Space Trivia Questions & Answers: Planets, Moon & Beyond

Space trivia works best when the answers are accurate enough to teach something. This quiz moves from the planets and Moon to spaceflight, stars, galaxies and a tougher astronomy challenge round, with a short explanation after every answer.

For related quizzes, try our science trivia questions, geography trivia questions and the Trivia hub.

How to Play

• Read the full question before anyone answers.
• Award 1 point for each correct answer.
• Use the final round as a tie-breaker if scores are close.
• Read the short explanation after each answer for extra context.

Solar System Basics

Q1. How many planets are in our solar system?

Answer: Eight. Why: NASA recognizes Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune as the eight planets.

Q2. Which planet is closest to the Sun?

Answer: Mercury. Why: Mercury is the innermost planet.

Q3. Which planet is the largest in our solar system?

Answer: Jupiter. Why: Jupiter is the largest planet by both mass and diameter.

Q4. Which planet is known as the Red Planet?

Answer: Mars. Why: Iron minerals in Martian soil give the surface a reddish color.

Q5. Which planet is famous for its bright ring system?

Answer: Saturn. Why: All four giant planets have rings, but Saturn’s are the most prominent.

Q6. Which planet has the hottest average surface temperature?

Answer: Venus. Why: Its thick carbon-dioxide atmosphere creates an extreme greenhouse effect.

Q7. Which planet is the only place where life has been confirmed?

Answer: Earth. Why: So far, Earth is the only world where life is known to exist.

Q8. Which former planet was reclassified as a dwarf planet in 2006?

Answer: Pluto. Why: The International Astronomical Union adopted a definition that placed Pluto in the dwarf-planet category.

Sun, Moon & Night Sky

Q9. What type of object is the Sun?

Answer: A star. Why: The Sun is the only star in our solar system.

Q10. About how long does sunlight take to reach Earth?

Answer: About 8 minutes and 20 seconds. Why: Earth is about one astronomical unit from the Sun.

Q11. What is Earth’s natural satellite called?

Answer: The Moon. Why: The Moon orbits Earth.

Q12. Who was the first person to walk on the Moon?

Answer: Neil Armstrong. Why: Armstrong stepped onto the lunar surface during Apollo 11 in 1969.

Q13. Which mission first landed humans on the Moon?

Answer: Apollo 11. Why: Apollo 11 landed Neil Armstrong and Buzz Aldrin on the Moon in July 1969.

Q14. Why do we usually see the same side of the Moon from Earth?

Answer: The Moon is tidally locked to Earth. Why: It rotates once in about the same time it takes to orbit Earth.

Q15. What causes the phases of the Moon?

Answer: Our changing view of the Moon’s sunlit half. Why: As the Moon orbits Earth, we see different portions of its illuminated side.

Q16. What galaxy contains our solar system?

Answer: The Milky Way. Why: The Sun lies in the Orion Spur of the Milky Way.

Spaceflight & Exploration

Q17. Who was the first human in space?

Answer: Yuri Gagarin. Why: He orbited Earth aboard Vostok 1 in 1961.

Q18. Who was the first woman in space?

Answer: Valentina Tereshkova. Why: She flew aboard Vostok 6 in 1963.

Q19. What was the first artificial satellite to orbit Earth?

Answer: Sputnik 1. Why: The Soviet Union launched Sputnik 1 in 1957.

Q20. What does NASA stand for?

Answer: National Aeronautics and Space Administration. Why: NASA is the U.S. civilian space agency.

Q21. In what year was the Hubble Space Telescope launched?

Answer: 1990. Why: Space Shuttle Discovery deployed Hubble in April 1990.

Q22. Which spacecraft became the first human-made object to enter interstellar space?

Answer: Voyager 1. Why: NASA determined that Voyager 1 crossed into interstellar space in 2012.

Q23. What space telescope launched in 2021 as Hubble’s major infrared successor?

Answer: The James Webb Space Telescope. Why: Webb launched in December 2021 and observes mainly in infrared wavelengths.

Q24. What laboratory orbits Earth and has hosted international crews since 2000?

Answer: The International Space Station. Why: The ISS is a multinational research station in low Earth orbit.

Stars, Galaxies & Deep Space

Q25. What is a light-year a measure of?

Answer: Distance. Why: A light-year is the distance light travels in one year.

Q26. What do we call a huge cloud of gas and dust in space?

Answer: A nebula. Why: Many nebulae are places where stars form or the remnants of dying stars.

Q27. What is a supernova?

Answer: A powerful stellar explosion. Why: Some stars end their lives in supernova explosions.

Q28. What is a black hole?

Answer: A region where gravity is so strong that not even light can escape from inside its event horizon. Why: Black holes can form from the collapse of massive stars and by other processes.

Q29. What is the name for the path one object follows around another in space?

Answer: An orbit. Why: Planets orbit stars and moons orbit planets.

Q30. What is a comet mostly made of?

Answer: Ice, dust and rocky material. Why: When a comet approaches the Sun, heating can produce a glowing coma and tails.

Q31. Which direction does a comet’s ion tail point relative to the Sun?

Answer: Away from the Sun. Why: The solar wind pushes the ion tail away from the Sun.

Q32. What dense stellar remnant can form after some supernova explosions?

Answer: A neutron star. Why: Neutron stars pack roughly stellar mass into a very small volume.

Space Challenge Round

Q33. Which planet was discovered by William Herschel in 1781?

Answer: Uranus. Why: It was the first planet discovered with the aid of a telescope in modern astronomy.

Q34. Which planet was discovered in 1846 after its position was predicted mathematically?

Answer: Neptune. Why: Its discovery followed calculations based on irregularities in Uranus’s orbit.

Q35. Where is the main asteroid belt located?

Answer: Between Mars and Jupiter. Why: Most main-belt asteroids orbit the Sun in that region.

Q36. What distant region is thought to be a source of many long-period comets?

Answer: The Oort Cloud. Why: It is a predicted vast shell of icy bodies far beyond the planets.

Q37. About what percentage of the solar system’s mass is in the Sun?

Answer: About 99.8 percent. Why: NASA notes that the Sun contains nearly all the mass of the solar system.

Q38. Which two planets have no natural moons?

Answer: Mercury and Venus. Why: They are the only planets in our solar system without moons.

Q39. What is the largest moon in our solar system?

Answer: Ganymede. Why: Jupiter’s moon Ganymede is larger than the planet Mercury.

Q40. What enormous volcano on Mars is the largest known volcano in the solar system?

Answer: Olympus Mons. Why: Olympus Mons is a giant shield volcano on Mars.

Reliable Sources

Important facts were checked against established science, film, museum or music-industry references:

• NASA Science — Solar System Facts
• NASA Science — About the Planets
• NASA Science — Sun Facts
• NASA Science — Moons Facts

FAQ

Is Pluto a planet? Under the International Astronomical Union’s 2006 definition, Pluto is classified as a dwarf planet.

Are these space questions suitable for families? Yes. The first four rounds are broad general-interest trivia, while the challenge round is better for stronger space fans.