Medium Space Quiz Questions for Kids (with Answers)
Use this printable quiz list for classroom warm-ups, car trips, or revision. Tap any question to reveal the answer and a short explanation — then play the full space quiz online with hints and stars.
Questions & answers
Tap a question to reveal the answer. 35 questions below.
1. How long does it take light from the Sun to reach Earth?Show answer
- 8 seconds
- 8 minutes — correct
- 8 hours
- 8 days
Sunlight takes about 8 minutes and 20 seconds to travel the 150 million kilometres to Earth!
☀️ If the Sun suddenly vanished, we would not know for about 8 minutes — we would still see its last light!
2. What is the Great Red Spot on Jupiter?Show answer
- A volcano
- A giant storm — correct
- A mountain
- A lake
The Great Red Spot is a gigantic anticyclonic storm larger than Earth that has raged for at least 400 years!
🌪️ Winds inside the Great Red Spot can reach speeds of about 640 kilometres per hour!
3. A day on Venus is longer than a year on Venus.Show answer
Answer: True
Venus rotates so slowly that one day (243 Earth days) is longer than its year (225 Earth days) — and it spins backwards compared to most planets!
🔄 On Venus the Sun would rise in the west and set in the east because of its retrograde rotation!
4. What type of star will the Sun become at the end of its life?Show answer
- Neutron star
- White dwarf — correct
- Black hole
- Red supergiant forever
In about 5 billion years the Sun will swell into a red giant, then shed its outer layers and leave behind a white dwarf!
⚪ A white dwarf is about the size of Earth but contains roughly half the Sun's mass — incredibly dense!
5. Which moon of Saturn has lakes of liquid methane on its surface?Show answer
- Europa
- Titan — correct
- Io
- Ganymede
Titan is the only moon with a thick atmosphere — lakes and rivers of liquid methane and ethane exist on its frigid surface!
🌙 Titan's atmosphere is so dense that a human with protection could walk on the surface without a pressurised suit!
6. What causes a solar eclipse?Show answer
- Earth passes between Sun and Moon
- The Moon blocks the Sun — correct
- The Sun turns off briefly
- A cloud covers the Sun
During a solar eclipse the Moon lines up between Earth and the Sun, casting a shadow on part of Earth's surface!
🌑 Total solar eclipses can only happen during a new moon and last only a few minutes at any one location!
7. The footprints left by Apollo astronauts on the Moon could last millions of years.Show answer
Answer: True
The Moon has no atmosphere, wind, or liquid water — so footprints and equipment left there erode extremely slowly!
👣 Micrometeoroid impacts slowly churn the surface, but Apollo footprints could survive for millions of years!
8. What is the Kuiper Belt?Show answer
- A ring around Saturn
- A region of icy bodies beyond Neptune — correct
- A galaxy near the Milky Way
- A type of star cluster
The Kuiper Belt is a disc of icy objects beyond Neptune — Pluto and many comets originate there!
❄️ The Kuiper Belt may contain hundreds of thousands of objects larger than 100 kilometres across!
9. Which planet has the most moons in our solar system?Show answer
- Saturn — correct
- Jupiter
- Uranus
- Neptune
Saturn currently holds the record for most known moons — over 140 have been confirmed!
🌙 Saturn's moon Enceladus shoots geysers of water ice from cracks near its south pole!
10. What is the Oort Cloud?Show answer
- A nebula near Orion
- A distant shell of comets — correct
- A ring of asteroids
- A type of galaxy
The Oort Cloud is a theoretical distant region of icy bodies surrounding the solar system — comets like Halley's may originate there!
☄️ The Oort Cloud may extend up to 100,000 astronomical units from the Sun — far beyond Pluto!
11. Io, a moon of Jupiter, is the most volcanically active body in the solar system.Show answer
Answer: True
Io's interior is heated by tidal forces from Jupiter — it has over 400 active volcanoes spewing sulfur!
🌋 Io's volcanoes can shoot plumes 500 kilometres high — taller than Mount Everest!
12. What is a supernova?Show answer
- A new planet forming
- An exploding star — correct
- A type of black hole
- A solar flare
A supernova is a catastrophic explosion when a massive star runs out of fuel and collapses — it spreads heavy elements into space!
💥 The iron in your blood was forged inside a star that exploded as a supernova billions of years ago!
13. How fast does the International Space Station travel?Show answer
- 500 km/h
- 5,000 km/h
- 28,000 km/h — correct
- 280,000 km/h
The ISS orbits at about 7.66 kilometres per second — roughly 28,000 kilometres per hour!
🛰️ At that speed astronauts on the ISS see 16 sunrises and sunsets every day!
14. Which moon is believed to have a subsurface ocean beneath its icy crust?Show answer
- Titan
- Europa — correct
- Phobos
- Triton
Europa likely has a global ocean of liquid water beneath its icy shell — more than twice the water in all Earth's oceans!
🌊 If life exists elsewhere in our solar system, Europa's ocean is one of the most promising places to look!
15. The Sun contains more than 99% of the total mass of the solar system.Show answer
Answer: True
The Sun accounts for about 99.86% of all mass in the solar system — Jupiter makes up most of the rest!
☀️ You could fit about 1,300 Earths inside the volume of the Sun!
16. What is the name of the boundary where the Sun's influence ends and interstellar space begins?Show answer
- Event horizon
- Heliopause — correct
- Magnetosphere
- Asteroid belt
The heliopause is where the solar wind from the Sun is stopped by the interstellar medium — Voyager 1 became the first human-made object to cross it!
🚀 Voyager 1 is now over 24 billion kilometres from Earth and still sending data!
17. What causes the seasons on Earth?Show answer
- Earth moving closer and farther from the Sun
- Earth's tilted axis — correct
- The Moon's gravity
- Solar flares
Earth's axis is tilted — as we orbit the Sun, each hemisphere tilts toward or away from the Sun, creating seasons!
🌍 Earth is actually closest to the Sun in January — seasons are caused by tilt, not distance!
18. Which space probe has left our solar system and entered interstellar space?Show answer
- Cassini
- Voyager 1 — correct
- New Horizons
- Pioneer 10 only
Voyager 1 crossed into interstellar space in 2012 — it is the farthest human-made object from Earth!
📻 Voyager's Golden Record includes greetings in 55 languages and music from Bach to Chuck Berry!
19. Neutron stars are so dense that a teaspoon of their material would weigh billions of tonnes on Earth.Show answer
Answer: True
Neutron stars pack more mass than the Sun into a sphere about 20 kilometres across — unimaginably dense!
⭐ A neutron star's gravity is so strong that mountains on its surface would be only millimetres tall!
20. What is the main fuel that stars like the Sun burn through nuclear fusion?Show answer
- Oxygen
- Hydrogen — correct
- Iron
- Carbon
Stars fuse hydrogen nuclei into helium in their cores, releasing enormous energy as light and heat!
☀️ The Sun converts about 600 million tonnes of hydrogen into helium every single second!
21. What was the purpose of the Apollo program?Show answer
- Build the ISS
- Land humans on the Moon — correct
- Explore Mars
- Launch the Hubble telescope
The Apollo program achieved the goal of landing astronauts on the Moon — six missions successfully landed between 1969 and 1972!
🌙 Apollo 17 in 1972 was the last time humans walked on the Moon — NASA's Artemis program aims to return!
22. What is a pulsar?Show answer
- A dying red giant
- A spinning neutron star — correct
- A type of comet
- A young galaxy
Pulsars are neutron stars that rotate very fast, sweeping beams of radiation past Earth like a cosmic lighthouse!
📡 The first pulsar was discovered in 1967 — its regular pulses were so precise they were nicknamed LGM-1 (Little Green Men)!
23. Mars once had liquid water flowing on its surface.Show answer
Answer: True
Orbital images and rover discoveries show Mars had rivers, lakes, and possibly an ocean billions of years ago!
💧 Mars still has water ice at its poles and beneath the surface — enough to cover the planet in 35 metres of water if melted!
24. What is the approximate age of the universe?Show answer
- 4.6 billion years
- 13.8 billion years — correct
- 100 billion years
- 1 billion years
The universe is about 13.8 billion years old — determined from the cosmic microwave background and expansion rate!
🌌 4.6 billion years is the age of our solar system — the universe is nearly three times older!
25. Which force prevented the solar system from collapsing into the Sun as it formed?Show answer
- Magnetism
- Angular momentum — correct
- Friction
- Dark energy
As the solar nebula collapsed, conservation of angular momentum made it spin faster and flatten into a disc rather than falling straight into the centre!
🌀 Most of the nebula's mass went to the Sun, but angular momentum kept planets orbiting in the leftover disc!
26. What is the Van Allen radiation belt?Show answer
- A ring of asteroids
- Trapped radiation around Earth — correct
- A layer of the Sun
- A galaxy cluster
The Van Allen belts are regions where Earth's magnetic field traps high-energy charged particles from the solar wind!
🛡️ The belts protect Earth from some solar radiation but would be dangerous to astronauts who stayed in them too long!
27. The Andromeda Galaxy is moving toward the Milky Way and will collide with it in about 4 billion years.Show answer
Answer: True
Andromeda is approaching at about 110 kilometres per second — in billions of years the two galaxies will merge!
🌌 Despite the collision, individual stars are so far apart that very few will actually hit each other!
28. What is escape velocity from Earth's surface?Show answer
- 1.2 km/s
- 11.2 km/s — correct
- 112 km/s
- 1,120 km/s
A rocket must reach about 11.2 km/s to escape Earth's gravitational pull without further propulsion!
🚀 The Moon's escape velocity is only 2.4 km/s — that is why lunar landers could return with much less fuel!
29. What instrument did the Event Horizon Telescope use to photograph a black hole?Show answer
- A single giant optical telescope
- A network of radio telescopes — correct
- The Hubble Space Telescope
- The James Webb telescope
The Event Horizon Telescope combined data from observatories worldwide to create an Earth-sized virtual telescope!
🕳️ The photographed black hole is in galaxy M87 — its shadow is about 2.5 times wider than the event horizon!
30. Why does Mercury have extreme temperature differences between day and night?Show answer
- It is closest to the Sun only
- It has no atmosphere to trap heat — correct
- It rotates very fast
- It has active volcanoes
Mercury's thin exosphere cannot hold heat — daytime reaches 430°C while nights plunge to −180°C!
🌡️ Despite being closest to the Sun, Mercury is not the hottest planet — Venus holds that title!
31. Ganymede, a moon of Jupiter, is larger than the planet Mercury.Show answer
Answer: True
Ganymede is about 5,268 km in diameter — larger than Mercury and only slightly smaller than Mars!
🌙 Ganymede is the only moon known to have its own magnetic field!
32. What is cosmic microwave background radiation?Show answer
- Radiation from the Sun
- Afterglow of the Big Bang — correct
- Radio waves from pulsars
- Light from distant quasars
The CMB is relic radiation from when the universe was about 380,000 years old — it provides strong evidence for the Big Bang!
📻 About 1% of the static on an old analogue TV comes from the cosmic microwave background!
33. What is the primary reason space appears cold even though it receives sunlight?Show answer
- The Sun is too far away
- There is no air to conduct or convect heat — correct
- Stars absorb the heat
- Dark matter cools space
In space, heat is lost mainly by radiation — without an atmosphere, objects in shadow cool rapidly!
🌡️ The ISS must carefully balance heating and cooling — outside temperatures swing from −157°C to 121°C!
34. Which NASA rover discovered evidence that Mars was once habitable in Gale Crater?Show answer
- Sojourner
- Spirit
- Curiosity — correct
- Perseverance
Curiosity found ancient streambeds and minerals that form in water — strong evidence Mars was once wetter and warmer!
🔴 Curiosity has been exploring Mars since 2012 and has driven over 30 kilometres!
35. The Moon is slowly moving away from Earth at about 3.8 centimetres per year.Show answer
Answer: True
Tidal interactions push the Moon into a slightly higher orbit each year — in the distant future, total solar eclipses will no longer be possible!
🌙 When the Moon formed it was much closer — ancient tides would have been enormous!
Medium Space Quiz Questions for Kids (with Answers)