Solar System for Kids: Solar System Explorer
Solar System Explorer is a free interactive solar system for kids. The planets go round the Sun at their real relative speeds, and one tap flies you to any planet, the Moon, the asteroid belt or the dwarf planet Pluto for a close-up look and a card of facts.
Solar System Explorer
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- Ages
- 5–12
- School years
- Grade R–Grade 6
- Skills
- The order of the planets from the Sun, Comparing the sizes of the Sun, planets and the Moon, Rocky planets, gas giants, ice giants and dwarf planets
- Time
- 2–5 minutes a round
- Cost
- Free, no sign-up
- Updated
How to play Solar System Explorer
- Press Explore to watch the solar system move. Use Slow, Normal and Fast to change the speed, and switch between Fit on screen and True distances to see how far apart the planets really are.
- Tap a planet, or use the buttons under the picture, to fly to it. Its fact card shows its size compared with Earth, how long its day and year last, its moons, its temperature and a wow fact. Visit all 12 places to complete your explorer’s log.
- For a challenge, choose a mission pack. Read each mission, such as “Visit the hottest planet”, then tap the right planet to fly your rocket there. Every flight uses fuel, so think before you fly!
- Some missions are quiz questions, and some ask you to put planets in order from the Sun or by size: drag the cards, or use the arrow buttons, then press Check. Finish every mission first time for 3 stars.
What your child learns
- The order of the planets from the Sun
- Comparing the sizes of the Sun, planets and the Moon
- Rocky planets, gas giants, ice giants and dwarf planets
- Why planets farther from the Sun have longer years
- Days, years, moons and temperatures on other worlds
- Understanding scale: how far apart the planets really are
About Solar System Explorer
The solar system is huge, and most pictures squash it to fit on a page. Solar System Explorer lets children see it both ways. Fit on screen spaces the planets out evenly so every one is easy to tap, while True distances draws the orbits to scale, so the four rocky planets huddle close to the Sun and Neptune and Pluto sit far out in the dark. The planets move at their real relative speeds, starting from roughly where they are in the sky today, so children can watch Mercury race round while Neptune barely moves.
Every body has a fact card written in simple, accurate language based on NASA information: its size next to Earth (drawn to scale), the length of its day and year, its moons, its temperature and a wow fact, such as Venus spinning backwards or Saturn being light enough to float. Easy missions, for Grade R to Grade 1, ask children to find the biggest planet, the red planet and our Moon, and to put the four rocky planets in order. Medium missions, for Grades 2–3, cover the hottest planet, the biggest storm, rings and dwarf planets. Hard missions, for Grades 4–6, ask about day length, wind speed, density and the speed of light, and finish with all eight planets sorted by size and by distance.
Which level should my child play?
| School year | Suggested level |
|---|---|
| Grade R | Easy |
| Grade 1 | Easy |
| Grade 2 | Medium |
| Grade 3 | Medium |
| Grade 4 | Hard |
| Grade 5 | Hard |
| Grade 6 | Hard |
Move up a level after getting three stars two or three times in a row.
🏆 Leaderboard
Full leaderboard →Play a round to get on the board! Create a free account to save your scores.
Frequently asked questions
How many planets are in our solar system?
There are 8 planets. In order from the Sun they are Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. A handy way to remember the order is “My Very Easy Method Just Speeds Up Naming”.
Is Pluto a planet?
Pluto is a dwarf planet. It is round like a planet, but it shares its path round the Sun with many other icy objects in the Kuiper Belt. In 2006 astronomers agreed that a full planet must clear its path of other large objects, so Pluto was renamed a dwarf planet. The game includes Pluto, and Ceres in the asteroid belt is a dwarf planet too.
Which is the biggest planet, and which is the smallest?
Jupiter is the biggest planet: about 11 times as wide as Earth, and more than 1,300 Earths could fit inside it. Mercury is the smallest planet, only just over a third as wide as Earth. The Sun is far bigger than any planet, about 109 times as wide as Earth.
Which planet is the hottest?
Venus is the hottest planet, at about 470°C (880°F), even though Mercury is closer to the Sun. Venus has a thick atmosphere of carbon dioxide that traps heat like a blanket, while Mercury has almost no air, so its nights are freezing.
Which planet has the most moons?
Saturn has the most known moons: more than 200, after a big batch of tiny moons was announced in 2025. Jupiter has more than 90. Astronomers keep finding new small moons, so the numbers change, which is why the fact cards say “more than” instead of an exact count.
Why does the solar system look different in True distances?
In True distances the orbits are drawn to scale. The inner planets are so close to the Sun compared with the outer planets that they crowd into the middle, so a zoomed-in box shows them. The planets themselves are still drawn much bigger than real, otherwise they would be far too small to see.
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Help your child shine in school
Practice at home is a great start. Success Tutoring offers personalised tutoring to build skills and confidence.