Jupiter

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This article is about the planet. For the Roman god, see Jupiter (mythology). For other uses, see Jupiter (disambiguation).

Fifth planet from the Sun in the Solar System

Jupiter
Near-true colour view in 2019[a]
Designations
Pronunciation/ˈpɪtər/ (listen)[1]
AdjectivesJovian
Orbital characteristics[6]
Epoch J2000
Aphelion816.62 million km (5.4588 AU)
Perihelion740.52 million km (4.9501 AU)
Semi-major axis
778.57 million km (5.2044 AU)
Eccentricity0.0489
Orbital period
  • 11.862 yr
  • 4,332.59 d
  • 10,475.8 Jovian solar days[2]
Synodic period
398.88 d
Average orbital speed
13.07 km/s (8.12 mi/s)
Mean anomaly
20.020°[3]
Inclination
  • 1.303° to ecliptic[3]
  • 6.09° to Sun's equator[3]
  • 0.32° to invariable plane[4]
Longitude of ascending node
100.464°
Argument of perihelion
273.867°[3]
Known satellites79 (as of 2018[update])[5]
Physical characteristics[6][14][15]
Mean radius
69,911 km (43,441 mi)[b]
Equatorial radius
  • 71,492 km (44,423 mi)[b]
  • 11.209 Earths
Polar radius
  • 66,854 km (41,541 mi)[b]
  • 10.517 Earths
Flattening0.06487
Surface area
  • 6.1419×1010 km2 (2.3714×1010 sq mi)[b][7]
  • 121.9 Earths
Volume
  • 1.4313×1015 km3 (3.434×1014 cu mi)[b]
  • 1,321 Earths
Mass
  • 1.8982×1027 kg (4.1848×1027 lb)
  • 317.8 Earths
  • 1/1047 Sun[8]
Mean density
1,326 kg/m3 (2,235 lb/cu yd)[c]
Surface gravity
24.79 m/s2 (81.3 ft/s2)[b]
2.528 g
Moment of inertia factor
0.2756±0.0006[9]
Escape velocity
59.5 km/s (37.0 mi/s)[b]
Sidereal rotation period
9.925 hours[10] (9 h 55 m 30 s)
Equatorial rotation velocity
12.6 km/s (7.8 mi/s; 45,000 km/h)
Axial tilt
3.13° (to orbit)
North pole right ascension
268.057°;  17h 52m 14s
North pole declination
64.495°
Albedo0.503 (Bond)[11]
0.538 (geometric)[12]
Surface temp. min mean max
1 bar level 165 K (−108 °C)
0.1 bar 112 K (−161 °C)
Apparent magnitude
−2.94[13] to −1.66[13]
Angular diameter
29.8″ to 50.1″
Atmosphere[6]
Surface pressure
20–200 kPa;[16] 70 kPa[17]
Scale height
27 km (17 mi)
Composition by volumeby volume:
89%±2.0% hydrogen (H
2
)
10%±2.0% helium (He)
0.3%±0.1% methane (CH
4
)
0.026%±0.004% ammonia (NH
3
)
0.0028%±0.001% hydrogen deuteride (HD)
0.0006%±0.0002% ethane (C
2
H
6
)
0.0004%±0.0004% water (H
2
O
)

Ices:

  • ammonia (NH
    3
    )
  • water (H
    2
    O
    )
  • ammonium hydrosulfide (NH
    4
    SH
    )

Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass one-thousandth that of the Sun, but two-and-a-half times that of all the other planets in the Solar System combined. Jupiter has been known to astronomers since antiquity.[18] It is named after the Roman god Jupiter.[19] When viewed from Earth, Jupiter can be bright enough for its reflected light to cast shadows,[20] and is on average the third-brightest natural object in the night sky after the Moon and Venus.

Jupiter is primarily composed of hydrogen with a quarter of its mass being helium, though helium comprises only about a tenth of the number of molecules. It may also have a rocky core of heavier elements,[21] but like the other giant planets, Jupiter lacks a well-defined solid surface. Because of its rapid rotation, the planet's shape is that of an oblate spheroid (it has a slight but noticeable bulge around the equator). The outer atmosphere is visibly segregated into several bands at different latitudes, resulting in turbulence and storms along their interacting boundaries. A prominent result is the Great Red Spot, a giant storm that is known to have existed since at least the 17th century when it was first seen by telescope. Surrounding Jupiter is a faint planetary ring system and a powerful magnetosphere. Jupiter has 79 known moons,[22] including the four large Galilean moons discovered by Galileo Galilei in 1610. Ganymede, the largest of these, has a diameter greater than that of the planet Mercury.

Jupiter has been explored on several occasions by robotic spacecraft, most notably during the early Pioneer and Voyager flyby missions and later by the Galileo orbiter. In late February 2007, Jupiter was visited by the New Horizons probe, which used Jupiter's gravity to increase its speed and bend its trajectory en route to Pluto. The latest probe to visit the planet is Juno, which entered into orbit around Jupiter on July 4, 2016.[23][24] Future targets for exploration in the Jupiter system include the probable ice-covered liquid ocean of its moon Europa.