How Well Do You Know Our Solar System? [Quiz]

General knowledge is important. While it might not come up in everyday life, it’s an effective intelligence barometer that can colour people’s perception of you and leave your reputation permanently tarnished. This got us to thinking — how much does the average human actually know about the solar system? Take our quiz to find out!

Solar system picture from Shutterstock

Most people can name all the planets in our solar system in order and understand how the sun’s orbit works, but beyond that, things start to get a bit sketchy. With that in mind, we’ve assembled a quiz of solar system trivia that every human should know.

We’ve included small hints to give space-shy readers a fighting chance. To keep you on your toes, there are also some questions relating to the sun and moons. The answers appear in small font at the end of the article. How well did you score? Let us know how you went in the comments!

#1 Name the planets in our solar system, in order from the sun.

If this one gives you trouble, maybe give up now, eh? (Also, remember that Pluto isn’t technically a fully-fledged planet.)

#2 How long does the Earth take to orbit the sun?

In a recent national poll, an astonishing 41% of Australians got this one wrong. For shame.

#3 How far away is Earth from the sun?

Come on. Remember your old science text book from high school!

#4 How many terrestrial planets are there in our solar system? Name them.

These are planets composed primarily of silicate rocks or metals rather than gases.

#5 Which planet in our solar system has the most moons? How many does it have?

Hint: it’s not Earth.

#6 Approximately how long ago was our solar system formed?

With respect to religious groups, we’re looking for the “scientific” answer here.

#7 How much of the solar system’s total mass is contained in the Sun?

For reference, the Earth could fit inside the Sun one million times over.

#8 Including Pluto, how many dwarf planets are recognised in our solar system? Name them.

That is, the discovered bodies officially recognised by the IAU.

#9 Which planet is the hottest (and how hot does it get?)

Derp reminder: the sun isn’t a planet.

#10 Which planet is coldest?

This may or may not be a trick question. (See #1.)

#11 How many humans have stepped foot on the moon?

Note to conspiracy nuts: the answer isn’t zero.

#12 What is the largest moon in the solar system?

We’ll also give you this one if you can name the planet it belongs to.

#13 In the night’s sky, how many planets are visible to the naked eye?

A bonus point if you can name them.

#14 In what year did a spacecraft first reach the Moon and what was it called?

This might not be the answer you’re thinking of.

#15 One day, the sun will expand into a red giant and potentially consume the Earth. How many years before this happens?

If you have no idea, start in the billions.


1. Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune.
2. One year.
3. 149,600,000 km.
4. Four. (Mercury, Venus, Earth and Mars.)
5. Jupiter. 63 confirmed moons.
6. 4.6 billion years ago.
7. 99.86%
8. Five. (Ceres, Pluto, Makemake, Eris, Haumea.)
9. Venus. 462 degrees Celsius.
10. Neptune.
11. 12.
12. Ganymede (orbiting Jupiter)
13. Five. (Mercury, Venus, Mars, Jupiter and Saturn.)
14. 1959. Luna 1.
15. 5 billion years.

This story originally appeared in 2015.

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