Jupiter

King of the planets — the biggest

Jupiter is the biggest planet in the Solar System. It's so huge that 1,300 Earths could fit inside! Jupiter is made of gas — there's no solid ground to stand on. It has a Great Red Spot — a giant storm that has been raging for 300 years!

Jupiter is the fifth planet from the Sun and the largest — a gas giant. It is mostly hydrogen and helium, similar to the Sun. Its mass is 2.5 times that of all the other planets combined. Jupiter spins very fast — a day lasts under 10 hours — so it bulges noticeably at the equator. The Great Red Spot is an anticyclonic storm larger than Earth. Jupiter has a powerful magnetic field and more than 90 moons; the largest are Io, Europa, Ganymede and Callisto (the Galilean moons). Europa is thought to hide an ocean beneath its icy crust.

Fun facts

• A day on Jupiter is only 10 hours — the shortest in the Solar System.
• Jupiter's moon Ganymede is bigger than the planet Mercury!
• Jupiter is a 'cosmic shield': its strong gravity flings many comets away from Earth.
• Jupiter has rings too, but they're very faint — nothing like Saturn's.