Jupiter

Jupiter

Full-disc view of Jupiter in natural color in April 2014
Designations
Pronunciation	i/ˈdʒuːpᵻtər/
Adjectives
Orbital characteristics
Epoch J2000
Aphelion	7011816044416838844♠5.45492 AU (7011816040000000000♠816.04 Gm)
Perihelion	7011740552843347502♠4.95029 AU (7011740550000000000♠740.55 Gm)
Semi-major axis	7011778297882103820♠5.20260 AU (7011778299000000000♠778.299 Gm)
Eccentricity	6998484980000000000♠0.048498
Orbital period	7001118618000000000♠11.8618 yr 7008374335776000000♠4,332.59 d 7004104758000000000♠10,475.8 Jovian solar days
Synodic period	7007344632320000000♠398.88 d
Average orbital speed	13.07 km/s
Mean anomaly	20.020°
Inclination	1.303° to ecliptic 6.09° to Sun's equator 0.32° to invariable plane
Longitude of ascending node	100.464°
Argument of perihelion	273.867°
Known satellites	67 (as of 2014[update])
Physical characteristics
Mean radius	7007699110000000000♠69,911±6 km
Equatorial radius	7007714920000000000♠71,492±4 km 11.209 Earths
Polar radius	7007668540000000000♠66,854±10 km 10.517 Earths
Flattening	6998648700000000000♠0.06487±0.00015
Surface area	7016614190000000000♠6.1419×1010 km2 121.9 Earths
Volume	7024143130000000000♠1.4313×1015 km3 7003132100000000000♠1,321 Earths
Mass	7027189860000000000♠1.8986×1027 kg 317.8 Earths 1/1047 Sun
Mean density	7003132600000000000♠1.326 g/cm3
Surface gravity	7001247900000000000♠24.79 m/s2 2.528 g
Moment of inertia factor	6999254000000000000♠0.254
Escape velocity	59.5 km/s
Sidereal rotation period	9.925 h (9 h 55 m 30 s)
Equatorial rotation velocity	12.6 km/s 7004125833333333333♠45300 km/h
Axial tilt	3.13° (to orbit)
North pole right ascension	268.057° 17h 52m 14s
North pole declination	64.496°
Albedo	0.343 (Bond) 0.52 (geom.)
Surface temp. min mean max 1 bar level 165 K (−108 °C) 0.1 bar 112 K
Apparent magnitude	2999840000000000000♠−1.6 to 2999706000000000000♠−2.94
Angular diameter	29.8″ to 50.1″
Atmosphere
Surface pressure	20–200 kPa (cloud layer)
Scale height	27 km
Composition by volume	by volume: 89.8±2.0% hydrogen (H2) 10.2±2.0% helium (He) ≈ 0.3% methane (CH4) ≈ 0.026% ammonia (NH3) ≈ 0.003% hydrogen deuteride (HD) 0.0006% ethane (C2H6) 0.0004% water (H2O) Ices: ammonia (NH3) water (H2O) ammonium hydrosulfide (NH4SH)

by volume:

Ices:

Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a giant planet 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 is a gas giant, along with Saturn, with the other two giant planets, Uranus and Neptune, being ice giants. Jupiter was known to astronomers of ancient times. The Romans named it after their god Jupiter. When viewed from Earth, Jupiter can reach an apparent magnitude of −2.94, bright enough for its reflected light to cast shadows, and making it on average the third-brightest 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, 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 at least 67 moons, 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.