The idea that 'Extraordinary claims require extraordinary evidence' was popularized by Carl Sagan, based on a similar statement by Marcello Truzzi, and originally aphorized in Théodore Flournoy's work.

Carl Sagan, an American astronomer, planetary scientist, and science communicator, was born on November 9, 1934. He is best known for his research on extraterrestrial life and the greenhouse effect on Venus.

At the age of four, Carl Sagan visited the 1939 New York World's Fair with his parents, where he was exposed to various technological exhibits that sparked his curiosity and wonder. This experience played a significant role in shaping his later interest in science and exploration.

In 1947, Sagan suspected that the 'flying saucers' reported might be alien spaceships, marking the beginning of his interest in UFO phenomena.

In 1948, when Carl Sagan was 14 years old, his family moved to Rahway, New Jersey, where he attended Rahway High School. Despite being a straight-A student, he felt bored and unchallenged by his classes.

In 1951, Carl Sagan graduated from Rahway High School. This marked an important milestone in his educational journey and laid the foundation for his future scientific endeavors.

On August 3, 1952, Sagan wrote a letter to U.S. Secretary of State Dean Acheson inquiring about the U.S. response to extraterrestrial flying saucers, showcasing his curiosity about the topic.

In 1954, Carl Sagan was awarded a Bachelor of Arts with general and special honors, jokingly referring to it as 'nothing'.

Carl Sagan received his undergraduate degree in physics from the University of Chicago.

Carl Sagan earned a master's degree in physics from the University of Chicago in 1956.

In 1957, Carl Sagan married biologist Lynn Margulis, with whom he had two children. Their marriage ended in 1964.

In 1958, Carl Sagan worked on Project A119 for the Armour Research Foundation, exploring the idea of detonating a nuclear device on the lunar surface.

Carl Sagan earned his Ph.D. in astrophysics from the University of California, Berkeley.

In 1961, Harvard University astronomers Fred Whipple and Donald Menzel offered Carl Sagan an assistant professor position after he gave a colloquium at the institution.

In 1962, Carl Sagan, while at Stanford University, published a controversial paper funded by a NASA research grant suggesting ancient alien intervention may have influenced human civilization.

In 1966, Sagan was part of the Ad Hoc Committee to Review Project Blue Book, critiquing the U.S. Air Force's UFO investigation project and advocating for a more scientific approach to studying UFO phenomena.

As part of his Ph.D. thesis, Carl Sagan explained the intense microwave radiation from Venus by revealing the planet's extreme greenhouse effect due to its dense carbon dioxide atmosphere. This discovery was later confirmed by the Pioneer Venus spacecraft.

In 1968, Carl Sagan was denied academic tenure at Harvard University, a decision that he found unexpected. The denial was attributed to his broad range of interests and his scientific advocacy, which some perceived as self-promotion.

During the 1969 AAAS symposium, Carl Sagan challenged the notion that UFOs were operated by aliens. Utilizing the Drake equation, he estimated the number of advanced civilizations capable of interstellar travel and raised thought-provoking questions about the feasibility of regular interstellar visits.

In 1970, Carl Sagan became a full professor at Cornell University, where he directed the Laboratory for Planetary Studies. This marked a significant milestone in his academic career.

In 1971, Carl Sagan became a full Professor at Cornell University in Ithaca. This appointment marked a significant milestone in his academic career and research contributions.

In 1972, Carl Sagan played a significant role in assembling the first physical message sent into space, showcasing his pioneering efforts in interstellar communication.

In 1973, Carl Sagan published The Cosmic Connection: An Extraterrestrial Perspective, establishing himself as a popular science writer.

In 1974, Frank Drake and Carl Sagan collaborated to send a radio message from the Arecibo radio telescope into space, aimed at potentially communicating with extraterrestrial beings.

In 1977, Carl Sagan played a key role in developing the Voyager Golden Record, a message sent out with the Voyager space probes. This record aimed to communicate with extraterrestrial civilizations.

In 1978, Carl Sagan was honored with the Pulitzer Prize for his nonfiction book 'The Dragons of Eden'.

Carl Sagan's book 'Cosmos' was published in 1980, becoming a bestseller and later adapted into an award-winning television series. It remains one of the most popular science books in history.

In June 1981, Carl Sagan married his third wife, Ann Druyan, which marked a turning point in his life as he became more politically active, particularly in opposing the nuclear arms race under President Ronald Reagan.

In 1982, Carl Sagan successfully advocated for the search for extraterrestrial intelligence (SETI) by getting a petition published in the journal Science, signed by 70 scientists, including seven Nobel Prize winners.

During his recovery from a life-threatening surgery, Carl Sagan strongly opposed President Reagan's proposal for a space-based anti-missile shield, considering it technically unfeasible and potentially dangerous. He actively campaigned against the project.

In 1985, Carl Sagan published the science-fiction novel Contact, which later served as the basis for the 1997 film Contact. The novel explores themes of extraterrestrial intelligence and communication.

Carl Sagan presented the concept of nuclear winter to the Soviet Central Committee, influencing their views on nuclear war and contributing to discussions that led to significant reductions in nuclear arsenals. His scientific insights played a role in easing tensions during the Cold War.

In 1989, Carl Sagan was interviewed by Ted Turner about his views on socialism. Sagan expressed a belief in government responsibility to care for the people, indicating a leaning towards socialist ideals.

In 1990, Carl Sagan received the Ørsted Medal from the American Association of Physics Teachers.

Carl Sagan, along with his colleagues, warned in January 1991 about the potential agricultural disruption in South Asia due to the smoke from Kuwaiti oil fires. This warning was based on the fear that the smoke could lead to a scenario similar to a nuclear winter.

In 1992, Carl Sagan controversially discussed the concept of 'testosterone poisoning,' suggesting that excessive testosterone in males could lead to genocidal tendencies. He argued that females were not affected by this 'poisoning.'

Carl Sagan received the Public Welfare Medal in 1994, which is the highest award of the National Academy of Sciences, for his contributions to science and society.

In 1995, as part of his book 'The Demon-Haunted World', Carl Sagan introduced a set of tools for skeptical thinking known as the 'baloney detection kit', a concept originally termed by Arthur Felberbaum.

Carl Sagan, a prominent figure in popularizing science, passed away on December 20, 1996.

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

The movie 'Contact', based on Carl Sagan's work, won the Hugo Award for Best Dramatic Presentation in 1998.

In 1999, the biography 'Carl Sagan: A Life' was published, shedding light on Sagan's advocacy and personal experiences with marijuana, which garnered media attention.

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.

In 2004, Carl Sagan was inducted into a prestigious group or organization. His contributions to the field of astronomy and science were recognized.

In 2006, Ann Druyan edited Carl Sagan's 1985 Glasgow Gifford Lectures into a book titled 'The Varieties of Scientific Experience', where Sagan elaborated on his views of divinity in the natural world.

In August 2007, the Independent Investigations Group (IIG) awarded Sagan posthumously a Lifetime Achievement Award.

In September 2008, musical composer Benn Jordan released his album Pale Blue Dot as a tribute to Carl Sagan's life.

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.

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