8 planets · orbital mechanics · comparative sizes · click to explore
Click a planet to see detailed information.
Our solar system contains the Sun and everything orbiting it — 8 planets, dozens of moons, asteroids, and comets — all held together by gravity across billions of kilometres.
Studying the solar system helps us understand Earth's climate, develop space technology, and explore the possibility of life elsewhere in the universe.
Which planet has the longest year? How many Earth years does one orbit take? Click each planet card to find out, then compare the orbital periods of all 8 planets.