The planet Jupiter is the fifth planet out from the Sun , and is two and a half times more massive than all the other planets in the solar system combined. It is made primarily of gases and is therefore known as a “ gas giant ”. Jupiter Planet Profile Equatorial Diameter: 142,984 km Polar Diameter: 133,709 km Mass: 1.90 × 10^27 kg (318 Earths) Moons: 79 ( Io , Europa , Ganymede & Callisto ) Rings: 4 Orbit Distance: 778,340,821 km (5.20 AU) Orbit Period: 4,333 days (11.9 years) Effective Temperature: -148 °C First Record: 7th or 8th century BC Recorded By: Babylonian astronomers Facts About Jupiter Jupiter is the fourth brightest object in the solar system. Only the Sun, Moon and Venus are brighter. It is one of five planets visible to the naked eye from Earth. The ancient Babylonians were the first to record their sightings of Jupiter. This was around the 7 th or 8 th cent...