The fifth planet from the Sun and the largest, with a diameter about 11 times that of Earth. Jupiter is a
gas giant made up mostly of hydrogen and helium. It turns on its axis faster than any other planet in the solar system, taking less than ten hours to complete one rotation; this rapid rotation draws its atmospheric clouds into distinct belts parallel to its equator. Jupiter has more known moons by far than any other planet in the solar system—as many as 63, with new ones being discovered regularly in recent years—and it has a faint ring system that was unknown until 1979, when the Voyager space probe investigated the planet. A persistent anticyclonic storm known as the
Great Red Spot is Jupiter's most prominent feature. See Table at
solar system.