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

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.


  • 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.
    10. 5 billion years.

      • Going with 8 light minutes, and 300km/s as the speed of light, thats 300,000*8*60, or 144m km.

        Thats within 5%, close enough for me.

    • I went with 365.25 revolutions around its own axis which is the answer that involves a comparable, measurable cosmic phenomenon, as opposed to silly terms thought up by the planet dwellers to name it.

  • My attempts:
    1 – Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus, Neptune
    2 – A year
    3 – 1 Astronomical Unit
    4 – 4: Mercury, Venus, Earth, Mars
    5 – Jupiter: Lots, too many to remember cause they keep finding more.
    6 – 4.5ish Billion years?
    7 – 99%
    8 – Ceres, Ganymede, Pluto….?
    9 – Venus? 600 degrees Celsius
    10 – Neptune?
    11 – 12
    12 – Ganymede
    13 – 7
    14 – 1956? Luna?
    15 – 5 billion years

      • My Attempts:
        1. …yeah, i should give up here.
        2. no idea
        3. no idea
        4. no idea
        5. no idea
        6. see #3
        7. No idea
        8. not many ideas here
        9. the one closest to the sun…which i still got wrong.
        10. the one furthest from the sun…which is right, but i didn’t know which planet was furthest from the sun.
        11. 30 (stab in the dark)
        12. I knew it belonged to jupiter cause i read some of the answers and the answer to number 5 gave it away. I mean considering it had the most moons, my chances were pretty good…but i did cheat.
        13. 5: Venus, Mars, Jupiter, Saturn

        I lied, looked at the answers.
        14. no idea
        15. I’ll just see myself out.

      • I have this memorised as 365.2422 days, but it turns out the length of the year varies just a little bit. The difference vs. 365.25 days is why the Gregorian calendar omits leap days on century years not divisible by 400.

        (I was really glad back around 2000 when I was recoding to avoid Y2K problems and realised I could defer Gregorian leap year oddities for a century.)

  • You are all wrong! According to those “Smart” Creationists in the US everything was created a little over 2000-5000 years ago and the sun revolves around the earth (Most likely flat) and the dinosaurs were all the size of sheep and only ate organic GM free corn on the cobb. What did I miss?

  • My record was:
    1, 2, 3, 4, 6, 7, 9, 12, 15 correct; also #13, see below.
    Partial credit for 5

    #10 is interesting. I guessed Neptune, but when I looked it up, it seems that Uranus is actually slightly colder (-224C rather than -218C). Look it up yourself – found the same answer in multiple sources. So this is one of those odd cases I used to treasure as a kid: I was wrong, but so was the “teacher”.

    I assume this is the case because Uranus’s axial tilt means that each hemisphere has really, really cold winters.

    #13 is also interesting. I guessed Mercury through to Uranus, as I had read that Uranus is sometimes visible with the naked eye. This turns out to be CORRECT; Uranus’ visible magnitude is around 5.83, and the human eye can see up to magnitude 6.5 or thereabouts. I’m giving myself full credit on this one (and LH a “must try harder”).

    [ Edited after double checking the facts on visibility of Uranus. ]

    • I just came here to be the smartarse and point out that I have a Monty Python record with two grooves on the one side. It’s pretty much just pure luck which decides which one you get when you drop the needle.

      That is all.

      • I was told about a record which had horse racing commentry on five grooves and you didn’t know which race you would hear.

      • When I bought that Python record, I made a tape to avoid wear on the record. That cassette broke, so I re-recorded it and was vastly puzzled that I’d never heard several of the tracks before!
        I’d assumed the track listing for three sides on the cover was the joke…

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

    Discounting Apollo 11 – 10 people walked on the moon.

  • Number 8 is a bit wrong. They’re the 5 recognised by the IAU there are another 6 named ones of the estimated 200+

  • Question1-Mercury,Venus,Earth,Mars,Jupiter,Saturn,uranus,neptune,Pluto


    The erath is the 3rd planet from the sun


    Jupiter it has 64 moons

    4.6 billion years ago with the gravitational collapse of a small part of a giant molleculer cloud

    The sun is by far the largest object in the solar system
    It cintains morethan 99.8°/.

    And all the planet that is behind pluto is called PLUTOIDS
    Pluto-ceres-make make-haumea-eris




    Ganymede which is jupiters moon


    1959 luna

    5 billion years

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