Special Relativity
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40 free Special Relativity trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Special relativity is the theory Albert Einstein published in 1905, and it changed what physicists mean by space and time. It says the speed of light is the same for every observer, and strange things follow from that: time can slow down, lengths can shrink, and two people can disagree about whether two events happened at once. This quiz covers the core ideas, the thought experiments used to explain them, the laboratory and real-world tests that confirmed them, and the scientists who came before and after Einstein. There are also questions on where relativity turns up in everyday technology and in films, books and music. The questions suit physics students revising the topic, teachers who want a ready-made class quiz, and anyone curious about how the universe keeps time. No equations need solving, and every answer comes with a short explanation.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Albert Einstein held a day job at what kind of workplace when he published special relativity in 1905?
A patent office
A patent office in Switzerland employed Einstein as an assistant examiner. The inventions that crossed his desk there included a gravel sorter and an electric typewriter.
Q 02Which navigation technology would drift by over 10 kilometres a day if its clocks ignored the effects of relativity?
GPS
GPS satellite clocks run about 38 microseconds a day fast: their speed slows them, but their height above Earth speeds them up by more. The system is built to correct for it.
Q 03In which classic film do astronauts on a near-light-speed voyage land some two thousand years after their launch?
Planet of the Apes
Planet of the Apes has the ship's chronometer read 3978 as the crew abandon it, about two millennia after their 1972 departure. Relativity lets a fast traveller skip ahead like that.
Q 04Which metal owes its colour to relativity, because its innermost electrons move at over half the speed of light?
Gold
Gold would be silvery like most other metals if relativity did not apply. Its innermost electrons travel at about 58% of light speed.
Q 05Albert Einstein won the 1921 Nobel Prize in Physics for explaining what, rather than for relativity?
The photoelectric effect
The photoelectric effect is named in his Nobel citation, and relativity is not. The 1921 prize was actually awarded a year late, in 1922.
Q 06Which particles seemed to outrun light between CERN and Italy in 2011, a result later traced to a loose cable?
Neutrinos
Neutrinos sent from CERN to the Gran Sasso lab appeared to arrive too early. A fibre cable that was not fully screwed in had skewed the timing, and two of the experiment's leaders resigned.
Q 07Which Italian scientist argued in 1632 that a passenger on a smoothly sailing ship has no sense of its motion?
Galileo Galilei
Galileo Galilei used the ship to answer critics who said a moving Earth would be felt. Einstein later stretched the same principle to cover light as well as mechanics.
Q 08Albert Einstein imagined lightning hitting both ends of which moving vehicle to show that simultaneity is relative?
A train
A train passing a platform is the setting: a bystander sees both bolts strike at once, while for a passenger in the middle carriage the front bolt strikes first. Neither is wrong.
Q 09Which equation of Albert Einstein's from 1905 shows that a little matter holds an enormous amount of energy?
E = mc²
E = mc² multiplies mass by the speed of light squared, a huge number. It came from a short follow-up paper whose title asked whether a body's inertia depends on its energy content.
Q 10Which effect of relativity makes astronauts on the International Space Station age slightly less than people on Earth?
Time dilation
Time dilation trims about 5 milliseconds off an astronaut's ageing during six months in orbit at 7.7 km per second. A faster ship would widen the gap.
Q 11Which invisible medium, once thought to fill space and carry light waves, did special relativity show was not needed?
The aether
The aether was the light-bearing medium that physicists assumed light waves must travel through. Experiments in the 1880s failed to find any sign of Earth moving through it.
Q 12What name did the physicist Gerald Feinberg coin in 1967 for hypothetical particles that always move faster than light?
Tachyons
Tachyons have never been detected. Physicists expect they cannot exist, because a faster-than-light particle could be used to send signals into the past.
Q 13Which force does special relativity leave out, the one Albert Einstein's general theory went on to explain?
Gravity
Q 21Which CERN machine pushes protons to 99.999999% of light speed, where they carry thousands of times their rest energy?
Large Hadron Collider
Large Hadron Collider protons end up only about 11 km/h slower than light itself. Adding more energy barely raises their speed, just as relativity predicts.
Q 22Joseph Hafele and Richard Keating tested relativity in 1971 by flying what around the world on airliners?
Atomic clocks
Atomic clocks flown east and then west were compared with ones left behind at the US Naval Observatory. The four travelling clocks went as ordinary passengers on commercial flights.
Q 23Since 1983, which SI unit has been defined using the speed of light and a fixed fraction of a second?
Metre
Gravity is absent from the 1905 theory, which deals with observers moving steadily in straight lines. Einstein needed about another decade to extend relativity to cover it.
Q 14Which 1887 experiment in Cleveland found light's speed unaffected by Earth's motion, a famous 'failed' result?
Michelson–Morley
Michelson–Morley has been called the most famous failed experiment in history, because it detected nothing. The pair then turned their technique to making light a standard of length.
Q 15Which short-lived cosmic-ray particles reach the ground only because their speed stretches their lifetimes?
Muons
Muons made high in the atmosphere last about two millionths of a second at rest. At 98% of light speed their lifetime is about five times longer, so many survive the trip down.
Q 16Which former teacher of Albert Einstein recast special relativity in 1908 as the geometry of four dimensions?
Hermann Minkowski
Hermann Minkowski taught Einstein at the Zurich Polytechnic. He argued that space and time are not separate things but parts of a single four-dimensional whole.
Q 17Which Dutch Nobel laureate is named in the equations that convert measurements between moving observers?
Hendrik Lorentz
Hendrik Lorentz derived the transformations before Einstein showed what they meant, and they were named after him in 1905. His 1902 Nobel Prize was for explaining the Zeeman effect.
Q 18Which British physicist united relativity and quantum mechanics in a 1928 equation that predicted antimatter?
Paul Dirac
Paul Dirac found that his equation implied a mirror-image partner for the electron. Carl Anderson observed that particle, the positron, in 1932, and Dirac shared the Nobel Prize a year later.
Q 19Which Greek letter stands for the factor by which time slows, equal to one at rest and soaring near light speed?
Gamma
Gamma also sets how much a moving object's length and energy change. The jets behind long bursts of cosmic radiation are thought to start with a value above 100.
Q 20Whose 1860s equations, which give light one fixed speed, clashed with the old rules of relative motion?
James Clerk Maxwell
James Clerk Maxwell showed that electric waves cross space at the speed of light. Einstein later ranked his work as the most profound and fruitful in physics since Newton.
Metre lengths were once set by a platinum-iridium bar kept near Paris. Tying the unit to light instead made the speed of light exact by definition, with nothing left to measure.
Q 24Which Serbian classmate, the only woman in Einstein's course at Zurich Polytechnic, was his wife in 1905?
Mileva Marić
Mileva Marić was married to Einstein from 1903 to 1919. Historians still disagree over whether she contributed to his 1905 papers, though many argue that she did not.
Q 25In which Swiss city was Albert Einstein living when he wrote his 1905 paper on special relativity?
Bern
Bern's Einsteinhaus, at Kramgasse 49, preserves the second-floor flat that Einstein rented from 1903 to 1905. It has been restored in the style of the period and is open to visitors.
Q 26Which French mathematician named the principle of relativity in 1904, a year before Einstein's theory appeared?
Henri Poincaré
Henri Poincaré said that no physical experiment can tell uniform motion from rest. A conjecture of his about shapes stayed unproven for almost a century.
Q 27Which particle has no rest mass, the property that lets it travel at the fastest speed relativity allows?
Photon
Photon speed is not a choice: a massless particle can only ever move at the speed of light in a vacuum. Anything with mass can approach that speed but never reach it.
Q 28Which blue glow in nuclear reactor pools is made by particles outrunning the slowed speed of light in water?
Cherenkov radiation
Cherenkov radiation breaks no rule, because only light's speed in a vacuum is the limit. Pavel Cherenkov shared the 1958 Nobel Prize for being the first to detect it.
Q 29Lise Meitner used Einstein's mass–energy formula in 1938 to explain the energy released by which newly found process?
Nuclear fission
Nuclear fission made sense on a winter walk with her nephew Otto Frisch. The pieces of a split uranium nucleus weigh a little less than the original, and the missing mass becomes energy.
Q 30Light in a vacuum covers roughly what distance each second, the speed limit at the heart of special relativity?
300,000 km
300,000 km is a rounding of 299,792 km, a figure now fixed by definition. Even at that pace, sunlight needs more than eight minutes to reach Earth.