70 free Galileo Galilei trivia questions with answers — science & nature quiz, new questions added Aug 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 70 questions with answers and explanations. Play the quiz
Q 01In which city was Galileo born in 1564?
Pisa
The city was then part of the Duchy of Florence; his family moved to Florence itself when he was about eight.
Q 02Galileo's father Vincenzo was a leading figure in which field?
Music
A lutenist and music theorist of the Florentine Camerata, he ran string-tension experiments that may be the oldest known non-linear law in physics; Galileo himself became an accomplished lutenist.
Q 03At his father's urging, Galileo enrolled at the University of Pisa in 1580 to study what?
Medicine
He had seriously considered the priesthood; a physician's income was the deciding argument, and he was deliberately kept away from mathematics.
Q 04Watching a swinging chandelier in 1581, Galileo timed its swings against what?
His own heartbeat
He concluded the swings took the same time whatever their size, an idea Huygens turned into an accurate clock a century later.
Q 05What chance event persuaded the young Galileo to abandon medicine for natural philosophy?
Attending a geometry lecture
He then had to talk his reluctant father into letting him change course.
Q 06Galileo's first publication, in 1586, described his design for what?
A hydrostatic balance
The little tract, La Bilancetta, first brought him to the attention of the scholarly world.
Q 07In 1588 Galileo took a teaching post at a Florentine academy devoted to what?
Fine art
He taught perspective and chiaroscuro and struck up a lifelong friendship with the painter Cigoli.
Q 08Galileo's two 1588 lectures to the Florentine Academy attempted a rigorous cosmological model of what?
Dante's Inferno
He tried to work out the shape, location and size of the hell described in the Divine Comedy.
Q 09From 1592 to 1610 Galileo taught geometry, mechanics and astronomy at which university?
Padua
It was during these years that he made most of his practical inventions and his first telescopic discoveries.
Q 10In 1594 Galileo obtained a patent from the Venetian Republic for what device?
A horse-powered water pump
His younger brother's debts gave him a lifelong incentive to invent things that would earn extra income.
Q 11What happened to Galileo's two illegitimate daughters, Virginia and Livia?
They became nuns
He considered them unmarriageable and placed them in the convent of San Matteo in Arcetri for life.
Q 12What religious name did Galileo's daughter Virginia take on entering the convent?
Maria Celeste
She is buried alongside her father in the Basilica of Santa Croce.
Q 13Galileo built his first telescope in 1609 after hearing of a device patented in which country?
Netherlands
Hans Lippershey's spyglass managed about 3x magnification; Galileo pushed his to roughly 30x.
Q 21Galileo's 1610 discovery that Venus shows a full set of phases made which model of the cosmos untenable?
The Ptolemaic
Most astronomers responded by switching to hybrid geo-heliocentric systems rather than to full heliocentrism.
Q 22When Galileo first observed Saturn in 1610, what did he take its rings to be?
Two companion planets
The 'bodies' vanished when the rings turned edge-on and reappeared in 1616, baffling him further.
Q 23Which planet did Galileo record in his notebooks in 1612 as just another dim star?
Neptune
He even noted its motion against the background stars before losing track of it.
Q 14On 25 August 1609 Galileo demonstrated one of his early telescopes to whom?
Venetian lawmakers
Telescopes were a profitable sideline; he sold them to merchants who found them useful at sea.
Q 15Galileo's 1610 treatise Sidereus Nuncius is known in English by what title?
The Starry Messenger
It was the first scientific treatise ever published from observations made through a telescope.
Q 16Which English mathematician observed the Moon by telescope four months before Galileo?
Thomas Harriot
Galileo went further, deducing that the ragged terminator was caused by mountains and craters, and even estimated their heights.
Q 17On 7 January 1610 Galileo noticed three 'fixed stars' in a line beside which planet?
Jupiter
Within a week he realised they were moons orbiting the planet, powerful evidence against an Earth-centred cosmos.
Q 18Galileo named his four newly found moons the 'Medicean stars' after the Grand Duke of where?
Tuscany
Later astronomers overruled him and called them the Galilean satellites instead.
Q 19Who spotted Jupiter's four moons a day after Galileo and later named them Io, Europa, Ganymede and Callisto?
Simon Marius
The names appeared in his Mundus Iovialis of 1614 and are the ones still used.
Q 20Galileo proposed eclipses of his newly found moons as a clock to solve which navigation problem?
Longitude
It proved impossible from a rolling deck but worked well on land, and was used to remap France.
Q 24Galileo's long feud with the Jesuit Christoph Scheiner was over who first discovered what?
Sunspots
Neither man knew that Johannes Fabricius had already published on them.
Q 25What did Galileo's telescope reveal the Milky Way to be?
A dense mass of stars
It had previously been thought nebulous; he also spotted the double star Mizar in 1617.
Q 26Galileo devised a way to measure a star's apparent size without a telescope, using what?
A thin hanging rope
He measured how far away the rope had to be to blot out the star; the tiny sizes he got helped answer Tycho's anti-Copernican argument.
Q 27The Dialogue Concerning the Two Chief World Systems was originally titled after which natural phenomenon?
The tides
Galileo considered his tide theory proof that the Earth moves; the Inquisition ordered the reference removed.
Q 28Galileo's theory of the tides wrongly implied how many high tides per day?
One
He blamed the two daily tides at Venice on the shape and depth of the sea.
Q 29Galileo rejected Kepler's correct idea that the tides are caused by what?
The Moon
His own explanation was the sloshing of the seas as the Earth rotated and orbited.
Q 30Galileo's The Assayer (1623) grew out of a dispute with a Jesuit over the nature of what?
Comets
The quarrel with Orazio Grassi widened into an argument about how science itself should be done.