Jupiter is the 5th planet from the sun and the largest in the solar system; It is 2.5 times more massive than all the other planets combined.
It is named after the Roman king of the gods.
One of the most fascinating features of Jupiter is the Great Red Spot, which is actually the top of a large cyclone twice the size of Earth. It has lasted for at least 400 years.
There are 67 known moons of Jupiter. The largest four are Io, Europa, Ganymede and Callisto. They are known as the Galilean moons because they were discovered by Galileo.
Jupiter is known as a gas giant (along with Saturn, Uranus, and Neptune) because its atmosphere is about 75% hydrogen and 24% helium by mass. The remaining 1% comprises methane, ammonia, water vapor and other compounds. Galileo is the only spacecraft to have ever orbited Jupiter, and the Galileo spacecraft gathered extensive information. Current missions such as Juno and JUICE are underway to learn more about Jupiter and its moons. Scientists are particularly interested in Europa, since its icy exterior is thought to harbour large liquid oceans, which may contain microbial life.