The largest planet, with a diameter of about 143 000 kilometres, Jupiter is the second brightest planet in the solar system.  It has four large moons, discovered by Galileo in 1610, and twelve smaller ones. The four large satellites are: Io and Europa, which are about the size of our moon, and Ganymede, which is larger than Mercury and Callisto which is about the same size as Mercury.

The atmosphere of Jupiter is made up of methane, ammonia, probably some water, hydrogen and helium.Jupiter has a Great Red Spot as a distinctive feature and is thought to be similar to a huge hurricane.

The temperature on Jupiter is about -128° C.

It takes Jupiter about 12 years to orbit the sun and almost 10 hours to rotate on its axis.