Jupiter

Jupiter - Rotating Model
Credit: Almond/NASA

Jupiter is the largest planet in the Solar System, its mass is 2.5 times that of all the other planets combined, but is still only one thousandth of the mass of the Sun. It is so large that all the other planets in our solar system would fit inside it with plenty of room spare!

Jupiter is a Gas Giant planet, just like Saturn, Neptune and Uranus. This means that is does not have a solid surface, but is a huge ball of gas - mostly hydrogen (75%) and helium (24%). Jupiter’s light coloured bands of cloud are composed of ammonia ice and are called zones. We don’t know for sure what causes the darker coloured bands, which are called belts, but the chemicals may include sulfur, phosphorus and carbon.

Jupiter with the shadow of the moon, Europa, on the surface.
Credit: NASA

Jupiter rotates faster than any other planet in the Solar System; a day on Jupiter is just under 10 hours long! If you look carefully at the rotating image, you will see the famous Red Spot going around. This is a single giant storm, a bit like a hurricane, that was first seen over 300 years ago. At its widest point, the storm is about three-and-a-half times the diameter of Earth.

Jupiter is known to have at least 67 moons. The largest four (Io, Europa, Ganymede and Callisto) were discovered in 1610 by Galileo. The first spacecraft to visit Jupiter was Pioneer 10 in 1973, since then seven other spacecraft have visited Jupiter, the most recent being the New Horizons probe in 2007 on its way to the dwarf planet, Pluto.