Jupiter

Jupiter is the fifth planet from the Sun, and the largest in the Solar System. It is a gas giant with a mass nearly 2.5 times that of all the other planets in the Solar System combined and slightly less than one-thousandth the mass of the Sun. The diameter of Jupiter is 11 times that of Earth and a tenth that of the Sun. It orbits the Sun at a distance of , with an orbital period of . Jupiter is the third-brightest natural object in the Earth's night sky, after the Moon and Venus, and has been observed since prehistoric times. It was named after Jupiter, the chief deity of ancient Roman religion. Jupiter was the first of the Sun's planets to form, and its inward migration during the primordial phase of the Solar System affected much of the formation history of the other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser interior. It contains traces of the elements carbon, oxygen, sulfur, neon, and compounds such as ammonia, water vapour, phosphine, hydrogen sulfide, and hydrocarbons. Jupiter's helium abundance is 80% of the Sun's, similar to Saturn's composition. The outer atmosphere is divided into a series of latitudinal bands, with turbulence and storms along their interacting boundaries; the most obvious result of this is the Great Red Spot, a giant storm that has been recorded since 1831.…

Jupiter is the fifth planet from the Sun, and the largest in the Solar System. It is a gas giant with a mass nearly 2.5 times that of all the other planets in the Solar System combined and slightly less than one-thousandth the mass of the Sun. The diameter of Jupiter is 11 times that of Earth and a tenth that of the Sun. It orbits the Sun at a distance of , with an orbital period of . Jupiter is the third-brightest natural object in the Earth's night sky, after the Moon and Venus, and has been observed since prehistoric times. It was named after Jupiter, the chief deity of ancient Roman religion. Jupiter was the first of the Sun's planets to form, and its inward migration during the primordial phase of the Solar System affected much of the formation history of the other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser interior. It contains traces of the elements carbon, oxygen, sulfur, neon, and compounds such as ammonia, water vapour, phosphine, hydrogen sulfide, and hydrocarbons. Jupiter's helium abundance is 80% of the Sun's, similar to Saturn's composition. The outer atmosphere is divided into a series of latitudinal bands, with turbulence and storms along their interacting boundaries; the most obvious result of this is the Great Red Spot, a giant storm that has been recorded since 1831. Because of Jupiter's rapid rotation rate, one turn in ten hours, the shape of the planet is an oblate spheroid; the radius at the equator is about 7% larger than the radius at its poles. Its internal structure is believed to consist of an outer mantle of fluid metallic hydrogen and a diffuse inner core of denser material. The ongoing contraction of Jupiter's interior generates more heat than the planet receives from the Sun. Jupiter's magnetic field is the strongest and second-largest contiguous structure in the Solar System, generated by eddy currents within the fluid, metallic hydrogen core. The solar wind interacts with the magnetosphere, extending it outward and affecting Jupiter's orbit. At least 115 moons orbit the planet; the four largest moons—Io, Europa, Ganymede, and Callisto—orbit within the magnetosphere and are visible with common binoculars. Ganymede, the largest of the four, is larger than the planet Mercury. Jupiter is surrounded by a faint system of planetary rings. The rings of Jupiter consist mainly of dust and have three main segments: an inner torus of particles known as the halo, a relatively bright main ring, and an outer gossamer ring. The rings have a reddish colour in visible and near-infrared light. The age of the ring system is unknown, possibly dating back to Jupiter's formation. Since 1973, Jupiter has been visited by nine robotic probes: seven flybys and two dedicated orbiters (with two more en route). Jupiter-like exoplanets have also been found in other planetary systems. | style="font-size:0.9em; text-align:center;" | The Galilean satellites Io, Europa, Ganymede, and Callisto (in order of increasing distance from Jupiter) in false colour |} of the longitudinal motion of Jupiter (☉) relative to Earth (🜨)|upright=1.2 Observations of Jupiter are attested by the Babylonian astronomers during the 7th–8th centuries BC. The ancient Chinese knew Jupiter as the ' star' ( ) and established their cycle of twelve earthly branches based on the approximate number of years it takes Jupiter to revolve around the Sun; the Chinese language still uses its name ( ; simplified as ) when referring to years of age. By the 4th century BC, these observations had developed into the Chinese zodiac, and each year became associated with a Tai Sui star and god controlling the region of the heavens opposite Jupiter's position in the night sky. These beliefs survive in some Taoist and folk religious practices and in the East Asian zodiac's twelve animals. The Chinese historian Xi Zezong has claimed that Gan De, an ancient Chinese astronomer, reported a small star "in alliance" with the planet, which may indicate a sighting of one of Jupiter's moons with the unaided eye. If true, this would predate Galileo's discovery by nearly two millennia. A 2016 paper reports that the trapezoidal rule was used by Babylonians before 50 BC for integrating the velocity of Jupiter along the ecliptic. In his 2nd century work the Almagest, the Hellenistic astronomer Claudius Ptolemaeus constructed a geocentric planetary model based on deferents and epicycles to explain Jupiter's motion relative to Earth, giving its orbital period around Earth as 4332.38 days, or 11.86 years.

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