Next in the Solar System come the four gas giant outer planets, which, in order of their distance from the Sun, are as follows.
The largest planet in the Solar System, Jupiter has a small rocky core, surrounded by a layer of liquid hydrogen and helium. Jupiter is over 1,335 times larger than Earth and has a slightly flattened shape at the poles due to the high speed of its rotation.
Jupiter has over 60 moons. The four largest moons, Ganymede, Io, Europa and Callisto, were discovered in 1610 by the astronomer Galileo Galilei. These four moons are now known as the Galilean satellites. Io is the most volcanic body in our whole Solar System. Ganymede is the largest moon in the Solar System, bigger than Mercury, and the only moon to have its own magnetic field. It is thought that there may be twice as much water on Europa as there is on Earth as its icy surface may be covering a huge ocean. The surface of Callisto is covered in ancient craters.
The Great Red Spot on Jupiter is in fact a giant storm, twice the size of Earth, which has been observed for over 300 years. More recently three other storms merged to form the Little Red Spot, which is about half the size of the Great Red Spot.
In 1973 Pioneer 10 became the first spacecraft to venture beyond the asteroid belt to Jupiter.
Since then both Voyager and the Galileo orbiter have flown past Jupiter. In July 2016 the Juno spacecraft, launched in 2011, arrived in orbit around Jupiter and is now sending scientific data back to Earth.
In Roman mythology Jupiter was the king of the gods and the god of the sky and thunder. An appropriate name for our largest planet!