Dark Matter Trivia
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60 free Dark Matter trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This dark matter trivia quiz covers the invisible stuff that makes up about 85 percent of the matter in the universe and still has never been detected in a laboratory. The easy questions are the ones any science fan can answer: what dark matter does not interact with, how much of the cosmos it makes up, and how it differs from dark energy. From there the set moves through the history: Lord Kelvin's dark bodies, Fritz Zwicky's dunkle Materie in the Coma Cluster, Vera Rubin and Kent Ford's flat rotation curves, and the 1974 papers from Princeton and Tartu that made galactic halos mainstream. The harder end is for physics buffs: the Bullet Cluster and why it embarrasses modified gravity, cold versus hot dark matter and free streaming length, why neutrinos cannot be the answer, WIMPs and the liquid xenon detectors hunting them, the axion that Frank Wilczek named after a laundry detergent, MACHOs, MOND, primordial black holes, the Lambda-CDM percentages, and the observatory in Chile that carries Rubin's name. Every answer was checked against encyclopaedia entries for dark matter, its discoverers, its candidate particles and its rival theories before publishing, and the supporting sentence is stored with each question. If you enjoy this one, try our Astronomy, Physics and Space quizzes next.
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Q 01Why are dark matter detectors such as LZ built deep underground?
To shield them from cosmic rays
To shield them from cosmic rays. Under Italy's Gran Sasso mountain, 1,400 metres of rock cut that rain of particles about a million times, so a single rare collision has a chance of standing out.
Q 02Dark matter outweighs ordinary matter, but what makes up the largest share of the universe?
Dark energy
Dark energy. It makes up roughly two-thirds of the universe, so dark matter, though it outweighs every star, planet and gas cloud put together, is only the runner-up.
Q 03Dark matter outweighs ordinary matter roughly how many times over?
5 times
5 times. Dark matter is about 85% of all matter, which is why the stars and gas we can see supply far too little gravity to hold a spinning galaxy together.
Q 04Dark matter is spread so thinly near the Sun that all of it inside Neptune's orbit weighs about as much as what?
A large asteroid
A large asteroid. Dark matter outweighs ordinary matter only because it fills the vast spaces of the galaxy; near the Sun it is spread far more thinly than normal matter.
Q 05Which British physicist speculated that many stars near the Sun might be dark bodies?
Lord Kelvin
Lord Kelvin. He treated the Milky Way's stars like the particles of a gas, worked out from their speeds how much mass could be present, and concluded that much of it might not shine.
Q 06Which French scientist wrote of 'matière obscure', or dark matter, in 1906?
Henri Poincaré
Henri Poincaré. He raised the idea only to play it down, reasoning that unseen stars could not outweigh the shining ones, a conclusion later measurements overturned.
Q 07Fritz Zwicky applied the virial theorem to which galaxy cluster in 1933?
Coma
Coma. Its galaxies were moving so fast that Zwicky reckoned the cluster needed some 400 times more matter than he could see to keep them from flying apart.
Q 08Why did Fritz Zwicky's 1930s estimates overstate the ratio of unseen to visible matter?
He used an obsolete Hubble constant
He used an obsolete Hubble constant. The 1930s value was about eight times today's, and correcting it shrinks his ratio by roughly that much, yet the cluster still needs far more mass than its stars supply.
Q 09In which animated comedy is dark matter a starship fuel, collected from the droppings of small aliens?
Futurama
Futurama. In the film Bender's Game the tycoon Mom corners the supply, and her dark matter 'mine' turns out to be a farm of captive Nibblonians, the species of the crew's pet Nibbler.
Q 10Which astronomical term did Fritz Zwicky help coin in the 1930s while proposing neutron stars?
Supernova
Supernova. Zwicky and his colleague Walter Baade began using the word in their lectures, then Zwicky set out to find the explosions himself and discovered dozens in other galaxies.
Q 11What was Zwicky's famous insult for people he disliked?
Spherical bastards
Spherical bastards. Zwicky explained the geometry: like a sphere, they looked exactly the same, bastards, from whichever angle you viewed them.
Q 12The LZ dark matter detector sits about a mile underground in South Dakota, inside a former what?
Gold mine
Gold mine. The Homestake mine had been worked since the Black Hills gold rush of 1876, and an experiment deep inside it was catching particles from the Sun in the 1960s, decades before the whole mine became a laboratory.
Q 13What did Vera Rubin find at spiral galaxies' outer edges?
They move as fast as material near the centre
Q 21Which galaxy cluster shows most of its mass sitting apart from its hot gas, as direct evidence for dark matter?
The Bullet Cluster
The Bullet Cluster. One cluster punched through another there: drag slowed the two clouds of hot gas like air resistance, while the dark matter, feeling only gravity, carried on ahead with the galaxies.
Q 22Colliding galaxy clusters, where mass and hot gas part company, challenge which type of theory?
Modified gravity
Modified gravity. If there were no unseen matter and gravity simply worked differently, the argument goes, the strongest pull should sit on the hot gas, which holds most of the ordinary matter, not off to one side of it.
Q 23Astronomers weigh a galaxy cluster from its gas, which at tens of millions of degrees glows in what kind of light?
They move as fast as material near the centre. Planets far from the Sun crawl along their orbits, so stars at a galaxy's rim should crawl too, unless unseen mass is pulling them along.
Q 14Which famous observatory, lacking a women's restroom, gave Vera Rubin permission to observe in 1965?
Palomar
Palomar. Warned that her time was limited because there was no ladies' room, Rubin cut a skirt out of paper, stuck it on the figure on the men's room door and got to work.
Q 15Under which famous physicist did Vera Rubin earn her PhD in 1954?
George Gamow
George Gamow. The thesis she wrote for him concluded that galaxies clump together instead of lying scattered at random, a finding that went largely unrecognised until the 1970s.
Q 16Which honour was Vera Rubin frequently tipped for but never awarded?
The Nobel Prize
The Nobel Prize. It cannot be awarded posthumously, so Rubin's chance ended when she died at 88, after years of being named as a candidate.
Q 17The Vera C. Rubin Observatory stands on a mountaintop in which country?
Chile
Chile. From its Andean peak it photographs the entire southern sky every few nights, and over ten years the frames will add up to a time-lapse film of the changing universe.
Q 18What record did the Rubin Observatory's main instrument set?
It is the largest camera ever built
It is the largest camera ever built. The size of a small car, it takes in about 45 full Moons of sky in one exposure, and a single image would need hundreds of ultra-HD screens to show in full.
Q 19Which European space telescope was launched in 2023 to map dark matter across a third of the sky?
Euclid
Euclid. It is named after the Greek founder of geometry, because the amount of matter and energy in the universe decides the geometry of space itself.
Q 20Radio astronomers traced galaxy rotation far beyond the visible stars using which emission?
The 21 cm line of atomic hydrogen
The 21 cm line of atomic hydrogen. Hydrogen gas stretches far past a galaxy's last stars, so its radio signal let astronomers clock the rotation where there was nothing else to see.
X-rays
X-rays. Three independent ways of weighing a cluster, by its galaxies' speeds, its X-ray gas and the light it bends, agree that most of its mass cannot be seen.
Q 24In 'cold dark matter', what does 'cold' mean?
Its particles moved slowly in the early cosmos
Its particles moved slowly in the early cosmos. Slow particles could start clumping at once, so small structures formed first and merged into ever bigger ones, the pattern surveys of galaxies show.
Q 25Which known particles were ruled out as the main dark matter because they move too fast to clump into galaxies?
Neutrinos
Neutrinos. Particles that fast would have built vast sheets the size of superclusters first and only later broken them into galaxies, but surveys show the galaxies came first.
Q 26What does the acronym WIMP stand for?
Weakly interacting massive particle
Weakly interacting massive particle. 'Weakly' points at the weak nuclear force: besides gravity, nothing stronger would link such a particle to ordinary matter, so it could pass through the whole Earth unnoticed.
Q 27Which substance fills the detectors of WIMP-hunting experiments such as LUX, PandaX and LZ?
Liquid xenon
Liquid xenon. LZ holds seven tonnes of it: when a particle strikes one of its atoms the liquid gives off a faint glimmer, and hundreds of light sensors above and below are waiting to catch it.
Q 28What is the 'neutrino fog' that hampers dark matter detectors?
An irreducible background of solar neutrino signals
An irreducible background of solar neutrino signals. No shield stops neutrinos from the Sun, and the rare trace one leaves in the tank looks just like the dark matter particle the detector is waiting for.
Q 29Which theory's failure to appear at the Large Hadron Collider has squeezed the case for WIMPs?
Supersymmetry
Supersymmetry. It gives every known particle a heavier partner, and the lightest of those partners would have made an ideal WIMP, but years of collisions have not produced a single one.
Q 30Which dark matter candidate did Frank Wilczek name after a brand of laundry detergent?
The axion
The axion. Wilczek had spotted Axion detergent in a supermarket and thought it sounded like a particle, so he used the name for one that 'cleaned up' a problem; a rival had wanted to call it the higglet.