Milky Way Trivia
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49 free Milky Way trivia questions with answers — science & nature quiz, new questions added Sep 2026.
This Milky Way trivia quiz is about our home galaxy, not the chocolate bar. The easy questions cover what most stargazers know: what kind of galaxy it is, roughly how many stars it holds, which spiral arm the Sun sits in, what lurks at the centre, and who first showed with a telescope that the hazy band is really made of stars. The harder end goes deeper: how long a galactic year takes, the Great Debate of 1920 and how Edwin Hubble settled it, the Fermi bubbles, the Kraken merger, the Magellanic Clouds and their stream, why the flat rotation curve is the best evidence for dark matter, the ancient names for the band from 'Birds' Path' to 'Silver River', and what happens when Andromeda arrives in about four billion years. Every answer was checked against the galaxy's encyclopaedia entry before publishing and the supporting sentence is stored with each question. If you enjoy this, our astronomy and space quizzes are the natural next stop.
30 of 49 questions with answers and explanations. Play the quiz
Q 01What type of galaxy is the Milky Way?
Barred spiral
Barred spiral: a long bar of old stars crosses the centre instead of the arms winding right in. A 2005 infrared survey of some 30 million stars showed the bar was far longer than astronomers had thought.
Q 02Roughly how many stars is the Milky Way estimated to contain?
Between 100 and 400 billion
Between 100 and 400 billion is the usual estimate. The range is wide because we count from inside the galaxy, and its dim, low-mass stars are very hard to detect.
Q 03The Sun sits in which spiral arm of the Milky Way?
The Orion Arm
The Orion Arm, a minor spur between two larger arms. It puts us about 26,000 light-years from the centre, roughly halfway to the edge, in what NASA calls the suburbs of the galaxy.
Q 04What is the intense radio source at the Galactic Center called?
Sagittarius A*
Sagittarius A*, said 'A-star', marks the galaxy's supermassive black hole. In 2022 the Event Horizon Telescope released the first image of it: a glowing ring of gas around a dark shadow.
Q 05Roughly how massive is the black hole at the centre of the Milky Way?
About 4 million solar masses
About 4 million solar masses, weighed by tracking stars that whip around an invisible object at the centre. That work won Reinhard Genzel and Andrea Ghez a share of the 2020 Nobel Prize in Physics.
Q 06In 1610, who first resolved the band of the Milky Way into individual stars with a telescope?
Galileo Galilei
Galileo Galilei. In his 1610 booklet Sidereus Nuncius he reported that the Galaxy is 'nothing else but a mass of innumerable stars', ending centuries of dispute over what the band was made of.
Q 07Whose 1923 observations showed the Milky Way was just one galaxy among many?
Edwin Hubble
Edwin Hubble found Cepheid variable stars, whose pulsing reveals their true distance, inside a spiral 'nebula'. They put it far outside the Milky Way, settling astronomy's 'Great Debate' of 1920.
Q 08Hunting static on transatlantic phone links around 1932, Karl Jansky traced a faint hiss to the Milky Way, founding which science?
Radio astronomy
Radio astronomy. The Bell Labs engineer tracked the hiss for months with a rotating antenna and found it came from a direction fixed among the stars, the heart of the Milky Way, not from storms or the Sun.
Q 09Why does the Milky Way appear as a band across the night sky?
We see its disc from inside
We see its disc from inside: the galaxy is flat, so looking along it piles the stars into a band. In a ball-shaped elliptical galaxy the stars would be spread all around the sky instead.
Q 10In Greek myth, whose spilled milk formed the Milky Way?
Hera's
Hera's. In the usual telling Zeus held the infant Heracles to his sleeping wife's breast to make him immortal; she woke and pushed the child away, and her milk sprayed across the sky.
Q 11In Irish, the Milky Way is called 'the Way of the White' what?
Cow
Cow: Bealach na Bó Finne. 'White cow' is also what the name of Bóinn, goddess of the Boyne, means, and the band seems to have been seen as the Boyne's reflection in the sky.
Q 12Around 1380, which English poet wrote of 'the Galaxye, which men clepeth the Milky Wey'?
Geoffrey Chaucer
Geoffrey Chaucer, in his poem The House of Fame. The English name is traced back to this line, a direct translation of the Latin via lactea, and he adds the reason himself: 'for hit is whyt'.
Q 13In Finnish, Estonian and several Turkic languages, the galaxy is named after what?
The path of migrating birds
Q 21A 2016 world atlas of light pollution ranked which country the worst, with the Milky Way hidden from every resident?
Singapore
Singapore, a city-state lit from edge to edge, where eyes never fully adapt to the dark. The same atlas found the band hidden from more than a third of humanity, including nearly 80% of North Americans.
Q 22Which philosopher wrote in Meteorologica that the Milky Way was part of Earth's upper atmosphere?
Aristotle
Aristotle took the band for a dry vapour set alight in the upper air, below the Moon. In the same book he waved away Democritus, who had already called the milky way the light of stars.
Q 23The Drake equation, drawn up in 1961, is a way of estimating the number of what in the Milky Way?
Alien civilisations
The path of migrating birds: Linnunrata in Finnish, Linnutee in Estonian. Northern peoples saw that birds heading south for the winter follow the line of the band across the sky.
Q 14What does the Chinese name for the Milky Way, used across East Asia, translate to?
Silver River
Silver River. In the legend behind China's Qixi and Japan's Tanabata festivals, it is the river that parts a weaver girl from her cowherd husband, who may cross it to meet her only once a year.
Q 15Pilgrims to which holy site traditionally used the Milky Way as a guide?
Santiago de Compostela
Santiago de Compostela. The band seemed to point pilgrims west across Spain, so Spaniards still call the Milky Way El Camino de Santiago; one medieval legend says it was made of dust kicked up by their feet.
Q 16What does 'Vintergatan', the Swedish name for the Milky Way, mean?
Winter Street
Winter Street. Nobody is sure why: one idea is that the bright summer nights of the far north hide the band, so it shows best in winter; another is that people once read it to forecast the coming winter.
Q 17In an Armenian legend echoed in Arabic and Turkish names for the galaxy, a fleeing thief spilled a trail of what?
Straw
Straw: Armenians called the galaxy the Straw Thief's Way, after the god Vahagn, who stole straw from the Assyrian king Barsham one cold winter and spilled some as he fled. Turkish Samanyolu still means 'straw road'.
Q 18The Gomeroi people of Australia see the dark dust lanes of the band as which giant animal?
An emu
An emu, whose head is the dark Coalsack nebula beside the Southern Cross, with neck and body trailing along the band. When it seems to run across the sky in April and May, real emus are laying and eggs can be gathered.
Q 19What are the swarms of ancient stars that orbit in the Milky Way's halo called?
Globular clusters
Globular clusters: tightly bound balls of up to millions of stars, among the oldest in the galaxy. Harlow Shapley mapped them in the 1910s and found they centre on a point far from the Sun, the true middle of the galaxy.
Q 20What is the dark region of the band where interstellar dust hides the stars behind called?
The Great Rift
The Great Rift, a dark river of dust and gas clouds running along the band from Cygnus towards the galaxy's centre. Infrared light slips through the dust, so infrared telescopes can see the stars it hides.
Alien civilisations whose signals we might detect. Frank Drake wrote it as the agenda for a small 1961 meeting in West Virginia, to organise what nobody knew rather than to reach a firm number.
Q 24Which philosopher proposed in 1755 that the Milky Way is a vast rotating system of stars, and faint nebulae other such systems?
Immanuel Kant
Immanuel Kant reasoned that whatever set the planets circling the Sun in a single plane could do the same for the stars. The idea of distant 'island universes' remained a guess until the 1920s, when the nebulae proved to be galaxies.
Q 25Which astronomer, the discoverer of Uranus, first tried to map the Milky Way's shape in 1785 by counting stars?
William Herschel
William Herschel counted the stars in patch after patch of sky with telescopes he built himself, reasoning that more stars meant a deeper galaxy. His map put the Sun near the middle, a mistake that stood for well over a century.
Q 26Which ESA spacecraft, launched in 2013, charted nearly two billion stars to build a 3D map of the Milky Way?
Gaia
Gaia measured each star's position dozens of times over more than a decade, until ESA switched it off in March 2025. Tiny shifts in position give a star's distance and its motion through the galaxy.
Q 27Roughly how long does the Solar System take to complete one orbit of the galaxy, a 'galactic year'?
About 240 million years
About 240 million years, though estimates run from roughly 220 to 250 million. Even at more than 200 km every second, the Sun has managed only about 20 laps since it formed.
Q 28Which Dutch astronomer, namesake of the distant cloud that supplies long-period comets, showed in the 1920s that the Milky Way rotates?
Jan Oort
Jan Oort showed that stars nearer the centre overtake the Sun while those farther out fall behind, just as inner planets pass outer ones. He was still in his twenties; his comet cloud came more than two decades later.
Q 29Which insect was shown in 2013 to keep a straight course at night by the glow of the Milky Way?
The dung beetle
The dung beetle: in a Johannesburg planetarium, beetles rolled their balls as straight under the band alone as under a full starry sky. A straight line is the fastest escape from rivals at the dung pile.
Q 30What is the other giant spiral in the Local Group besides the Milky Way?
The Andromeda Galaxy
The Andromeda Galaxy, 2.5 million light-years away, is the nearest major galaxy and can be seen with the naked eye. The light you see tonight left it long before our species existed.