Solar system quiz
Checked on 11 November 2026
Question 1 of 10
Discover
What is the largest planet in our solar system?
Show the answer
Right Not quite
The answer is Jupiter.
Jupiter is so big that about 1,000 Earths could fit inside it if it were a hollow shell.
Discover
Which planet is closest to the Sun?
Show the answer
Right Not quite
The answer is Mercury.
Mercury is the first planet from the Sun and also the smallest planet, only slightly larger than our Moon.
Discover
Which planet is known as the "Red Planet"?
Show the answer
Right Not quite
The answer is Mars.
Iron minerals in the Martian dirt rust, which gives Mars its orange-red look.
Discover
Which planet is the hottest in our solar system?
Show the answer
Right Not quite
The answer is Venus.
Even though Mercury is closer to the Sun, Venus's thick carbon dioxide atmosphere traps heat and makes it the hottest planet.
Practise
What is the largest moon in our solar system?
Show the answer
Right Not quite
The answer is Ganymede.
Jupiter's icy moon Ganymede is the largest moon in the solar system and even bigger than the planet Mercury.
Practise
Olympus Mons, the largest volcano in the solar system, is found on which planet?
Show the answer
Right Not quite
The answer is Mars.
Olympus Mons on Mars is about 2.5 times the height of Mount Everest above sea level.
Practise
Which planet did William Herschel discover in 1781, the first found with the aid of a telescope?
Show the answer
Right Not quite
The answer is Uranus.
Uranus is visible to the naked eye but very dim, and it was not recognized as a planet until William Herschel observed it in 1781.
Expert
Which planet is tilted so far over that it appears to spin on its side as it orbits the Sun?
Show the answer
Right Not quite
The answer is Uranus.
Uranus rotates at a nearly 90-degree angle to its orbit, so it rolls around the Sun like a ball.
Expert
Which large moon orbits its planet in the opposite direction to the planet's rotation, the only large moon in the solar system to do so?
Show the answer
Right Not quite
The answer is Triton.
Neptune's largest moon Triton has a retrograde orbit and may once have been a Kuiper Belt object captured by Neptune.
Expert
Which moon is the only one in the solar system known to have a thick atmosphere?
Show the answer
Right Not quite
The answer is Titan.
Saturn's largest moon Titan has an atmosphere denser than Earth's and lakes of liquid on its surface.