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50 free Milky Way trivia questions with answers — science & nature quiz, new questions added Aug 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 50 questions with answers and explanations. Play the quiz
Q 01What type of galaxy is the Milky Way?
Barred spiral
Astronomers began suspecting a central bar in the 1960s, and infrared observations in 2005 confirmed it was bigger than expected.
Q 02Roughly how many stars is the Milky Way estimated to contain?
Between 100 and 400 billion
The uncertainty comes from very-low-mass stars that are hard to detect; there are thought to be at least as many planets as stars.
Q 03The Sun sits on the inner edge of which spiral arm?
The Orion Arm
We are about 27,000 light-years from the Galactic Center; the next arm out, the Perseus Arm, is around 6,500 light-years away.
Q 04What is the intense radio source at the Galactic Center called?
Sagittarius A*
It marks a supermassive black hole; the '*' is pronounced 'star'.
Q 05Roughly how massive is the black hole at the centre of the Milky Way?
About 4 million solar masses
It is a quiet giant, accreting only about a hundred-thousandth of a solar mass per year, typical of an inactive galactic nucleus.
Q 06Who first resolved the band of the Milky Way into individual stars with a telescope, in 1610?
Galileo Galilei
Until the early 1920s most astronomers still thought the Milky Way contained every star in the universe.
Q 07Whose 1923 observations showed the Milky Way was just one galaxy among many?
Edwin Hubble
He used Cepheid variables and the 100-inch Hooker telescope to put the Andromeda Nebula far outside the Milky Way.
Q 08The 1920 'Great Debate' about the scale of the universe was between Harlow Shapley and which astronomer?
Heber Doust Curtis
Curtis had noticed that novae in the Andromeda Nebula were about 10 magnitudes fainter than those in the Milky Way, and argued it was a separate 'island universe'.
Q 09Which instrument did Hubble use to settle the debate over spiral nebulae?
The 100-inch Hooker telescope at Mount Wilson
Its light-gathering power let him photograph individual stars in the outer parts of spiral nebulae.
Q 10In Greek myth, whose spilled milk formed the Milky Way?
Hera's
Zeus put the infant Heracles to her breast while she slept; when she woke and pushed him away, the milk sprayed across the sky.
Q 11The word 'galaxy' comes from a Greek root meaning what?
Milk
Galaxias kyklos meant 'milky circle', one of 11 circles the Greeks drew on the sky alongside the zodiac and the tropics.
Q 12Which English poet's work from around 1380 gives the earliest English name for the galaxy?
Geoffrey Chaucer
He wrote of 'the Galaxye which men clepeth the Milky Wey, for hit is whyt' in The House of Fame.
Q 13In Finnish, Estonian and several Turkic languages, the galaxy is named after what?
The path of migrating birds
Northern peoples noticed that migrating birds follow the band; Chuvash and Tatar call it the 'Way of the grey goose'.
Q 21Roughly what fraction of humanity cannot see the Milky Way from home due to light pollution?
More than one-third
The sky needs to be darker than about 20.2 magnitudes per square arcsecond for the band to appear at all.
Q 22Which philosopher wrote in Meteorologica that the Milky Way was part of Earth's upper atmosphere?
Aristotle
Olympiodorus the Younger later objected that a sublunary band would show parallax and look different from different places, which it does not.
Q 23Which Persian scholar wrote c.1000 AD that the Milky Way was 'countless fragments' of nebulous stars?
Al-Biruni
Q 14What does the Chinese name for the Milky Way, used across East Asia, translate to?
Silver River
In Japan the band is also called the 'River of Heaven' (Ama no gawa), and in Japanese and Korean the 'silver river' word means any galaxy.
Q 15Pilgrims to which holy site traditionally used the Milky Way as a guide?
Santiago de Compostela
Oddly, the pilgrimage road itself was also nicknamed 'La Voje Ladee', the Milky Way.
Q 16Swedes call the galaxy 'Vintergatan'. What does it mean?
Winter Street
At high latitudes the summer sky never gets fully dark, so the band shows best in winter.
Q 17In Arabic and other West Asian languages, the galaxy's name refers to which material?
Straw
Darb at-Tabbanah means 'Pathway of the Straw'; medieval Arabs may have borrowed the image from Armenians.
Q 18The Gomeroi people of Australia see the dark dust lanes of the band as which giant animal?
An emu
Southern peoples including the Inca built 'dark cloud constellations' out of the dust regions rather than the stars.
Q 19In which constellation does the Galactic Center lie, where the band appears brightest?
Sagittarius
The band runs from there around the whole sky to the anticentre in Auriga, splitting the sky into two near-equal halves.
Q 20What is the dark region of the band where interstellar dust hides the stars behind called?
The Great Rift
The Zone of Avoidance is different: it is the part of the sky where the Milky Way's own dust blocks our view of galaxies beyond.
Nasir al-Din al-Tusi later wrote that it was made of small, tightly clustered stars that only 'seem to be cloudy patches'.
Q 24Which philosopher speculated in 1755 that the Milky Way was a rotating disc of stars and coined 'island universes'?
Immanuel Kant
He was building on, and misreading, Thomas Wright's suggestion that the galaxy was shaped like a balloon.
Q 25Who first tried to map the Milky Way's shape in 1785 by counting stars across the sky?
William Herschel
His diagram put the Solar System near the centre, an error that would not be corrected for well over a century.
Q 26Which ESA mission launched in 2013 measured parallaxes of about a billion Milky Way stars?
Gaia
Gaia, which ended science observations in January 2025, expanded the number of precisely measured stars from about 2 million in the 1990s to 2 billion and detected a wobble in the galactic disc.
Q 27Roughly how long does the Solar System take to complete one orbit of the galaxy, a 'galactic year'?
About 240 million years
The Sun has managed roughly 18-20 laps in its lifetime and about 1/1250 of a lap since humans appeared.
Q 28At roughly what speed does the Solar System orbit the centre of the galaxy?
About 220 km/s
That is about 490,000 mph, or 0.073% of the speed of light.
Q 29The Sun's general motion through the galaxy is towards which bright star?
Deneb
This 'solar apex' is roughly 90 degrees away from the direction of the Galactic Center.
Q 30What is the other giant spiral in the Local Group besides the Milky Way?
The Andromeda Galaxy
The two are effectively a binary system among about 50 gravitationally bound galaxies.