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50 free The Big Bang trivia questions with answers — science & nature quiz, new questions added Aug 2026.
The Big Bang is the theory that the universe expanded from a hot, dense early state about 13.8 billion years ago. It was proposed by a Belgian priest, named by a man who did not believe it, and confirmed by two radio engineers who thought the hiss in their antenna was pigeon droppings. Today it rests on four pillars: the expansion Hubble measured, the microwave background, the abundance of light elements and the way galaxies have changed over time. These 50 questions run from the basics to the frontier: who coined the name and on which broadcaster, what Lemaître called his starting point, who actually found the cosmic microwave background and when they got their Nobel, what inflation is and which problems it fixes, how much of the universe is dark energy, and what the Big Crunch, Big Freeze and Big Rip would mean. Easy questions cover the age of the universe and Hubble's law; the expert tier asks about ylem, the Sakharov conditions, the lithium problem, the magazine that tried to rename the Big Bang and the astronomer who found a beginning of time 'repugnant'. Every answer is cited to a page we checked, with a short explanation. Play it solo or print it for a science night.
30 of 50 questions with answers and explanations. Play the quiz
Q 01How old do expansion-rate measurements say the universe is?
About 13.8 billion years
The figure is 13.787 billion years give or take 20 million, and it agrees with the ages of the oldest stars.
Q 02Which astronomer is credited with coining the term 'Big Bang' in 1949?
Fred Hoyle
He backed the rival steady-state model and later denied he meant the phrase as a put-down.
Q 03Hoyle coined the phrase during a 1949 radio broadcast on which broadcaster?
BBC
It was the Third Programme; the name did not really catch on until the 1970s.
Q 04What was Hoyle's rival theory, with matter created as space expands, called?
Steady-state model
In that picture the universe looks roughly the same at any point in time, with no beginning.
Q 05Which Belgian priest-physicist proposed the 'primeval atom' in 1931?
Georges Lemaître
Critics complained that a beginning in time smuggled religion into physics, not helped by his being a priest.
Q 06Hubble's law says a galaxy's recession speed rises in proportion to what?
Its distance
Friedmann in 1922 and Lemaître in 1927 had predicted the relation from general relativity before Hubble measured it.
Q 07Who accidentally discovered the cosmic microwave background in 1964?
Penzias and Wilson
The omnidirectional microwave hiss matched predictions made by Alpher, Herman and Gamow around 1950.
Q 08The CMB's discoverers received the Nobel Prize in Physics in which year?
1978
By then the radiation had been shown to match a blackbody spectrum in every direction.
Q 09The cosmic microwave background today corresponds to a temperature of roughly what?
2.7 K
COBE pinned it at 2.726 K in 1990; newer measurements give 2.7255 K.
Q 10Recombination, when atoms formed and the universe turned transparent, came about when?
380,000 years
The photons that last scattered then are what we now see as the microwave background.
Q 11Minutes after the Big Bang, neutrons and protons fused into nuclei of which element?
Helium
Most protons stayed single as hydrogen; the temperature was about a billion kelvin at the time.
Q 12Who introduced the idea of an early epoch of rapid expansion, 'inflation', in 1981?
Alan Guth
It resolved the horizon, flatness and monopole problems, though some of its own founders now doubt it.
Q 13During inflation the universe doubled in size more than how many times?
80
That happened in a span a billion trillion times shorter than a trillionth of a second.
Inflation fixes the flatness puzzle and which other puzzle about the CMB's uniformity?
Q 21Who assisted Hubble in the 1929 work that produced Hubble's law?
Milton Humason
Most of the redshifts they used had been measured earlier by Vesto Slipher.
Q 22Which two associates of George Gamow predicted the cosmic background radiation?
Alpher and Herman
Their prediction dated from around 1950, fourteen years before the radiation was stumbled upon.
Q 23What did George Gamow call the primordial material of the early universe?
Ylem
Lemaître preferred 'primeval atom' for the same hot, dense starting state.
Horizon problem
Without inflation, regions more than about two degrees apart on the sky could never have shared a temperature.
Q 15Grand unified theories predicted a glut of which objects that inflation dilutes away?
Magnetic monopoles
None has ever been found; inflation sweeps such point defects out of the observable universe.
Q 16Dark energy makes up roughly what share of the universe's mass-energy density?
68%
Dark matter is about 27 per cent and everything luminous less than 5.
Q 17Luminous matter such as stars makes up less than what share of the universe's density?
5%
The rest is dark matter and dark energy, neither of which has been detected directly.
Q 18Which Russian derived the expanding-universe equations from relativity in 1922?
Alexander Friedmann
His result contradicted the static universe Einstein favoured at the time.
Q 19Who measured the first Doppler shift of a 'spiral nebula' in 1912?
Vesto Slipher
He found almost all of them receding but did not grasp what that meant for cosmology.
Q 20Hubble measured galaxies' remoteness with the 100-inch Hooker reflector at which observatory?
Mount Wilson
His 1924 measurements showed the spiral nebulae were separate galaxies, not part of the Milky Way.
Q 24Which NASA satellite, launched in 1989, found tiny fluctuations in the CMB temperature?
COBE
The anisotropies, found in 1992, were at the level of about one part in 100,000.
Q 25Who shared the 2006 physics Nobel for mapping the CMB's spectrum and anisotropies?
Mather and Smoot
John Mather and George Smoot led the two key results from the satellite.
Q 26WMAP measured the Hubble constant at roughly what value?
About 70 km/s/Mpc
Its figure was 70.4 km/s/Mpc; CMB-based and supernova-based values still disagree slightly.
Q 27What is the mismatch between CMB-based and supernova-based expansion rates called?
Hubble tension
The CMB route gives a lower number than the local measurements do.
Q 28The puzzle of why the universe holds far more matter than antimatter is called what?
Baryon asymmetry
The early excess was tiny, of the order of one part in tens of millions, but it is everything we see.
Q 29The requirements for baryogenesis to create a matter excess are known as whose conditions?
Sakharov
They demand baryon-number violation, C and CP violation, and a departure from equilibrium.
Q 30Observations of which objects revealed that the expansion of the universe is accelerating?
Type Ia supernovae
Their redshift-magnitude relation showed the speed-up began when the universe was about half its present age.