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168-514: The atmosphere of Jupiter lacks a clear lower boundary and gradually transitions into the liquid interior of the planet. From lowest to highest, the atmospheric layers are the troposphere , stratosphere , thermosphere and exosphere . Each layer has characteristic temperature gradients . The lowest layer, the troposphere, has a complicated system of clouds and hazes composed of layers of ammonia, ammonium hydrosulfide , and water. The upper ammonia clouds visible at Jupiter's surface are organized in

336-527: A system of multiple protostars , which are quite common, with Jupiter being the second but failed protostar. But the Solar System never developed into a system of multiple stars and Jupiter does not qualify as a protostar or brown dwarf since it does not have enough mass to fuse hydrogen. According to the " grand tack hypothesis ", Jupiter began to form at a distance of roughly 3.5  AU (520 million  km ; 330 million  mi ) from

504-495: A vacuum filled with an " aether ", or just a cold, dark vacuum continued up until the 1950s. Tufts University Professor of astronomy, Kenneth R. Lang, writing in 2000 noted, "Half a century ago, most people visualized our planet as a solitary sphere traveling in a cold, dark vacuum of space around the Sun". In 2002, Akasofu stated "The view that interplanetary space is a vacuum into which the Sun intermittently emitted corpuscular streams

672-607: A "permanent spot" by Gian Domenico Cassini after observing the feature in July 1665 with his instrument-maker Eustachio Divini . According to a report by Giovanni Battista Riccioli in 1635, Leander Bandtius, whom Riccioli identified as the Abbot of Dunisburgh who possessed an "extraordinary telescope", observed a large spot that he described as "oval, equaling one seventh of Jupiter's diameter at its longest." According to Riccioli, "these features are seldom able to be seen, and then only by

840-556: A 1:2 resonance, which caused Saturn to shift into a higher orbit, disrupting the orbits of Uranus and Neptune, depleting the Kuiper belt, and triggering the Late Heavy Bombardment . Based on Jupiter's composition, researchers have made the case for an initial formation outside the molecular nitrogen (N 2 ) snow line, which is estimated at 20–30 AU (3.0–4.5 billion km; 1.9–2.8 billion mi) from

1008-440: A 3:2 mean motion resonance at approximately 1.5 AU (220 million km; 140 million mi) from the Sun. This changed the direction of migration, causing them to migrate away from the Sun and out of the inner system to their current locations. All of this happened over a period of 3–6   million years, with the final migration of Jupiter occurring over several hundred thousand years. Jupiter's migration from

1176-464: A Greek zeta with a horizontal stroke , ⟨Ƶ⟩ , as an abbreviation for Zeus . In Latin, Iovis is the genitive case of Iuppiter , i.e. Jupiter. It is associated with the etymology of Zeus ('sky father'). The English equivalent, Jove , is known to have come into use as a poetic name for the planet around the 14th century. Jovian is the adjectival form of Jupiter. The older adjectival form jovial , employed by astrologers in

1344-464: A South Tropical Disturbance. It is not known exactly what causes the Great Red Spot's reddish color. Theories supported by laboratory experiments suppose that the color may be caused by complex organic molecules, red phosphorus, or yet another sulfur compound. The GRS varies greatly in hue, from almost brick-red to pale salmon, or even white. The higher temperature of the reddest central region

1512-472: A combined mass 7–25 times the Earth. This mixing process could have arisen during formation, while the planet accreted solids and gases from the surrounding nebula. Alternatively, it could have been caused by an impact from a planet of about ten Earth masses a few million years after Jupiter's formation, which would have disrupted an originally compact Jovian core. Outside the layer of metallic hydrogen lies

1680-801: A decade (this was the case during the Voyager encounters), making the North Temperate Zone (NTZ) apparently merge into the North Tropical Zone (NTropZ). Other times, the NTZ is divided by a narrow belt into northern and southern components. The North Tropical Region is composed of the NTropZ and the North Equatorial Belt (NEB). The NTropZ is generally stable in coloration, changing in tint only in tandem with activity on

1848-492: A direct result of its steady reduction in size. In 2010, astronomers imaged the GRS in the far infrared (from 8.5 to 24 μm) with a spatial resolution higher than ever before and found that its central, reddest region is warmer than its surroundings by between 3–4  K . The warm airmass is located in the upper troposphere in the pressure range of 200–500 mbar. This warm central spot slowly counter-rotates and may be caused by

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2016-410: A dozen zonal bands parallel to the equator and are bounded by powerful zonal atmospheric flows (winds) known as jets, exhibiting a phenomenon known as atmospheric super-rotation . The bands alternate in color: the dark bands are called belts , while light ones are called zones . Zones, which are colder than belts, correspond to upwellings, while belts mark descending gas. The zones' lighter color

2184-401: A drop of 340−110=230 °C over 90+50=140 km. The adiabatic lapse rate on Earth is around 9.8 °C per km. The adiabatic lapse rate is proportional to the average molecular weight and the gravitational force . The latter is about 2.5 times stronger than on Earth, but the average molecular weight is about 15 times less.) In the stratosphere, the temperatures rise to about 200 K at

2352-462: A faint system of planetary rings that were discovered in 1979 by Voyager 1 and further investigated by the Galileo orbiter in the 1990s. The Jovian ring system consists mainly of dust and has 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

2520-406: A few tens of kilometers above the visible clouds. As of 2008, the early hypothesis that the vortices are deep convective plumes (or convective columns) is not shared by the majority of planetary scientists . The Great Red Spot (GRS) is a persistent anticyclonic storm , 22° south of Jupiter's equator; observations from Earth establish a minimum storm lifetime of 350 years. A storm was described as

2688-574: A few white ovals appeared as a result of instability of the southern temperate zone; they later merged to form Oval BA. In contrast to anticyclones, the Jovian cyclones tend to be small, dark and irregular structures. Some of the darker and more regular features are known as brown ovals (or badges). However the existence of a few long–lived large cyclones has been suggested. In addition to compact cyclones, Jupiter has several large irregular filamentary patches, which demonstrate cyclonic rotation . One of them

2856-414: A large one in the centre and eight others around it, while its southern counterpart also consists of a centre vortex but is surrounded by five large storms and a single smaller one for a total of 7 storms. In 2000, an atmospheric feature formed in the southern hemisphere that is similar in appearance to the Great Red Spot, but smaller. This was created when smaller, white oval-shaped storms merged to form

3024-533: A mass of 60.4   M J . Theoretical models indicate that if Jupiter had over 40% more mass, the interior would be so compressed that its volume would decrease despite the increasing amount of matter. For smaller changes in its mass, the radius would not change appreciably. As a result, Jupiter is thought to have about as large a diameter as a planet of its composition and evolutionary history can achieve. The process of further shrinkage with increasing mass would continue until appreciable stellar ignition

3192-408: A period of about 121 days, moving backward through an angle of 9.9° before returning to prograde movement. Because the orbit of Jupiter is outside that of Earth, the phase angle of Jupiter as viewed from Earth is always less than 11.5°; thus, Jupiter always appears nearly fully illuminated when viewed through Earth-based telescopes. It was during spacecraft missions to Jupiter that crescent views of

3360-460: A radius of 60,000 km (37,000 mi) (11,000 km (6,800 mi) below the cloud tops) and merge again at 50,000 km (31,000 mi) (22,000 km (14,000 mi) beneath the clouds). Rainfalls of diamonds have been suggested to occur, as well as on Saturn and the ice giants Uranus and Neptune. The temperature and pressure inside Jupiter increase steadily inward as the heat of planetary formation can only escape by convection. At

3528-573: A similar spot had appeared farther to the north. Oval BA is a red storm in Jupiter's southern hemisphere similar in form to, though smaller than, the Great Red Spot (it is often affectionately referred to as "Red Spot Jr.", "Red Jr." or "The Little Red Spot"). A feature in the South Temperate Belt, Oval BA was first seen in 2000 after the collision of three small white storms, and has intensified since then. Jupiter Jupiter

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3696-530: A single feature—these three smaller white ovals were formed in 1939–1940. The merged feature was named Oval BA . It has since increased in intensity and changed from white to red, earning it the nickname "Little Red Spot". In April 2017, a "Great Cold Spot" was discovered in Jupiter's thermosphere at its north pole . This feature is 24,000 km (15,000 mi) across, 12,000 km (7,500 mi) wide, and 200 °C (360 °F) cooler than surrounding material. While this spot changes form and intensity over

3864-529: A study by scientists at the University of California, Berkeley , between 1996 and 2006 the spot lost 15 percent of its diameter along its major axis. Xylar Asay-Davis, who was on the team that conducted the study, noted that the spot is not disappearing because "velocity is a more robust measurement because the clouds associated with the Red Spot are also strongly influenced by numerous other phenomena in

4032-437: A surface depth where the atmospheric pressure level is 1  bar (0.10  MPa ), the temperature is around 165 K (−108 °C; −163 °F). The region where supercritical hydrogen changes gradually from a molecular fluid to a metallic fluid spans pressure ranges of 50–400 GPa with temperatures of 5,000–8,400 K (4,730–8,130 °C; 8,540–14,660 °F), respectively. The temperature of Jupiter's diluted core

4200-402: A telescope of exceptional quality and magnification". The Great Spot has been continually observed since the 1870s, however. The GRS rotates counter-clockwise, with a period of about six Earth days or 14  Jovian days. Its dimensions are 24,000–40,000 km east-to-west and 12,000–14,000 km north-to-south. The spot is large enough to contain two or three planets the size of Earth. At

4368-403: A transparent interior atmosphere of hydrogen. At this depth, the pressure and temperature are above molecular hydrogen's critical pressure of 1.3 MPa and critical temperature of 33  K (−240.2  °C ; −400.3  °F ). In this state, there are no distinct liquid and gas phases—hydrogen is said to be in a supercritical fluid state. The hydrogen and helium gas extending downward from

4536-408: A weak subsidence of air in the center of GRS. The Great Red Spot's latitude has been stable for the duration of good observational records, typically varying by about a degree. Its longitude , however, is subject to constant variation. Because Jupiter's visible features do not rotate uniformly at all latitudes, astronomers have defined three different systems for defining the longitude. System II

4704-405: Is a gas giant , meaning its chemical composition is primarily hydrogen and helium. These materials are classified as gasses in planetary geology, a term that does not denote the state of matter. It is the largest planet in the Solar System, with a diameter of 142,984 km (88,846 mi) at its equator , giving it a volume 1,321 times that of the Earth. Its average density, 1.326 g/cm ,

4872-482: Is a decrease of the speed of the strongest eastward jet located at the boundary between the North Tropical zone and North Temperate belts at 23°N. However bands vary in coloration and intensity over time (see "specific band"). These variations were first observed in the early seventeenth century. Meridional circulation cells are a large-scale atmospheric motion where gas rises at a certain latitude, travel in

5040-566: Is a red spot a third the size of GRS that formed in 2000 from the merging of three white ovals. Jupiter has powerful storms, often accompanied by lightning strikes. The storms are a result of moist convection in the atmosphere connected to the evaporation and condensation of water. They are sites of strong upward motion of the air, which leads to the formation of bright and dense clouds. The storms form mainly in belt regions. The lightning strikes on Jupiter are hundreds of times more powerful than those seen on Earth, and are assumed to be associated with

5208-516: Is about 10. Jupiter's thermosphere is located at pressures lower than 1 μbar and demonstrates such phenomena as airglow , polar aurorae and X-ray emissions. Within it lie layers of increased electron and ion density that form the ionosphere . The high temperatures prevalent in the thermosphere (800–1000 K) have not been explained yet; existing models predict a temperature no higher than about 400 K. They may be caused by absorption of high-energy solar radiation (UV or X-ray), by heating from

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5376-496: Is about 25 years. The Equatorial Region (EZ) is one of the most stable regions of the planet, in latitude and in activity. The northern edge of the EZ hosts spectacular plumes that trail southwest from the NEB, which are bounded by dark, warm (in infrared ) features known as festoons (hot spots). Though the southern boundary of the EZ is usually quiescent, observations from the late 19th into

5544-454: Is about 50 km (31 mi) deep and consists of at least two decks of ammonia clouds: a thin, clearer region on top and a thicker, lower deck. There may be a thin layer of water clouds underlying the ammonia clouds, as suggested by flashes of lightning detected in the atmosphere of Jupiter. These electrical discharges can be up to a thousand times as powerful as lightning on Earth. The water clouds are assumed to generate thunderstorms in

5712-462: Is about ten times larger than Earth ( 11.209  R 🜨 ) and smaller than the Sun ( 0.102 76   R ☉ ). Jupiter's mass is 318 times that of Earth; 2.5 times that of all the other planets in the Solar System combined. It is so massive that its barycentre with the Sun lies above the Sun's surface at 1.068  solar radii from the Sun's centre. Jupiter's radius is about one tenth

5880-419: Is also responsible for the strength of the Sun's magnetic field at the orbit of the Earth being over 100 times greater than originally anticipated. If space were a vacuum, then the Sun's 10 tesla magnetic dipole field would reduce with the cube of the distance to about 10 tesla. But satellite observations show that it is about 100 times greater at around 10 tesla. Magnetohydrodynamic (MHD) theory predicts that

6048-444: Is an oblate spheroid, meaning that the diameter across its equator is longer than the diameter measured between its poles . On Jupiter, the equatorial diameter is 9,276 km (5,764 mi) longer than the polar diameter. Three systems are used as frames of reference for tracking planetary rotation, particularly when graphing the motion of atmospheric features. System I applies to latitudes from 7° N to 7° S; its period

6216-475: Is believed to result from ammonia ice; what gives the belts their darker colors is uncertain. The origins of the banded structure and jets are not well understood, though a "shallow model" and a "deep model" exist. The Jovian atmosphere shows a wide range of active phenomena, including band instabilities, vortices ( cyclones and anticyclones ), storms and lightning. The vortices reveal themselves as large red, white or brown spots (ovals). The largest two spots are

6384-482: Is by far the most active region on the planet, as it is home to its strongest retrograde jet stream. The SEB is usually the broadest, darkest belt on Jupiter; it is sometimes split by a zone (the SEBZ), and can fade entirely every 3 to 15 years before reappearing in what is known as an SEB Revival cycle. A period of weeks or months following the belt's disappearance, a white spot forms and erupts dark brownish material which

6552-520: Is called the Rhines scale. Its existence is connected to production of Rossby waves . This process works as follows: when the largest turbulent structures reach a certain size, the energy begins to flow into Rossby waves instead of larger structures, and the inverse cascade stops. Since on the spherical rapidly rotating planet the dispersion relation of the Rossby waves is anisotropic , the Rhines scale in

6720-443: Is caused by differences in the opacity of the clouds. Ammonia concentration is higher in zones, which leads to the appearance of denser clouds of ammonia ice at higher altitudes, which in turn leads to their lighter color. On the other hand, in belts clouds are thinner and are located at lower altitudes. The upper troposphere is colder in zones and warmer in belts. The exact nature of chemicals that make Jovian zones and bands so colorful

6888-413: Is denser, with a composition of roughly 71% hydrogen, 24% helium, and 5% other elements by mass. The atmospheric proportions of hydrogen and helium are close to the theoretical composition of the primordial solar nebula . Neon in the upper atmosphere consists of 20 parts per million by mass, which is about a tenth as abundant as in the Sun. Jupiter's helium abundance is about 80% that of the Sun due to

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7056-535: Is dominant over the Sun 's. This disrupts the flow of the solar wind, which is channelled around the magnetosphere. Material from the solar wind can "leak" into the magnetosphere, causing aurorae and also populating the Van Allen radiation belts with ionised material. The interplanetary medium is responsible for several optical phenomena visible from Earth. Zodiacal light is a broad band of faint light sometimes seen after sunset and before sunrise, stretched along

7224-411: Is estimated to be 20,000 K (19,700 °C; 35,500 °F) with a pressure of around 4,000 GPa. The atmosphere of Jupiter is primarily composed of molecular hydrogen and helium, with a smaller amount of other compounds such as water, methane, hydrogen sulfide, and ammonia. Jupiter's atmosphere extends to a depth of approximately 3,000 km (2,000 mi) below the cloud layers. Jupiter

7392-399: Is likely to be in the form of helium rain: as hydrogen turns into the metallic state at depths of more than 10,000 km, helium separates from it forming droplets which, being denser than the metallic hydrogen, descend towards the core. This can also explain the severe depletion of neon (see Table), an element that easily dissolves in helium droplets and would be transported in them towards

7560-476: Is located to the west of the GRS (in its wake region) in the southern equatorial belt. These patches are called cyclonic regions (CR). The cyclones are always located in the belts and tend to merge when they encounter each other, much like anticyclones. The deep structure of vortices is not completely clear. They are thought to be relatively thin, as any thickness greater than about 500 km will lead to instability. The large anticyclones are known to extend only

7728-670: Is lower than those of the four terrestrial planets . The atmosphere of Jupiter is approximately 76% hydrogen and 24% helium by mass. By volume, the upper atmosphere is about 90% hydrogen and 10% helium, with the lower proportion owing to the individual helium atoms being more massive than the molecules of hydrogen formed in this part of the atmosphere. The atmosphere contains trace amounts of elemental carbon , oxygen , sulfur , and neon , as well as ammonia , water vapour , phosphine , hydrogen sulfide , and hydrocarbons like methane , ethane and benzene . Its outermost layer contains crystals of frozen ammonia. The planet's interior

7896-457: Is markedly different from that in the atmosphere of Earth . The interior of Jupiter is fluid and lacks any solid surface. Therefore, convection may occur throughout the planet's outer molecular envelope. As of 2008, a comprehensive theory of the dynamics of the Jovian atmosphere has not been developed. Any such theory needs to explain the following facts: the existence of narrow stable bands and jets that are symmetric relative to Jupiter's equator,

8064-489: Is nearly circular. This low eccentricity is at odds with exoplanet discoveries, which have revealed Jupiter-sized planets with very high eccentricities. Models suggest this may be due to there being two giant planets in our Solar System, as the presence of a third or more giant planets tends to induce larger eccentricities. The axial tilt of Jupiter is 3.13°, which is relatively small, so its seasons are insignificant compared to those of Earth and Mars. Jupiter's rotation

8232-406: Is no sharp boundary between gas and liquid phases. Hydrogen is considered a supercritical fluid when the temperature is above 33 K and the pressure is above 13 bar. Since the lower boundary of the atmosphere is ill-defined, the pressure level of 10  bars , at an altitude of about 90 km below 1 bar with a temperature of around 340  K , is commonly treated as the base of

8400-663: Is not completely clear, though it may resemble the cloud structure of Earth's Hadley cells . The simplest interpretation is that zones are sites of atmospheric upwelling , whereas belts are manifestations of downwelling . When air enriched in ammonia rises in zones, it expands and cools, forming high and dense white clouds. In belts, however, the air descends, warming adiabatically as in a convergence zone on Earth, and white ammonia clouds evaporate, revealing lower, darker clouds. The location and width of bands, speed and location of jets on Jupiter are remarkably stable, having changed only slightly between 1980 and 2000. One example of change

8568-404: Is not known, but they may include complicated compounds of sulfur , phosphorus and carbon . The Jovian bands are bounded by zonal atmospheric flows (winds), called jets . The eastward ( prograde ) jets are found at the transition from zones to belts (going away from the equator), whereas westward ( retrograde ) jets mark the transition from belts to zones. Such flow velocity patterns mean that

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8736-400: Is one of the major drivers of terrestrial weather. The production of the jets in this model is related to a well-known property of two dimensional turbulence—the so-called inverse cascade, in which small turbulent structures (vortices) merge to form larger ones. The finite size of the planet means that the cascade can not produce structures larger than some characteristic scale, which for Jupiter

8904-477: Is one of the most active belts on the planet. It is characterized by anticyclonic white ovals and cyclonic "barges" (also known as "brown ovals"), with the former usually forming farther north than the latter; as in the NTropZ, most of these features are relatively short-lived. Like the South Equatorial Belt (SEB), the NEB has sometimes dramatically faded and "revived". The timescale of these changes

9072-512: Is perhaps more prominent, but also generally quiet. Other minor belts and zones in the region are occasionally observed. The North Temperate Region is part of a latitudinal region easily observable from Earth, and thus has a superb record of observation. It also features the strongest prograde jet stream on the planet—a westerly current that forms the southern boundary of the North Temperate Belt (NTB). The NTB fades roughly once

9240-675: Is perpetually covered with clouds of ammonia crystals, which may contain ammonium hydrosulfide as well. The clouds are located in the tropopause layer of the atmosphere, forming bands at different latitudes, known as tropical regions. These are subdivided into lighter-hued zones and darker belts . The interactions of these conflicting circulation patterns cause storms and turbulence . Wind speeds of 100 metres per second (360 km/h; 220 mph) are common in zonal jet streams . The zones have been observed to vary in width, colour and intensity from year to year, but they have remained stable enough for scientists to name them. The cloud layer

9408-457: Is scarcer. Other chemical compounds such as arsine (AsH 3 ) and germane (GeH 4 ) are present only in trace amounts. The upper atmosphere of Jupiter contains small amounts of simple hydrocarbons such as ethane , acetylene , and diacetylene , which form from methane under the influence of the solar ultraviolet radiation and charged particles coming from Jupiter's magnetosphere . The carbon dioxide , carbon monoxide and water present in

9576-429: Is so rarefied , it does not exhibit thermodynamic equilibrium . Instead, different components have different temperatures. The solar wind exhibits temperatures consistent with Chapman's estimate in cislunar space , and dust particles near Earth's orbit exhibit temperatures 257–298 K (3–77 °F), averaging about 283 K (50 °F). In general, the solar wind temperature decreases proportional to

9744-587: Is stretched into a new belt by Jupiter's winds. The belt most recently disappeared in May 2010. Another characteristic of the SEB is a long train of cyclonic disturbances following the Great Red Spot. Like the NTropZ, the STropZ is one of the most prominent zones on the planet; not only does it contain the GRS, but it is occasionally rent by a South Tropical Disturbance (STropD), a division of the zone that can be very long-lived;

9912-451: 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 that of 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

10080-414: Is the fastest of all the Solar System's planets, completing a rotation on its axis in slightly less than ten hours; this creates an equatorial bulge easily seen through an amateur telescope. Because Jupiter is not a solid body, its upper atmosphere undergoes differential rotation . The rotation of Jupiter's polar atmosphere is about 5 minutes longer than that of the equatorial atmosphere. The planet

10248-511: Is the fifth planet from the Sun and the largest in the Solar System . It is a gas giant with a mass more than 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. Its diameter is eleven times that of Earth , and a tenth that 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

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10416-601: Is the first evidence that the Spot's color is affected by environmental factors. The spot occasionally disappears from the visible spectrum, becoming evident only through the Red Spot Hollow, which is its niche in the South Equatorial Belt ;(SEB). The visibility of GRS is apparently coupled to the appearance of the SEB; when the belt is bright white, the spot tends to be dark, and when it is dark,

10584-530: Is the planet's shortest, at 9h 50 m 30.0s. System II applies at latitudes north and south of these; its period is 9h 55 m 40.6s. System III was defined by radio astronomers and corresponds to the rotation of the planet's magnetosphere; its period is Jupiter's official rotation. Jupiter is usually the fourth brightest object in the sky (after the Sun, the Moon , and Venus ), although at opposition Mars can appear brighter than Jupiter. Depending on Jupiter's position with respect to

10752-448: Is the strongest of any planet in the Solar System, with a dipole moment of 4.170 gauss (0.4170  mT ) that is tilted at an angle of 10.31° to the pole of rotation. The surface magnetic field strength varies from 2 gauss (0.20 mT) up to 20 gauss (2.0 mT). This field is thought to be generated by eddy currents —swirling movements of conducting materials—within the fluid, metallic hydrogen core. At about 75 Jupiter radii from

10920-477: Is used for latitudes of more than 10°, and was originally based on the average rotation rate of the Great Red Spot of 9h 55m 42s. Despite this, the spot has "lapped" the planet in System ;II at least 10 times since the early 19th century. Its drift rate has changed dramatically over the years and has been linked to the brightness of the South Equatorial Belt, and the presence or absence of

11088-495: The Earth , it contains about 5 particles/cm , but values as high as 100 particles/cm have been observed. The temperature of the interplanetary medium varies through the solar system. Joseph Fourier estimated that interplanetary medium must have temperatures comparable to those observed at Earth's poles , but on faulty grounds : lacking modern estimates of atmospheric heat transport , he saw no other means to explain

11256-468: The Equatorial band (EB), North Equatorial belt zone (NEBZ, a white zone within the belt) and South Equatorial belt zone (SEBZ). Belts are also occasionally split by a sudden disturbance. When a disturbance divides a normally singular belt or zone, an N or an S is added to indicate whether the component is the northern or southern one; e.g., NEB(N) and NEB(S). Circulation in Jupiter's atmosphere

11424-589: The Galileo Probe found that the winds on Jupiter extend well below the water clouds at 5–7 bar and do not show any evidence of decay down to 22 bar pressure level, which implies that circulation in the Jovian atmosphere may in fact be deep. The deep model was first proposed by Busse in 1976. His model was based on another well-known feature of fluid mechanics, the Taylor–Proudman theorem . It holds that in any fast-rotating barotropic ideal liquid,

11592-541: The Great Red Spot (GRS) and Oval BA , which is also red. These two and most of the other large spots are anticyclonic. Smaller anticyclones tend to be white. Vortices are thought to be relatively shallow structures with depths not exceeding several hundred kilometers. Located in the southern hemisphere, the GRS is the largest known vortex in the Solar System. It could engulf two or three Earths and has existed for at least three hundred years. Oval BA, south of GRS,

11760-549: The Middle Ages , has come to mean 'happy' or 'merry', moods ascribed to Jupiter's influence in astrology . The original Greek deity Zeus supplies the root zeno- , which is used to form some Jupiter-related words, such as zenography . Jupiter is believed to be the oldest planet in the Solar System, having formed just one million years after the Sun and roughly 50 million years before Earth. Current models of Solar System formation suggest that Jupiter formed at or beyond

11928-440: The Solar System , and through which all the larger Solar System bodies, such as planets , dwarf planets , asteroids , and comets , move. The IPM stops at the heliopause , outside of which the interstellar medium begins. Before 1950, interplanetary space was widely considered to either be an empty vacuum, or consisting of " aether ". The interplanetary medium includes interplanetary dust , cosmic rays , and hot plasma from

12096-500: The Taylor-Proudman theorem . The Galileo Probe measured the vertical profile of a jet along its descent trajectory into Jupiter's atmosphere, finding the winds to decay over two to three scale heights above the clouds, while below the cloud level, winds increase slightly and then remain constant down to at least 22 bar—the maximum operational depth reached by the probe. The origin of Jupiter's colored banded structure

12264-508: The ecliptic and appearing brightest near the horizon. This glow is caused by sunlight scattered by dust particles in the interplanetary medium between Earth and the Sun. A similar phenomenon centered at the antisolar point , gegenschein is visible in a naturally dark, moonless night sky . Much fainter than zodiacal light, this effect is caused by sunlight backscattered by dust particles beyond Earth's orbit. The term "interplanetary" appears to have been first used in print in 1691 by

12432-439: The lunar regolith has acted as a collector for solar wind particles, and so studies of rocks from the lunar surface can be valuable in studies of the solar wind. High-energy particles from the solar wind impacting on the lunar surface also cause it to emit faintly at X-ray wavelengths. Planets with their own magnetic field, such as the Earth and Jupiter , are surrounded by a magnetosphere within which their magnetic field

12600-605: The precipitation of these elements as helium-rich droplets, a process that happens deep in the planet's interior. Based on spectroscopy , Saturn is thought to be similar in composition to Jupiter, but the other giant planets Uranus and Neptune have relatively less hydrogen and helium and relatively more of the next most common elements , including oxygen, carbon, nitrogen, and sulfur. These planets are known as ice giants because during their formation, these elements are thought to have been incorporated into them as ice; however, they probably contain very little ice. Jupiter

12768-402: The snow line : a distance from the early Sun where the temperature was sufficiently cold for volatiles such as water to condense into solids. First forming a solid core, the planet then accumulated its gaseous atmosphere. Therefore, the planet must have formed before the solar nebula was fully dispersed. During its formation, Jupiter's mass gradually increased until it had 20 times the mass of

12936-402: The solar wind . The density of the interplanetary medium is very low, decreasing in inverse proportion to the square of the distance from the Sun. It is variable, and may be affected by magnetic fields and events such as coronal mass ejections . Typical particle densities in the interplanetary medium are about 5-40 particles/cm , but exhibit substantial variation. In the vicinity of

13104-420: The troposphere , stratosphere , thermosphere and exosphere . Unlike the Earth's atmosphere , Jupiter's lacks a mesosphere . Jupiter does not have a solid surface, and the lowest atmospheric layer, the troposphere, smoothly transitions into the planet's fluid interior. This is a result of having temperatures and the pressures well above those of the critical points for hydrogen and helium, meaning that there

13272-490: The " Suì Star" ( Suìxīng 歲星 ) and established their cycle of 12 earthly branches based on the approximate number of years it takes Jupiter to rotate around the Sun; the Chinese language still uses its name ( simplified as 歲 ) 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

13440-423: The 1660s, Giovanni Cassini used a new telescope to discover spots in Jupiter's atmosphere, observe that the planet appeared oblate, and estimate its rotation period. In 1692, Cassini noticed that the atmosphere undergoes a differential rotation. The Great Red Spot may have been observed as early as 1664 by Robert Hooke and in 1665 by Cassini, although this is disputed. The pharmacist Heinrich Schwabe produced

13608-408: The 1960s. They were partly based on terrestrial meteorology , which had become well developed by that time. Those shallow models assumed that the jets on Jupiter are driven by small scale turbulence , which is in turn maintained by moist convection in the outer layer of the atmosphere (above the water clouds). The moist convection is a phenomenon related to the condensation and evaporation of water and

13776-464: The EZ, the North and South Equatorial belts (NEB and SEB) extend to 18°N and 18°S, respectively. Farther from the equator lie the North and South Tropical zones (NtrZ and STrZ). The alternating pattern of belts and zones continues until the polar regions at approximately 50 degrees latitude, where their visible appearance becomes somewhat muted. The difference in the appearance between zones and belts

13944-583: The Earth's atmosphere, can be divided into two classes: cyclones and anticyclones . Cyclones rotate in the direction similar to the rotation of the planet ( counterclockwise in the northern hemisphere and clockwise in the southern); anticyclones rotate in the reverse direction. However, unlike in the terrestrial atmosphere , anticyclones predominate over cyclones on Jupiter—more than 90% of vortices larger than 2000 km in diameter are anticyclones. The lifetime of Jovian vortices varies from several days to hundreds of years, depending on their size. For instance,

14112-450: The Earth, approximately half of which was made up of silicates, ices and other heavy-element constituents. When the proto-Jupiter grew larger than 50 Earth masses it created a gap in the solar nebula. Thereafter, the growing planet reached its final mass in 3–4   million years. Since Jupiter is made of the same elements as the Sun (hydrogen and helium) it has been suggested that the Solar System might have been early in its formation

14280-485: The Earth, it can vary in visual magnitude from as bright as −2.94 at opposition down to −1.66 during conjunction with the Sun. The mean apparent magnitude is −2.20 with a standard deviation of 0.33. The angular diameter of Jupiter likewise varies from 50.1 to 30.5 arc seconds . Favourable oppositions occur when Jupiter is passing through the perihelion of its orbit, bringing it closer to Earth. Near opposition, Jupiter will appear to go into retrograde motion for

14448-526: The Ferrel cells on Earth. While on Earth, the return flow in the cells' lower branch is balanced by friction in the Ekman layer , the balance in Jupiter in yet unknown, but one possibility is that the friction is maintained by magnetic drag. The belts and zones that divide Jupiter's atmosphere each have their own names and unique characteristics. They begin below the North and South Polar Regions, which extend from

14616-476: The Great Red Spot (GRS) and the Oval BA; the latter formed only in 2000. In contrast to white ovals, these structures are red, arguably due to dredging up of red material from the planet's depths. On Jupiter the anticyclones usually form through merges of smaller structures including convective storms (see below), although large ovals can result from the instability of jets. The latter was observed in 1938–1940, when

14784-428: The Jovian atmosphere are molecular hydrogen ( H 2 ) and helium . The helium abundance is 0.157 ± 0.004 relative to molecular hydrogen by number of molecules, and its mass fraction is 0.234 ± 0.005 , which is slightly lower than the Solar System's primordial value. The reason for this low abundance is not entirely understood, but some of the helium may have condensed into the core of Jupiter. This condensation

14952-442: The Jovian atmosphere are similar to those of the atmosphere of Earth . The temperature of the troposphere decreases with height until it reaches a minimum at the tropopause , which is the boundary between the troposphere and stratosphere. On Jupiter, the tropopause is approximately 50 km above the visible clouds (or 1 bar level). The pressure and temperature at the tropopause are about 0.1 bar and 110 K. (This gives

15120-568: The NTB's southern jet stream. Like the NTZ, it too is sometimes divided by a narrow band, the NTropB. On rare occasions, the southern NTropZ plays host to "Little Red Spots". As the name suggests, these are northern equivalents of the Great Red Spot. Unlike the GRS, they tend to occur in pairs and are always short-lived, lasting a year on average; one was present during the Pioneer 10 encounter. The NEB

15288-448: The Sun is 778 million km ( 5.2  AU ) and it completes an orbit every 11.86 years. This is approximately two-fifths the orbital period of Saturn, forming a near orbital resonance . The orbital plane of Jupiter is inclined 1.30° compared to Earth. Because the eccentricity of its orbit is 0.049, Jupiter is slightly over 75 million km nearer the Sun at perihelion than aphelion , which means that its orbit

15456-532: The Sun, and possibly even outside the argon snow line, which may be as far as 40 AU (6.0 billion km; 3.7 billion mi). Having formed at one of these extreme distances, Jupiter would then have, over a roughly 700,000-year period, migrated inwards to its current location, during an epoch approximately 2–3 million years after the planet began to form. In this model, Saturn, Uranus, and Neptune would have formed even further out than Jupiter, and Saturn would also have migrated inwards. Jupiter

15624-406: The Sun. As the young planet accreted mass, its interaction with the gas disk orbiting the Sun and the orbital resonances from Saturn caused it to migrate inward. This upset the orbits of several super-Earths orbiting closer to the Sun, causing them to collide destructively. Saturn would later have begun to migrate inwards at a faster rate than Jupiter until the two planets became captured in

15792-413: The accepted value for the deuterium abundance is (2.25 ± 0.35) × 10 , which probably represents the primordial value in the protosolar nebula that gave birth to the Solar System. The ratio of nitrogen isotopes in the Jovian atmosphere, N to N , is 2.3 × 10, a third lower than that in the Earth's atmosphere (3.5 × 10). The latter discovery is especially significant since

15960-531: The ancient Greek and Roman civilizations, Jupiter was named after the chief god of the divine pantheon : Zeus to the Greeks and Jupiter to the Romans. The International Astronomical Union formally adopted the name Jupiter for the planet in 1976 and has since named its newly discovered satellites for the god's lovers, favourites, and descendants. The planetary symbol for Jupiter, [REDACTED] , descends from

16128-418: The average lifetime of an anticyclone between 1000 and 6000 km in diameter is 1–3 years. Vortices have never been observed in the equatorial region of Jupiter (within 10° of latitude), where they are unstable. As on any rapidly rotating planet, Jupiter's anticyclones are high pressure centers, while cyclones are low pressure. The anticyclones in Jupiter's atmosphere are always confined within zones, where

16296-591: The belts, indicative of upward atmospheric motion, gave indication for a reversed motion in the deeper atmosphere. Juno's microwave measurements probe the atmosphere down to ~240 bar. These measurements confirmed the existence of these motions as a part of mid-latitudes large circulation cells with upward motion in the belts and downward motions in the zones, extending from ~1 bar down to at least ~240 bar. So far, 8 cells have been identified at each of Jupiter's hemispheres along latitudes 20°-60° N\S. The mid-latitude cells are driven by breaking of atmospheric waves , similar to

16464-404: The characteristics of a plasma, rather than a simple gas. For example, it carries the Sun's magnetic field with it, is highly electrically conductive (resulting in the heliospheric current sheet ), forms plasma double layers where it comes into contact with a planetary magnetosphere or at the heliopause , and exhibits filamentation (such as in aurorae ). The plasma in the interplanetary medium

16632-603: The charged particles precipitating from the Jovian magnetosphere, or by dissipation of upward-propagating gravity waves . The thermosphere and exosphere at the poles and at low latitudes emit X-rays, which were first observed by the Einstein Observatory in 1983. The energetic particles coming from Jupiter's magnetosphere create bright auroral ovals, which encircle the poles. Unlike their terrestrial analogs, which appear only during magnetic storms , aurorae are permanent features of Jupiter's atmosphere. The thermosphere

16800-409: The chromophores from view. Jupiter has a low axial tilt , thus ensuring that the poles always receive less solar radiation than the planet's equatorial region. Convection within the interior of the planet transports energy to the poles, balancing out temperatures at the cloud layer. A well-known feature of Jupiter is the Great Red Spot , a persistent anticyclonic storm located 22° south of

16968-481: The cloud layer gradually transitions to a liquid in deeper layers, possibly resembling something akin to an ocean of liquid hydrogen and other supercritical fluids. Physically, the gas gradually becomes hotter and denser as depth increases. Rain-like droplets of helium and neon precipitate downward through the lower atmosphere, depleting the abundance of these elements in the upper atmosphere. Calculations suggest that helium drops separate from metallic hydrogen at

17136-527: The core as well. The atmosphere contains various simple compounds such as water , methane (CH 4 ), hydrogen sulfide (H 2 S), ammonia (NH 3 ) and phosphine (PH 3 ). Their abundances in the deep (below 10 bar) troposphere imply that the atmosphere of Jupiter is enriched in the elements carbon , nitrogen , sulfur and possibly oxygen by a factor of 2–4 relative to the Sun. The noble gases argon , krypton and xenon also appear in abundance relative to solar levels (see table), while neon

17304-461: The direction parallel to the equator is larger than in the direction orthogonal to it. The ultimate result of the process described above is production of large scale elongated structures, which are parallel to the equator. The meridional extent of them appears to match the actual width of jets. Therefore, in shallow models vortices actually feed the jets and should disappear by merging into them. While these weather–layer models can successfully explain

17472-423: The earliest known drawing to show details of the Great Red Spot in 1831. The Red Spot was reportedly lost from sight on several occasions between 1665 and 1708 before becoming quite conspicuous in 1878. It was recorded as fading again in 1883 and at the start of the 20th century. Interplanetary medium The interplanetary medium ( IPM ) or interplanetary space consists of the mass and energy which fills

17640-476: The early 20th century show that this pattern was then reversed relative to today. The EZ varies considerably in coloration, from pale to an ochre , or even coppery hue; it is occasionally divided by an Equatorial Band (EB). Features in the EZ move roughly 390 km/h relative to the other latitudes. The South Tropical Region includes the South Equatorial Belt (SEB) and the South Tropical Zone. It

17808-499: The equator. It was first observed in 1831, and possibly as early as 1665. Images by the Hubble Space Telescope have shown two more "red spots" adjacent to the Great Red Spot. The storm is visible through Earth-based telescopes with an aperture of 12 cm or larger. The storm rotates counterclockwise, with a period of about six days. The maximum altitude of this storm is about 8 km (5 mi) above

17976-565: The existence of a dozen narrow jets, they have serious problems. A glaring failure of the model is the prograde (super-rotating) equatorial jet: with some rare exceptions shallow models produce a strong retrograde (subrotating) jet, contrary to observations. In addition, the jets tend to be unstable and can disappear over time. Shallow models cannot explain how the observed atmospheric flows on Jupiter violate stability criteria. More elaborated multilayer versions of weather–layer models produce more stable circulation, but many problems persist. Meanwhile,

18144-419: The first time-lapse movies from the Voyager flybys. The spot is spatially confined by a modest eastward jet stream (prograde) to its south and a very strong westward (retrograde) one to its north. Though winds around the edge of the spot peak at about 120 m/s (432 km/h), currents inside it seem stagnant, with little inflow or outflow. The rotation period of the spot has decreased with time, perhaps as

18312-403: The flows are organized in a series of cylinders parallel to the rotational axis. The conditions of the theorem are probably met in the fluid Jovian interior. Therefore, the planet's molecular hydrogen mantle may be divided into cylinders, each cylinder having a circulation independent of the others. Those latitudes where the cylinders' outer and inner boundaries intersect with the visible surface of

18480-496: The formation of Jupiter with orbital properties that are close to those of the present-day planet. Other models predict Jupiter forming at distances much farther out, such as 18 AU (2.7 billion km; 1.7 billion mi). According to the Nice model , the infall of proto- Kuiper belt objects over the first 600 million years of Solar System history caused Jupiter and Saturn to migrate from their initial positions into

18648-494: The four largest moons of Jupiter (now known as the Galilean moons ) using a telescope. This is thought to be the first telescopic observation of moons other than Earth's. Just one day after Galileo, Simon Marius independently discovered moons around Jupiter, though he did not publish his discovery in a book until 1614. It was Marius's names for the major moons, however, that stuck: Io, Europa, Ganymede, and Callisto. The discovery

18816-400: The halo, a relatively bright main ring, and an outer gossamer ring. These rings appear to be made of dust, whereas Saturn's rings are made of ice. The main ring is most likely made out of material ejected from the satellites Adrastea and Metis , which is drawn into Jupiter because of the planet's strong gravitational influence. New material is added by additional impacts. In a similar way,

18984-516: The hydrogen. The orange and brown colours in the clouds of Jupiter are caused by upwelling compounds that change colour when they are exposed to ultraviolet light from the Sun. The exact makeup remains uncertain, but the substances are thought to be made up of phosphorus, sulfur or possibly hydrocarbons. These colourful compounds, known as chromophores , mix with the warmer clouds of the lower deck. The light-coloured zones are formed when rising convection cells form crystallising ammonia that hides

19152-472: The inner solar system eventually allowed the inner planets—including Earth—to form from the rubble. There are several unresolved issues with the grand tack hypothesis. The resulting formation timescales of terrestrial planets appear to be inconsistent with the measured elemental composition. Jupiter would likely have settled into an orbit much closer to the Sun if it had migrated through the solar nebula . Some competing models of Solar System formation predict

19320-414: The inverse-square of the distance to the Sun; the temperature of the dust decreases proportional to the inverse cube root of the distance. For dust particles within the asteroid belt , typical temperatures range from 200 K (−100 °F) at 2.2 AU down to 165 K (−163 °F) at 3.2 AU. Since the interplanetary medium is a plasma , or gas of ions , the interplanetary medium has

19488-450: The jets' eastward momentum decreases in belts and increases in zones from the equator to the pole. Therefore, wind shear in belts is cyclonic , while in zones it is anticyclonic . The EZ is an exception to this rule, showing a strong eastward (prograde) jet and has a local minimum of the wind speed exactly at the equator. The jet speeds are high on Jupiter, reaching more than 100 m/s. These speeds correspond to ammonia clouds located in

19656-520: The late 1800s showed it to be approximately 41,000 km (25,500 mi) across. As of 2015 , the storm was measured at approximately 16,500 by 10,940 km (10,250 by 6,800 mi), and was decreasing in length by about 930 km (580 mi) per year. In October 2021, a Juno flyby mission measured the depth of the Great Red Spot, putting it at around 300–500 kilometres (190–310 miles). Juno missions found several cyclone groups at Jupiter's poles. The northern group contains nine cyclones, with

19824-401: The magnetosphere, which protects them from solar wind. The volcanoes on the moon Io emit large amounts of sulfur dioxide , forming a gas torus along its orbit. The gas is ionized in Jupiter's magnetosphere , producing sulfur and oxygen ions . They, together with hydrogen ions originating from the atmosphere of Jupiter, form a plasma sheet in Jupiter's equatorial plane. The plasma in

19992-461: The main cloud layers. The stratospheric haze layers are made from condensed heavy polycyclic aromatic hydrocarbons or hydrazine , which are generated in the upper stratosphere (1–100 μbar) from methane under the influence of the solar ultraviolet radiation (UV). The methane abundance relative to molecular hydrogen in the stratosphere is about 10, while the abundance ratio of other light hydrocarbons, like ethane and acetylene, to molecular hydrogen

20160-420: The moons Thebe and Amalthea are believed to produce the two distinct components of the dusty gossamer ring. There is evidence of a fourth ring that may consist of collisional debris from Amalthea that is strung along the same moon's orbit. Jupiter is the only planet whose barycentre with the Sun lies outside the volume of the Sun, though by 7% of the Sun's radius. The average distance between Jupiter and

20328-483: The most famous one lasted from 1901 to 1939. The South Temperate Region, or South Temperate Belt (STB), is yet another dark, prominent belt, more so than the NTB; until March 2000, its most famous features were the long-lived white ovals BC, DE, and FA, which have since merged to form Oval BA ("Red Jr."). The ovals were part of South Temperate Zone, but they extended into STB partially blocking it. The STB has occasionally faded, apparently due to complex interactions between

20496-413: The most obvious result of this is the Great Red Spot , a giant storm that has been recorded since 1831. 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. Jupiter is surrounded by

20664-419: The motion of a conducting fluid (e.g., the interplanetary medium) in a magnetic field induces electric currents which in turn generate magnetic fields, and in this respect it behaves like an MHD dynamo . The outer edge of the heliosphere is the boundary between the flow of the solar wind and the interstellar medium . This boundary is known as the heliopause and is believed to be a fairly sharp transition of

20832-431: The north-south (meridional) direction, descends, and get back to the origin in a closed cell circulation. On Earth, the meridional circulation is composed of 3 cells in each hemisphere: Hadley , Ferrel and Polar cells. On Jupiter, the visible cloud bands gave indication for upward motion in the zones and downward motion in the belts, indicative only for the upper few bars. However, higher frequency of lightning flashes in

21000-399: The order of 110 to 160 astronomical units from the Sun. The interplanetary medium thus fills the roughly spherical volume contained within the heliopause. How the interplanetary medium interacts with planets depends on whether they have magnetic fields or not. Bodies such as the Moon have no magnetic field and the solar wind can impact directly on their surface. Over billions of years,

21168-422: The other planets. Jupiter's atmosphere consists of 76% hydrogen and 24% helium by mass, with a denser interior. It contains trace elements like carbon , oxygen , sulfur , neon , ammonia , water vapour , phosphine , hydrogen sulfide , and hydrocarbons . Jupiter's helium abundance is 80% of the Sun's, similar to Saturn 's composition. The ongoing contraction of Jupiter's interior generates more heat than

21336-415: The outer 20–30%. The driving of deep circulation is another problem. The deep flows can be caused both by shallow forces (moist convection, for instance) or by deep planet-wide convection that transports heat out of the Jovian interior. Which of these mechanisms is more important is not clear yet. As has been known since 1966, Jupiter radiates much more heat than it receives from the Sun. It is estimated that

21504-599: The planet as a whole. Jupiter's atmosphere is the most comprehensively understood of those of all the giant planets because it was observed directly by the Galileo atmospheric probe when it entered the Jovian atmosphere on December 7, 1995. Other sources of information about Jupiter's atmospheric composition include the Infrared Space Observatory (ISO), the Galileo and Cassini orbiters, and Earth-based observations. The two main constituents of

21672-462: The planet collapsed directly from the gaseous protoplanetary disk , it was expected to completely lack a core, consisting instead of a denser and denser fluid (predominantly molecular and metallic hydrogen) all the way to the centre. Data from the Juno mission showed that Jupiter has a diffuse core that mixes into its mantle, extending for 30–50% of the planet's radius, and comprising heavy elements with

21840-423: The planet correspond to the jets; the cylinders themselves are observed as zones and belts. The deep model easily explains the strong prograde jet observed at the equator of Jupiter; the jets it produces are stable and do not obey the 2D stability criterion. However it has major difficulties; it produces a very small number of broad jets, and realistic simulations of 3D flows are not possible as of 2008, meaning that

22008-455: 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 rate of rotation, one turn in ten hours, Jupiter is an oblate spheroid ; it has 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;

22176-471: The planet were obtained. A small telescope will usually show Jupiter's four Galilean moons and the cloud belts across Jupiter's atmosphere . A larger telescope with an aperture of 4–6 inches (10–15 cm) will show Jupiter's Great Red Spot when it faces Earth. Observation of Jupiter dates back to at least the Babylonian astronomers of the 7th or 8th century BC. The ancient Chinese knew Jupiter as

22344-617: The planet's upper atmosphere. The Great Red Spot should not be confused with the Great Dark Spot, a feature observed near Jupiter's north pole (bottom) in 2000 by the Cassini–Huygens spacecraft. A feature in the atmosphere of Neptune was also called the Great Dark Spot . The latter feature, imaged by Voyager 2 in 1989, may have been an atmospheric hole rather than a storm. It was no longer present in 1994, although

22512-457: The planet, the interaction of the magnetosphere with the solar wind generates a bow shock . Surrounding Jupiter's magnetosphere is a magnetopause , located at the inner edge of a magnetosheath —a region between it and the bow shock. The solar wind interacts with these regions, elongating the magnetosphere on Jupiter's lee side and extending it outward until it nearly reaches the orbit of Saturn. The four largest moons of Jupiter all orbit within

22680-399: The polar regions of Jupiter. As a result, radio waves are generated through a cyclotron maser mechanism , and the energy is transmitted out along a cone-shaped surface. When Earth intersects this cone, the radio emissions from Jupiter can exceed the radio output of the Sun. Jupiter has a faint planetary ring system composed of three main segments: an inner torus of particles known as

22848-432: The poles than in the equatorial region. This leads to a uniform temperature in the troposphere. While heat is transported from the equator to the poles mainly via the atmosphere on Earth, on Jupiter deep convection equilibrates heat. The convection in the Jovian interior is thought to be driven mainly by the internal heat. The atmosphere of Jupiter is home to hundreds of vortices —circular rotating structures that, as in

23016-533: The poles to roughly 40–48° N/S. These bluish-gray regions are usually featureless. The North North Temperate Region rarely shows more detail than the polar regions, due to limb darkening , foreshortening , and the general diffuseness of features. However, the North-North Temperate Belt (NNTB) is the northernmost distinct belt, though it occasionally disappears. Disturbances tend to be minor and short-lived. The North-North Temperate Zone (NNTZ)

23184-425: The precipitation of helium into the core. The internal heat may be important for the dynamics of the Jovian atmosphere. While Jupiter has a small obliquity of about 3°, and its poles receive much less solar radiation than its equator, the tropospheric temperatures do not change appreciably from the equator to poles. One explanation is that Jupiter's convective interior acts like a thermostat, releasing more heat near

23352-476: The pressure range 0.7–1 bar. The prograde jets are generally more powerful than the retrograde jets. The jets extend thousands of kilometers into the interior, as measured by the gravitometer instrument onboard of the Juno spacecraft . The direction at which the jets extend into the planet is parallel to Jupiter's axis of rotation rather than in a radial direction (toward the center of the planet), consistent with

23520-412: The previous theories of Solar System formation considered the terrestrial value for the ratio of nitrogen isotopes to be primordial. The visible surface of Jupiter is divided into several bands parallel to the equator. There are two types of bands: lightly colored zones and relatively dark belts. The wider Equatorial Zone (EZ) extends between latitudes of approximately 7°S to 7°N. Above and below

23688-411: The radius of the Sun, and its mass is one thousandth the mass of the Sun , as the densities of the two bodies are similar. A " Jupiter mass " ( M J or M Jup ) is used as a unit to describe masses of other objects, particularly extrasolar planets and brown dwarfs . For example, the extrasolar planet HD 209458 b has a mass of 0.69   M J , while the brown dwarf Gliese 229 b has

23856-450: The ratio of the thermal power emitted by the planet to the thermal power absorbed from the Sun is 1.67 ± 0.09 . The internal heat flux from Jupiter is 5.44 ± 0.43 W/m , whereas the total emitted power is 335 ± 26 petawatts . The latter value is approximately equal to one billionth of the total power radiated by the Sun. This excess heat is mainly the primordial heat from the early phases of Jupiter's formation, but may result in part from

24024-588: The region of the heavens opposite Jupiter's position in the night sky. These beliefs survive in some Taoist 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 trapezoidal rule

24192-459: The relative consistency of Earth's climate . A very hot interplanetary medium remained a minor position among geophysicists as late as 1959, when Chapman proposed a temperature on the order of 10000 K, but observation in Low Earth orbit of the exosphere soon contradicted his position. In fact, both Fourier and Chapman's final predictions were correct: because the interplanetary medium

24360-476: The ring system is unknown, possibly dating back to Jupiter's formation. At least 95 moons orbit the planet; the four largest moons — Io , Europa , Ganymede , and Callisto —orbit within the magnetosphere, and were discovered by Galileo Galilei in 1610. Ganymede, the largest of the four, is larger than the planet Mercury . Since 1973, Jupiter has been visited by nine robotic probes : seven flybys and two dedicated orbiters, with two more en route. In both

24528-559: The same way as terrestrial thunderstorms, driven by the heat rising from the interior. The Juno mission revealed the presence of "shallow lightning" which originates from ammonia-water clouds relatively high in the atmosphere. These discharges carry "mushballs" of water-ammonia slushes covered in ice, which fall deep into the atmosphere. Upper-atmospheric lightning has been observed in Jupiter's upper atmosphere, bright flashes of light that last around 1.4   milliseconds. These are known as "elves" or "sprites" and appear blue or pink due to

24696-402: The scientist Robert Boyle : "The air is different from the æther (or vacuum) in the... interplanetary spaces" Boyle Hist. Air . In 1898, American astronomer Charles Augustus Young wrote: "Inter-planetary space is a vacuum, far more perfect than anything we can produce by artificial means..." ( The Elements of Astronomy , Charles Augustus Young, 1898). The notion that space is considered to be

24864-435: The sheet co-rotates with the planet, causing deformation of the dipole magnetic field into that of a magnetodisk. Electrons within the plasma sheet generate a strong radio signature, with short, superimposed bursts in the range of 0.6–30  MHz that are detectable from Earth with consumer-grade shortwave radio receivers . As Io moves through this torus, the interaction generates Alfvén waves that carry ionized matter into

25032-434: The short term, it has maintained its general position in the atmosphere for more than 15 years. It may be a giant vortex similar to the Great Red Spot, and appears to be quasi-stable like the vortices in Earth's thermosphere. This feature may be formed by interactions between charged particles generated from Io and the strong magnetic field of Jupiter, resulting in a redistribution of heat flow. Jupiter's magnetic field

25200-410: The simplified models used to justify deep circulation may fail to catch important aspects of the fluid dynamics within Jupiter. One model published in 2004 successfully reproduced the Jovian band-jet structure. It assumed that the molecular hydrogen mantle is thinner than in all other models; occupying only the outer 10% of Jupiter's radius. In standard models of the Jovian interior, the mantle comprises

25368-408: The spot is usually light. The periods when the spot is dark or light occur at irregular intervals; in the 50 years from 1947 to 1997, the spot was darkest in the periods 1961–1966, 1968–1975, 1989–1990, and 1992–1993. In November 2014, an analysis of data from NASA's Cassini mission revealed that the red color is likely a product of simple chemicals being broken apart by solar ultraviolet irradiation in

25536-415: The stable interior. The latter hypothesis postulates that the observed atmospheric flows are only a surface manifestation of deeply rooted circulation in the outer molecular envelope of Jupiter. As both theories have their own successes and failures, many planetary scientists think that the true theory will include elements of both models. The first attempts to explain Jovian atmospheric dynamics date back to

25704-435: The start of 2004, the Great Red Spot had approximately half the longitudinal extent it had a century ago, when it was 40,000 km in diameter. At the present rate of reduction, it could potentially become circular by 2040, although this is unlikely because of the distortion effect of the neighboring jet streams. It is not known how long the spot will last, or whether the change is a result of normal fluctuations. According to

25872-415: The strong prograde jet observed at the equator, the difference between zones and belts, and the origin and persistence of large vortices such as the Great Red Spot. The theories regarding the dynamics of the Jovian atmosphere can be broadly divided into two classes: shallow and deep. The former hold that the observed circulation is largely confined to a thin outer (weather) layer of the planet, which overlays

26040-423: The surrounding atmosphere." Infrared data have long indicated that the Great Red Spot is colder (and thus, higher in altitude) than most of the other clouds on the planet; the cloudtops of the GRS are about 8 km above the surrounding clouds. Furthermore, careful tracking of atmospheric features revealed the spot's counterclockwise circulation as far back as 1966 – observations dramatically confirmed by

26208-434: The surrounding cloud tops. The Spot's composition and the source of its red colour remain uncertain, although photodissociated ammonia reacting with acetylene is a likely explanation. The Great Red Spot is larger than the Earth. Mathematical models suggest that the storm is stable and will be a permanent feature of the planet. However, it has significantly decreased in size since its discovery. Initial observations in

26376-490: The temperatures are too high for it to condense. The water clouds form the densest layer of clouds and have the strongest influence on the dynamics of the atmosphere. This is a result of the higher condensation heat of water and higher water abundance as compared to the ammonia and hydrogen sulfide (oxygen is a more abundant chemical element than either nitrogen or sulfur). Various tropospheric (at 200–500 mbar) and stratospheric (at 10–100 mbar) haze layers reside above

26544-497: The time of its formation, Jupiter was hotter and was about twice its current diameter. Before the early 21st century, most scientists proposed one of two scenarios for the formation of Jupiter. If the planet accreted first as a solid body, it would consist of a dense core , a surrounding layer of fluid metallic hydrogen (with some helium) extending outward to about 80% of the radius of the planet, and an outer atmosphere consisting primarily of molecular hydrogen . Alternatively, if

26712-636: The transition into the thermosphere, at an altitude and pressure of around 320 km and 1 μbar. In the thermosphere, temperatures continue to rise, eventually reaching 1000 K at about 1000 km, where pressure is about 1 nbar. Jupiter's troposphere contains a complicated cloud structure. The upper clouds, located in the pressure range 0.6–0.9 bar, are made of ammonia ice. Below these ammonia ice clouds, denser clouds made of ammonium hydrosulfide ((NH 4 )SH) or ammonium sulfide ((NH 4 ) 2 S, between 1–2 bar) and water (3–7 bar) are thought to exist. There are no methane clouds as

26880-437: The troposphere. In scientific literature, the 1 bar pressure level is usually chosen as a zero point for altitudes—a "surface" of Jupiter. As is generally the case, the top atmospheric layer, the exosphere, does not have a specific upper boundary. The density gradually decreases until it smoothly transitions into the interplanetary medium approximately 5,000 km above the "surface". The vertical temperature gradients in

27048-435: The upper atmosphere are thought to originate from impacting comets , such as Shoemaker-Levy 9 . The water cannot come from the troposphere because the cold tropopause acts like a cold trap, effectively preventing water from rising to the stratosphere (see Vertical structure above). Earth- and spacecraft-based measurements have led to improved knowledge of the isotopic ratios in Jupiter's atmosphere. As of July 2003,

27216-432: The water clouds. Recent Juno observations suggest Jovian lightning strikes occur above the altitude of water clouds (3-7 bars). A charge separation between falling liquid ammonia-water droplets and water ice particles may generate higher-altitude lightning. Upper-atmospheric lightning has also been observed 260 km above the 1 bar level. The atmosphere of Jupiter is classified into four layers, by increasing altitude:

27384-616: The white ovals and the GRS. The appearance of the South Temperate Zone (STZ)—the zone in which the white ovals originated—is highly variable. There are other features on Jupiter that are either temporary or difficult to observe from Earth. The South South Temperate Region is harder to discern even than the NNTR; its detail is subtle and can only be studied well by large telescopes or spacecraft. Many zones and belts are more transient in nature and are not always visible. These include

27552-487: The wind speed increases in direction from the equator to the poles. They are usually bright and appear as white ovals. They can move in longitude , but stay at approximately the same latitude as they are unable to escape from the confining zone. The wind speeds at their periphery are about 100 m/s. Different anticyclones located in one zone tend to merge when they approach each other. However Jupiter has two anticyclones that are somewhat different from all others. They are

27720-592: Was a major point in favour of the heliocentric theory of the motions of the planets by Nicolaus Copernicus ; Galileo's outspoken support of the Copernican theory led to him being tried and condemned by the Inquisition . In the autumn of 1639, the Neapolitan optician Francesco Fontana tested a 22-palm telescope of his own making and discovered the characteristic bands of the planet's atmosphere. During

27888-512: Was achieved. Although Jupiter would need to be about 75 times more massive to fuse hydrogen and become a star , its diameter is sufficient as the smallest red dwarf may be slightly larger in radius than Saturn. Jupiter radiates more heat than it receives through solar radiation, due to the Kelvin–Helmholtz mechanism within its contracting interior. This process causes Jupiter to shrink by about 1 mm (0.039 in) per year. At

28056-411: Was the first place outside the Earth where the trihydrogen cation ( H 3 ) was discovered. This ion emits strongly in the mid-infrared part of the spectrum, at wavelengths between 3 and 5 μm; this is the main cooling mechanism of the thermosphere. 3.2 ± 1.4 (9–12 bar) 0.19–0.58 (19 bar) (0.08–2.8 bar) The composition of Jupiter's atmosphere is similar to that of

28224-573: 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. In 1610, Italian polymath Galileo Galilei discovered

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