Jupiter. Computer artwork of the gas giant planet Jupiter (left), partially illuminated by the Sun (upper right). Jupiter, the fifth planet from the Sun, orbits at around 778 million kilometres from the Sun, five times as distant as Earth. It is the largest planet of the solar system, being more than twice the mass of all the other planets combined. Its diameter of about 143, a gas giant, Jupiter mainly comprises hydrogen and helium. Traces of methane, ammonia and water produce the swirling bands of coloured clouds.