60 free Carl Sagan trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This Carl Sagan trivia quiz covers the astronomer who made half a billion people care about the universe. The easy questions handle Cosmos, Pale Blue Dot, Contact, the Golden Record, the Planetary Society and 'billions and billions'. From there it moves through the life: the garment-worker father, the 1939 World's Fair, the librarian who first handed him a book of movie stars, the University of Chicago at 16, the Air Force plan to detonate a bomb on the Moon, and the Harvard tenure that never came. The harder end covers the hot Venus prediction, the moons he suspected of hiding oceans, the journal he edited, the Cornell astronomer who hired him, the Baloney Detection Kit, the origins of the extraordinary-claims maxim, the TTAPS paper, the arrests in Nevada, the pseudonymous essay on marijuana, Apple's Butt-Head Astronomer, the licence plate on the Porsche and the science-fiction writer who said only two people out-thought him. Every answer was checked against Sagan's encyclopaedia entry before publishing and the supporting sentence is stored with each question. Our space and astronomy quizzes are the natural next stop.
30 of 60 questions with answers and explanations. Play the quiz
Q 01Sagan's 1980 series Cosmos: A Personal Voyage has been seen by at least how many people worldwide?
500 million
It won two Emmys and a Peabody and was American public television's most watched series until The Civil War in 1990.
Q 02For which book did Sagan win the 1978 Pulitzer Prize for General Nonfiction?
The Dragons of Eden
It introduced the Cosmic Calendar, compressing the history of the universe into a single year.
Q 03Which director filmed Sagan's novel Contact, completing it after his death?
Robert Zemeckis
The film ends with the dedication 'For Carl', and his photo appears in it.
Q 04In which New York City borough was Sagan born in 1934?
Brooklyn
The family lived in a modest apartment in Bensonhurst.
Q 05What was the trade of Sagan's Ukrainian-born father, Samuel?
Garment worker
In the worst Depression years he also worked as a movie theatre usher.
Q 06Sagan described a visit to which 1939 event, with its Futurama exhibit and time capsule, as a defining moment?
The New York World's Fair
As an adult he would build his own time capsules and fire them into space.
Q 07When the young Sagan asked a librarian for something on the stars, what did she first bring him?
Portraits of Hollywood actors
The right book told him the stars were suns, but very far away, 'a kind of religious experience'.
Q 08Sagan's family moved in 1948 to which New Jersey town, where he went to high school?
Rahway
He was president of the chemistry club and voted most likely to succeed.
Q 09Sagan's prize-winning high school essay compared human contact with advanced aliens to what?
Native Americans meeting Europeans
The judges thought the subject controversial but were won over by his rhetoric.
Q 10At what age did Sagan enter the University of Chicago, one of the few colleges that would take him?
16
He found himself in a physics department 'orbiting around Enrico Fermi'.
Q 11Who supervised Sagan's doctoral thesis on the physical study of the solar system's worlds?
Gerard Kuiper
Kuiper was then the only full-time planetary astronomer, and taught him back-of-the-envelope calculation.
Q 12Secret 1958 Project A119, on which Sagan and Kuiper worked, planned a nuclear detonation where?
On the Moon
Sagan later leaked the classified paper titles in a scholarship application, a slip revealed in 1999.
Q 13From radio observations, Sagan concluded that the surface of Venus was roughly how hot?
500 °C
Mariner 2 confirmed his dry, hellish Venus in 1962, against those who imagined a balmy paradise.
Q 21Sagan concluded that the changing colours on Mars were caused not by vegetation but by what?
Windblown dust
He also helped solve the mystery of Titan's reddish haze: organic molecules raining down.
Q 22In 1985 Sagan testified to the US Congress about which threat to Earth's climate?
The greenhouse effect
He likened it to the runaway warming that had turned Venus into a furnace.
Q 23Which planetary science journal did Sagan edit from 1975 to 1979?
Icarus
He served the journal in various roles for twelve years.
Q 14Which Nobel laureate and former mentor wrote to Harvard's tenure committee recommending against Sagan?
Harold Urey
Urey, an old-time empiricist, thought Sagan got too much publicity and theorised too freely.
Q 15Which Cornell astronomer had courted Sagan to move to Ithaca even before Harvard denied him tenure?
Thomas Gold
Sagan stayed at Cornell for nearly thirty years, until his death.
Q 16At Cornell, Sagan directed the Laboratory for what?
Planetary Studies
He became the David Duncan Professor of Astronomy and Space Sciences in 1976.
Q 17As a NASA adviser, Sagan briefed which astronauts before their flights?
The Apollo crews
He later argued that robotic missions were a better use of money than the Shuttle and the space station.
Q 18Sagan assembled the first physical message sent into space, a gold-plated plaque on which 1972 probe?
Pioneer 10
Pioneer 11 carried a copy the next year.
Q 19Alongside Bach and Beethoven, which rock and roll star's music is on the Golden Record launched in 1977?
Chuck Berry
The record, aboard both Voyagers, is a sample of the sights and sounds of Earth.
Q 20Sagan was among the first to suggest which moon of Jupiter might hide a subsurface ocean of water?
Europa
The Galileo spacecraft later confirmed it indirectly; he also proposed liquid oceans on Saturn's Titan.
Q 24Sagan co-founded which organisation in 1980 and served as its first president?
The Planetary Society
He also sat on the board of the SETI Institute.
Q 25Sagan's first wife, who later updated his Encyclopaedia Britannica entry on Life, was which biologist?
Lynn Margulis
Their sons Dorion and Jeremy were born before the marriage ended in 1964.
Q 26Sagan delivered the 1977 Royal Institution Christmas Lectures on what subject?
The Planets
They came the same year the Voyagers left Earth carrying his Golden Record.
Q 27Cosmos drew notably on which earlier documentary series by Jacob Bronowski?
The Ascent of Man
Sagan co-wrote the 13 episodes with Ann Druyan.
Q 28The production of Cosmos recreated which lost building of the ancient world?
The Library of Alexandria
Sagan used it to mourn the knowledge lost when it burned.
Q 29Besides Bach and Vivaldi, which electronic composer's music featured prominently in Cosmos?
Vangelis
His 'Heaven and Hell' became the series' signature theme.
Q 30Sagan wrote the introduction to which physicist's runaway bestseller?
Stephen Hawking's A Brief History of Time
In 1988 he, Hawking and Arthur C. Clarke discussed 'God, the Universe and Everything Else' on television.