Galileo Galilei Trivia
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68 free Galileo Galilei trivia questions with answers — science & nature quiz, new questions added Oct 2026.
This Galileo Galilei trivia quiz covers the whole arc of the man Einstein called the father of modern science. The easy questions handle what everyone half-knows: Pisa, the telescope, the moons of Jupiter, the trial, 'and yet it moves'. Then it moves into the details that make him interesting: the medical degree he abandoned after wandering into a geometry lecture, the military compass he sold with an instruction manual, the daughters he sent to a convent, and the tide theory he was so proud of that he wanted it in the title of his most famous book. The harder end covers the Assayer and the comet quarrel, the Letter to the Grand Duchess Christina, Cardinal Bellarmine's 1616 order, the character of Simplicio, the penance of the penitential psalms, the shuttered-lantern speed-of-light test, the pump that could not lift water past 34 feet, and the long, slow reversal by the Church that ended only in 1992. Every answer was checked against Galileo's encyclopaedia entry before publishing and the supporting sentence is stored with each question. Our astronomy and physics quizzes are the natural next stop.
30 of 68 questions with answers and explanations. Play the quiz
Q 01Which physicist was born on 8 January 1942, exactly 300 years after Galileo died?
Stephen Hawking
Stephen Hawking counted Galileo among his inspirations, and his official biography calls the dates a fitting symmetry. In 1981 he first set out his idea of a universe with no boundary at a conference held in the Vatican.
Q 02Galileo's father Vincenzo was a leading figure in which field?
Music
Music: Vincenzo Galilei was a court musician and theorist who put the old rules of harmony to the test, experimenting on how a string's tension changes its pitch. His son may well have helped him.
Q 03At his father's urging, Galileo enrolled at the University of Pisa to study what?
Medicine
Medicine was his father's choice, made after calling the boy home from a monastery where he was thinking of becoming a monk. It never held him: after four years he left the university without a degree.
Q 04In the famous story of the swinging cathedral lamp, the student Galileo timed its swings against what?
His own heartbeat
His own heartbeat, as the story goes: wide swings and narrow ones seemed to take the same time. Doubters point out that the lamp shown to visitors today was hung only in 1587, after he had left the university.
Q 05In the traditional story, what chance event drew the young Galileo away from his university course?
Attending a geometry lecture
Attending a geometry lecture by Ostilio Ricci, a court tutor in Florence, is the usual account. Galileo then brought Ricci home to help talk his reluctant father into letting him change studies.
Q 06Galileo's first scientific work, written in 1586, described his design for what?
A hydrostatic balance
A hydrostatic balance: at 22 he refined the practice of weighing metals first dry and then under water, so that the share of gold in an alloy could be read from the scale. The tract, La Bilancetta, circulated in manuscript.
Q 07The gal, a unit named after Galileo and used by geophysicists, measures what?
Acceleration
Acceleration: one gal is a change of one centimetre per second every second. Gravity surveyors work in thousandths of it, because a mountain or a pocket of light rock shifts the local pull by only that much.
Q 08In 1588 the Florentine Academy invited Galileo to lecture on the shape, location and size of what?
Dante's Inferno
Dante's Inferno: he measured the poem's hell like a surveyor, even working out how thick its roof must be. The physicist Mark Peterson traces his later discovery of scaling laws back to these two lectures.
Q 09From 1592 to 1610 Galileo taught geometry, mechanics and astronomy at which university?
Padua
Padua paid him far better than his first post, yet as head of a family he was always short of money: he ran a workshop at home, sold instruments of his own design and took in private pupils.
Q 10In 1594 Galileo was granted a patent for what device?
A horse-powered water pump
A horse-powered water pump, invented the year before. He needed the money: his father's death had left him head of the family, with a sister's large dowry still to be paid.
Q 11What happened to Galileo's two illegitimate daughters, Virginia and Livia?
They became nuns
They became nuns. Galileo apparently judged daughters born out of wedlock unmarriageable, and he placed both girls in the convent of San Matteo in Arcetri for life while they were still children.
Q 12At his final interrogation in 1633, the Inquisition formally threatened Galileo with what?
Torture
Torture. It stayed a threat: he stuck to his denial that he had held Copernican views since 1616, was never racked or thrown in a dungeon, and was sentenced the next day.
Q 13To prove Galileo right about falling bodies, an Apollo 15 astronaut dropped a hammer and what on the lunar surface?
A feather
Q 21Galileo's 1610 discovery that Venus shows a full set of phases made which model of the cosmos untenable?
The Ptolemaic
The Ptolemaic. Yet the phases fitted Tycho Brahe's rival scheme too, with planets circling the Sun and the Sun circling a fixed Earth, so many astronomers switched to that compromise, not to Copernicus.
Q 22When Galileo first observed Saturn in 1610, what did he take its rings to be?
Two companion planets
Two companion planets. He drew Saturn as a large globe with a smaller one on each side, then in 1612 found both had vanished and wondered whether Saturn had swallowed his children.
Q 23Which planet did Galileo record in his notebooks in 1612 as just another dim star?
Neptune
A feather. In the lunar vacuum the falcon feather fell exactly as fast as the geological hammer, and the two hit the dust together, live on television.
Q 14In August 1609 Galileo demonstrated one of his first telescopes to whom?
Venetian lawmakers
Venetian lawmakers. Galileo presented an eight-power spyglass to the Senate, which rewarded him by doubling his salary and making his university post a job for life.
Q 15Which short book set out Galileo's first discoveries with the telescope?
The Starry Messenger
The Starry Messenger. Galileo rushed it into print in March 1610, about two months after his January sightings, and by the next spring the Jesuits' own astronomers had confirmed what he saw and feted him.
Q 16Why is Thomas Harriot's telescope drawing of the Moon, made before Galileo's, so little known?
Never published
Never published. Harriot kept his Moon sketches among his private papers all his life, while Galileo had his own drawings in print within four months of making them.
Q 17On 7 January 1610 Galileo noticed three 'fixed stars' in a line beside which planet?
Jupiter
Jupiter. About a week later he realised the 'stars' were moons circling the planet, which showed that not everything in the sky revolves around the Earth.
Q 18Galileo named his four newly found moons the 'Medicean stars' after the Grand Duke of where?
Tuscany
Tuscany. The flattery worked: within months Cosimo II de' Medici gave Galileo a court post for life, and he left his university job and moved back to Florence.
Q 19Which astronomer suggested the names Io, Europa, Ganymede and Callisto for the four moons Galileo discovered?
Johannes Kepler
Johannes Kepler. Simon Marius, who claimed to have seen the moons himself, printed Kepler's suggestion, but astronomers ignored the names and used plain numbers for more than two centuries.
Q 20Galileo proposed eclipses of his newly found moons as a clock to solve which navigation problem?
Longitude
Longitude. The method failed on a rolling deck but worked on land, where French astronomers used it to redraw the map of France and found the country smaller than everyone had thought.
Neptune. It went unrecognised as a planet until 1846, when astronomers found it by calculating where an unseen world must lie to be pulling Uranus off its predicted path.
Q 24Galileo's long feud with the Jesuit Christoph Scheiner was over who first discovered what?
Sunspots
Sunspots. While the two men quarrelled over who came first, neither knew that a German, Johannes Fabricius, had already beaten both of them into print with a book in 1611.
Q 25What did Galileo's telescope reveal the Milky Way to be?
A dense mass of stars
A dense mass of stars. Until then its glow had been taken for a kind of cloud; his spyglass broke it into countless stars too faint and too crowded for the naked eye to tell apart.
Q 26Ganymede, the largest moon Galileo discovered, is wider than Mercury but far lighter because it is rich in what?
Water ice
Water ice. Ganymede is so icy that it has under half of Mercury's mass, and in 2015 Hubble found signs of a salty ocean beneath the crust by watching how the moon's auroras rock.
Q 27The Dialogue Concerning the Two Chief World Systems was originally titled after which natural phenomenon?
The tides
The tides. Galileo believed the seas' ebb and flow proved that the Earth circles the Sun, so Church censors made him strike the tides from the title rather than seem to endorse his proof.
Q 28Which 1975 Queen hit calls out the name Galileo again and again?
Bohemian Rhapsody
Bohemian Rhapsody. Queen's producer recalled that its middle section kept swelling because the singer kept arriving at the studio with a few more 'Galileos' to overdub.
Q 29In Galileo's Dialogue, which of the three speakers stands in for Galileo himself?
Salviati
Salviati. He and the neutral listener, Sagredo, bear the names of two real friends of Galileo's who had died long before the book came out, one in 1614 and one in 1620.
Q 30Galileo's The Assayer grew out of a quarrel with a Jesuit about which objects, three of which appeared in 1618?
Comets
Comets. Galileo was on the wrong side: he suggested they might be mere tricks of light near the Earth, while the Jesuit Orazio Grassi rightly placed them far out in space.