Oval BA
   HOME

TheInfoList



OR:

The atmosphere of Jupiter is the largest planetary atmosphere in the
Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding astronomical nomenclature, specifies capitalizing the names of all individual astronomical objects but uses mixed "Solar ...
. It is mostly made of
molecular hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, ...
and
helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
in roughly solar proportions; other chemical compounds are present only in small amounts and include
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...
,
ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
, hydrogen sulfide, and
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
. Although water is thought to reside deep in the atmosphere, its directly measured concentration is very low. The
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
, sulfur, and
noble gas The noble gases (historically also the inert gases; sometimes referred to as aerogens) make up a class of chemical elements with similar properties; under standard conditions, they are all odorless, colorless, monatomic gases with very low ch ...
abundances in Jupiter's atmosphere exceed solar values by a factor of about three. The atmosphere of
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...
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 The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...
, stratosphere,
thermosphere The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the ...
and exosphere. Each layer has characteristic temperature gradients. The lowest layer, the troposphere, has a complicated system of clouds and hazes, comprising layers of ammonia,
ammonium hydrosulfide Ammonium hydrosulfide is the chemical compound with the formula . Composition It is the salt derived from the ammonium cation and the hydrosulfide anion. The salt exists as colourless, water-soluble, micaceous crystals. On Earth the compound ...
and water. The upper ammonia clouds visible at Jupiter's surface are organized in a dozen zonal bands parallel to the equator and are bounded by powerful zonal atmospheric flows (winds) known as ''jets''. 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 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
anticyclone An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from ...
s), storms and lightning. The vortices reveal themselves as large red, white or brown spots (ovals). The largest two spots are the Great Red Spot (GRS) and Oval BA, which is also red. These two and most of the other large spots are anticyclonic. Smaller
anticyclone An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from ...
s 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, 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 the water clouds. Recent
Juno Juno commonly refers to: *Juno (mythology), the Roman goddess of marriage and queen of the gods *Juno (film), ''Juno'' (film), 2007 Juno may also refer to: Arts, entertainment and media Fictional characters *Juno, in the film ''Jenny, Juno'' *Ju ...
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 the higher-altitude lightning. Upper-atmospheric lightning has also been observed 260 km above the 1 bar level.


Vertical structure

The atmosphere of Jupiter is classified into four layers, by increasing altitude: the
troposphere The troposphere is the first and lowest layer of the atmosphere of the Earth, and contains 75% of the total mass of the planetary atmosphere, 99% of the total mass of water vapour and aerosols, and is where most weather phenomena occur. From ...
, stratosphere,
thermosphere The thermosphere is the layer in the Earth's atmosphere directly above the mesosphere and below the exosphere. Within this layer of the atmosphere, ultraviolet radiation causes photoionization/photodissociation of molecules, creating ions; the ...
and exosphere. Unlike the
Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
, 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 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. Guillot (1999) Since the lower boundary of the atmosphere is ill-defined, the pressure level of 10 
bar Bar or BAR may refer to: Food and drink * Bar (establishment), selling alcoholic beverages * Candy bar * Chocolate bar Science and technology * Bar (river morphology), a deposit of sediment * Bar (tropical cyclone), a layer of cloud * Bar (u ...
s, at an altitude of about 90 km below 1 bar with a temperature of around 340  K, is commonly treated as the base of 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. Yelle (2004), p. 1 The density gradually decreases until it smoothly transitions into the
interplanetary medium The interplanetary medium (IPM) or interplanetary space consists of the mass and energy which fills the Solar System The Solar System Capitalization of the name varies. The International Astronomical Union, the authoritative body regarding ...
approximately 5,000 km above the "surface". The vertical temperature gradients in the Jovian atmosphere are similar to those of the
atmosphere of Earth The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
. The temperature of the troposphere decreases with height until it reaches a minimum at the
tropopause The tropopause is the atmospheric boundary that demarcates the troposphere from the stratosphere; which are two of the five layers of the atmosphere of Earth. The tropopause is a thermodynamic gradient-stratification layer, that marks the end of ...
, 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 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 In physics, gravity () is a fundamental interaction which causes mutual attraction between all things with mass or energy. Gravity is, by far, the weakest of the four fundamental interactions, approximately 1038 times weaker than the strong ...
. 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 the transition into the thermosphere, at an altitude and pressure of around 320 km and 1 μbar. Sieff ''et al.'' (1998) 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 Ammonium hydrosulfide is the chemical compound with the formula . Composition It is the salt derived from the ammonium cation and the hydrosulfide anion. The salt exists as colourless, water-soluble, micaceous crystals. On Earth the compound ...
((NH4)SH) or
ammonium sulfide Ammonium hydrosulfide is the chemical compound with the formula . Composition It is the salt derived from the ammonium cation and the hydrosulfide anion An ion () is an atom or molecule with a net electrical charge. The charge of an e ...
((NH4)2S, between 1–2 bar) and water (3–7 bar) are thought to exist. West ''et al.'' (2004), pp. 9–10, 20–23 There are no methane clouds as 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). Ingersoll (2004), pp. 13–14 Various tropospheric (at 200–500 mbar) and stratospheric (at 10–100 mbar) haze layers reside above the main cloud layers. Ingersoll (2004), p. 8 The stratospheric haze layers are made from condensed heavy
polycyclic aromatic hydrocarbon A polycyclic aromatic hydrocarbon (PAH) is a class of organic compounds that is composed of multiple aromatic rings. The simplest representative is naphthalene, having two aromatic rings and the three-ring compounds anthracene and phenanthrene. ...
s 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 10−4, while the abundance ratio of other light hydrocarbons, like ethane and acetylene, to molecular hydrogen is about 10−6. Jupiter's thermosphere is located at pressures lower than 1 μbar and demonstrates such phenomena as
airglow Airglow (also called nightglow) is a faint emission of light by a planetary atmosphere. In the case of Earth's atmosphere, this optical phenomenon causes the night sky never to be completely dark, even after the effects of starlight and diffu ...
, polar aurorae and
X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10  picometers to 10  nanometers, corresponding to frequencies in the range 30&nb ...
emissions. Yelle (2004), pp. 1–12 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; Yelle (2004), pp. 15–16 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 the charged particles precipitating from the Jovian magnetosphere, or by dissipation of upward-propagating gravity waves. Yelle (2004), pp. 22–27 The thermosphere and exosphere at the poles and at low latitudes emit X-rays, which were first observed by the
Einstein Observatory Einstein Observatory (HEAO-2) was the first fully imaging X-ray telescope put into space and the second of NASA's three High Energy Astrophysical Observatories. Named HEAO B before launch, the observatory's name was changed to honor Albert E ...
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 storm A geomagnetic storm, also known as a magnetic storm, is a temporary disturbance of the Earth's magnetosphere caused by a solar wind shock wave and/or cloud of magnetic field that interacts with the Earth's magnetic field. The disturbance that d ...
s, aurorae are permanent features of Jupiter's atmosphere. The thermosphere was the first place outside the Earth where the
trihydrogen cation The trihydrogen cation or protonated molecular hydrogen is a cation (positive ion) with formula , consisting of three hydrogen nuclei (protons) sharing two electrons. The trihydrogen cation is one of the most abundant ions in the universe. It is ...
() 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.


Chemical composition

The composition of Jupiter's atmosphere is similar to that of the planet as a whole. Jupiter's atmosphere is the most comprehensively understood of those of all the
gas giant A gas giant is a giant planet composed mainly of hydrogen and helium. Gas giants are also called failed stars because they contain the same basic elements as a star. Jupiter and Saturn are the gas giants of the Solar System. The term "gas giant" ...
s 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 The Infrared Space Observatory (ISO) was a space telescope for infrared light designed and operated by the European Space Agency (ESA), in cooperation with ISAS (now part of JAXA) and NASA. The ISO was designed to study infrared light at wavelengt ...
(ISO), the '' Galileo'' and '' Cassini'' orbiters, Kunde ''et al.'' (2004) and Earth-based observations. The two main constituents of the Jovian atmosphere are
molecular hydrogen Hydrogen is the chemical element with the symbol H and atomic number 1. Hydrogen is the lightest element. At standard conditions hydrogen is a gas of diatomic molecules having the formula . It is colorless, odorless, tasteless, non-toxic, ...
() and
helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...
. The helium abundance is relative to molecular hydrogen by number of molecules, and its mass fraction is , 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 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 the core as well. The atmosphere contains various simple compounds such as
water Water (chemical formula ) is an Inorganic compound, inorganic, transparent, tasteless, odorless, and Color of water, nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living ...
,
methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The relative abundance of methane on Ea ...
(CH4), hydrogen sulfide (H2S),
ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
(NH3) and
phosphine Phosphine (IUPAC name: phosphane) is a colorless, flammable, highly toxic compound with the chemical formula , classed as a pnictogen hydride. Pure phosphine is odorless, but technical grade samples have a highly unpleasant odor like rotting ...
(PH3). Their abundances in the deep (below 10 bar) troposphere imply that the atmosphere of Jupiter is enriched in the elements
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
,
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
, sulfur and possibly
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
by a factor of 2–4 relative to the Sun. The noble gases
argon Argon is a chemical element with the symbol Ar and atomic number 18. It is in group 18 of the periodic table and is a noble gas. Argon is the third-most abundant gas in Earth's atmosphere, at 0.934% (9340 ppmv). It is more than twice as ...
,
krypton Krypton (from grc, κρυπτός, translit=kryptos 'the hidden one') is a chemical element with the symbol Kr and atomic number 36. It is a colorless, odorless, tasteless noble gas that occurs in trace amounts in the atmosphere and is often ...
and
xenon Xenon is a chemical element with the symbol Xe and atomic number 54. It is a dense, colorless, odorless noble gas found in Earth's atmosphere in trace amounts. Although generally unreactive, it can undergo a few chemical reactions such as the ...
also appear in abundance relative to solar levels (see table), while neon is scarcer. Other chemical compounds such as
arsine Arsine (IUPAC name: arsane) is an inorganic compound with the formula As H3. This flammable, pyrophoric, and highly toxic pnictogen hydride gas is one of the simplest compounds of arsenic. Despite its lethality, it finds some applications in ...
(AsH3) and germane (GeH4) are present only in trace amounts. The upper atmosphere of Jupiter contains small amounts of simple
hydrocarbon In organic chemistry, a hydrocarbon is an organic compound consisting entirely of hydrogen and carbon. Hydrocarbons are examples of group 14 hydrides. Hydrocarbons are generally colourless and hydrophobic, and their odors are usually weak or ...
s such as
ethane Ethane ( , ) is an organic chemical compound with chemical formula . At standard temperature and pressure, ethane is a colorless, odorless gas. Like many hydrocarbons, ethane is isolated on an industrial scale from natural gas and as a petroc ...
, acetylene, and diacetylene, which form from methane under the influence of the solar
ultraviolet radiation Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
and charged particles coming from
Jupiter's magnetosphere The magnetosphere of Jupiter is the cavity created in the solar wind by the planet's magnetic field. Extending up to seven million kilometers in the Sun's direction and almost to the orbit of Saturn in the opposite direction, Jupiter's magnet ...
. The
carbon dioxide Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is trans ...
,
carbon monoxide Carbon monoxide (chemical formula CO) is a colorless, poisonous, odorless, tasteless, flammable gas that is slightly less dense than air. Carbon monoxide consists of one carbon atom and one oxygen atom connected by a triple bond. It is the simple ...
and water present in the upper atmosphere are thought to originate from impacting
comet A comet is an icy, small Solar System body that, when passing close to the Sun, warms and begins to release gases, a process that is called outgassing. This produces a visible atmosphere or coma, and sometimes also a tail. These phenomena ...
s, such as Shoemaker-Levy 9. The water cannot come from the troposphere because the cold
tropopause The tropopause is the atmospheric boundary that demarcates the troposphere from the stratosphere; which are two of the five layers of the atmosphere of Earth. The tropopause is a thermodynamic gradient-stratification layer, that marks the end of ...
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, the accepted value for the
deuterium Deuterium (or hydrogen-2, symbol or deuterium, also known as heavy hydrogen) is one of two stable isotopes of hydrogen (the other being protium, or hydrogen-1). The nucleus of a deuterium atom, called a deuteron, contains one proton and one ...
abundance is , 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, 15N to 14N, is 2.3, a third lower than that in the
Earth's atmosphere The atmosphere of Earth is the layer of gases, known collectively as air, retained by Earth's gravity that surrounds the planet and forms its planetary atmosphere. The atmosphere of Earth protects life on Earth by creating pressure allowing fo ...
(3.5). The latter discovery is especially significant since the previous theories of Solar System formation considered the terrestrial value for the ratio of nitrogen isotopes to be primordial.


Zones, belts and jets

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.'' Ingersoll (2004), pp. 2–5 The wider Equatorial Zone (EZ) extends between
latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
s of approximately 7°S to 7°N. Above and below 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. Rogers (1995), p. 81. The difference in the appearance between zones and belts 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. Ingersoll (2004), pp. 5–7 The upper troposphere is colder in zones and warmer in belts. The exact nature of chemicals that make Jovian zones and bands so colorful is not known, but they may include complicated compounds of sulfur,
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
and
carbon Carbon () is a chemical element with the symbol C and atomic number 6. It is nonmetallic and tetravalent—its atom making four electrons available to form covalent chemical bonds. It belongs to group 14 of the periodic table. Carbon mak ...
. 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 the jets' eastward momentum decreases in belts and increases in zones from the equator to the pole. Therefore,
wind shear Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizont ...
in belts is
cyclonic In meteorology, a cyclone () is a large air mass that rotates around a strong center of low atmospheric pressure, counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere as viewed from above (opposite to an anti ...
, while in zones it is
anticyclonic An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from abov ...
. Vasavada (2005), p. 1937 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 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 ''Juno'' is a NASA space probe orbiting the planet Jupiter. It was built by Lockheed Martin and is operated by NASA Jet Propulsion Laboratory. The spacecraft was launched from Cape Canaveral Air Force Station on August 5, 2011 UTC, as part ...
. 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 the Taylor-Proudman theorem. The
Galileo Probe ''Galileo'' was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was ...
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 height In atmospheric, earth, and planetary sciences, a scale height, usually denoted by the capital letter ''H'', is a distance ( vertical or radial) over which a physical quantity decreases by a factor of e (the base of natural logarithms, approxima ...
s 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. Ingersoll (2004), p. 12 The origin of Jupiter's colored banded structure is not completely clear, though it may resemble the cloud structure of Earth's
Hadley cell The Hadley cell, named after George Hadley, is a global-scale tropical atmospheric circulation that features air rising near the equator, flowing poleward at a height of 10 to 15 kilometers above the earth's surface, descending in the subtropics ...
s. The simplest interpretation is that zones are sites of atmospheric
upwelling Upwelling is an oceanographic phenomenon that involves wind-driven motion of dense, cooler, and usually nutrient-rich water from deep water towards the ocean surface. It replaces the warmer and usually nutrient-depleted surface water. The nut ...
, whereas belts are manifestations of
downwelling Downwelling is the process of accumulation and sinking of higher density material beneath lower density material, such as cold or saline water beneath warmer or fresher water or cold air beneath warm air. It is the ''sinking'' limb of a convecti ...
. 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 A convergence zone in meteorology is a region in the atmosphere where two prevailing flows meet and interact, usually resulting in distinctive weather conditions. This causes a mass accumulation that eventually leads to a vertical movement a ...
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 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. Ingersoll (2004), p. 5 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

Meridional circulation cells are a large-scale atmospheric motion where gas rises at a certain latitude, travel in 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 Polar may refer to: Geography Polar may refer to: * Geographical pole, either of two fixed points on the surface of a rotating body or planet, at 90 degrees from the equator, based on the axis around which a body rotates * Polar climate, the c ...
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 the belts, indicative of upward atmospheric motion, gave indication for a revered 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 An atmospheric wave is a periodic disturbance in the fields of atmospheric variables (like surface pressure or geopotential height, temperature, or wind velocity) which may either propagate (''traveling wave'') or not ('' standing wave''). Atmo ...
, similar to 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 Ekman layer is the layer in a fluid where there is a force balance between pressure gradient force, Coriolis force and turbulent drag. It was first described by Vagn Walfrid Ekman. Ekman layers occur both in the atmosphere and in the ocean ...
, the balance in Jupiter in yet unknown, but one possibility is that the friction is maintained by magnetic drag.


Specific bands

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 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 Limb darkening is an optical effect seen in stars (including the Sun), where the central part of the disk appears brighter than the edge, or ''limb''. Its understanding offered early solar astronomers an opportunity to construct models with such ...
,
foreshortening Linear or point-projection perspective (from la, perspicere 'to see through') is one of two types of graphical projection perspective in the graphic arts; the other is parallel projection. Linear perspective is an approximate representation, ...
, 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) 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. Rogers (1995), pp. 101–105. 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 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 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 ''Pioneer 10'' (originally designated Pioneer F) is an American space probe, launched in 1972 and weighing , that completed the first mission to the planet Jupiter. Thereafter, ''Pioneer 10'' became the first of five artificial objects to ach ...
'' encounter. The NEB 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 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 Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
) features known as festoons (hot spots). Though the southern boundary of the EZ is usually quiescent, observations from the late 19th into 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 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 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; 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 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 the ''Equatorial band'' (EB), Rogers ''et al.'' (2003) ''North Equatorial belt zone'' (NEBZ, a white zone within the belt) and ''South Equatorial belt zone'' (SEBZ). Rogers and Metig (2001) 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).


Dynamics

Circulation in Jupiter's atmosphere is markedly different from that in the atmosphere of Earth. The interior of Jupiter is fluid and lacks any solid surface. Therefore,
convection Convection is single or multiphase fluid flow that occurs spontaneously due to the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the conve ...
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, 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. Vasavada (2005), p. 1942–1974 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 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. Vasavada (2005), pp. 1943–1945 As both theories have their own successes and failures, many planetary scientists think that the true theory will include elements of both models. Heimpel ''et al.'' (2005)


Shallow models

The first attempts to explain Jovian atmospheric dynamics date back to the 1960s.See, e. g., Ingersoll ''et al.'' (1969) They were partly based on terrestrial
meteorology Meteorology is a branch of the atmospheric sciences (which include atmospheric chemistry and physics) with a major focus on weather forecasting. The study of meteorology dates back millennia, though significant progress in meteorology did no ...
, which had become well developed by that time. Those shallow models assumed that the jets on Jupiter are driven by small scale
turbulence In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to a laminar flow, which occurs when a fluid flows in parallel layers, with no disruption between ...
, which is in turn maintained by moist convection in the outer layer of the atmosphere (above the water clouds). Ingersoll (2004), pp. 16–17 The moist convection is a phenomenon related to the condensation and evaporation of water and is one of the major drivers of terrestrial weather. Ingersoll (2004), pp. 14–15 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. Vasavada (2005), pp. 1947–1958 The finite size of the planet means that the cascade can not produce structures larger than some characteristic scale, which for Jupiter is called the Rhines scale. Its existence is connected to production of
Rossby wave Rossby waves, also known as planetary waves, are a type of inertial wave naturally occurring in rotating fluids. They were first identified by Sweden-born American meteorologist Carl-Gustaf Arvid Rossby. They are observed in the atmospheres an ...
s. 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. Vasavada (2005), p. 1949 Since on the spherical rapidly rotating planet the
dispersion relation In the physical sciences and electrical engineering, dispersion relations describe the effect of dispersion on the properties of waves in a medium. A dispersion relation relates the wavelength or wavenumber of a wave to its frequency. Given t ...
of the Rossby waves is anisotropic, the Rhines scale in 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 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. Vasavada (2005), pp. 1945–1947 More elaborated multilayer versions of weather–layer models produce more stable circulation, but many problems persist. Vasavada (2005), pp. 1962–1966 Meanwhile, the
Galileo Probe ''Galileo'' was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was ...
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.


Deep models

The deep model was first proposed by Busse in 1976. Vasavada (2005), p. 1966 Busse (1976) His model was based on another well-known feature of fluid mechanics, the
Taylor–Proudman theorem In fluid mechanics, the Taylor–Proudman theorem (after Geoffrey Ingram Taylor and Joseph Proudman) states that when a solid body is moved slowly within a fluid that is steadily rotated with a high angular velocity \Omega, the fluid velocity will ...
. It holds that in any fast-rotating barotropic ideal liquid, 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. Vasavada (2005), pp. 1966–1972 Those latitudes where the cylinders' outer and inner boundaries intersect with the visible surface of 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 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 the outer 20–30%. Vasavada (2005), p. 1970 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.


Internal heat

As has been known since 1966, Low (1966) Jupiter radiates much more heat than it receives from the Sun. It is estimated that the ratio of the thermal power emitted by the planet to the thermal power absorbed from the Sun is . The internal heat flux from Jupiter is , whereas the total emitted power is . 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 the precipitation of helium into the core. The
internal heat {{Unreferenced, date=February 2012 Internal heat is the heat source from the interior of celestial objects, such as stars, brown dwarfs, planets, moons, dwarf planets, and (in the early history of the Solar System) even asteroids such as Vesta, r ...
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 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. Ingersoll (2004), pp. 11, 17–18


Discrete features


Vortices

The atmosphere of Jupiter is home to hundreds of
vortices In fluid dynamics, a vortex ( : vortices or vortexes) is a region in a fluid in which the flow revolves around an axis line, which may be straight or curved. Vortices form in stirred fluids, and may be observed in smoke rings, whirlpools in th ...
—circular rotating structures that, as in the Earth's atmosphere, can be divided into two classes: cyclones and
anticyclone An anticyclone is a weather phenomenon defined as a large-scale circulation of winds around a central region of high atmospheric pressure, clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere as viewed from ...
s. Vasavada (2005), p. 1974 Cyclones rotate in the direction similar to the rotation of the planet (
counterclockwise Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite ...
in the northern hemisphere and
clockwise Two-dimensional rotation can occur in two possible directions. Clockwise motion (abbreviated CW) proceeds in the same direction as a clock's hands: from the top to the right, then down and then to the left, and back up to the top. The opposite ...
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. Vasavada (2005), p. 1978 The lifetime of Jovian vortices varies from several days to hundreds of years, depending on their size. For instance, the average lifetime of an anticyclone between 1000 and 6000 km in diameter is 1–3 years. Vasavada (2005), p. 1977 Vortices have never been observed in the equatorial region of Jupiter (within 10° of latitude), where they are unstable. Vasavada (2005), p. 1976 As on any rapidly rotating planet, Jupiter's anticyclones are high
pressure Pressure (symbol: ''p'' or ''P'') is the force applied perpendicular to the surface of an object per unit area over which that force is distributed. Gauge pressure (also spelled ''gage'' pressure)The preferred spelling varies by country and e ...
centers, while cyclones are low pressure. Vasavada (2005), pp. 1987–1989 The anticyclones in Jupiter's atmosphere are always confined within zones, where 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 Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lette ...
, 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 the Great Red Spot (GRS) Vasavada (2005), pp. 1978–1980 and the Oval BA; Vasavada (2005), pp. 1980–1982 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 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 Cyclonic rotation, or cyclonic circulation, is atmospheric motion in the same direction as a planet's rotation, as opposed to anticyclonic rotation. For Earth, the Coriolis effect causes cyclonic rotation to be in a counterclockwise direction in the ...
. One of them is located to the west of the GRS (in its wake region) in the southern equatorial belt. Vasavada (2005), p. 1979 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 a few tens of kilometers above the visible clouds. The early hypothesis that the vortices are deep convective plumes (or convective columns) as of 2008 is not shared by the majority of
planetary scientist Planetary science (or more rarely, planetology) is the scientific study of planets (including Earth), celestial bodies (such as moons, asteroids, comets) and planetary systems (in particular those of the Solar System) and the processes of their ...
s.


Great Red Spot

The Great Red Spot (GRS) is a persistent
anticyclonic storm An anticyclonic storm is a storm with a high-pressure center, in which winds flow in the direction opposite to that of the flow above a region of low pressure. These storms can create powerful mesoanticylonic supercell storms that can generate ...
, 22° south of Jupiter's equator; observations from Earth establish a minimum storm lifetime of 350 years. A storm was described as a "permanent spot" by Gian Domenico Cassini after observing the feature in July 1665 with his instrument-maker
Eustachio Divini Eustachio Divini (4 October 1610 – 22 February 1685) was an Italian manufacturer and experimenter of optical instruments for scientific use in Rome. The origins Eustachio was born on 4 October 1610 in San Severino Marche, from the illustrious ...
. According to a report by
Giovanni Battista Riccioli Giovanni Battista Riccioli, SJ (17 April 1598 – 25 June 1671) was an Italian astronomer and a Catholic priest in the Jesuit order. He is known, among other things, for his experiments with pendulums and with falling bodies, for his discussion ...
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 a telescope of exceptional quality and magnification". The Great Spot has been nearly continually observed since the 1870s, however. The GRS rotates counter-clockwise, with a period of about six Earth days or 14 
Jovian Jovian is the adjectival form of Jupiter and may refer to: * Jovian (emperor) (Flavius Iovianus Augustus), Roman emperor (363–364 AD) * Jovians and Herculians, Roman imperial guard corps * Jovian (lemur), a Coquerel's sifaka known for ''Zoboomafo ...
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 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.
Irwin Irwin may refer to: Places ;United States * Irwin, California * Irwin, Idaho * Irwin, Illinois * Irwin, Iowa * Irwin, Nebraska * Irwin, Ohio * Irwin, Pennsylvania * Irwin, South Carolina * Irwin County, Georgia * Irwin Township, Venango County ...
, 2003, p. 171
It is not known how long the spot will last, or whether the change is a result of normal fluctuations. According to a study by scientists at the
University of California, Berkeley The University of California, Berkeley (UC Berkeley, Berkeley, Cal, or California) is a public land-grant research university in Berkeley, California. Established in 1868 as the University of California, it is the state's first land-grant u ...
, 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 the surrounding atmosphere."
Infrared Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from around ...
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
cloud In meteorology, a cloud is an aerosol consisting of a visible mass of miniature liquid droplets, frozen crystals, or other particles suspended in the atmosphere of a planetary body or similar space. Water or various other chemicals may ...
tops 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 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 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 a weak subsidence of air in the center of GRS. Fletcher (2010), p. 306 The Great Red Spot's latitude has been stable for the duration of good observational records, typically varying by about a degree. Its
longitude Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lette ...
, 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 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 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 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, 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. Beebe (1997), pp. 38–41. 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 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 Great Dark Spot (also known as GDS-89, for Great Dark Spot, 1989) was one of a series of dark spots on Neptune similar in appearance to Jupiter's Great Red Spot. In 1989, GDS-89 was the first Great Dark Spot on Neptune to be observed by NASA's ...
. The latter feature, imaged by ''
Voyager 2 ''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, '' Voyager 1'', o ...
'' in 1989, may have been an atmospheric hole rather than a storm. It was no longer present in 1994, although a similar spot had appeared farther to the north.


Oval BA

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. Sanchez-Lavega ''et al.'' (2001) The formation of the three white oval storms that later merged into Oval BA can be traced to 1939, when the South Temperate Zone was torn by dark features that effectively split the zone into three long sections. Jovian observer Elmer J. Reese labeled the dark sections AB, CD, and EF. The rifts expanded, shrinking the remaining segments of the STZ into the white ovals FA, BC, and DE. Ovals BC and DE merged in 1998, forming Oval BE. Then, in March 2000, BE and FA joined, forming Oval BA. (see White ovals, below) Oval BA slowly began to turn red in August 2005. Go ''et al.'' (2006) On February 24, 2006,
Filipino Filipino may refer to: * Something from or related to the Philippines ** Filipino language, standardized variety of 'Tagalog', the national language and one of the official languages of the Philippines. ** Filipinos, people who are citizens of th ...
amateur astronomer Christopher Go discovered the color change, noting that it had reached the same shade as the GRS. As a result, NASA writer Dr. Tony Phillips suggested it be called "Red Spot Jr." or "Red Jr." In April 2006, a team of astronomers, believing that Oval BA might converge with the GRS that year, observed the storms through the
Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...
. The storms pass each other about every two years, but the passings of 2002 and 2004 did not produce anything exciting. Dr.
Amy Simon Amy Simon is an American planetary scientist at NASA's Goddard Space Flight Center, involved in several missions of the Solar System Exploration Program. Education Simon is from Union Township, Union County, New Jersey, where she attended ...
-Miller, of the Goddard Space Flight Center, predicted the storms would have their closest passing on July 4, 2006. On July 20, the two storms were photographed passing each other by the
Gemini Observatory The Gemini Observatory is an astronomical observatory consisting of two 8.1-metre (26.6 ft) telescopes, Gemini North and Gemini South, which are located at two separate sites in Hawaii and Chile, respectively. The twin Gemini telescopes prov ...
without converging. Why Oval BA turned red is not understood. According to a 2008 study by Dr. Santiago Pérez-Hoyos of the University of the Basque Country, the most likely mechanism is "an upward and inward diffusion of either a colored compound or a coating vapor that may interact later with high energy solar photons at the upper levels of Oval BA." Some believe that small storms (and their corresponding white spots) on Jupiter turn red when the winds become powerful enough to draw certain gases from deeper within the atmosphere which change color when those gases are exposed to sunlight. Oval BA is getting stronger according to observations made with the Hubble Space Telescope in 2007. The wind speeds have reached 618 km/h; about the same as in the Great Red Spot and far stronger than any of the progenitor storms. As of July 2008, its size is about the diameter of
Earth Earth is the third planet from the Sun and the only astronomical object known to harbor life. While large volumes of water can be found throughout the Solar System, only Earth sustains liquid surface water. About 71% of Earth's surfa ...
—approximately half the size of the Great Red Spot. Oval BA should not be confused with another major storm on Jupiter, the South Tropical Little Red Spot (LRS) (nicknamed "the Baby Red Spot" by NASA), which was destroyed by the GRS. The new storm, previously a white spot in Hubble images, turned red in May 2008. The observations were led by Imke de Pater of the University of California, at Berkeley, US. The Baby Red Spot encountered the GRS in late June to early July 2008, and in the course of a collision, the smaller red spot was shredded into pieces. The remnants of the Baby Red Spot first orbited, then were later consumed by the GRS. The last of the remnants with a reddish color to have been identified by astronomers had disappeared by mid-July, and the remaining pieces again collided with the GRS, then finally merged with the bigger storm. The remaining pieces of the Baby Red Spot had completely disappeared by August 2008. During this encounter Oval BA was present nearby, but played no apparent role in the destruction of the Baby Red Spot.


Storms and lightning

The storms on Jupiter are similar to
thunderstorm A thunderstorm, also known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Relatively weak thunderstorms are some ...
s on Earth. They reveal themselves via bright clumpy clouds about 1000 km in size, which appear from time to time in the belts' cyclonic regions, especially within the strong westward (retrograde) jets. Vasavada (2005), pp. 1982, 1985–1987 In contrast to vortices, storms are short-lived phenomena; the strongest of them may exist for several months, while the average lifetime is only 3–4 days. They are believed to be due mainly to moist convection within Jupiter's troposphere. Storms are actually tall convective columns ( plumes), which bring the wet air from the depths to the upper part of the troposphere, where it condenses in clouds. A typical vertical extent of Jovian storms is about 100 km; as they extend from a pressure level of about 5–7 bar, where the base of a hypothetical water cloud layer is located, to as high as 0.2–0.5 bar. Sanchez-Lavega ''et al.'' (2008), pp. 437–438 Storms on Jupiter are always associated with
lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an avera ...
. The imaging of the night–side hemisphere of Jupiter by '' Galileo'' and '' Cassini'' spacecraft revealed regular light flashes in Jovian belts and near the locations of the westward jets, particularly at 51°N, 56°S and 14°S latitudes. Vasavada (2005), pp. 1983–1985 On Jupiter lightning strikes are on average a few times more powerful than those on Earth. However, they are less frequent; the light
power Power most often refers to: * Power (physics), meaning "rate of doing work" ** Engine power, the power put out by an engine ** Electric power * Power (social and political), the ability to influence people or events ** Abusive power Power may a ...
emitted from a given area is similar to that on Earth. A few flashes have been detected in polar regions, making Jupiter the second known planet after Earth to exhibit polar lightning. A Microwave Radiometer (''Juno'') detected many more in 2018. Every 15–17 years Jupiter is marked by especially powerful storms. They appear at 23°N latitude, where the strongest eastward jet, that can reach 150 m/s, is located. The last time such an event was observed was in March–June 2007. Two storms appeared in the northern temperate belt 55° apart in longitude. They significantly disturbed the belt. The dark material that was shed by the storms mixed with clouds and changed the belt's color. The storms moved with a speed as high as 170 m/s, slightly faster than the jet itself, hinting at the existence of strong winds deep in the atmosphere.


Circumpolar cyclones

Other notable features of Jupiter are its cyclones near the northern and southern poles of the planet. These are called circumpolar cyclones (CPCs) and they have been observed by the Juno Spacecraft using JunoCam and JIRAM. The cyclones have now been observed for about 5 years, as Juno completed 39 orbits around Jupiter. The northern pole has eight cyclones moving around a central cyclone (NPC) while the southern pole only has five cyclones around a central cyclone (SPC), with a gap between the first and second cyclones. The cyclones look like the hurricanes on Earth with trailing spiral arms and a denser center, although there are differences between the centers depending on the individual cyclone. Northern CPCs generally maintain their shape and position compared to the southern CPCs and this could be due to the faster wind speeds that are experienced in the south, where the maximum wind velocities are around 80 m/s to 90 m/s. Although there is more movement among the southern CPCs they tend to retain the pentagonal structure relative to the pole. It has also been observed that the angular wind velocity increases as the center is approached and radius becomes smaller, except for one cyclone in the north, which may have rotation in the opposite direction. The difference in the number of cyclones in the north compared to the south is probably due to the size of the cyclones. The southern CPCs tend to be bigger with radii ranging from 5,600 km to 7,000 km while northern CPCs range from 4,000 km to 4,600 km. The mechanism for the stability of these two symmetric structures of cyclones is an outcome of Beta-drift, a known effect causing cyclones to move poleward and anti-cyclones to move equatorward due to the conservation of momentum along streamlines in a vortex, under the change of the
Coriolis parameter The Coriolis frequency ''ƒ'', also called the Coriolis parameter or Coriolis coefficient, is equal to twice the rotation rate ''Ω'' of the Earth multiplied by the sine of the latitude \varphi. :f = 2 \Omega \sin \varphi.\, The rotation rate ...
. Thus, cyclones forming in the polar regions may congregate at the pole and form a polar cyclone such as those observed on Saturn's poles. The polar cyclone (the central cyclone in the polygons) also emit a
vorticity In continuum mechanics, vorticity is a pseudovector field that describes the local spinning motion of a continuum near some point (the tendency of something to rotate), as would be seen by an observer located at that point and traveling along wi ...
field which can repel other cyclones (see
Fujiwhara effect The Fujiwhara effect, sometimes referred to as the Fujiwara effect, Fujiw(h)ara interaction or binary interaction, is a phenomenon that occurs when two nearby cyclonic vortices move around each other and close the distance between the circulations ...
) similar to the beta-effect. The
latitude In geography, latitude is a coordinate that specifies the north– south position of a point on the surface of the Earth or another celestial body. Latitude is given as an angle that ranges from –90° at the south pole to 90° at the north pol ...
where the circumpolar cyclones are positioned (~84°) fits, in calculations, the hypothesis that the poleward beta-drift force balances the equatorward rejection of the polar cyclone on the circumpolar cyclones, assuming they have an anticyclonic ring around them, consistent with model simulations and observations. The northern cyclones tend to maintain an octagonal structure with the NPC as a center point. Northern cyclones have less data than southern cyclones because of limited illumination in the north-polar winter, making it difficult for JunoCam to obtain accurate measurements of northern CPC positions at each perijove (53 days), but JIRAM is able to collect enough data to understand the northern CPCs. The limited illumination makes it difficult to see the northern central cyclone, but by making four orbits, the NPC can be partially seen and the octagonal structure of the cyclones can be identified. Limited illumination also makes it difficult to view the motion of the cyclones, but early observations show that the NPC is offset from the pole by about 0.5˚ and the CPCs generally maintained their position around the center. Despite data being harder to obtain, it has been observed that the northern CPCs have a drift rate of about 1˚ to 2.5˚ per perijove to the west. The seventh cyclone in the north (n7) drifts a little more than the others and this is due to an anticyclonic white oval (AWO) that pulls it farther from the NPC, which causes the octagonal shape to be slightly distorted. The instantanoues locations of the south polar cyclones have been tracked for 5 years by the
JIRAM Jovian Infrared Auroral Mapper (JIRAM) is an instrument on the ''Juno'' spacecraft in orbit of the planet Jupiter. It is an image spectrometer and was contributed by Italy. Similar instruments are on ESA ''Rosetta'', ''Venus Express'', and '' C ...
instrument and by
JunoCam JunoCam (or JCM) is the visible-light camera/telescope onboard NASA's ''Juno'' spacecraft currently orbiting Jupiter. The camera is operated by the JunoCam Digital Electronics Assembly (JDEA). Both the camera and JDEA were built by Malin Space ...
. The locations over time were revealed to form an oscillatory motion of each of the 6 cyclones, with periods of approximately one (Earth) year and radii of about 400 km. These oscillations around the CPCs' mean positions were explained to be a result of imbalances between the beta-drift, pulling the CPCs toward the pole and the rejection forces that develop due to the interactions between the cyclones, similar to a 6-body spring system. In addition to this periodic motion, the south polar cyclones were observed to drift westward by 7.5±0.7˚ per year. The reason for this drift is still unknown. The circumpolar cyclones have different morphologies, especially in the north, where cyclones have a "filled" or "chaotic" structure. The inner part of the "chaotic" cyclones have small-scale cloud streaks and flecks. The "filled" cyclones have a sharply-bound, lobate area that is bright white near the edge with a dark inner portion. There are four "filled" cyclones and four "chaotic" cyclones in the north. The southern cyclones all have an extensive fine-scale spiral structure on their outside but they all differ in size and shape. There is very little observation of the cyclones due to low sun angles and a haze that is typically over the atmosphere but what little has been observed shows the cyclones to be a reddish color.


Disturbances

The normal pattern of bands and zones is sometimes disrupted for periods of time. One particular class of disruption are long-lived darkenings of the South Tropical Zone, normally referred to as "South Tropical Disturbances" (STD). The longest lived STD in recorded history was followed from 1901 until 1939, having been first seen by
Percy B. Molesworth Percy Braybrooke Molesworth (2 April 1867 in Colombo – 25 December 1908) was a Major in the corps of Royal Engineers and an amateur astronomer. Life and work Molesworth was the youngest son of Sir Guildford Molesworth, and was educated at ...
on February 28, 1901. It took the form of darkening over part of the normally bright South Tropical zone. Several similar disturbances in the South Tropical Zone have been recorded since then.


Hot spots

Some of the most mysterious features in the atmosphere of Jupiter are hot spots. In them, the air is relatively free of clouds and heat can escape from the depths without much absorption. The spots look like bright spots in the infrared images obtained at the wavelength of about 5 μm. They are preferentially located in the belts, although there is a train of prominent hot spots at the northern edge of the Equatorial Zone. The ''Galileo'' Probe descended into one of those equatorial spots. Each equatorial spot is associated with a bright cloudy plume located to the west of it and reaching up to 10,000 km in size. Hot spots generally have round shapes, although they do not resemble vortices. The origin of hot spots is not clear. They can be either
downdraft In meteorology, an updraft is a small-scale current of rising air, often within a cloud. Overview Localized regions of warm or cool air will exhibit vertical movement. A mass of warm air will typically be less dense than the surrounding region, ...
s, where the descending air is adiabatically heated and dried or, alternatively, they can be a manifestation of planetary scale waves. The latter hypotheses explains the periodical pattern of the equatorial spots.


The possibility of life

In 1953, Miller Urey experiment proved that the combination of lightning and compounds existing in the primitive Earth's atmosphere can form organic matter (including amino acids), which can be used as the cornerstone of life. The simulated atmosphere consists of water, methane, ammonia and hydrogen molecules; All of these substances are found in today's Jupiter atmosphere. Jupiter's atmosphere has a strong vertical air flow that carries these compounds into lower regions. But there are higher temperatures inside Jupiter, which will decompose these chemicals and hinder the formation of life similar to earth. This was speculated by Carl Sagan and
Edwin E. Salpeter Edwin Ernest Salpeter (3 December 1924 – 26 November 2008,) was an Austrian–Australian–American astrophysicist. Life Born in Vienna to a Jewish family, Salpeter emigrated from Austria to Australia while in his teens to escape the Nazis. He ...
.


Observational history

Early modern astronomers, using small telescopes, recorded the changing appearance of Jupiter's atmosphere. Their descriptive terms—belts and zones, brown spots and red spots, plumes, barges, festoons, and streamers—are still used. Ingersoll (2004), p. 2 Other terms such as vorticity, vertical motion, cloud heights have entered in use later, in the 20th century. The first observations of the Jovian atmosphere at higher resolution than possible with Earth-based telescopes were taken by the ''
Pioneer Pioneer commonly refers to a settler who migrates to previously uninhabited or sparsely inhabited land. In the United States pioneer commonly refers to an American pioneer, a person in American history who migrated west to join in settling and de ...
'' '' 10'' and '' 11'' spacecraft. The first truly detailed images of Jupiter's atmosphere were provided by the '' Voyagers''. The two spacecraft were able to image details at a resolution as low as 5 km in size in various spectra, and also able to create "approach movies" of the atmosphere in motion. The
Galileo Probe ''Galileo'' was an American robotic space probe that studied the planet Jupiter and its moons, as well as the asteroids Gaspra and Ida. Named after the Italian astronomer Galileo Galilei, it consisted of an orbiter and an entry probe. It was ...
, which suffered an antenna problem, saw less of Jupiter's atmosphere but at a better average resolution and a wider spectral bandwidth. Today, astronomers have access to a continuous record of Jupiter's atmospheric activity thanks to telescopes such as Hubble Space Telescope. These show that the atmosphere is occasionally wracked by massive disturbances, but that, overall, it is remarkably stable. The vertical motion of Jupiter's atmosphere was largely determined by the identification of trace gases by ground-based telescopes.
Spectroscopic Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter wa ...
studies after the collision of
Comet Shoemaker–Levy 9 Comet Shoemaker–Levy 9 ( formally designated D/1993 F2) broke apart in July 1992 and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects. This generated a ...
gave a glimpse of the Jupiter's composition beneath the cloud tops. The presence of
diatomic sulfur Disulfur is the diatomic molecule with the formula S2. It is analogous to the dioxygen molecule but rarely occurs at room temperature. This violet gas is the dominant species in hot sulfur vapors. S2 is one of the minor components of the atmos ...
(S2) and
carbon disulfide Carbon disulfide (also spelled as carbon disulphide) is a neurotoxic, colorless, volatile liquid with the formula and structure . The compound is used frequently as a building block in organic chemistry as well as an industrial and chemical n ...
(CS2) was recorded—the first detection of either in Jupiter, and only the second detection of S2 in any astronomical object— together with other molecules such as
ammonia Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous wa ...
(NH3) and hydrogen sulfide (H2S), while
oxygen Oxygen is the chemical element with the symbol O and atomic number 8. It is a member of the chalcogen group in the periodic table, a highly reactive nonmetal, and an oxidizing agent that readily forms oxides with most elements as ...
-bearing molecules such as sulfur dioxide were not detected, to the surprise of astronomers. Noll (1995), p. 1307 The ''Galileo'' atmospheric probe, as it plunged into Jupiter, measured the wind, temperature, composition, clouds, and radiation levels down to 22 bar. However, below 1 bar elsewhere on Jupiter there is uncertainty in the quantities.


Great Red Spot studies

The first sighting of the GRS is often credited to Robert Hooke, who described a spot on the planet in May 1664; however, it is likely that Hooke's spot was in the wrong belt altogether (the North Equatorial Belt, versus the current location in the South Equatorial Belt). Much more convincing is
Giovanni Cassini Giovanni Domenico Cassini, also known as Jean-Dominique Cassini (8 June 1625 – 14 September 1712) was an Italian (naturalised French) mathematician, astronomer and engineer. Cassini was born in Perinaldo, near Imperia, at that time in the ...
's description of a "permanent spot" in the following year. With fluctuations in visibility, Cassini's spot was observed from 1665 to 1713. Rogers (2008), pp.111–112 A minor mystery concerns a Jovian spot depicted around 1700 on a canvas by
Donato Creti Donato Creti (24 February 1671 – 31 January 1749) was an Italian painter of the Rococo period, active mostly in Bologna. Born in Cremona, he moved to Bologna, where he was a pupil of Lorenzo Pasinelli. He is described by Wittkower as the "Bol ...
, which is exhibited in the
Vatican Vatican may refer to: Vatican City, the city-state ruled by the pope in Rome, including St. Peter's Basilica, Sistine Chapel, Vatican Museum The Holy See * The Holy See, the governing body of the Catholic Church and sovereign entity recognized ...
. Rogers (1995), p. 188 Hockey, 1999, pp. 40–41. It is a part of a series of panels in which different (magnified) heavenly bodies serve as backdrops for various Italian scenes, the creation of all of them overseen by the astronomer
Eustachio Manfredi Eustachio Manfredi (20 September 1674 – 15 February 1739) was an Italian mathematician, astronomer and poet. Biography Eustachio Manfredi was born in Bologna on 20 September 1674. He attended Jesuit school, then studied at the University of ...
for accuracy. Creti's painting is the first known to depict the GRS as red. No Jovian feature was officially described as red before the late 19th century. The present GRS was first seen only after 1830 and well-studied only after a prominent apparition in 1879. A 118-year gap separates the observations made after 1830 from its 17th-century discovery; whether the original spot dissipated and re-formed, whether it faded, or even if the observational record was simply poor are unknown. The older spots had a short observational history and slower motion than that of the modern spot, which make their identity unlikely. On February 25, 1979, when the ''
Voyager 1 ''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...
'' spacecraft was 9.2 million kilometers from Jupiter it transmitted the first detailed image of the Great Red Spot back to Earth. Cloud details as small as 160 km across were visible. The colorful, wavy cloud pattern seen to the west (left) of the GRS is the spot's wake region, where extraordinarily complex and variable cloud motions are observed.


White ovals

The white ovals that were to become Oval BA formed in 1939. They covered almost 90 degrees of
longitude Longitude (, ) is a geographic coordinate that specifies the east– west position of a point on the surface of the Earth, or another celestial body. It is an angular measurement, usually expressed in degrees and denoted by the Greek lette ...
shortly after their formation, but contracted rapidly during their first decade; their length stabilized at 10 degrees or less after 1965. Rogers (1995), pp. 224–5. Although they originated as segments of the STZ, they evolved to become completely embedded in the South Temperate Belt, suggesting that they moved north, "digging" a niche into the STB. Indeed, much like the GRS, their circulations were confined by two opposing jet streams on their northern and southern boundaries, with an eastward jet to their north and a retrograde westward one to the south. The longitudinal movement of the ovals seemed to be influenced by two factors: Jupiter's position in its
orbit In celestial mechanics, an orbit is the curved trajectory of an object such as the trajectory of a planet around a star, or of a natural satellite around a planet, or of an artificial satellite around an object or position in space such as ...
(they became faster at
aphelion An apsis (; ) is the farthest or nearest point in the orbit of a planetary body about its primary body. For example, the apsides of the Earth are called the aphelion and perihelion. General description There are two apsides in any ell ...
), and their proximity to the GRS (they accelerated when within 50 degrees of the Spot). The overall trend of the white oval drift rate was deceleration, with a decrease by half between 1940 and 1990. During the ''Voyager'' fly-bys, the ovals extended roughly 9000 km from east to west, 5000 km from north to south, and rotated every five days (compared to six for the GRS at the time).


See also

*
Comet Shoemaker–Levy 9 Comet Shoemaker–Levy 9 ( formally designated D/1993 F2) broke apart in July 1992 and collided with Jupiter in July 1994, providing the first direct observation of an extraterrestrial collision of Solar System objects. This generated a ...
*
Extrasolar planet An exoplanet or extrasolar planet is a planet outside the Solar System. The first possible evidence of an exoplanet was noted in 1917 but was not recognized as such. The first confirmation of detection occurred in 1992. A different planet, init ...
(many larger than Jupiter) * Galileo Spacecraft (a mission that included both an orbiter and an atmospheric-entry probe) *
Juno Juno commonly refers to: *Juno (mythology), the Roman goddess of marriage and queen of the gods *Juno (film), ''Juno'' (film), 2007 Juno may also refer to: Arts, entertainment and media Fictional characters *Juno, in the film ''Jenny, Juno'' *Ju ...
probe *
2009 Jupiter impact event The 2009 Jupiter impact event, occasionally referred to as the Wesley impact, was a July 2009 impact event on Jupiter that caused a black spot in the planet's atmosphere. The impact area covered 190 million square kilometers, similar in area ...
*
2010 Jupiter impact event The 2010 Jupiter impact event was a bolide impact event on Jupiter by an object estimated to be about in diameter. The impactor may have been an asteroid, comet, centaur, extinct comet, or temporary satellite capture. Observation The impac ...
*
Ulysses (spacecraft) ''Ulysses'' ( , ) was a robotic space probe whose primary mission was to orbit the Sun and study it at all latitudes. It was launched in 1990 and made three "fast latitude scans" of the Sun in 1994/1995, 2000/2001, and 2007/2008. In additi ...
*
Voyager 1 ''Voyager 1'' is a space probe launched by NASA on September 5, 1977, as part of the Voyager program to study the outer Solar System and interstellar space beyond the Sun's heliosphere. Launched 16 days after its twin ''Voyager 2'', ''Voya ...
,
Voyager 2 ''Voyager 2'' is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun's heliosphere. As a part of the Voyager program, it was launched 16 days before its twin, '' Voyager 1'', o ...


Notes

  1. The scale height ''sh'' is defined as , where is the
    gas constant The molar gas constant (also known as the gas constant, universal gas constant, or ideal gas constant) is denoted by the symbol or . It is the molar equivalent to the Boltzmann constant, expressed in units of energy per temperature increment per ...
    , is the average molar mass in the Jovian atmosphere, ''T'' is temperature and is the gravitational acceleration at the surface of Jupiter. As the temperature varies from 110 K in the tropopause up to 1000 K in the thermosphere, the scale height can assume values from 15 to 150 km.
  2. The ''Galileo'' atmospheric probe failed to measure the deep abundance of oxygen, because the water concentration continued to increase down to the pressure level of 22 bar, when it ceased operating. While the actually measured oxygen abundances are much lower than the solar value, the observed rapid increase of water content of the atmosphere with depth makes it highly likely that the deep abundance of oxygen indeed exceeds the solar value by a factor of about 3—much like other elements.
  3. Various explanations of the overabundance of carbon, oxygen, nitrogen and other elements have been proposed. The leading one is that Jupiter captured a large number of icy
    planetesimal Planetesimals are solid objects thought to exist in protoplanetary disks and debris disks. Per the Chamberlin–Moulton planetesimal hypothesis, they are believed to form out of cosmic dust grains. Believed to have formed in the Solar System a ...
    s during the later stages of its accretion. The volatiles like noble gases are thought to have been trapped as clathrate hydrates in water ice.
  4. NASA's
    Hubble Space Telescope The Hubble Space Telescope (often referred to as HST or Hubble) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most vers ...
    recorded on 25 August 2020, a storm traveling around the planet at . In addition, researches from the
    California Institute of Technology The California Institute of Technology (branded as Caltech or CIT)The university itself only spells its short form as "Caltech"; the institution considers other spellings such a"Cal Tech" and "CalTech" incorrect. The institute is also occasional ...
    reported that storms on Jupiter are similar to those on Earth, which form close to the equator, then move towards the poles. However, Jupiter's storms do not experience any friction from the land or oceans; hence, they drift until they reach the poles, which generate the so-called
    polygon In geometry, a polygon () is a plane figure that is described by a finite number of straight line segments connected to form a closed ''polygonal chain'' (or ''polygonal circuit''). The bounded plane region, the bounding circuit, or the two to ...
    storms.


References


Cited sources

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *


Further reading

* * * * * * * * * * * * * * *


External links

*
Planetary Society The Planetary Society is an American internationally-active non-governmental nonprofit organization. It is involved in research, public outreach, and political space advocacy for engineering projects related to astronomy, planetary science, a ...
br>blog post
(2017-05-09) by Peter Rosén describing assembly of
video
of Jupiter's atmospheric activity from 19 December 2014 to 31 March 2015 from amateur astronomer images
The Atmosphere
{{DEFAULTSORT:Atmosphere Of Jupiter Jupiter
Jupiter Jupiter is the fifth planet from the Sun and the largest in the Solar System. It is a gas giant with a mass more than two and a half times that of all the other planets in the Solar System combined, but slightly less than one-thousandth t ...