Jupiter
Jupiter is the fifth planet from the Sun and the largest in the Solar System. A gas giant, Jupiter's mass is more than two and a half times that of all the other planets in the Solar System combined and slightly less than one one-thousandth the mass of the Sun. Jupiter orbits the Sun at a distance of 5.20 AU (778.5 Gm) with an orbital period of 11.86 years. It is the third brightest natural object in the Earth's night sky after the Moon and Venus and has been observed since prehistoric times. Its name derives from Jupiter, the chief deity of ancient Roman religion.
Jupiter captured by New Horizons space probe. The small spot on top of Jupiter is the shadow cast by its moon Ganymede. | |||||||||||||
| Designations | |||||||||||||
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| Pronunciation | /ˈdʒuːpɪtər/ ⓘ | ||||||||||||
Named after | Jupiter | ||||||||||||
| Adjectives | Jovian /ˈdʒoʊviən/ | ||||||||||||
| Symbol | |||||||||||||
| Orbital characteristics | |||||||||||||
| Epoch J2000 | |||||||||||||
| Aphelion | 5.4570 AU (816.363 million km) | ||||||||||||
| Perihelion | 4.9506 AU (740.595 million km) | ||||||||||||
Semi-major axis | 5.2038 AU (778.479 million km) | ||||||||||||
| Eccentricity | 0.0489 | ||||||||||||
Orbital period (sidereal) |
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Orbital period (synodic) | 398.88 d | ||||||||||||
Average orbital speed | 13.07 km/s (8.12 mi/s) | ||||||||||||
Mean anomaly | 20.020° | ||||||||||||
| Inclination |
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Longitude of ascending node | 100.464° | ||||||||||||
| 21 January 2023 | |||||||||||||
| 273.867° | |||||||||||||
| Known satellites | 95 (as of 2023) | ||||||||||||
| Physical characteristics | |||||||||||||
Mean radius | 69,911 km (43,441 mi) 10.973 of Earth's | ||||||||||||
Equatorial radius | 71,492 km (44,423 mi) 11.209 R🜨 (of Earth's) 0.10045 R☉ (of Sun's) | ||||||||||||
Polar radius | 66,854 km (41,541 mi) 10.517 of Earth's | ||||||||||||
| Flattening | 0.06487 | ||||||||||||
Surface area | 6.1469×1010 km2 (2.3733×1010 sq mi) 120.4 of Earth's | ||||||||||||
| Volume | 1.4313×1015 km3 (3.434×1014 cu mi) 1,321 of Earth's | ||||||||||||
| Mass | 1.8982×1027 kg (4.1848×1027 lb)
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Mean density | 1.326 g/cm3 (0.0479 lb/cu in) | ||||||||||||
Equatorial surface gravity | 24.79 m/s2 (81.3 ft/s2) 2.528 g | ||||||||||||
Moment of inertia factor | 0.2756±0.0006 | ||||||||||||
Equatorial escape velocity | 59.5 km/s (37.0 mi/s) | ||||||||||||
Synodic rotation period | 9.9258 h (9 h 55 m 33 s) | ||||||||||||
Sidereal rotation period | 9.9250 hours (9 h 55 m 30 s) | ||||||||||||
Equatorial rotation velocity | 12.6 km/s (7.8 mi/s; 45,000 km/h) | ||||||||||||
| 3.13° (to orbit) | |||||||||||||
North pole right ascension | 268.057°; 17h 52m 14s | ||||||||||||
North pole declination | 64.495° | ||||||||||||
| 0.503 (Bond) 0.538 (geometric) | |||||||||||||
| Temperature | 88 K (−185 °C) (blackbody temperature) | ||||||||||||
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| −2.94 to −1.66 | |||||||||||||
| −9.4 | |||||||||||||
| 29.8" to 50.1" | |||||||||||||
| Atmosphere | |||||||||||||
Surface pressure | 200–600 kPa (30–90 psi) (opaque cloud deck) | ||||||||||||
Scale height | 27 km (17 mi) | ||||||||||||
| Composition by volume |
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Jupiter was the first planet to form, and its inward migration during the primordial Solar System impacted much of the formation history of the other planets. Hydrogen constitutes 90% of Jupiter's volume, followed by helium, which forms 25% of its mass and 10% of its volume. The ongoing contraction of Jupiter's interior generates more heat than the planet receives from the Sun. Its internal structure is believed to consist of an outer mantle of fluid metallic hydrogen and a diffuse inner core of denser material. Because of its rapid rotation rate of one rotation per ten hours, Jupiter's shape is an oblate spheroid; it possesses a slight but noticeable bulge around the equator. 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 at least 1831.
Jupiter is surrounded by a faint planetary ring system and has a powerful magnetosphere, the second largest contiguous structure in the Solar System (after the heliosphere). Jupiter forms a system of 95 known moons and probably many more, including the four large moons discovered by Galileo Galilei in 1610: Io, Europa, Ganymede, and Callisto. Ganymede, the largest of the four, is larger than the planet Mercury. Callisto is the second largest; Io and Europa are approximately the size of Earth's Moon.
Since 1973, Jupiter has been visited by nine robotic probes: seven flybys and two dedicated orbiters, with one more en route and one awaiting launch.