Kuwaiti Oil Fires Facts on File Archived from the original on January 2 2014 FIRST ISRAELI SCUD FATALITIES OIL FIRES IN KUWAIT Nightline January 22 1991 ABC yes Sagan 1995 p 257 Head 2006 p 86 87 a b c Sagan Carl Ostro Steven J Summer 1994 Long Range Consequences Of Interplanetary Collisions PDF Issues in Science and Technology 10 4 67 72 Bibcode 1994IST 10 67S ISSN 0748 5492 Archived from the original PDF on December 3 2013 Retrieved August 31 2013 a b Chapter 18 The Marsh of Camarina Pale Blue Dot A Vision of the Human Future in Space e reading club Archived from the original on September 24 2015 Retrieved September 1 2015 Morrison David October 3 2007 Taking a Hit Asteroid Impacts amp Evolution Astronomical Society of the Pacific Podcast Astronomical Society of the Pacific Archived from the original on August 18 2014 Retrieved August 31 2013 Gault Matthew November 28 2013 When Earth Dreamed of Nuking the Moon medium com War is Boring Archived from the original on December 3 2013 Retrieved November 28 2013 Sagan Carl writer host November 9 1980 The Backbone of Night Cosmos A Personal Voyage Episode 7 PBS a b Palmer Rob March 31 2020 Exploring Possible Worlds With Ann Druyan Skepticalinquirer org CFI Archived from the original on April 1 2020 Retrieved April 17 2020 Rensberger Boyce May 29 1977 Carl Sagan Obliged to Explain The New York Times Archived from the original on March 23 2019 Retrieved March 23 2019 Asimov I 1994 I Asimov A Memoir New York Bantam Books p 452 Davidson 1999 p 202 Davidson 1999 p 227 Davidson 1999 p 341 a b c d e Davidson 1999 p 203 a b Davidson 1999 p 297 Druyan Ann November 2000 A New Sense of the Sacred Carl Sagan s Cosmic Connection The Humanist 60 6 Archived from the original on October 3 2022 Retrieved August 29 2013 YouTube YouTube Archived from the original on July 11 2015 Spangenburg amp Moser 2004 p 106 Morris Julian 2000 Rethinking Risk and the Precautionary Principle Butterworth Heinemann p 116 ISBN 978 0 08 051623 3 Extract of page 116 Archived December 20 2019 at the Wayback Machine Women On War Archived October 6 2014 at the Wayback Machine Daniela Gioseffi Brewster Melanie E 2014 Atheists in America reprinted ed Columbia University Press p 102 ISBN 978 0 231 53700 1 Archived from the original on December 23 2019 Retrieved February 28 2016 Extract of page 102 Archived December 21 2019 at the Wayback Machine Ted Turner asks Carl Sagan if he is a socialist Archived from the original on November 24 2021 via www youtube com Dear Uncle Ezra archived from the original on June 6 2013 retrieved August 16 2016 Fahy Declan March 6 2015 The New Celebrity Scientists Out of the Lab and into the Limelight Rowman amp Littlefield p 4 ISBN 978 1 4422 3343 0 Archived from the original on October 3 2022 Retrieved June 21 2022 Poundstone 1999 p 364 Linzmayer Owen Chaffin Bryan November 15 2004 This Week in Apple History November 14 20 McIntosh IIe Killed Butt Head Astronomer The Mac Observer The Mac Observer Inc Archived from the original on February 19 2012 Retrieved July 23 2012 Poundstone 1999 pp 374 375 Frazier Ruth 2019 Finding Science and Wonder Making Meaning Skeptical Inquirer 43 6 62 63 Sasha Sagan on Making Jewish Rituals Meaningful for Secular Jews Kveller October 23 2019 Archived from the original on November 6 2019 Retrieved November 6 2019 Maggio Rosalie How They Said it Prentice Hall Press 2000 p 20 Carl Sagan The Nebula Awards Archived from the original on May 17 2021 Retrieved May 17 2021 Photo of Asimov and Sagan Archived from the original on March 5 2016 Retrieved November 4 2016 Asimov Isaac 1981 Originally published 1980 Garden City NY Doubleday In Joy Still Felt The Autobiography of Isaac Asimov 1954 1978 New York Avon pp 217 302 ISBN 978 0 380 53025 0 LCCN 79003685 OCLC 7880716 Sagan Carl 1980 Originally published 1979 Broca s Brain Reflections on the Romance of Science Reprint ed New York Ballantine Books p 330 ISBN 978 0 345 33689 7 LCCN 78021810 OCLC 428008204 Treharne Trevor 2012 How to Prove God Does Not Exist The Complete Guide to Validating Atheism Universal Publishers p 200 ISBN 978 1 61233 118 8 Archived from the original on March 15 2021 Retrieved May 10 2020 Head 2006 p 70 Archived September 21 2014 at the Wayback Machine Schei Kenneth A 1996 An Atheist for Jesus Synthesis ISBN 978 0 926491 01 4 Carl Sagan Encyclopaedia Britannica December 16 2022 Retrieved March 21 2023 Sagan Carl Druyan Ann 1997 The Demon Haunted World Science as a Candle in the Dark Ballantine Books ISBN 0345409469 Sagan Carl 1990 Guest Comment Preserving and cherishing the Earth An appeal for joint commitment in science and religion American Journal of Physics American Association of Physics Teachers AAPT 58 7 615 617 Bibcode 1990AmJPh 58 615S doi 10 1119 1 16418 ISSN 0002 9505 Archived from the original on January 26 2021 Retrieved April 23 2022 Head Tom 1997 Conversations with Carl Skeptic 13 1 32 38 Excerpted in Head 2006 Sagan Carl 1997 Originally published 1995 The Demon Haunted World Science as a Candle in the Dark 1st Ballantine Books ed New York Ballantine Books p 278 ISBN 978 0 345 40946 1 LCCN 95034076 OCLC 36504316 Margulis Lynn Sagan Dorion eds 2007 Dazzle Gradually Reflections on the Nature of Nature Chelsea Green Publishing p 14 ISBN 978 1933392318 Druyan Ann November December 2003 Ann Druyan Talks About Science Religion Wonder Awe and Carl Sagan Skeptical Inquirer 27 6 ISSN 0194 6730 Archived from the original on August 10 2010 Retrieved July 27 2010 Sagan Carl writer host December 14 1980 Encyclopaedia Galactica Cosmos A Personal Voyage Episode 12 01 24 minutes in PBS Rawson Hugh 2008 Sagan s Standard The Unwritten Laws of Life CSBC Ltd Archived from the original on January 12 2012 Retrieved September 1 2013 Truzzi Marcello 1978 On the Extraordinary An Attempt at Clarification PDF Zetetic Scholar 1 1 11 Archived PDF from the original on April 11 2019 Retrieved May 9 2011 Truzzi Marcello 1998 Binkowski Edward ed On Some Unfair Practices towards Claims of the Paranormal Oxymoron Annual Thematic Anthology of the Arts and Sciences 2 The Fringe ISSN 1090 2236 OCLC 35240974 Archived from the original on October 20 2013 Retrieved September 1 2013 Flournoy Theodore 1983 Originally published 1899 Geneva Edition Atar Des Indes a la Planete Mars Etude sur un cas de Somnambulisme avec Glossolalie From India to the Planet Mars A Study of a Case of Somnambulism with Glossolalia in French Introduction by Helene Boursinhac translation by Daniel B Vermilye Reprint ed Geneva Editions Slatkine pp 344 345 ISBN 978 2 05 100499 2 OCLC 11558608 Archived from the original on December 26 2019 Retrieved February 24 2018 Sagan 1980 1985 ed p 108 Grinspoon Lester 1994 2nd ed published 1977 Cambridge MA Harvard University Press Marihuana Reconsidered New introduction by author 2nd reprint ed Oakland CA Quick American Archives ISBN 978 0 932551 13 9 LCCN 77076767 OCLC 32410025 Sagan Carl Mr X Marijuana Uses com Archived from the original on January 20 2012 Retrieved August 7 2009 Whitehouse David October 15 1999 Carl Sagan A life in the cosmos BBC News BBC Archived from the original on July 25 2014 Retrieved August 30 2013 Davidson Keay August 22 1999 Billions and Billions of 60s Flashbacks The San Francisco Examiner Archived from the original on June 13 2010 Retrieved May 2 2007 Larsen Dana November 1 1999 Carl Sagan toking astronomer Cannabis Culture Vancouver B C Archived from the original on September 27 2011 Retrieved May 2 2007 Foundation Board of Directors NORML org Washington D C NORML and the NORML Foundation August 13 2010 Archived from the original on January 4 2011 Retrieved September 2 2013 Ann Druyan NORML org Washington D C NORML and the NORML Foundation Archived from the original on December 13 2007 Retrieved July 20 2011 Davidson 1999 pp 51 52 a b Westrum Ron 2000 Limited Access Six Natural Scientists and the UFO Phenomenon In Jacobs David M ed UFOs and Abductions Challenging the Borders of Knowledge Lawrence KS University Press of Kansas pp 31 55 ISBN 978 0 7006 1032 7 LCCN 00028970 OCLC 43615835 Appelle Stuart 2000 Ufology and Academia The UFO Phenomenon as a Scholarly Discipline In Jacobs David M ed UFOs and Abductions Challenging the Borders of Knowledge Lawrence KS University Press of Kansas pp 7 30 ISBN 978 0 7006 1032 7 LCCN 00028970 OCLC 43615835 Sagan 1995 pp 81 96 99 104 Davidson 1999 p 168 Sagan Carl 2000 Originally published 1973 Hello Central Casting Send Me Twenty Extraterrestrials Carl Sagan s Cosmic Connection An Extraterrestrial Perspective Produced by Jerome Agel new contributions by Freeman Dyson Ann Druyan and David Morrison 2nd ed Cambridge New York Cambridge University Press p 183 ISBN 978 0 521 78303 3 LCCN 00020378 OCLC 460747781 Archived from the original on January 4 2017 Retrieved February 28 2016 David Jacobs The UFO Controversy In America 1987 p 122 124 Quarles Norma December 20 1996 Carl Sagan dies at 62 CNN Archived from the original on March 11 2010 Retrieved December 5 2011 Sagan was a noted astronomer whose lifelong passion was searching for intelligent life in the cosmos APS Fellow Archive APS Archived from the original on October 7 2020 Retrieved October 5 2020 From the AHA archives Carl Sagan s 1981 Humanist of the year speech americanhumanist org Archived from the original on December 26 2014 Retrieved December 25 2014 American Philosophical Society Member History Philadelphia PA American Philosophical Society Archived from the original on November 13 2013 Retrieved September 3 2013 Shore Lys Ann 1987 Controversies in Science and Fringe Science From Animals and SETI to Quackery and SHC The Skeptical Inquirer 12 1 12 13 Karr Barry 1994 Five Honored with CSICOP Awards Skeptical Inquirer 18 5 461 462 John F Kennedy Astronautics Award Springfield VA American Astronautical Society Archived from the original on September 19 2013 Retrieved September 3 2013 The John W Campbell Memorial Award Lawrence KS Center for the Study of Science Fiction Archived from the original on December 29 2012 Retrieved September 3 2013 Carl Sagan 1975 The Joseph Priestley Award Dickinson University Archived from the original on November 13 2017 Retrieved February 1 2017 Golden Plate Awardees of the American Academy of Achievement www achievement org American Academy of Achievement Archived from the original on December 15 2016 Retrieved May 21 2020 Chapter 4 The Space Age Begins PDF History nasa gov Archived PDF from the original on June 26 2020 Retrieved March 1 2019 Public Welfare Medal Washington D C National Academy of Sciences Archived from the original on August 9 2013 Retrieved February 18 2011 THE UCLA MEDAL RECIPIENTS 1979 PRESENT ALPHABETICAL PDF Eventsprotocol ucla edu Archived PDF from the original on April 11 2019 Retrieved March 1 2019 X Prize Group Founder to Speak at Induction El Paso Times El Paso Texas October 17 2004 p 59 Archived from the original on December 23 2019 Retrieved March 27 2019 via Newspapers com Greatest American IMDb Archived from the original on September 22 2020 Retrieved September 2 2019 Mascarenhas Rohan May 3 2009 2009 New Jersey Hall of Fame inductees welcomed at NJPAC The Star Ledger Newark NJ Archived from the original on November 5 2013 Retrieved September 3 2013 CSICOP becomes CSI after thirty years Committee for Skeptical Inquiry November 20 2006 Archived from the original on August 15 2009 The Pantheon of Skeptics CSI Committee for Skeptical Inquiry Archived from the original on January 31 2017 Retrieved April 30 2017 Cidadaos Estrangeiros Agraciados com Ordens Portuguesas Pagina Oficial das Ordens Honorificas Portuguesas Archived from the original on February 8 2012 Retrieved March 20 2019 Honorary Degrees Whittier College Archived from the original on September 10 2018 Retrieved January 28 2020 Fiction Book Review Contact by Carl Sagan Author Simon amp Schuster 18 45 0p ISBN 978 0 671 43400 7 www publishersweekly com October 1985 Archived from the original on November 6 2019 Retrieved November 6 2019 Sagan Planet Walk sciencenter org Ithaca NY Sciencenter Archived from the original on February 5 2013 Retrieved March 10 2013 Sagan Award for Public Understanding of Science Council of Scientific Society Presidents Archived from the original on July 26 2007 Retrieved May 2 2007 The 2007 IIG Awards IIG Los Angeles Independent Investigations Group August 18 2007 Archived from the original on July 18 2011 Retrieved July 1 2011 Two and a Half Questions with Benn Jordan Headphone Commute December 12 2008 Archived from the original on December 11 2019 Retrieved December 11 2019 Pale Blue Dot by Benn Jordan Benn Jordan Archived from the original on December 11 2019 Retrieved December 11 2019 Boswell John November 9 2009 A Glorious Dawn 7 in 17 5 cm gramophone record Nashville TN Third Man Records Archived from the original on November 24 2021 Retrieved September 3 2013 D Orazio Dante November 30 2014 Wonderful short film imagines the day when we conquer the solar system The Verge Archived from the original on December 3 2014 Retrieved February 19 2016 David Leonard December 1 2014 Epic Short Film Wanderers Envisions Humanity s Future in Space Space com Archived from the original on February 11 2016 Retrieved February 21 2016 Latest News Nightwish The Official Website nightwish com Archived from the original on November 19 2017 Retrieved February 9 2015 WARNER BROS HEADS TO THE COSMOS WITH CARL SAGAN BIOPIC Archived August 18 2015 at the Wayback Machine Tracking Board August 17 2015 Frazier Kendrick January February 2020 It s the Carl Sagan amp Ann Druyan Theater A Gala Event in Los Angeles Skeptical Inquirer 44 5 Archived from the original on March 2 2020 Retrieved March 2 2020 Future Of Life Award Future of Life Institute Archived from the original on August 14 2022 Retrieved August 23 2022 2023 National Recording Registry selections Library of Congress Retrieved April 12 2023 National Recording Registry Inducts Music from Madonna Mariah Carey Queen Latifah Daddy Yankee Library of Congress Retrieved April 12 2023 Andrew Garfield Daisy Edgar Jones Playing Carl Sagan and Ann Druyan in Sebastian Lelio s Voyagers for FilmNation Entertainment Variety May 5 2023 Further reading editTerzian Yervant Trimble Virginia January 1 1997 Carl Sagan 1934 1996 Bulletin of the AAS 29 4 Terzian Yervant Bilson Elizabeth eds 1997 Carl Sagan s Universe Cambridge New York Cambridge University Press ISBN 978 0 521 57603 1 LCCN 96040511 OCLC 36130681 Achenbach Joel 1999 Captured by Aliens The Search for Life and Truth in a Very Large Universe New York Simon amp Schuster ISBN 978 0 684 84856 3 LCCN 99037592 OCLC 41606346 Davidson Keay 1999 Carl Sagan A Life New York John Wiley amp Sons ISBN 978 0 471 25286 3 LCCN 99036206 OCLC 41580617 Poundstone William 1999 Carl Sagan A Life in the Cosmos New York Henry Holt and Company ISBN 978 0 8050 5766 9 LCCN 99014615 OCLC 40979822 Spangenburg Ray Moser Kit 2004 Carl Sagan A Biography Westport CT Greenwood Publishing Group ISBN 978 0 313 32265 5 LCCN 2004015176 OCLC 55846272 Head Tom ed 2006 Conversations with Carl Sagan 1st ed Jackson MS University Press of Mississippi ISBN 978 1 57806 736 7 LCCN 2005048747 OCLC 60375648 Morrison David 2006 Carl Sagan The People s Astronomer AmeriQuests 3 2 doi 10 15695 amqst v3i2 84 ISSN 1553 4316 External links editCarl Sagan at Wikipedia s sister projects nbsp Definitions from Wiktionary nbsp Media from Commons nbsp Quotations from Wikiquote nbsp Texts from Wikisource nbsp Scholia has a profile for Carl Sagan Q410 The Carl Sagan Portal David Morrison Carl Sagan Biographical Memoirs of the National Academy of Sciences 2014 Sagan interviewed by Ted Turner CNN 1989 video 44 minutes BBC Radio program Great Lives on Carl Sagan s life A man whose time has come Interview with Carl Sagan by Ian Ridpath New Scientist July 4 1974 Carl Sagan at IMDb Carl Sagan s Life and Legacy as Scientist Teacher and Skeptic by David Morrison Committee for Skeptical Inquiry FBI Records The Vault Carl Sagan at fbi gov NASA Technical Reports Server NTRS 19630011050 Direct Contact Among Galactic Civilizations by Relativistic Interstellar Spaceflight Carl Sagan when he was at Stanford University in 1962 produced a controversial paper funded by a NASA research grant that concludes ancient alien intervention may have sparked human civilization Scientist of the Day Carl Sagan at Linda Hall Library Carl Sagan demonstrates how Eratosthenes determined that the Earth was round and the approximate circumference of the earth Portals nbsp Biography nbsp Physics nbsp Astronomy nbsp Stars nbsp Spaceflight nbsp Solar System nbsp Cannabis Retrieved from https en wikipedia org w index php title Carl Sagan amp oldid 1182399714, wikipedia, wiki, book, books, library,

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