Space Trivia: 20 Mind-Blowing Facts About Our Universe

The universe is the ultimate quiz category: strange, enormous and full of facts that sound made up but are completely real. Here are 20 of our favourites to get you ready for any astronomy round — each with the short explanation that makes it stick.

Our Solar System

1. A day on Venus is longer than its year. It spins so slowly that one rotation (about 243 Earth days) takes longer than one orbit of the Sun (about 225 days).
2. The Sun makes up about 99.8% of all the mass in the Solar System. Everything else — planets, moons, asteroids — shares the remaining 0.2%.
3. Around a million Earths could fit inside the Sun.
4. Saturn is less dense than water. Given a big enough bathtub, it would float.
5. Jupiter is the largest planet — more than 1,300 Earths could fit inside it. Its Great Red Spot is a storm bigger than Earth that has raged for centuries.
6. Olympus Mons on Mars is the tallest volcano in the Solar System, about two and a half times the height of Mount Everest. Mars also has the largest canyon, Valles Marineris, and dust storms that can cover the whole planet.
7. Uranus rotates on its side. Its axis is tilted by about 98 degrees, probably after a giant collision long ago.
8. A year on Mercury lasts just 88 Earth days.
9. Pluto was reclassified as a dwarf planet in 2006, leaving the Solar System with eight planets.
10. Sunsets on Mars are blue. Fine dust in the Martian atmosphere scatters blue light around the Sun as it sets.

Earth, Moon and Light

11. Sunlight takes about eight minutes to reach Earth, travelling 150 million kilometres.
12. The Moon is slowly drifting away — about 3.8 centimetres a year, roughly as fast as your fingernails grow.
13. Footprints on the Moon could last millions of years, because there is no wind or water to erase them.
14. The International Space Station circles Earth about every 90 minutes, so astronauts see around 16 sunrises a day.
15. Looking at stars means looking into the past. Light from distant stars left them years, centuries or even thousands of years ago.

Stars and Beyond

16. There are probably more stars in the observable universe than grains of sand on every beach on Earth. Our own galaxy, the Milky Way, alone contains hundreds of billions of stars.
17. A teaspoon of neutron-star material would weigh billions of tonnes. Neutron stars can also spin hundreds of times every second.
18. Space is silent. Sound needs a medium like air to travel, and space is almost a perfect vacuum.
19. Black holes are not cosmic vacuum cleaners. From a distance, a black hole's gravity behaves like that of any object of the same mass. You would have to get very close before it trapped you.
20. Voyager 1, launched in 1977, is the most distant human-made object. It has travelled beyond the Sun's bubble of solar wind into interstellar space and still sends signals home.

Space Exploration Milestones

• 1957 — Sputnik 1, the first artificial satellite, launched by the Soviet Union.
• 1961 — Yuri Gagarin became the first human in space.
• 1963 — Valentina Tereshkova became the first woman in space.
• 1969 — Neil Armstrong and Buzz Aldrin walked on the Moon during Apollo 11.
• 1990 — the Hubble Space Telescope was launched.
• 2021 — the James Webb Space Telescope was launched, looking deeper into the universe's past than ever before.

How to Remember the Planets

The order of the planets from the Sun is Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A classic memory aid: "My Very Educated Mother Just Served Us Nachos." Attach one fact to each planet — Venus's long day, Saturn's low density, Uranus's tilt — and the whole Solar System falls into place.

Memorise a handful of these and you will have an answer ready the next time a space question appears. Ready to test yourself? Jump into the free Space & Astronomy quiz.