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This space exploration trivia quiz has 96 free questions with answers and covers the missions, machines and people that took humanity off the planet: Sputnik and Gagarin, Mercury, Gemini and Apollo, the Space Shuttle and the ISS, the Mars rovers and the probes now leaving the solar system, and the James Webb telescope. It also has a proper rocket trivia section: the Song-dynasty gunpowder rockets, the Congreve rockets in the US national anthem, Tsiolkovsky's equation, Goddard's 41-foot first flight, the V-2 that reached space in 1944, the 363-foot Saturn V and its thirteen launches, and SpaceX's Falcon 9 landing and reflying its boosters. Difficulty runs from easy to expert and is shown on every question. Every answer has been checked against a primary reference and each question carries its citation.
30 of 96 questions with answers and explanations. Play the quiz
Q 01What is the closest star to Earth, besides the Sun?
Proxima Centauri
Proxima Centauri is the closest star to our Sun at approximately 4.24 light-years away. It is a small red dwarf star and part of the Alpha Centauri triple star system. It is too faint to be seen with the naked eye.
Q 02In what year did the International Astronomical Union demote the former ninth planet to dwarf-planet status?
2006
The August 2006 vote created the 'dwarf planet' category; the demoted world failed the new requirement that a planet must clear the neighbourhood around its orbit.
Q 03Which planet had the most confirmed moons as of 2025?
Saturn
A batch of 128 newly confirmed moons announced in March 2025 lifted Saturn's confirmed total to 274, far ahead of any other planet at the time.
Q 04What is the point of no return around a black hole called?
Event horizon
Past the event horizon, escape velocity exceeds the speed of light, so nothing gets out; David Finkelstein sharpened the definition in 1958.
Q 05Approximately how long does it take sunlight to reach Earth?
About 8 minutes
Sunlight takes approximately 8 minutes and 20 seconds to travel from the Sun to Earth. The Sun is about 150 million kilometers away, and light travels at about 300,000 km/s.
Q 06Which space telescope, launched on Christmas Day 2021 aboard an Ariane 5, observes in the infrared from 1.5 million km beyond Earth?
James Webb
James Webb lifted off from Kourou, French Guiana, on 25 December 2021 aboard an Ariane 5 and observes in the infrared from the Sun-Earth L2 point, about 1.5 million km beyond Earth.
Q 07What type of galaxy is the Milky Way?
Barred spiral
The Milky Way is classified as a barred spiral galaxy. It has a central bar-shaped structure made of stars, with spiral arms extending from its ends. It contains an estimated 100 to 400 billion stars.
Q 08Which planet has the highest surface temperature in our solar system?
Venus
Venus has the highest surface temperature at about 465°C (867°F), hot enough to melt lead. Despite being farther from the Sun than Mercury, Venus's thick CO2 atmosphere creates an extreme greenhouse effect that traps heat.
Q 09What was the name of the first artificial satellite launched into space?
Sputnik 1
Sputnik 1, launched by the Soviet Union on 4 October 1957, was the first artificial satellite; the 83.6 kg polished sphere circled Earth about every 96 minutes.
Q 10The most extensive planetary ring system in the Solar System is made almost entirely of what?
Water ice
Saturn's rings are about 99.9% water ice; the particles range from micrometres to metres across, with only a trace of rocky material mixed in.
Q 11Who was the first woman to travel to space?
Valentina Tereshkova
Valentina Tereshkova, a 26-year-old amateur parachutist, flew solo aboard Vostok 6 from 16 June 1963, orbiting Earth 48 times in almost three days.
Q 12What is a light-year a measure of?
Distance
A light-year is a unit of distance, not time. It is the distance light travels in one year — approximately 9.46 trillion kilometers (5.88 trillion miles). It is commonly used to express distances between stars and galaxies.
Q 13Which NASA rover landed on Mars in February 2021?
Perseverance
NASA's Perseverance rover landed on Mars on February 18, 2021, in Jezero Crater. It is tasked with searching for signs of ancient microbial life and collecting rock samples for future return to Earth.
Q 21Which of Jupiter's four large moons is the likeliest candidate for harboring extraterrestrial life?
Europa
Europa is considered one of the most promising places to search for life beyond Earth. It has a subsurface ocean of liquid water beneath its icy crust that may contain more water than all of Earth's oceans combined.
Q 22Approximately how old is the universe?
13.8 billion years
Based on observations of the cosmic microwave background by the Planck spacecraft, the universe is approximately 13.8 billion years old. This estimate is widely accepted by the astronomical community.
Q 23How far away is the Andromeda Galaxy from the Milky Way?
2.5 million light-years
Q 14What is the tallest known volcano in the solar system?
Olympus Mons
Olympus Mons, a shield volcano on Mars, rises about 21 km, roughly 2.5 times the height of Mount Everest above sea level, and spans about 600 km across.
Q 15Which moon in our solar system is the only one known to have a dense atmosphere?
Titan
Titan, Saturn's largest moon, holds a thick atmosphere of mainly nitrogen with some methane, and it is wider, though less massive, than Mercury.
Q 16At roughly what speed does the International Space Station orbit Earth?
17,500 mph
The ISS orbits Earth at approximately 17,500 mph (28,000 km/h), completing one orbit roughly every 90 minutes. At this speed, the crew sees about 16 sunrises and sunsets every day.
Q 17What was the first animal to orbit the Earth?
Laika the dog
A stray mongrel from the streets of Moscow, she flew aboard the second Soviet satellite on 3 November 1957; re-entry technology did not yet exist, so she did not survive the flight.
Q 18Which planet has an axial tilt of about 98 degrees, so it rotates nearly on its side?
Uranus
Uranus has an extreme axial tilt of about 97.8 degrees, making it appear to rotate on its side. This means its poles take turns pointing almost directly at the Sun, creating extreme 42-year-long seasons.
Q 19In what year did the Event Horizon Telescope release the first image of a black hole?
2019
The first image of a black hole was released on April 10, 2019. It showed the supermassive black hole at the center of galaxy M87, about 55 million light-years from Earth, with a mass of 6.5 billion solar masses.
Q 20What causes the seasons on Earth?
The tilt of its rotation axis
The axis is tilted about 23.4 degrees, so as the planet moves around the Sun first one hemisphere and then the other is angled toward it; distance from the Sun plays a negligible role.
The Andromeda Galaxy is approximately 2.5 million light-years from the Milky Way. It is the nearest large galaxy to our own and can be seen with the naked eye from dark locations. The two galaxies are approaching each other.
Q 24Which famous astronomer used a telescope in 1610 to discover four of Jupiter's moons?
Galileo Galilei
Galileo Galilei observed Jupiter through his improved telescope in January 1610 and discovered its four largest moons: Io, Europa, Ganymede, and Callisto. These are still known today as the Galilean moons.
Q 25On the innermost planet, one solar day (sunrise to sunrise) lasts how many of that planet's own years?
Two
A solar day on Mercury lasts about 176 Earth days, two of its 88-day years, a consequence of its 3:2 spin-orbit resonance: three rotations for every two orbits.
Q 26What is the approximate speed of light?
186,000 miles per second
Light travels at approximately 186,282 miles per second (299,792 km/s) in a vacuum. This speed is the fastest that any information or matter can travel in the universe, according to Einstein's theory of relativity.
Q 27What is the disc of icy bodies extending from roughly 30 to 50 AU from the Sun called?
Kuiper Belt
The Kuiper Belt is a doughnut-shaped region beyond Neptune, roughly 30 to 50 AU from the Sun, home to dwarf planets including Pluto, Haumea and Makemake.
Q 28Which spacecraft became the first human-made object to enter interstellar space?
Voyager 1
Voyager 1, launched on 5 September 1977, crossed into interstellar space on 25 August 2012, the first spacecraft to do so; Voyager 2 followed in November 2018.
Q 29How long does the outermost planet in the Solar System take to complete one orbit around the Sun?
About 165 Earth years
Neptune takes about 165 Earth years to orbit the Sun; it completed its first full orbit since its 1846 discovery only in July 2011.
Q 30Which 2020 SpaceX flight first carried astronauts to the ISS in a Crew Dragon?
Demo-2
Demo-2 launched on 30 May 2020, carrying Doug Hurley and Bob Behnken to the ISS in the first crewed orbital launch from U.S. soil since the Space Shuttle retired in 2011.