Wonderdome Planet Quiz
Our Wonderdome presenters really enjoy a question-and-answer session at the end of a show.
Children – and adults – ask great questions about space.
Now it’s our turn to ask the questions.
How will you do in our Planet Quiz?
Questions & Answers
We have 20 questions in four groups of five.
We give 3 possible answers to each question, labelled A, B and C.
Just choose the one that you think is correct.
What you need
You only need a pen and paper.
And maybe a watch or clock for the time.,
Write down your answer to each question (just the letter will do).
Then check your answers with the correct ones at the end of the blog.
To add a time factor, allow just 10 minutes for the quiz.
No peeping! Good luck.
Planet Quiz, 1 to 5
1. What are planets Mercury, Venus, Earth and Mars mainly made of?
A. Gas B. Rock C. Carbon
2. What are planets Jupiter, Saturn, Uranus and Neptune made of?
A. Gas B. Rock C. Carbon
3. Which is the biggest planet?
A. Jupiter B. Saturn C. Neptune
4. Which is the smallest planet?
A. Mercury B. Venus C. Mars
5. Which of these is called the red planet?
A. Mercury B. Venus C. Mars
OK, let’s move on to the next five.
These are a bit more difficult.
Planet Quiz, Q6 to Q10
6. How long does sunlight take to reach Earth?
A. 5 minutes B. 8 minutes C. 11 minutes
7. Which planet has a storm called the Great Red Spot?
A. Venus B. Mars C. Jupiter
8. Which is the hottest planet?
A. Mercury B. Venus C. Jupiter
9. Which planet is sometimes called an ice giant?
A. Jupiter B. Saturn C. Uranus
10. Which planet is tipped on its side?
A. Jupiter B. Saturn C. Uranus
That’s half way through our quiz.
Let’s try the next five, more difficult still.
Planet Quiz, Q11 to Q 15
11. Which planet rotates clockwise?
A. Mercury B. Venus C. Mars
12. Which planet orbits the Sun in 88 days?
A. Mercury B. Venus C. Mars
13. Europa, Ganymede and Callisto are moons of which planet?
A. Jupiter B. Saturn C. Uranus
14. Oberon, Titania and Miranda are moons of which planet?
A. Jupiter B. Saturn C. Uranus
15.. Which planet has most known moons?
A. Jupiter B. Saturn C. Uranus
Now we’ve reached the final five, the hardest of the quiz!
Q16 to Q20
16. How fast does the Earth spin round in its daily rotation?
A. 1,000 miles per hour B. 10,000 mph C. 100,000 mph
17. Which of these dwarf planets goes round the Sun inside the orbit of Neptune?
A. Makemake B. Sedna C. Ceres
18. In which year was Pluto discovered?
A. 1910 B. 1920 C. 1930
19. What kind of object is Gliese 581C ?
A. Exoplanet B. Asteroid C. Comet
20. How old are the planets of the Solar System?
A. 1.5 billion years B. 4.5 billion years C. 13.8 billion years
Thanks for making it through our quiz.
Now let’s see the answers.
Answers
- What are planets Mercury, Venus, Earth and Mars mainly made of?
B. Rock
These are the Inner Planets or terrestrial planets. They are close to the Sun and have cores made of iron.
2. What are planets Jupiter, Saturn, Uranus and Neptune made of?
A. Gas
These are the Outer Planets, gas giants lying further from the Sun. They are made mainly of hydrogen gas.
3. Which is the biggest planet?
A. Jupiter
With a diameter of almost 143,000 km, Jupiter is so big that all the other planets could fit inside it.
4. Which is the smallest planet?
A. Mercury
Mercury is 4,881 km in diameter.
5. Which of these is called the red planet?
C. Mars
Mars is covered in red sand, made of iron oxide.
Did you get the first 5 correct?
Let’s see the next five answers.
6. How long does sunlight take to reach Earth?
B. 8 minutes
The actual time for sunlight to reach Earth is 8 minutes and 20 seconds
7. Which planet has a storm called the Great Red Spot?
C. Jupiter
The Great Red Spot is a storm on Jupiter which was first observed in 1831.
8. Which is the hottest planet?
B. Venus
The thick carbon dioxide atmosphere on Venus absorbs and retains heat from the Sun.
9. Which planet is sometimes called an ice giant?
C. Uranus
Though made mainly of gas, Uranus (and Neptune) contain a lot of ice.
10. Which planet is tipped on its side?
C. Uranus
Uranus is tilted at an angle of 98 degrees.
This is probably a result of a collision with another planet billions of years ago.
That’s halfway through the answers.
How are you doing?
Here come the next five.
11. Which planet rotates clockwise?
B. Venus
All the planets rotate on their axis in an anti-clockwise direction – except Venus.
This is probably because another planet crashed into Venus as the Solar System was being made.
12. Which planet orbits the Sun in 88 days?
A. Mercury
Mercury is the closest planet to the Sun and has the smallest orbit.
13. Europa, Ganymede and Callisto are moons of which planet?
A. Jupiter
These are three of the four big moons first seen by Galileo in 1610.
14. Oberon, Titania and Miranda are moons of which planet?
C. Uranus
Uranus has 29 known moons.
They are named after characters in the plays of Shakespeare ( and a poem by Alexander Pope).
15. Which planet has most known moons?
B. Saturn
As of June, 2026, Saturn has 293 known moons, more than all the other planets put together.
Phew! They were more difficult. How are you doing?
Let’s see the final five answers.
16. How fast does the Earth spin round in its daily rotation?
A. 1,000 miles per hour
Earth spins round in 24 hours, one day.
17. Which of these dwarf planets goes round the Sun inside the orbit of Neptune?
C. Ceres
Ceres is a dwarf planet in the asteroid belt between Mars and Jupiter.
18. In which year was Pluto discovered?
C. 1930
Pluto was discovered by Clyde Tombaugh at Lowell Observatory, Arizona, in 1930.
19. What kind of object is Gliese 581C ?
A. Exoplanet
Gliese 581C is a planet in orbit around a distant star – an exoplanet.
20. How old are the planets of the Solar System?
B. 4.5 billion years
The Solar System was made from a cloud of gas and dust pulled together by gravity.
The Universe is thought to be 13.8 billion years old.
How did you do?
Please count up your correct answers.
That gives you a score out of 20.
Planet ratings
5 or less: Dwarf Planet – have another go!
*******
6 to 10: Terrestrial planet, pretty good.
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11 to 15: Giant planet, that’s great.
*******
16 to 20: Out of this world, congratulations!
I hope that you have enjoyed our Wonderdome Planet Quiz.
We’ll try another astronomy quiz sometime soon.
More on our website
If you would like to learn more about the Solar System, click on Big Space Book.
And we also have fun activities.
Take a look now!
The author: Dennis Ashton, MBE, is a Fellow of the Royal Astronomical Society and a Wonderdome presenter.
In 2024, Dennis received the Special Contribution award from the British Association of Planetaria.
In 2025 he became a Member of the Order of the British Empire for over 50 years work in Astronomy Education.
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