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Encyclopedia > Uranus
Uranus   Astronomical symbol of Uranus
Uranus, as seen by Voyager 2
Discovery
Discovered by William Herschel
Discovery date March 13, 1781
Epoch J2000
Aphelion 3,004,419,704 km
20.08330526 AU
Perihelion 2,748,938,461 km
18.37551863 AU
Semi-major axis 2,876,679,082 km
19.22941195 AU
Eccentricity 0.044405586
Orbital period 30,799.095 days
84.323326 yr
Synodic period 369.66 days[3]
Average orbital speed 6.81 km/s[3]
Mean anomaly 142.955717°
Inclination 0.772556°
6.48° to Sun's equator
Longitude of ascending node 73.989821°
Argument of perihelion 96.541318°
Satellites 27
Physical characteristics
Equatorial radius 25,559 ± 4 km
4.007 Earths[4][5]
Polar radius 24,973 ± 20 km
3.929 Earths[4][5]
Flattening 0.0229 ± 0.0008
Surface area 8.1156×109 km²[6][5]
15.91 Earths
Volume 6.833×1013 km³[3][5]
63.086 Earths
Mass 8.6810 ± 13×1025 kg
14.536 Earths[7]
GM=5,793,939 ± 13 km³/s²
Mean density 1.27 g/cm³[3][5]
Equatorial surface gravity 8.69 m/s²[3][5]
0.886 g
Escape velocity 21.3 km/s[3][5]
Sidereal rotation
period
0.71833 day
17 h 14 min 24 s[4]
Equatorial rotation velocity 2.59 km/s
9,320 km/h
Axial tilt 97.77°[4]
North pole right ascension 17 h 9 min 15 s
257.311°[4]
North pole declination −15.175°[4]
Albedo 0.300 (bond)
0.51 (geom.)[3]
Surface temp.
   1 bar level[9]
   0.1 bar
(tropopause)[10]
min mean max
76 K
49 K 53 K 57 K
Apparent magnitude 5.9[8] to 5.32[3]
Angular diameter 3.3"–4.1"[3]
Adjectives Uranian
Scale height 27.7 km[3]
Composition (Below 1.3 bar)
83±3% Hydrogen (H2)
15±3% Helium
2.3% Methane
0.009%
(0.007-0.015%)
Hydrogen deuteride (HD)[14]
Ices:
Ammonia
water
ammonium hydrosulfide (NH4SH)
methane (CH4)

Uranus (pronounced /ˈjʊərənəs/ or /jʊˈreɪnəs/[15]) is the seventh planet from the Sun and the third-largest and fourth-most massive planet in the solar system. It is named after the ancient Greek deity of the sky (Uranus, Οὐρανός), the father of Kronos (Saturn) and grandfather of Zeus (Jupiter). Uranus was the first planet discovered in modern times. Though it is visible to the naked eye like the five classical planets, it was never recognized as a planet by ancient observers due to its dimness.[16] Sir William Herschel announced its discovery on March 13, 1781, expanding the known boundaries of the solar system for the first time in modern history. This was also the first discovery of a planet made using a telescope. Uranus can refer to: Uranus, the seventh planet from the Sun Uranus (astrology) astrological aspects of Uranus Uranus (mythology), a deity in Greek mythology Sailor Uranus, from the popular media franchise Sailor Moon Uranus (1990 movie) Uranus is used euphemistically and humorously as a pun, as it can be pronounced... Image File history File links Uranus_symbol. ... Image File history File linksMetadata Download high-resolution version (1724x1716, 89 KB) A photo of Uranus taken by Voyager 2. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... For other persons named William Herschel, see William Herschel (disambiguation). ... is the 72nd day of the year (73rd in leap years) in the Gregorian calendar. ... 1781 was a common year starting on Monday (see link for calendar). ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... In astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. ... The J2000. ... A diagram of Keplerian orbital elements. ... A kilometer (Commonwealth spelling: kilometre), symbol: km is a unit of length in the metric system equal to 1,000 metres (from the Greek words χίλια (khilia) = thousand and μέτρο (metro) = count/measure). ... The astronomical unit (AU or au or a. ... A diagram of Keplerian orbital elements. ... The semi-major axis of an ellipse In geometry, the term semi-major axis (also semimajor axis) is used to describe the dimensions of ellipses and hyperbolae. ... (This page refers to eccitricity in astrodynamics. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... Look up day in Wiktionary, the free dictionary. ... In astronomy, a Julian year is a unit of time defined as exactly 365. ... The orbital period is the time it takes a planet (or another object) to make one full orbit. ... The orbital speed of a body, generally a planet, a natural satellite, an artificial satellite, or a multiple star, is the speed at which it orbits around the barycenter of a system, usually around a more massive body. ... In the study of orbital dynamics the mean anomaly is a measure of time, specific to the orbiting body p, which is a multiple of 2π radians at and only at periapsis. ... For the science fiction novella by William Shunn, see Inclination (novella). ... Sol redirects here. ... The Longitude of the ascending node (☊, also noted Ω) is one of the orbital elements used to specify the orbit of an object in space. ... The argument of periapsis (ω) is the orbital element describing the angle between an orbiting bodys ascending node (the point where the body crosses the plane of reference from South to North) and its periapsis (the point of closest approach to the central body), measured in the orbital plane and... A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called the primary. ... Uranus has 27 known moons. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... A geographical pole is either of two fixed points on the surface of a spinning body or planet, at 90 degrees from the equator, based on the axis around which a body spins. ... The flattening, ellipticity, or oblateness of an oblate spheroid is the relative difference between its equatorial radius a and its polar radius b: The flattening of the Earth is 1:298. ... In mathematics, a spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. ... For other uses, see Volume (disambiguation). ... For other uses, see Mass (disambiguation). ... Kg redirects here. ... In astrodynamics, the standard gravitational parameter () of a celestial body is the product of the gravitational constant () and the mass : The units of the standard gravitational parameter are km3s-2 Small body orbiting a central body Under standard assumptions in astrodynamics we have: where: is the mass of the orbiting... For other uses, see Density (disambiguation). ... The surface gravity of a Killing horizon is the acceleration, as exerted at infinity, needed to keep an object at the horizon. ... Acceleration is the time rate of change of velocity and/or direction, and at any point on a velocity-time graph, it is given by the slope of the tangent to the curve at that point. ... The term g force or gee force refers to the symbol g, the force of acceleration due to gravity at the earths surface. ... Space Shuttle Atlantis launches on mission STS-71. ... In astronomy, a rotation period is the time an astronomical object takes to complete one revolution around its rotation axis relative to the background stars. ... This article is about retrograde motion. ... The hour (symbol: h) is a unit of time. ... A minute is a unit of time equal to 1/60th of an hour and to 60 seconds. ... This article is about the unit of time. ... In astronomy, axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... Equatorial Coordinates Right ascension (abbrev. ... In astronomy, declination (abbrev. ... For other uses, see Albedo (disambiguation). ... The Bond albedo is the fraction of power in the total electromagnetic radiation incident on an astronomical body that is scattered back out into space. ... The geometric albedo of an astronomical body is the ratio of its total brightness at zero phase angle to that of an idealised fully reflecting, diffusively scattering (Lambertian) disk with the same cross-section. ... For other uses, see Temperature (disambiguation). ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... The tropopause is between the troposphere and the stratosphere. ... For other uses, see Kelvin (disambiguation). ... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... A scale height is a term often used in scientific contexts for a distance over which a quantity decreases by a factor of e. ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... Methane is a chemical compound with the molecular formula . ... Hydrogen deuteride is a bi-atomic compund of the two isotopes of hydrogen: the majority isotope 1H protium and 2H deuterium. ... For other uses, see Ammonia (disambiguation). ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Ammonium sulfide, (NH4)2S, is obtained, in the form of micaceous crystals, by passing hydrogen sulfide mixed with a slight excess of ammonia through a well-cooled vessel; the hydrosulfide NH4·HS is formed at the same time. ... Methane is a chemical compound with the molecular formula . ... This article is about the astronomical term. ... Sol redirects here. ... This article is about the Solar System. ... For other uses, see Uranus (disambiguation). ... Cronus is not to be confused with Chronos, the personification of time. ... Saturnus, Caravaggio, 16th c. ... For other uses, see Zeus (disambiguation). ... For the planet see Jupiter. ... The term Modern Times is used by historians to loosely describe the period of time immediately following what is known as the Early Modern Times. ... The final definition left the solar system with eight planets, pictured above (not to scale). ... For other persons named William Herschel, see William Herschel (disambiguation). ... is the 72nd day of the year (73rd in leap years) in the Gregorian calendar. ... 1781 was a common year starting on Monday (see link for calendar). ... This article is about the Solar System. ... This article does not cite any references or sources. ...


Uranus and Neptune have internal and atmospheric compositions different from those of the larger gas giants Jupiter and Saturn. As such, astronomers sometimes place them in a separate category, the "ice giants". Uranus' atmosphere, while similar to Jupiter and Saturn in being composed primarily of hydrogen and helium, contains a higher proportion of "ices" such as water, ammonia and methane, along with the usual traces of hydrocarbons. It is the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224 °C). It has a complex, layered cloud structure, with water thought to make up the lowest clouds, and methane thought to make up the uppermost layer of clouds.[10] For other uses, see Neptune (disambiguation). ... Atmospheric chemistry is a branch of atmospheric science in which the chemistry of the Earths atmosphere and that of other planets is studied. ... This article does not cite any references or sources. ... Atmospheric characteristics Atmospheric pressure 70 kPa Hydrogen ~86% Helium ~14% Methane 0. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... From top: Neptune, Uranus, Saturn, and Jupiter. ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Ammonia (disambiguation). ... Methane is a chemical compound with the molecular formula . ... Look up Hydrocarbon in Wiktionary, the free dictionary. ... For other uses, see Kelvin (disambiguation). ... For other uses, see Celsius (disambiguation). ... For other uses, see Cloud (disambiguation). ...


Like the other giant planets, Uranus has a ring system, a magnetosphere, and numerous moons. The Uranian system has a unique configuration among the planets because its axis of rotation is tilted sideways, nearly into the plane of its revolution about the Sun; its north and south poles lie where most other planets have their equators.[17] Seen from Earth, Uranus' rings can appear to circle the planet like an archery target and its moons revolve around it like the hands of a clock, though in 2007 and 2008 the rings appear edge-on. In 1986, images from Voyager 2 showed Uranus as a virtually featureless planet in visible light without the cloud bands or storms associated with the other giants.[17] However, terrestrial observers have seen signs of seasonal change and increased weather activity in recent years as Uranus approached its equinox. The wind speeds on Uranus can reach 250 meters per second.[18] A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ... A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called the primary. ... The axis of rotation of a rotating body is a line such that the distance between any point on the line and any point of the body remains constant under the rotation. ... Modern competitive archery is governed by the International Archery Federation, abbreviated FITA (Fédération Internationale de Tir à lArc). ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... Categories: Stub ... This article or section is in need of attention from an expert on the subject. ... For the geological process, see Weathering or Erosion. ... For other uses, see Equinox (disambiguation). ... For other uses, see Wind (disambiguation). ...

Contents

Discovery

Uranus had been observed on many occasions prior to its discovery as a planet, but it was generally mistaken for a star. The earliest recorded sighting was in 1690 when John Flamsteed catalogued Uranus as 34 Tauri and observed it at least six times. The French astronomer, Pierre Lemonnier, observed Uranus at least twelve times between 1750 and 1769,[19] including on four consecutive nights. John Flamsteed - Wikipedia, the free encyclopedia /**/ @import /skins-1. ... Taurus (IPA: , Latin: , symbol , ) is one of the constellations of the zodiac. ... Pierre Charles Le Monnier (November 23, 1715 – May 31, 1799) was a French astronomer. ...


Sir William Herschel observed the planet on 13 March 1781 while in the garden of his house at 19 New King Street in the town of Bath, Somerset (now the Herschel Museum of Astronomy),[20] but initially reported it (on 26 April 1781) as a "comet".[21] Herschel "engaged in a series of observations on the parallax of the fixed stars",[22] using a telescope of his own design. For other persons named William Herschel, see William Herschel (disambiguation). ... is the 72nd day of the year (73rd in leap years) in the Gregorian calendar. ... 1781 was a common year starting on Monday (see link for calendar). ... , Bath is a small city in Somerset, England most famous for its historic baths fed by three hot springs. ... This article is about the county of Somerset in England. ... , The Herschel Museum of Astronomy (also known as the William Herschel Museum) is a small independent museum dedicated to the life and works of the famous astronomer, William Herschel and his sister, Caroline Herschel. ... is the 116th day of the year (117th in leap years) in the Gregorian calendar. ... 1781 was a common year starting on Monday (see link for calendar). ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ...


He recorded in his journal "In the quartile near ζ Tauri … either [a] Nebulous star or perhaps a comet".[23] On March 17, he noted, "I looked for the Comet or Nebulous Star and found that it is a Comet, for it has changed its place".[24] When he presented his discovery to the Royal Society, he continued to assert that he had found a comet while also implicitly comparing it to a planet:[25] is the 76th day of the year (77th in leap years) in the Gregorian calendar. ... For other uses, see Royal Society (disambiguation). ...

The power I had on when I first saw the comet was 227. From experience I know that the diameters of the fixed stars are not proportionally magnified with higher powers, as planets are; therefore I now put the powers at 460 and 932, and found that the diameter of the comet increased in proportion to the power, as it ought to be, on the supposition of its not being a fixed star, while the diameters of the stars to which I compared it were not increased in the same ratio. Moreover, the comet being magnified much beyond what its light would admit of, appeared hazy and ill-defined with these great powers, while the stars preserved that lustre and distinctness which from many thousand observations I knew they would retain. The sequel has shown that my surmises were well-founded, this proving to be the Comet we have lately observed.

Herschel notified the Astronomer Royal, Nevil Maskelyne, of his discovery and received this flummoxed reply from him on April 23: "I don't know what to call it. It is as likely to be a regular planet moving in an orbit nearly circular to the sun as a Comet moving in a very eccentric ellipsis. I have not yet seen any coma or tail to it".[26] Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. ... Nevil Maskelyne. ... is the 113th day of the year (114th in leap years) in the Gregorian calendar. ...


While Herschel continued to cautiously describe his new object as a comet, other astronomers had already begun to suspect otherwise. Russian astronomer Anders Johan Lexell estimated its distance as 18 times the distance of the Sun from the Earth, and no comet had yet been observed with a perihelion of even four times the Earth–Sun distance.[27] Berlin astronomer Johann Elert Bode described Herschel's discovery as "a moving star that can be deemed a hitherto unknown planet-like object circulating beyond the orbit of Saturn".[28] Bode concluded that its near-circular orbit was more like a planet than a comet.[29] Anders Johan Lexell (December 24, 1740 – December 11, 1784 (Julian calendar: November 30)) was a Swedish_Russian astronomer and mathematician. ... This article is about several astronomical terms (apogee & perigee, aphelion & perihelion, generic equivalents based on apsis, and related but rarer terms. ... Johann Elert Bode Johann Elert Bode (January 19, 1747 – November 23, 1826) was a German astronomer known for his contribution to the Titius-Bode law and his works to determine the orbit of Uranus, for which he also suggested the name. ...


The object was soon universally accepted as a new planet. By 1783, Herschel himself acknowledged this fact to Royal Society president Joseph Banks: "By the observation of the most eminent Astronomers in Europe it appears that the new star, which I had the honour of pointing out to them in March 1781, is a Primary Planet of our Solar System."[30] In recognition of his achievement, King George III gave Herschel an annual stipend of £200 on the condition that he move to Windsor so the Royal Family could have a chance to look through his telescopes.[31] For clothing store, see JoS. A. Bank Clothiers. ... George III redirects here. ...


Naming

Maskelyne asked Herschel to "do the astronomical world the faver [sic] to give a name to your planet, which is entirely your own, & which we are so much obliged to you for the discovery of."[32] In response to Maskelyne's request, Herschel decided to name the object Georgium Sidus (George's Star), or the "Georgian Planet" in honour of his new patron, King George III.[33] He explained this decision in a letter to Joseph Banks:[30]

William Herschel, discoverer of Uranus
William Herschel, discoverer of Uranus
In the fabulous ages of ancient times the appellations of Mercury, Venus, Mars, Jupiter and Saturn were given to the Planets, as being the names of their principal heroes and divinities. In the present more philosophical era it would hardly be allowable to have recourse to the same method and call it Juno, Pallas, Apollo or Minerva, for a name to our new heavenly body. The first consideration of any particular event, or remarkable incident, seems to be its chronology: if in any future age it should be asked, when this last-found Planet was discovered? It would be a very satisfactory answer to say, 'In the reign of King George the Third.

Astronomer Jérôme Lalande proposed the planet be named Herschel in honour of its discoverer.[34] Bode, however, opted for Uranus, the Latinized version of the Greek god of the sky, Ouranos. Bode argued that just as Saturn was the father of Jupiter, the new planet should be named after the father of Saturn.[31][35][36] The earliest citation of the name Uranus in an official publication is in 1823, a year after Herschel's death.[37][38] The name Georgium Sidus or "the Georgian" was still used infrequently (by the British alone) for some time thereafter; the final holdout was HM Nautical Almanac Office, which did not switch to Uranus until 1850.[35] Image File history File linksMetadata William_Herschel01. ... Image File history File linksMetadata William_Herschel01. ... Joseph Jérôme Lefrançais de Lalande (July 11, 1732 – April 4, 1807) was a French astronomer. ... The bust of Zeus found at Otricoli (Sala Rotonda, Museo Pio-Clementino, Vatican) Greek mythology is the body of stories belonging to the Ancient Greeks concerning their gods and heroes, the nature of the world and the origins and significance of their own cult and ritual practices. ... For other uses, see Uranus (disambiguation). ... Her Majestys Nautical Almanac Office (HMNAO), now part of the United Kingdom Hydrographic Office, was established in 1832 on the site of the Royal Greenwich Observatory (RGO), where the Nautical Almanac had been published since 1767. ...


The preferred pronunciation of the name Uranus among astronomers is [ˈjʊərənəs], with the first syllable stressed and a short a (ūrănŭs);[39] this is more classically correct than the alternate [jʊˈɹeɪ.nəs], with stress on the second syllable and a "long a" (ūrānŭs), which is often used in the English-speaking world. For the computer operating system, see Syllable (operating system). ...


Uranus is the only planet whose name is derived from a figure from Greek mythology rather than Roman mythology. (The Roman equivalent would have been Caelus.) The adjective of Uranus is "Uranian". The element uranium, discovered in 1789, was named in its honour by its discoverer, Martin Klaproth.[40] The bust of Zeus found at Otricoli (Sala Rotonda, Museo Pio-Clementino, Vatican) Greek mythology is the body of stories belonging to the Ancient Greeks concerning their gods and heroes, the nature of the world and the origins and significance of their own cult and ritual practices. ... A head of Minerva found in the ruins of the Roman baths in Bath Roman mythology, the mythological beliefs of the people of Ancient Rome, can be considered as having two parts. ... Caelus was the Latin name that the Romans used for the Greek sky god Uranus. ... This article is about the chemical element. ... Martin Heinrich Klaproth (December 1, 1743 – January 1, 1817) was a German chemist. ...


Its astronomical symbol is Astronomical symbol for Uranus. It is a hybrid of the symbols for Mars and the Sun because Uranus was the Sky in Greek mythology, which was thought to be dominated by the combined powers of the Sun and Mars.[41] Its astrological symbol is , suggested by Lalande in 1784. In a letter to Herschel, Lalande described it as "un globe surmonté par la première lettre de votre nom" ("a globe surmounted by the first letter of your name").[34] In the Chinese, Japanese, Korean, and Vietnamese languages, the planet's name is literally translated as the sky king star (天王星).[42][43] Chinese Celestial symbols on an antique bronze mirror Astronomical symbols are symbols used to represent various celestial objects, theoretical constructs and observational events. ... Image File history File links Uranus_symbol. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Sol redirects here. ... ... Image File history File links Uranus's_astrological_symbol. ...


Orbit and rotation

HST image of Uranus showing cloud bands, rings, and moons
HST image of Uranus showing cloud bands, rings, and moons

Uranus revolves around the Sun once every 84 Earth years. Its average distance from the Sun is roughly 3 billion km (about 20 AU). The intensity of sunlight on Uranus is about 1/400 that of Earth.[44] Its orbital elements were first calculated in 1783 by Pierre-Simon Laplace.[27] With time, discrepancies began to appear between the predicted and observed orbits, and in 1841, John Couch Adams first proposed that the differences might be due to the gravitational tug of an unseen planet. In 1845, Urbain Le Verrier began his own independent research into Uranus' orbit. On September 23, 1846, Johann Gottfried Galle located a new planet, later named Neptune, at nearly the position predicted by Le Verrier.[45] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... Billion may mean: 1,000,000,000 (one thousand million; ), used by most English-speaking countries (American and usual modern British meaning) 1,000,000,000,000 (one million million; ), used by most other countries outside Asia (older British meaning). ... The astronomical unit (AU or au or a. ... Pierre-Simon, marquis de Laplace (March 23, 1749 - March 5, 1827) was a French mathematician and astronomer whose work was pivotal to the development of mathematical astronomy. ... John Couch Adams (June 5, 1819 – January 21, 1892), was a British mathematician and astronomer. ... Urbain Le Verrier. ... is the 266th day of the year (267th in leap years) in the Gregorian calendar. ... 1846 was a common year starting on Thursday (see link for calendar). ... Johann Gottfried Galle Johann Gottfried Galle (June 9, 1812 in Radis, Saxony-Anhalt – July 10, 1910 in Potsdam, Brandenburg) was a German astronomer at the Berlin Observatory who, with the assistance of student Heinrich Louis dArrest, was the first person to view the planet Neptune, and know what he... For other uses, see Neptune (disambiguation). ...


The rotational period of the interior of Uranus is 17 hours, 14 minutes. However, as on all giant planets, its upper atmosphere experiences very strong winds in the direction of rotation. In effect, at some latitudes, such as about two-thirds of the way from the equator to the south pole, visible features of the atmosphere move much faster, making a full rotation in as little as 14 hours.[46]


Axial tilt

Uranus' axis of rotation lies on its side with respect to the plane of the solar system, with an axial tilt of 98 degrees. This makes its exchange of seasons completely unlike those of the other major planets. Other planets can be visualized to rotate like tilted spinning tops relative to the plane of the solar system, while Uranus rotates more like a tilted rolling ball. Near the time of Uranian solstices, one pole faces the Sun continually while the other pole faces away. Only a narrow strip around the equator experiences a rapid day-night cycle, but with the Sun very low over the horizon as in the Earth's polar regions. At the other side of Uranus' orbit the orientation of the poles towards the Sun is reversed. Each pole gets around 42 years of continuous sunlight, followed by 42 years of darkness.[47] Near the time of the equinoxes, the Sun faces the equator of Uranus giving a period of day-night cycles similar to those seen on most of the other planets. Uranus reached its most recent equinox on 7 December 2007.[48][49] For other uses, see Top (disambiguation). ... For other uses, see Ball (disambiguation). ... “Summer solstice” redirects here. ... Sol redirects here. ... For other uses, see Equinox (disambiguation). ... is the 341st day of the year (342nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ...

Northern hemisphere Year Southern hemisphere
Winter solstice 1902, 1986 Summer solstice
Vernal equinox 1923, 2007 Autumnal equinox
Summer solstice 1944, 2028 Winter solstice
Autumnal equinox 1965, 2049 Vernal equinox

One result of this axis orientation is that, on average during the year, the polar regions of Uranus receive a greater energy input from the Sun than its equatorial regions. Nevertheless, Uranus is hotter at its equator than at its poles. The underlying mechanism which causes this is unknown. The reason for Uranus' unusual axial tilt is also not known with certainty, but the usual speculation is that during the formation of the Solar System, an Earth sized protoplanet collided with Uranus, causing the skewed orientation.[50] Uranus' south pole was pointed almost directly at the Sun at the time of Voyager 2's flyby in 1986. The labeling of this pole as "south" uses the definition currently endorsed by the International Astronomical Union, namely that the north pole of a planet or satellite shall be the pole which points above the invariable plane of the solar system, regardless of the direction the planet is spinning.[51][52] However, a different convention is sometimes used, where a body's north and south poles are defined according to the right-hand rule in relation to the direction of rotation.[53] In terms of this latter coordinate system it was Uranus' north pole which was in sunlight in 1986. Astronomer Patrick Moore, commenting on the issue, summed it up by saying "Take your pick!"[54] Protoplanets are moon-sized planet embryos within protoplanetary discs. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... IAU redirects here. ... The left-handed orientation is shown on the left, and the right-handed on the right. ... For other persons named Patrick Moore, see Patrick Moore (disambiguation). ...


Visibility

From 1995 to 2006, Uranus' apparent magnitude fluctuated between +5.6 and +5.9, placing it just within the limit of naked eye visibility at +6.5.[8] Its angular diameter is between 3.4 and 3.7 arcseconds, compared with 16 to 20 arcseconds for Saturn and 32 to 45 arcseconds for Jupiter.[8] At opposition, Uranus is visible to the naked eye in dark, un-light polluted skies, and becomes an easy target even in urban conditions with binoculars.[6] In larger amateur telescopes with an objective diameter of between 15 and 23 cm, the planet appears as a pale cyan disk with distinct limb darkening. With a large telescope of 25 cm or wider, cloud patterns, as well as some of the larger satellites, such as Titania and Oberon, may be visible.[55] The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ... The naked eye is a figure of speech referring to human visual perception that is unaided by enhancing equipment, such as a telescope or binoculars. ... This article is about the planet. ... For other uses, see Jupiter (disambiguation). ... This time exposure photo of New York City shows sky glow, one form of light pollution. ... The limb darkened Sun - An image of the Sun in visible light showing the limb darkening effect as a drop in intensity towards the edge or limb of the solar disk. ... Not to be confused with the Saturnian moon Titan or the asteroid 593 Titania. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ...


Physical characteristics

Internal structure

Size comparison of Earth and Uranus
Size comparison of Earth and Uranus

Uranus' mass is roughly 14.5 times that of the Earth, making it the least massive of the giant planets, while its density of 1.27 g/cm³ makes it the second least dense planet, after Saturn.[7] Though having a diameter similar to Neptune (roughly four times Earth's), it is less massive.[4] These values indicate that it is made primarily of various ices, such as water, ammonia, and methane.[9] The total mass of ice in Uranus' interior is not precisely known, as different figures emerge depending on the model chosen; however, it must be between 9.3 and 13.5 Earth masses.[9][56] Hydrogen and helium constitute only a small part of the total, with between 0.5 and 1.5 Earth masses.[9] The remainder of the mass (0.5 to 3.7 Earth masses) is accounted for by rocky material.[9] Image File history File linksMetadata Download high resolution version (900x900, 146 KB)Sources: Image:The Earth seen from Apollo 17. ... Image File history File linksMetadata Download high resolution version (900x900, 146 KB)Sources: Image:The Earth seen from Apollo 17. ... Volatiles are that group of compounds with low boiling points (see volatile) that are associated with a planets or moons crust and/or atmosphere. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... For other uses, see Ammonia (disambiguation). ... Methane is a chemical compound with the molecular formula . ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... This article is about the geological substance. ...


The standard model of Uranus' structure is that it consists of three layers: a rocky core in the center, an icy mantle in the middle and an outer gaseous hydrogen/helium envelope.[9][57] The core is relatively small, with a mass of only 0.55 Earth masses and a radius less than 20 percent Uranus'; the mantle comprises the bulk of the planet, with around 13.4 Earth masses, while the upper atmosphere is relatively insubstantial, weighing about 0.5 Earth masses and extending for the last 20 percent of Uranus' radius.[9][57] Uranus' core density is around 9 g/cm³, with a pressure at the core/mantle boundary of 8 million bars (800 GPa) and a temperature of about 5000 K.[56][57] The ice mantle is not in fact composed of ice in the conventional sense, but of a hot and dense fluid consisting of water, ammonia and other volatiles.[9][57] This fluid, which has a high electrical conductivity, is sometimes called a water–ammonia ocean.[58] The bulk compositions of Uranus and Neptune are very different from those of Jupiter and Saturn, with ice dominating over gases, hence justifying their separate classification as ice giants. Earth cutaway from core to exosphere. ... Earth cutaway from core to exosphere. ... This article is about the chemistry of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... For other uses, see Density (disambiguation). ... This article is about pressure in the physical sciences. ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... The gigapascal, symbol GPa is an SI unit of pressure. ... For other uses, see Kelvin (disambiguation). ... For other uses, see Ammonia (disambiguation). ... Volatiles are that group of compounds with low boiling points (see volatile) that are associated with a planets or moons crust and/or atmosphere. ... For other uses, see Jupiter (disambiguation). ... This article is about the planet. ... From top: Neptune, Uranus, Saturn, and Jupiter. ...


While the model considered above is more or less standard, it is not unique; other models also satisfy observations. For instance, if substantial amounts of hydrogen and rocky material are mixed in the ice mantle, the total mass of ices in the interior will be lower, and, correspondingly, the total mass of rocks and hydrogen will be higher. Presently available data does not allow us to determine which model is correct.[56] The fluid interior structure of Uranus means that it has no solid surface. The gaseous atmosphere gradually transitions into the internal liquid layers.[9] However for the sake of convenience an oblate spheroid of revolution, where pressure equals 1 bar (100 kPa), is designated conditionally as a ‘surface’. It has equatorial and polar radii of 25,559 ± 4 and 24,973 ± 20 km, respectively.[4] This surface will be used throughout this article as a zero point for altitudes. A fluid is defined as a substance that continually deforms (flows) under an applied shear stress regardless of the magnitude of the applied stress. ... This box:      For other uses, see Solid (disambiguation). ... An open surface with X-, Y-, and Z-contours shown. ... Oblate also refers to a member of the Roman Catholic religious order of the Missionary Oblates of Mary Immaculate, or in some cases to a lay or religious person who has officially associated himself (or herself) with a monastic community such as the Benedictines for reasons of personal enrichment without... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ... A geographical pole is either of two fixed points on the surface of a spinning body or planet, at 90 degrees from the equator, based on the axis around which a body spins. ... Altitude is the elevation of an object from a known level or datum. ...


Internal heat

Uranus' internal heat appears markedly lower than that of the other giant planets; in astronomical terms, it has a low thermal flux.[59][18] Why Uranus' internal temperature is so low is still not understood. Neptune, which is Uranus' near twin in size and composition, radiates 2.61 times as much energy into space as it receives from the Sun.[18] Uranus, by contrast, radiates hardly any excess heat at all. The total power radiated by Uranus in the far infrared (i.e. heat) part of the spectrum is 1.06 ± 0.08 times the solar energy absorbed in its atmosphere.[60][10] In fact, Uranus' heat flux is only 0.042 ± 0.047 W/m², which is lower than the internal heat flux of Earth of about 0.075 W/m².[60] The lowest temperature recorded in Uranus' tropopause is 49 K (−224 °C), making Uranus the coldest planet in the Solar System.[60][10] Internal heat is the heat source from the interior celestial objects, such as planets, brown dwarfs, and stars, caused by gravity and decaying radioactive materials. ... For other uses, see Neptune (disambiguation). ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... Atmospheres redirects here. ... flux in science and mathematics. ...


Hypotheses for this discrepancy include that when Uranus was "knocked over" by the supermassive impactor which caused its extreme axial tilt, the event also caused it to expel most of its primordial heat, leaving it with a depleted core temperature.[61] Another hypothesis is that some form of barrier exists in Uranus' upper layers which prevents the core's heat from reaching the surface.[9] For example, convection may take place in a set of compositionally different layers, which may inhibit the upward heat transport.[10][60] Convection in the most general terms refers to the movement of currents within fluids (i. ... Heat conduction or thermal conduction is the spontaneous transfer of thermal energy through matter, from a region of higher temperature to a region of lower temperature, and acts to equalize temperature differences. ...


Atmosphere

Main article: Atmosphere of Uranus

Although there is no well-defined solid surface within Uranus' interior, the outermost part of Uranus' gaseous envelope that is accessible to remote sensing is called its atmosphere.[10] Remote sensing capability extends down to roughly 300 km below the 1 bar (100 kPa) level, with a corresponding pressure around 100 bar (10 MPa) and temperature of 320 K.[62] The tenuous corona of the atmosphere extends remarkably over two planetary radii from the nominal surface at 1 bar pressure.[63] The Uranian atmosphere can be divided into three layers: the troposphere, between altitudes of −300 and 50 km and pressures from 100 to 0.1 bar; (10 MPa to 10 kPa) the stratosphere, spanning altitudes between 50 and 4000 km and pressures of between 0.1 and 10–10 bar; (10 kPa to 10 µPa)and the thermosphere/corona extending from 4,000 km to as high as 50,000 km from the surface.[10] There is no mesosphere. The bland face of Uranus, as imaged by Voyager 2 in 1986. ... Atmospheres redirects here. ... The kelvin (symbol: K) is the SI unit of temperature and is one of the seven SI base units. ... This article is about the astronomical term. ... Atmosphere diagram showing the mesosphere and other layers. ... Atmosphere diagram showing stratosphere. ... The pascal (symbol: Pa) is the SI unit of pressure. ... The thermosphere is the layer of the earths atmosphere directly above the mesosphere and directly below the exosphere. ... This article is about the astronomical term. ... The mesosphere (from the Greek words mesos = middle and sphaira = ball) is the layer of the Earths atmosphere that is directly above the stratosphere and directly below the thermosphere. ...


Composition

The composition of the Uranian atmosphere is different from the composition of Uranus as a whole, consisting as it does mainly of molecular hydrogen and helium.[10] The helium molar fraction, i.e. the number of helium atoms per molecule of gas, is 0.15 ± 0.03[12] in the upper troposphere, which corresponds to a mass fraction 0.26 ± 0.05.[10][60] This value is very close to the protosolar helium mass fraction of 0.275 ± 0.01,[64] indicating that helium has not settled in the center of the planet as it has in the gas giants.[10] The third most abundant constituent of the Uranian atmosphere is methane (CH4).[10] Methane possesses prominent absorption bands in the visible and near-infrared (IR) making Uranus aquamarine or cyan in color.[10] Methane molecules account for 2.3% of the atmosphere by molar fraction below the methane cloud deck at the pressure level of 1.3 bar (130 kPa); this represents about 20 to 30 times the carbon abundance found in the Sun.[10][11][65] The mixing ratio[66] is much lower in the upper atmosphere due to its extremely low temperature, which lowers the saturation level and causes excess methane to freeze out.[67] The abundances of less volatile compounds such as ammonia, water and hydrogen sulfide in the deep atmosphere are poorly known. However they are probably also higher than solar values.[10][68] In addition to methane, trace amounts of various hydrocarbons are found in the upper atmosphere of Uranus, which are thought to be produced from methane by photolysis induced by the solar ultraviolet (UV) radiation.[69] They include ethane (C2H6), acetylene (C2H2), methylacetylene (CH3C2H), diacetylene (C2HC2H).[67][70][71] Spectroscopy has also uncovered traces of water vapor, carbon monoxide and carbon dioxide in the upper atmosphere, which can only originate from an external source such as infalling dust and comets.[71][70][72] Molecular hydrogen, H2, is a molecule formed from two atoms of hydrogen. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... For other uses, see Atom (disambiguation). ... 3D (left and center) and 2D (right) representations of the terpenoid molecule atisane. ... Atmospheres redirects here. ... Methane is a chemical compound with the molecular formula . ... An absorption band is a range of wavelengths (or, equivalently, frequencies) in the electromagnetic spectrum within which electromagnetic energy is absorbed by a substance. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. ... Aquamarine is a color, a shade between green and cyan. ... Cyan (from Greek κυανοs, meaning blue) may be used as the name of any of a number of a range of colors in the blue/green part of the spectrum. ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... For other uses, see Ammonia (disambiguation). ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence. ... Look up Hydrocarbon in Wiktionary, the free dictionary. ... Photolysis refers to any chemical reaction in which a compound is broken down by light. ... For other uses, see Ultraviolet (disambiguation). ... This article is about a chemical compound. ... Acetylene (systematic name: ethyne) is a hydrocarbon belonging to the group of alkynes. ... Methylacetylene (propyne) is an alkyne with the chemical formula CH3C≡CH. It is a component of MAPP gas, which is commonly used in gas welding. ... Diacetylene is an unsaturated hydrocarbon with chemical formula HCCCCH. Categories: Stub ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ...


Troposphere

Temperature profile of the Uranian troposphere and lower stratosphere. Cloud and haze layers are also indicated.

The troposphere is the lowest and densest part of the atmosphere and is characterized by a decrease in temperature with altitude.[10] The temperature falls from about 320 K at the base of the nominal troposphere at −300 km to 53 K at 50 km.[62][65] The temperatures in the coldest upper region of the troposphere (the tropopause) actually vary in the range between 49 and 57 K depending on planetary latitude.[10][59] The tropopause region is responsible for the vast majority of the planet’s thermal far infrared emissions, thus determining its effective temperature of 59.1 ± 0.3 K.[59][60] Image File history File links Size of this preview: 776 × 600 pixelsFull resolution (3300 × 2550 pixel, file size: 110 KB, MIME type: image/png) This graph shows temperature profile in the troposphere and in the lower stratosphere of Uranus. ... Image File history File links Size of this preview: 776 × 600 pixelsFull resolution (3300 × 2550 pixel, file size: 110 KB, MIME type: image/png) This graph shows temperature profile in the troposphere and in the lower stratosphere of Uranus. ... The tropopause is between the troposphere and the stratosphere. ... Image of a small dog taken in mid-infrared (thermal) light (false color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than visible light, but shorter than microwave radiation. ... The effective temperature of a star is the temperature of a black body with the same luminosity (L) as the star and is defined according to the Stefan-Boltzman law L = sigma T_{eff}^{4}. The effective temperature of our Sun is around 5,800 kelvins (K) and correspond to...


The troposphere is believed to possess a highly complex cloud structure; water clouds are hypothesised to lie in the pressure range of 50 to 100 bar (5 to 10 MPa), ammonium hydrosulfide clouds in the range of 20 to 40 bar (2 to 4 MPa), ammonia or hydrogen sulfide clouds at between 3 and 10 bar (0.3 to 1 MPa) and finally directly detected thin methane clouds at 1 to 2 bar (0.1 to 0.2 MPa).[10][62][73][11] The troposphere is a very dynamic part of the atmosphere, exhibiting strong winds, bright clouds and seasonal changes, which will be discussed below.[18] For other uses, see Cloud (disambiguation). ... Ammonium sulfide, (NH4)2S, is obtained, in the form of micaceous crystals, by passing hydrogen sulfide mixed with a slight excess of ammonia through a well-cooled vessel; the hydrosulfide NH4·HS is formed at the same time. ... For other uses, see Ammonia (disambiguation). ... Hydrogen sulfide (hydrogen sulphide in British English) is the chemical compound with the formula H2S. This colorless, toxic and flammable gas is responsible for the foul odor of rotten eggs and flatulence. ... Methane is a chemical compound with the molecular formula . ...


Upper atmosphere

The middle layer of the Uranian atmosphere is the stratosphere, where temperature generally increases with altitude from 53 K in the tropopause to between 800 and 850 K at the base of the thermosphere.[63] The heating of the stratosphere is caused by absorption of solar UV and IR radiation by methane and other hydrocarbons that form in this part of the atmosphere as a result of methane photolysis.[67][69] Heating from the hot thermosphere may also be significant.[74][75] The hydrocarbons occupy a relatively narrow layer at altitudes of between 100 and 280 km corresponding to a pressure range of 10 to 0.1 mbar (1000 to 10 kPa) and temperatures of between 75 and 170 K.[67] The most abundant hydrocarbons are acetylene and ethane with mixing ratios of around ×10−7 relative to hydrogen, which is similar to the mixing ratios of methane and carbon monoxide at these altitudes.[67][70][72] Heavier hydrocarbons and carbon dioxide have mixing ratios three orders of magnitude lower.[70] The abundance ratio of water is around 7×10-9.[71] Ethane and acetylene tend to condense in the colder lower part of stratosphere and tropopause forming haze layers,[69] which may be partly responsible for the bland appearance of Uranus. However, the concentration of hydrocarbons in the Uranian stratosphere above the haze is significantly lower than in the stratospheres of the other giant planets.[67][74] Atmosphere diagram showing stratosphere. ... The tropopause is between the troposphere and the stratosphere. ... The thermosphere is the layer of the earths atmosphere directly above the mesosphere and directly below the exosphere. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... For other uses, see Infrared (disambiguation). ... Methane is a chemical compound with the molecular formula . ... Look up Hydrocarbon in Wiktionary, the free dictionary. ... Photolysis refers to any chemical reaction in which a compound is broken down by light. ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... Acetylene (systematic name: ethyne) is a hydrocarbon belonging to the group of alkynes. ... This article is about a chemical compound. ... The parts-per notations are used to denote extremely low concentrations of chemical elements. ... This article is about the chemistry of hydrogen. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ... Haze is an atmospheric phenomenon where dust, smoke and other pollutant particles obscure the normal clarity of the sky. ... Metroplex (in shadow) and Giant Planet Gigantion, or Giant Planet, is a fictional planet home to giant Transformers in the animated television program, Transformers: Cybertron; it is referred to as Gigalonia in Transformers: Galaxy Force, the Japanese version of the show. ...


The outermost layer of the Uranian atmosphere is the thermosphere and corona, which has a uniform temperature around 800 to 850 K.[10][74] The heat sources necessary to sustain such a high value are not understood, since neither solar far UV and extreme UV radiation nor auroral activity can provide the necessary energy, although weak cooling efficiency due to the lack of hydrocarbons in the upper part of the stratosphere may also contribute.[63][74] In addition to molecular hydrogen, the thermosphere-corona contains a large proportion of free hydrogen atoms. Their small molecular mass together with the high temperatures may help to explain why the corona extends as far as 50,000 km or two Uranian radii from the planet.[63][74] This extended corona is a unique feature of Uranus.[74] Its effects include a drag on small particles orbiting Uranus, causing a general depletion of dust in the Uranian rings.[63] The Uranian thermosphere, together with the upper part of the stratosphere, corresponds to the ionosphere of Uranus.[65] Observations show that the ionosphere occupies altitudes from 2,000 to 10,000 km.[65] The Uranian ionosphere is denser than that of either Saturn or Neptune, which may arise from the low concentration of hydrocarbons in the stratosphere.[74][76] The ionosphere is mainly sustained by solar UV radiation and its density depends on the solar activity.[77] Auroral activity is not as significant as at Jupiter and Saturn.[74][78] This article is about the astronomical term. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... The Aurora Borealis, or Northern Lights, shines above Bear Lake Aurora Borealis as seen over Canada at 11,000m (36,000 feet) Red and green Aurora in Fairbanks,Alaska For other uses, see Aurora (disambiguation). ... Molecular hydrogen, H2, is a molecule formed from two atoms of hydrogen. ... Depiction of a hydrogen atom showing the diameter as about twice the Bohr model radius. ... This article is about the astronomical term. ... An object moving through a gas or liquid experiences a force in direction opposite to its motion. ... Look up dust in Wiktionary, the free dictionary. ... Relationship of the atmosphere and ionosphere The ionosphere is the uppermost part of the atmosphere, distinguished because it is ionized by solar radiation. ... 20 years of solar irradiance data from satellites Solar variation refers to fluctuation in the amount of energy emitted by the Sun. ... The Aurora Borealis, or Northern Lights, shines above Bear Lake Aurora Borealis as seen over Canada at 11,000m (36,000 feet) Red and green Aurora in Fairbanks,Alaska For other uses, see Aurora (disambiguation). ...


Planetary rings

Main article: Rings of Uranus
Uranus' inner rings. The bright outer ring is the epsilon ring, eight other rings are present
An enhanced colour schematic of the inner rings

Uranus has a faint planetary ring system, composed of dark particulate matter up to ten meters in diameter.[17] It was the second ring system to be discovered in the Solar System after Saturn's.[79] Thirteen distinct rings are presently known, the brightest being the epsilon ring. Uranus’ rings are probably quite young; gaps in their circumference as well as differences in their opacity suggest that they did not form with Uranus. The matter in the rings may once have been part of a moon which was shattered by a high-speed impact or tidal forces.[79][80] This is a list of the named planetary rings of Uranus. ... Image File history File links Size of this preview: 615 × 600 pixelsFull resolution (754 × 735 pixel, file size: 186 KB, MIME type: image/jpeg) Voyager 2 picture of Uranus rings taken on January 22, 1986, from a distance of 2. ... Image File history File links Size of this preview: 615 × 600 pixelsFull resolution (754 × 735 pixel, file size: 186 KB, MIME type: image/jpeg) Voyager 2 picture of Uranus rings taken on January 22, 1986, from a distance of 2. ... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... A planetary ring is a ring of dust and other small particles orbiting around a planet in a flat disc-shaped region. ... The full set of rings, photographed as Saturn eclipsed the sun from the vantage of the Cassini spacecraft on September 15, 2006 (brightness has been exaggerated in this image). ...


William Herschel claimed to have seen rings at Uranus in 1789 (see below), however this is doubtful as in the two following centuries no rings were noted by other observers. The ring system was definitively discovered on March 10, 1977 by James L. Elliot, Edward W. Dunham, and Douglas J. Mink using the Kuiper Airborne Observatory. The discovery was serendipitous; they planned to use the occultation of the star SAO 158687 by Uranus to study the planet's atmosphere. However, when their observations were analyzed, they found that the star had disappeared briefly from view five times both before and after it disappeared behind the planet. They concluded that there must be a ring system around the planet.[81] The rings were directly imaged when Voyager 2 passed Uranus in 1986.[17] Voyager 2 also discovered two additional faint rings bringing the total number to eleven.[17] For other persons named William Herschel, see William Herschel (disambiguation). ... is the 69th day of the year (70th in leap years) in the Gregorian calendar. ... Also: 1977 (album) by Ash. ... James L. Elliot is a Professor of Physics; Professor of Earth, Atmospheric, and Planetary Sciences; and the Director, George R. Wallace, Jr. ... Douglas J Mink is a Astronomical Software Developer and Data Archivist at the Harvard-Smithsonian Center for Astrophysics. ... Categories: Astronomy stubs | Astronomical observatories ... In this July, 1997 still frame captured from video, the bright star Aldebaran has just reappeared on the dark limb of the waning crescent moon in this predawn occultation. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ...


In December 2005, the Hubble Space Telescope detected a pair of previously unknown rings. The largest is located at twice the distance from the planet of the previously known rings. These new rings are so far from the planet that they are being called the "outer" ring system. Hubble also spotted two small satellites, one of which, Mab, shares its orbit with the outermost newly discovered ring. The new rings bring the total number of Uranian rings to 13.[82] In April 2006, images of the new rings with the Keck Observatory yielded the colours of the outer rings: the outermost is blue and the other red.[83][84] One hypothesis concerning the outer ring's blue colour is that it is composed of minute particles of water ice from the surface of Mab that are small enough to scatter blue light.[83][85] The planet's inner rings appear grey.[83] Regarding William Herschel's observations in the 18th century, the first mention of a Uranian ring system comes from his notes detailing his observations of Uranus, which include the following passage: "February 22, 1789: A ring was suspected".[86] Herschel drew a small diagram of the ring and noted that it was "a little inclined to the red". The Keck Telescope in Hawaii has since confirmed this to be the case.[83] Herschel's notes were published in a Royal Society journal in 1797. However, in the two centuries between 1797 and 1977 the rings are rarely mentioned, if at all. This casts serious doubt whether Herschel could have seen anything of the sort while hundreds of other astronomers saw nothing. Still, it has been claimed by some that Herschel actually gave accurate descriptions of the ring's size relative to Uranus, its changes as Uranus travelled around the Sun, and its colour.[87] The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... Atmospheric pressure 0 kPa Mab (mab, IPA [mæb]) is a natural satellite of Uranus. ... The Mauna Kea Observatory, an institute of the University of Hawaii, is considered one of the most important land-based observatories in the world for its isolated, unobstructed views of space without interference from man-made light sources. ... is the 53rd day of the year in the Gregorian calendar. ... Year 1789 (MDCCLXXXIX) was a common year starting on Thursday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the 11-day slower Julian calendar). ...


Magnetic field

The magnetic field of Uranus as seen by Voyager 2 in 1986. S and N are magnetic south and north poles.

Prior to the arrival of Voyager 2, no measurements of the Uranian magnetosphere had been taken, so its nature remained a mystery. Before 1986, astronomers had expected the magnetic field of Uranus to be in line with the solar wind, since it would then align with the planet's poles that lie in the ecliptic.[88] Image File history File links Size of this preview: 800 × 585 pixelsFull resolution (900 × 658 pixel, file size: 47 KB, MIME type: image/gif) This image depicts the magnetic field of Uranus as seen by Voyager 2 in 1986. ... Image File history File links Size of this preview: 800 × 585 pixelsFull resolution (900 × 658 pixel, file size: 47 KB, MIME type: image/gif) This image depicts the magnetic field of Uranus as seen by Voyager 2 in 1986. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ... The plasma in the solar wind meeting the heliopause The solar wind is a stream of charged particles (i. ... The plane of the ecliptic is well seen in this picture from the 1994 lunar prospecting Clementine spacecraft. ...


Voyager's observations revealed that the magnetic field is peculiar, both because it does not originate from the planet's geometric center, and because it is tilted at 59° from the axis of rotation.[88][89] In fact the magnetic dipole is shifted from the center of the planet towards the south rotational pole by as much as one third of the planetary radius.[88] This unusual geometry results in a highly asymmetric magnetosphere, where the magnetic field strength on the surface in the southern hemisphere can be as low as 0.1 gauss (10 µT), whereas in the northern hemisphere it can be as high 1.1 gauss (110 µT).[88] The average field at the surface is 0.23 gauss (23 µT).[88] In comparison, the magnetic field of Earth is roughly as strong at either pole, and its "magnetic equator" is roughly parallel with its physical equator.[89] The dipole moment of Uranus is 50 times that of Earth.[88][89] Neptune has a similarly displaced and tilted magnetic field, suggesting that this may be a common feature of ice giants.[89] One hypothesis is that, unlike the magnetic fields of the terrestrial and gas giant planets, which are generated within their cores, the ice giants' magnetic fields are generated by motion at relatively shallow depths, for instance, in the water–ammonia ocean.[58][90] For the indie-pop band, see The Magnetic Fields. ... The gauss, abbreviated as G, is the cgs unit of magnetic flux density (B), named after the German mathematician and physicist Carl Friedrich Gauss. ... The tesla (symbol T) is the SI derived unit of magnetic flux density (or magnetic induction). ...


Despite its curious alignment, in other respects the Uranian magnetosphere is like those of other planets: it has a bow shock located at about 23 Uranian radii ahead of it, a magnetopause at 18 Uranian radii, a fully developed magnetotail and radiation belts.[88][89][91] Overall, the structure of the magnetosphere of Uranus is different from that of Jupiter's and more similar to that of Saturn's.[88][89] Uranus' magnetotail trails behind the planet into space for millions of kilometers and is twisted by the planet's sideways rotation into a long corkscrew.[88][92] In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops as a result of its approach to the magnetopause. ... A magnetopause flows along the boundary between a magnetic field, (see: magnetosphere) and surrounding plasma. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ... Van Allen belts The Van Allen radiation belt is a torus of energetic charged particles around Earth, trapped by Earths magnetic field. ... For other uses, see Jupiter (disambiguation). ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ...


Uranus' magnetosphere contains charged particles: protons and electrons with small amount of H2+ ions.[89][91] No heavier ions have been detected. Many of these particles probably derive from the hot atmospheric corona.[91] The ion and electron energies can be as high as 4 and 1.2 megaelectronvolts, respectively.[91] The density of low energy (below 100 electronvolts) ions in the inner magnetosphere is about 2 cm-3.[93] The particle population is strongly affected by the Uranian moons that sweep through the magnetosphere leaving noticeable gaps.[91] The particle flux is high enough to cause darkening or space weathering of the moon’s surfaces on an astronomically rapid timescale of 100,000 years.[91] This may be the cause of the uniformly dark colouration of the moons and rings.[80] Uranus has relatively well developed aurorae, which are seen as bright arcs around both magnetic poles.[74] However, unlike Jupiter's, Uranus' aurorae seem to be insignificant for the energy balance of the planetary thermosphere.[78] In physics, a charged particle is a particle with an electric charge. ... For other uses, see Proton (disambiguation). ... For other uses, see Electron (disambiguation). ... This article is about the electrically charged particle. ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... The electronvolt (symbol eV) is a unit of energy. ... flux in science and mathematics. ... Please wikify (format) this article as suggested in the Guide to layout and the Manual of Style. ... The Aurora Borealis, or Northern Lights, shines above Bear Lake Aurora Borealis as seen over Canada at 11,000m (36,000 feet) Red and green Aurora in Fairbanks, Alaska Aurora Borealis redirects here. ... The thermosphere is the layer of the earths atmosphere directly above the mesosphere and directly below the exosphere. ...


Climate

Main article: Climate of Uranus
Uranus' southern hemisphere in approximate natural colour (left) and in higher wavelengths (right), showing its faint cloud bands and atmospheric "hood" as seen by Voyager 2
Uranus' southern hemisphere in approximate natural colour (left) and in higher wavelengths (right), showing its faint cloud bands and atmospheric "hood" as seen by Voyager 2

Uranus' atmosphere is remarkably bland in comparison to the other gas giants, even to Neptune, which it otherwise closely resembles.[18] When Voyager 2 flew by Uranus in 1986, it observed a total of ten cloud features across the entire planet.[17][94] One proposed explanation for this dearth of features is that Uranus' internal heat appears markedly lower than that of the other giant planets. The lowest temperature recorded in Uranus' tropopause is 49 K, making Uranus the coldest planet in the Solar System, colder than Neptune.[60][10] Image File history File links Size of this preview: 800 × 423 pixelsFull resolution (864 × 457 pixel, file size: 134 KB, MIME type: image/png) Uranus, http://nssdc. ... Image File history File links Size of this preview: 800 × 423 pixelsFull resolution (864 × 457 pixel, file size: 134 KB, MIME type: image/png) Uranus, http://nssdc. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... Internal heat is the heat source from the interior celestial objects, such as planets, brown dwarfs, and stars, caused by gravity and decaying radioactive materials. ... For other uses, see Neptune (disambiguation). ...


Banded structure, winds and clouds

Zonal wind speeds on Uranus. Shaded areas show the southern collar and its future northern counterpart. The red curve is a symmetrical fit to the data.

In 1986 Voyager 2 found that the visible southern hemisphere of Uranus can be subdivided into two regions: a bright polar cap and dark equatorial bands (see figure on the right).[17] Their boundary is located at about −45 degrees of latitude. A narrow band straddling the latitudinal range from −45 to −50 degrees is the brightest large feature on the visible surface of the planet.[17][95] It is called a southern "collar". The cap and collar are thought to be a dense region of methane clouds located within the pressure range of 1.3 to 2 bar (see above).[96] Unfortunately Voyager 2 arrived during the height of the planet's southern summer and could not observe the northern hemisphere. However, at the beginning of the twenty-first century, when the northern polar region came into view, Hubble Space Telescope (HST) and Keck telescope observed neither a collar nor a polar cap in the northern hemisphere.[95] So Uranus appears to be asymmetric: bright near the south pole and uniformly dark in the region north of the southern collar.[95] Image File history File links Size of this preview: 443 × 600 pixelsFull resolution (1194 × 1616 pixel, file size: 30 KB, MIME type: image/png) The figure shows zonal winds on Uranus as listed in Hammel, H.B.; Rages, K.; Lockwood, G.W.; et. ... Image File history File links Size of this preview: 443 × 600 pixelsFull resolution (1194 × 1616 pixel, file size: 30 KB, MIME type: image/png) The figure shows zonal winds on Uranus as listed in Hammel, H.B.; Rages, K.; Lockwood, G.W.; et. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... This article is about the geographical term. ... Methane is a chemical compound with the molecular formula . ... The bar (symbol bar), decibar (symbol dbar) and the millibar (symbol mbar, also mb) are units of pressure. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... The W. M. Keck Observatory is home to the two largest optical/near-infrared telescopes at the 4,145 meter (13,600 ft) summit of Mauna Kea in Hawaii. ...


In addition to large-scale banded structure, Voyager 2 observed ten small bright clouds, most lying several degrees to the north from the collar.[17] In all other respects Uranus looked like a dynamically dead planet in 1986. However in the 1990s the number of the observed bright cloud features grew considerably.[18] The majority of them were found in the northern hemisphere as it started to become visible.[18] The common explanation of this fact is that bright clouds are easier to identify in the dark part of the planet, whereas in the southern hemisphere the bright collar masks them.[97] Nevertheless there are differences between the clouds of each hemisphere. The northern clouds are smaller, sharper and brighter.[98] They appear to lie at a higher altitude.[98] The lifetime of clouds spans several orders of magnitude. Some small clouds live for hours, while at least one southern cloud has persisted since Voyager flyby.[18][94] Recent observation also discovered that cloud-features on Uranus have a lot in common with those on Neptune, although the weather on Uranus is much calmer.[18] The dark spots common on Neptune had never been observed on Uranus before 2006, when the first such feature was imaged.[99] Altitude is the elevation of an object from a known level or datum. ... For other uses, see Neptune (disambiguation). ...

The first dark spot observed on Uranus. Image obtained by ACS on HST in 2006.

The tracking of numerous cloud features allowed determination of zonal winds blowing in the upper troposphere of Uranus.[18] At the equator winds are retrograde, which means that they blow in the reverse direction to the planetary rotation. Their speeds are from −100 to −50 m/s.[18][95] Wind speeds increase with the distance from the equator, reaching zero values near ±20° latitude, where the troposphere's temperature minimum is located.[59][18] Closer to the poles, the winds shift to a prograde direction, flowing with the planet's rotation. Windspeeds continue to increase reaching maxima at ±60° latitude before falling to zero at the poles.[18] Windspeeds at −40° latitude range from 150 to 200 m/s. Since the collar obscures all clouds below that parallel, speeds between it and the southern pole are impossible to measure.[18] In contrast, in the northern hemisphere maximum speeds as high as 240 m/s are observed near +50 degrees of latitude.[18][95][100] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Introduction The Advanced Camera for Surveys (ACS) is a third generation axial instrument aboard the Hubble Space Telescope (HST). ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ... Look up zonal, meridional in Wiktionary, the free dictionary. ... Atmosphere diagram showing the mesosphere and other layers. ... World map showing the equator in red In tourist areas, the equator is often marked on the sides of roads The equator marked as it crosses Ilhéu das Rolas, in São Tomé and Príncipe. ...


Seasonal variation

Uranus in 2005. Rings, southern collar and a bright cloud in the northern hemisphere are visible.

For a short period from March to May 2004, a number of large clouds appeared in the Uranian atmosphere, giving it a Neptune-like appearance.[98][101] Observations included record-breaking wind speeds of 229 m/s (824 km/h) and a persistent thunderstorm referred to as "Fourth of July fireworks".[94] On August 23, 2006, researchers at the Space Science Institute (Boulder, CO) and the University of Wisconsin observed a dark spot on Uranus' surface, giving astronomers more insight into the planet's atmospheric activity.[99] Why this sudden upsurge in activity should be occurring is not fully known, but it appears that Uranus' extreme axial tilt results in extreme seasonal variations in its weather.[49][102] Determining the nature of this seasonal variation is difficult because good data on Uranus' atmosphere has existed for less than 84 years, or one full Uranian year. A number of discoveries have however been made. Photometry over the course of half a Uranian year (beginning in the 1950s) has shown regular variation in the brightness in two spectral bands, with maxima occurring at the solstices and minima occurring at the equinoxes.[103] A similar periodic variation, with maxima at the solstices, has been noted in microwave measurements of the deep troposphere begun in the 1960s.[104] Stratospheric temperature measurements beginning in 1970s also showed maximum values near 1986 solstice.[75] The majority of this variability is believed to occur due to changes in the viewing geometry.[97] Image File history File links Size of this preview: 257 × 599 pixelsFull resolution (282 × 657 pixel, file size: 29 KB, MIME type: image/jpeg) Image of Uranus obtained in 2005 by ACS on HST. Rings, southern collar and a bright cloud in the northern hemisphere are visible. ... Image File history File links Size of this preview: 257 × 599 pixelsFull resolution (282 × 657 pixel, file size: 29 KB, MIME type: image/jpeg) Image of Uranus obtained in 2005 by ACS on HST. Rings, southern collar and a bright cloud in the northern hemisphere are visible. ... For other uses, see Neptune (disambiguation). ... {| style=float:right; |- | |- | |} is the 235th day of the year (236th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... In astronomy, axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... This article is about divisions of a year. ... Photometry is a technique of astronomy concerned with measuring the flux, or intensity of an astronomical objects electromagnetic radiation. ... Spectral bands are part of optical spectra of polyatomic systems, including condensed materials, large molecules etc. ... “Summer solstice” redirects here. ... For other uses, see Equinox (disambiguation). ... This article is about the type of Electromagnetic radiation. ... Atmosphere diagram showing stratosphere. ... For other uses, see Geometry (disambiguation). ...


However there are some reasons to believe that physical seasonal changes are happening in Uranus. While the planet is known to have a bright south polar region, the north pole is fairly dim, which is incompatible with the model of the seasonal change outlined above.[102] During its previous northern solstice in 1944, Uranus displayed elevated levels of brightness, which suggests that the north pole was not always so dim.[103] This information implies that the visible pole brightens some time before the solstice and darkens after the equinox.[102] Detailed analysis of the visible and microwave data revealed that the periodical changes of brightness are not completely symmetrical around the solstices, which also indicates a change in the meridional albedo patterns.[102] Finally in the 1990s, as Uranus moved away from its solstice, Hubble and ground based telescopes revealed that the south polar cap darkened noticeably (except the southern collar, which remained bright),[96] while the northern hemisphere demonstrates increasing activity,[94] such as cloud formations and stronger winds, bolstering expectations that it should brighten soon.[98] For other uses, see Equinox (disambiguation). ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... This article is about the type of Electromagnetic radiation. ... Meridional is a geographic term that means along a north-south direction, or relative to a meridian (opposite: zonal, east-west). ... For other uses, see Albedo (disambiguation). ... “Summer solstice” redirects here. ... The Hubble Space Telescope (HST; also known colloquially as the Hubble or just Hubble) is a space telescope that was carried into Earth orbit by the Space Shuttle in April 1990. ...


The mechanism of physical changes is still not clear.[102] Near the summer and winter solstices, Uranus' hemispheres lie alternately either in full glare of the Sun's rays or facing deep space. The brightening of the sunlit hemisphere is thought to result from the local thickening of the methane clouds and haze layers located in the troposphere.[96] The bright collar at −45° latitude is also connected with methane clouds.[96] Other changes in the southern polar region can be explained by changes in the lower cloud layers.[96] The variation of the microwave emission from the planet is probably caused by a changes in the deep tropospheric circulation, because thick polar clouds and haze may inhibit convection.[105] Now that the spring and autumn equinoxes are arriving on Uranus, the dynamics are changing and convection can occur again.[94][105] “Summer solstice” redirects here. ... Methane is a chemical compound with the molecular formula . ... For other uses, see Cloud (disambiguation). ... Haze is an atmospheric phenomenon where dust, smoke and other pollutant particles obscure the normal clarity of the sky. ... Atmosphere diagram showing the mesosphere and other layers. ... This article is about the type of Electromagnetic radiation. ... In physics, emission is the process by which the energy of a photon is released by another entity, for example, by an atom whose valence electrons make a transition between two electronic energy levels. ... In fluid dynamics, circulation is the path integral around a closed curve of the fluid velocity. ... For other uses, see Equinox (disambiguation). ...


Formation

See also: Nebular hypothesis

Many argue that the differences between the ice giants and the gas giants extend to their formation.[106][107] The Solar System is believed to have formed from a giant rotating ball of gas and dust known as the presolar nebula. As it condensed, it formed into a disc with a slowly collapsing Sun in the middle.[106][107] Much of the nebula's gas, primarily hydrogen and helium, formed the Sun, while the dust grains collected together to form the first protoplanets. As the planets grew, some of them eventually accreted enough matter for their gravity to hold onto the nebula's leftover gas.[106][107] The more gas they held onto, the larger they became; the larger they became, the more gas they held onto until a critical point was reached, and their size began to increase exponentially. The ice giants, with only a few Earth masses of nebular gas, never reached that critical point.[107][108][106] Current theories of solar system formation have difficulty accounting for the presence of Uranus and Neptune so far out from Jupiter and Saturn. They are too large to have formed from the amount of material expected at that distance. Rather, some scientists expect that both formed closer to the Sun but were scattered outward by Jupiter.[106] However, more recent simulations, which take into account planetary migration, seem to be able to form Uranus and Neptune near their present locations.[107] In this artists conception, a planet spins through a clearing in a nearby stars dusty, planet-forming disc In cosmogony, the nebular hypothesis is the most widely accepted model explaining the formation and evolution of the Solar System. ... This article is about the Solar System. ... A planetary disk forming in the Orion Nebula In this artists conception, of a planet spins through a clearing in a nearby stars dusty, planet-forming disc In cosmogony, the nebular hypothesis is the currently accepted argument about how Earths Solar System formed. ... Planetary migration is the act of a stellar satellite altering its orbital parameters, especially semi-major axis, through various means during its lifetime. ...


Moons

Main article: Moons of Uranus
See also: Timeline of discovery of Solar System planets and their natural satellites
Major moons of Uranus compared, at their proper relative sizes (montage of Voyager 2 photographs)
Major moons of Uranus compared, at their proper relative sizes (montage of Voyager 2 photographs)

Uranus has 27 known natural satellites.[108] The names for these satellites are chosen from characters from the works of Shakespeare and Alexander Pope.[57][109] The five main satellites are Miranda, Ariel, Umbriel, Titania and Oberon.[57] The Uranian satellite system is the least massive among the gas giants; indeed, the combined mass of the five major satellites would be less than half that of Triton alone.[7] The largest of the satellites, Titania, has a radius of only 788.9 km, or less than half that of the Moon, but slightly more than Rhea, the second largest moon of Saturn, making Titania the eighth largest moon in the Solar System. The moons have relatively low albedos; ranging from 0.20 for Umbriel to 0.35 for Ariel (in green light).[17] The moons are ice-rock conglomerates composed of roughly fifty percent ice and fifty percent rock. The ice may include ammonia and carbon dioxide.[110][80] Uranus has twenty-seven known moons. ... This timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. ... Image File history File links Download high resolution version (1726x527, 71 KB) Summary A montage of Voyager 2 photos of the Uranian family of moons. ... Image File history File links Download high resolution version (1726x527, 71 KB) Summary A montage of Voyager 2 photos of the Uranian family of moons. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... -1... Shakespeare redirects here. ... For other uses, see Alexander Pope (disambiguation). ... Miranda (IPA: ) is the smallest and innermost of Uranus five major moons. ... Atmospheric pressure 0 kPa Ariel (air-ee-É™l, IPA ) is a moon of Uranus discovered on 24 October 1851 by William Lassell. ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Not to be confused with the Saturnian moon Titan or the asteroid 593 Titania. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... This article is about Earths moon. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... This is a list of natural satellites in the solar system, ordered from largest to smallest by average diameter. ... This article is about the Solar System. ... For other uses, see Albedo (disambiguation). ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Atmospheric pressure 0 kPa Ariel (air-ee-É™l, IPA ) is a moon of Uranus discovered on 24 October 1851 by William Lassell. ... For other uses, see Ammonia (disambiguation). ... Carbon dioxide (chemical formula: ) is a chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom. ...


Among the satellites, Ariel appears to have the youngest surface with the fewest impact craters, while Umbriel's appears oldest.[17][80] Miranda possesses fault canyons 20 kilometers deep, terraced layers, and a chaotic variation in surface ages and features.[17] Miranda's past geologic activity is believed to have been driven by tidal heating at a time when its orbit was more eccentric than currently, probably as a result of a formerly present 3:1 orbital resonance with Umbriel.[111] Extensional processes associated with upwelling diapirs are likely the origin of the moon's 'racetrack'-like coronae.[112][113] Similarly, Ariel is believed to have once been held in a 4:1 resonance with Titania.[114] Miranda (IPA: ) is the smallest and innermost of Uranus five major moons. ... Tidal acceleration is an effect of the tidal forces between an orbiting natural satellite ( a moon), and the planet (called the primary) that it orbits. ... In celestial mechanics, an orbital resonance occurs when two orbiting bodies exert a regular, periodic gravitational influence on each other. ... In geology, a rift is a place where the Earths lithosphere is expanding. ... A lava lamp illustrates the basic principle of diapirism. ... In planetary geology, a corona (plural: coronae) is an oval-shaped feature. ...


Exploration

Main article: Exploration of Uranus
A picture of Uranus taken by Voyager 2 as it headed to Neptune
A picture of Uranus taken by Voyager 2 as it headed to Neptune

In 1986, NASA's Voyager 2 visited Uranus. This visit is the only attempt to investigate the planet from a short distance and no other visits are currently planned. Launched in 1977, Voyager 2 made its closest approach to Uranus on January 24, 1986, coming within 81,500 kilometers of the planet's cloud tops, before continuing its journey to Neptune. Voyager 2 studied structure and chemical composition of the atmosphere,[65] discovered 10 new moons and studied the planet's unique weather, caused by its axial tilt of 97.77°; and examined its ring system.[115][17] It also studied the magnetic field, its irregular structure, its tilt and its unique corkscrew magnetotail brought on by Uranus' sideways orientation.[88] It made the first detailed investigations of its five largest moons, and studied all nine of the system's known rings, discovering two new ones.[80][17] Uranus viewed from 18 million kilometers. ... Image File history File links Download high-resolution version (794x960, 20 KB) Original Caption Released with Image: This view of Uranus was recorded by Voyager 2 on Jan 25, 1986, as the spacecraft left the planet behind and set forth on the cruise to Neptune Voyager was 1 million kilometers... Image File history File links Download high-resolution version (794x960, 20 KB) Original Caption Released with Image: This view of Uranus was recorded by Voyager 2 on Jan 25, 1986, as the spacecraft left the planet behind and set forth on the cruise to Neptune Voyager was 1 million kilometers... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... For other uses, see NASA (disambiguation). ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... is the 24th day of the year in the Gregorian calendar. ... Year 1986 (MCMLXXXVI) was a common year starting on Wednesday (link displays 1986 Gregorian calendar). ... For other uses, see Neptune (disambiguation). ... Uranus has 27 known moons. ... In astronomy, axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... This is a list of the named planetary rings of Uranus. ... For the indie-pop band, see The Magnetic Fields. ... A magnetosphere is the region around an astronomical object in which phenomena are dominated or organized by its magnetic field. ...


See also

Solar System Portal


Image File history File links Download high resolution version (1024x1274, 113 KB) Original caption released with image This is a montage of planetary images taken by spacecraft managed by the Jet Propulsion Laboratory in Pasadena, CA. Included are (from top to bottom) images of Mercury, Venus, Earth (and Moon), Mars... The planet Uranus has appeared in various forms of fiction: // Mr. ... Planets in astrology have a different meaning to the modern astronomical understanding of what a planet is. ... Some of the moons of the outer planets of the solar system are large enough to be suitable places for colonization. ...


References

  1. ^ Yeomans, Donald K. (July 13, 2006). HORIZONS System. NASA JPL. Retrieved on 2007-08-08. — At the site, go to the "web interface" then select "Ephemeris Type: ELEMENTS", "Target Body: Uranus Barycenter" and "Center: Sun".
  2. ^ Orbital elements refer to the barycenter of the Uranus system, and are the instantaneous osculating values at the precise J2000 epoch. Barycenter quantities are given because, in contrast to the planetary center, they do not experience appreciable changes on a day-to-day basis from to the motion of the moons.
  3. ^ a b c d e f g h i j Williams, Dr. David R. (January 31, 2005). Uranus Fact Sheet. NASA. Retrieved on 2007-08-10.
  4. ^ a b c d e f g h Seidelmann, P. Kenneth; Archinal, B. A.; A’hearn, M. F.; et.al. (2007). "Report of the IAU/IAGWorking Group on cartographic coordinates and rotational elements: 2006". Celestial Mech. Dyn. Astr. 90: 155–180. doi:10.1007/s10569-007-9072-y. 
  5. ^ a b c d e f g Refers to the level of 1 bar atmospheric pressure
  6. ^ a b Munsell, Kirk (May 14, 2007). NASA: Solar System Exploration: Planets: Uranus: Facts & Figures. NASA. Retrieved on 2007-08-13.
  7. ^ a b c Jacobson, R.A.; Campbell, J.K.; Taylor, A.H.; Synnott, S.P. (1992). "The masses of Uranus and its major satellites from Voyager tracking data and Earth-based Uranian satellite data". The Astronomical Journal 103 (6): 2068–2078. doi:10.1086/116211. 
  8. ^ a b c Fred Espenak (2005). Twelve Year Planetary Ephemeris: 1995 - 2006. NASA. Retrieved on 2007-06-14.
  9. ^ a b c d e f g h i j Podolak, M.; Weizman, A.; Marley, M. (1995). "Comparative model of Uranus and Neptune". Planet. Space Sci. 43 (12): 1517–1522. 
  10. ^ a b c d e f g h i j k l m n o p q r s t Lunine, Jonathan. I. (1993). "The Atmospheres of Uranus and Neptune". Annual Review of Astronomy and Astrophysics 31: 217–263. doi:10.1146/annurev.aa.31.090193.001245. 
  11. ^ a b c Lindal, G.F.; Lyons, J.R.; Sweetnam, D.N.; et.al. (1987). "The Atmosphere of Uranus: Results of Radio Occultation Measurements with Voyager 2". J. of Geophys. Res. 92: 14,987-15,001. 
  12. ^ a b B. Conrath et al.. "The helium abundance of Uranus from Voyager measurements". Journal of Geophysical Research 92: 15003-15010. 
  13. ^ Calculation of He, H2 and CH4 molar fractions is based on a 2.3% mixing ratio of methane to hydrogen and the 15/85 He/H2 proportions measured at the tropopause.
  14. ^ Feuchtgruber, H.; Lellouch, E.; B. Bezard; et.al. (1999). "Detection of HD in the atmospheres of Uranus and Neptune: a new determination of the D/H ratio". Astronomy and Astrophysics 341: L17–L21. 
  15. ^ "Uranus". Oxford English Dictionary (Second edition). (1989). 
  16. ^ MIRA's Field Trips to the Stars Internet Education Program. Monterey Institute for Research in Astronomy. Retrieved on 2007-08-27.
  17. ^ a b c d e f g h i j k l m n Smith, B.A.; Soderblom, L.A.; Beebe, A.; et.al. (1986). "Voyager 2 in the Uranian System: Imaging Science Results". Science 233: 97-102. 
  18. ^ a b c d e f g h i j k l m n o Sromovsky, L.A.; Fry, P.M. (2005). "Dynamics of cloud features on Uranus". Icarus 179: 459-483. doi:10.1016/j.icarus.2005.07.022. 
  19. ^ Dunkerson, Duane. Uranus—About Saying, Finding, and Describing It. thespaceguy.com. Retrieved on 2007-04-17.
  20. ^ Bath Preservation Trust. Retrieved on 2007-09-29.
  21. ^ William Herschel. "Account of a Comet, By Mr. Herschel, F. R. S.; Communicated by Dr. Watson, Jun. of Bath, F. R. S.". Philosophical Transactions of the Royal Society of London: 492–501. 
  22. ^ Journal of the Royal Society and Royal Astronomical Society 1, 30, quoted in Ellis D. Miner, Uranus: The Planet, Rings and Satellites, New York, John Wiley and Sons, 1998 p. 8
  23. ^ Royal Astronomical Society MSS W.2/1.2, 23; quoted in Miner p. 8
  24. ^ RAS MSS Herschel W.2/1.2, 24, quoted in Miner p. 8
  25. ^ Journal of the Royal Society and Royal Astronomical Society 1, 30; quoted in Miner p. 8
  26. ^ RAS MSS Herschel W1/13.M, 14 quoted in Miner p. 8
  27. ^ a b George Forbes (1909). History of Astronomy. Retrieved on 2007-08-07.
  28. ^ Johann Elert Bode, Berliner Astronomisches Jahrbuch, p. 210, 1781, quoted in Miner p. 11
  29. ^ Miner p. 11
  30. ^ a b J. L. E. Dreyer, (1912). The Scientific Papers of Sir William Herschel 1. Royal Society and Royal Astronomical Society, 100. 
  31. ^ a b Miner p. 12
  32. ^ RAS MSS Herschel W.1/12.M, 20, quoted in Miner p. 12
  33. ^ "Voyager at Uranus" (1986). NASA JPL 7 (85): 400–268. 
  34. ^ a b Francisca Herschel (1917). The meaning of the symbol H+o for the planet Uranus. The Observatory. Retrieved on 2007-08-05.
  35. ^ a b Littmann, Mark (2004). Planets Beyond: Discovering the Outer Solar System. Courier Dover Publications, pp. 10–11. ISBN 0-486-43602-0. 
  36. ^ Daugherty, Brian. Astronomy in Berlin. Brian Daugherty. Retrieved on 2007-05-24.
  37. ^ Query Results from the ADS Database. Smithsonian/NASA Astrophysics Data System (ADS). Retrieved on 2007-05-24.
  38. ^ Friedrich Magnus Schwerd. "Opposition des Uranus 1821". Astronomische Nachrichten 1: 18–21. 
  39. ^ How to speak like a BBC newsreader. Daily Mail (2006). Retrieved on 2007-12-13.
  40. ^ Mark D Bowles (2006). Science in Flux (PDF). NASA History Series. Retrieved on 2007-08-04.
  41. ^ Planet symbols. NASA Solar System exploration. Retrieved on 2007-08-04.
  42. ^ Sailormoon Terms and Information. The Sailor Senshi Page. Retrieved on 2006-03-05.
  43. ^ "Asian Astronomy 101" (October 1997). Hamilton Amateur Astronomers 4 (11). Retrieved on 2007-08-05. 
  44. ^ Next Stop Uranus (1986). Retrieved on 2007-06-09.
  45. ^ J J O'Connor and E F Robertson (1996). Mathematical discovery of planets. Retrieved on 2007-06-13.
  46. ^ Peter J. Gierasch and Philip D. Nicholson (2004). Uranus. NASA World Book. Retrieved on 2007-06-09.
  47. ^ Lawrence Sromovsky (2006). Hubble captures rare, fleeting shadow on Uranus. University of Wisconsin Madison. Retrieved on 2007-06-09.
  48. ^ Hammel, Heidi B. (September 5, 2006). "Uranus nears Equinox.". A report from the 2006 Pasadena Workshop. 
  49. ^ a b Hubble Discovers Dark Cloud In The Atmosphere Of Uranus. Science Daily. Retrieved on 2007-04-16.
  50. ^ Jay T.Bergstralh, Ellis Miner, Mildred Matthews (1991). Uranus, 485–486. 
  51. ^ Report of the IAU/IAG working group on cartographic coordinates and rotational elements of the planets and satellites: 2000. IAU (2000). Retrieved on 2007-06-13.
  52. ^ Cartographic Standards (PDF). NASA. Retrieved on 2007-06-13.
  53. ^ Coordinate Frames Used in MASL (2003). Retrieved on 2007-06-13.
  54. ^ Moore, Patrick (September). "Observing the green giant". Sky at Night Magazine: 47. 
  55. ^ Gary T. Nowak (2006). Uranus: the Threshold Planet of 2006. Retrieved on 2007-06-14.
  56. ^ a b c Podolak, M.; Podolak, J.I.; Marley, M.S. (2000). "Further investigations of random models of Uranus and Neptune". Planet. Space Sci. 48: 143–151. 
  57. ^ a b c d e f Faure, Gunter & Teresa Mensing (2007), "Uranus: What Happened Here?", in Faure, Gunter; Mensing, Teresa M., Introduction to Planetary Science, Springer Netherlands, DOI 10.1007/978-1-4020-5544-7_18
  58. ^ a b Atreya, S.; Egeler, P.; Baines, K. (2006). "Water-ammonia ionic ocean on Uranus and Neptune?" (pdf). Geophysical Research Abstracts 8: 05179. 
  59. ^ a b c d Hanel, R.; Conrath, B.; Flasar, F.M.; et.al. (1986). "Infrared Observations of the Uranian System". Science 233: 70–74. 
  60. ^ a b c d e f g Pearl, J.C.; Conrath, B.J.; Hanel, R.A.; and Pirraglia, J.A. (1990). "The Albedo, Effective Temperature, and Energy Balance of Uranus as Determined from Voyager IRIS Data". Icarus 84: 12-28. doi:10.1016/0019-1035(90)90155-3. 
  61. ^ David Hawksett (August). "Ten Mysteries of the Solar System: Why is Uranus So Cold?". Astronomy Now: 73. 
  62. ^ a b c dePater, Imke; Romani, Paul N.; Atreya, Sushil K. (1991). "Possible Microwave Absorption in by H2S gas Uranus’ and Neptune’s Atmospheres" (PDF). Icarus 91: 220–233. doi:10.1016/0019-1035(91)90020-T. 
  63. ^ a b c d e Herbert, Floyd; Sandel, B.R.; Yelle, R.V.; et.al. (1987). "The Upper Atmosphere of Uranus: EUV Occultations Observed by Voyager 2" (PDF). J. of Geophys. Res. 92: 15,093-15,109. 
  64. ^ Lodders, Katharin (2003). "Solar System Abundances and Condensation Temperatures of the Elements". The Astrophysical Journal 591: 1220–1247. doi:10.1086/375492. 
  65. ^ a b c d e Tyler, J.L.; Sweetnam, D.N.; Anderson, J.D.; et.al. (1986). "Voyger 2 Radio Science Observations of the Uranian System: Atmosphere, Rings, and Satellites". Science 233: 79–84. 
  66. ^ Mixing ratio is defined as the number of molecules of a compound per a molecule of hydrogen
  67. ^ a b c d e f Bishop, J.; Atreya, S.K.; Herbert, F.; and Romani, P. (1990). "Reanalysis of Voyager 2 UVS Occultations at Uranus: Hydrocarbon Mixing Ratios in the Equatorial Stratosphere" (PDF). Icarus 88: 448–463. doi:10.1016/0019-1035(90)90094-P. 
  68. ^ dePater, Imke; Romani, Paul N.; Atreya, Sushil K. (1989). "Uranius Deep Atmosphere Revealed" (PDF). Icarus 82 (12): 288–313. doi:10.1016/0019-1035(89)90040-7. 
  69. ^ a b c Summers, Michael E.; Strobel, Darrell F. (1989). "Photochemistry of the Atmosphere of Uranus". The Astrophysical Journal 346: 495–508. doi:10.1086/168031. 
  70. ^ a b c d Burgorf, Martin; Orton, Glenn; van Cleve, Jeffrey; et.al. (2006). "Detection of new hydrocarbons in Uranus' atmosphere by infrared spectroscopy". Icarus 184: 634–637. doi:10.1016/j.icarus.2006.06.006. 
  71. ^ a b c Encrenaz, Therese (2003). "ISO observations of the giant planets and Titan: what have we learnt?". Planet. Space Sci. 51: 89–103. doi:10.1016/S0032-0633(02)00145-9. 
  72. ^ a b Encrenaz, Th.; Lellouch, E.; Drossart, P. (2004). "First detection of CO in Uranus" (PDF). Astronomy&Astrophysics 413: L5–L9. doi:10.1051/0004-6361:20034637. Retrieved on 2007-08-05. 
  73. ^ Atreya, Sushil K.; Wong, Ah-San (2005). "Coupled Clouds and Chemistry of the Giant Planets — a Case for Multiprobes". Space Sci. Rev. 116: 121–136. doi:10.1007/s11214-005-1951-5. 
  74. ^ a b c d e f g h i Herbert, Floyd; Sandel, Bill R. (1999). "Ultraviolet Observations of Uranus and Neptune". Planet. Space Sci. 47: 1119–1139. 
  75. ^ a b Young, Leslie A.; Bosh, Amanda S.; Buie, Marc; et.al. (2001). "Uranus after Solstice: Results from the 1998 November 6 Occultation" (PDF). Icarus 153: 236–247. doi:10.1006/icar.2001.6698. 
  76. ^ Trafton, L.M.; Miller, S.; Geballe, T.R.; et.al. (1999). "H2 Quadrupole and H3+ Emission from Uranus: the Uranian Thermosphere, Ionosphere, and Aurora". The Astrophysical Journal 524: 1059–1023. doi:10.1086/307838. 
  77. ^ Encrenaz, Th.; Drossart, P.; Orton, G.; et.al (2003). "The rotational temperature and column density of H+3 in Uranus" (PDF). Planetary and Space Sciences 51: 1013–1016. doi:10.1016/S0032-0633(03)00132-6. 
  78. ^ a b Lam, Hoanh An; Miller, Steven; Joseph, Robert D.; et.al (1997). "Variation in the H+3 emission from Uranus". The Astrophysical Journal 474: L73–L76. doi:10.1086/310424. 
  79. ^ a b Esposito, L. W. (2002). "Planetary rings" (pdf). Reports On Progress In Physics 65: 1741–1783. 
  80. ^ a b c d e Voyager Uranus Science Summary. NASA/JPL (1988). Retrieved on 2007-06-09.
  81. ^ J. L. Elliot, E. Dunham & D. Mink (1977). The rings of Uranus. Cornell University. Retrieved on 2007-06-09.
  82. ^ NASA's Hubble Discovers New Rings and Moons Around Uranus. Hubblesite (2005). Retrieved on 2007-06-09.
  83. ^ a b c d dePater, Imke; Hammel, Heidi B.; Gibbard, Seran G.; Showalter Mark R. (2006). "New Dust Belts of Uranus: Two Ring, red Ring, Blue Ring". Science 312: 92-94. doi:10.1126/science.1125110. 
  84. ^ Sanders, Robert (2006-04-06). Blue ring discovered around Uranus. UC Berkeley News. Retrieved on 2006-10-03.
  85. ^ Stephen Battersby (2006). Blue ring of Uranus linked to sparkling ice. NewScientistSpace. Retrieved on 2007-06-09.
  86. ^ "Uranus rings 'were seen in 1700s'", BBC News, April 19, 2007. Retrieved on 2007-04-19. 
  87. ^ Did William Herschel Discover The Rings Of Uranus In The 18th Century?. Physorg.com (2007). Retrieved on 2007-06-20.
  88. ^ a b c d e f g h i j Ness, Norman F.; Acuna, Mario H.; Behannon, Kenneth W.; et.al. (1986). "Magnetic Fields at Uranus". Science 233: 85-89. 
  89. ^ a b c d e f g Russell, C.T. (1993). "Planetary Magnetospheres" (pdf). Rep. Prog. Phys. 56: 687-732. 
  90. ^ Stanley, Sabine; Bloxham, Jeremy (2004). "Convective-region geometry as the cause of Uranus’ and Neptune’s unusual magnetic fields" (PDF). Letters to Nature 428: 151–153. doi:10.1038/nature02376. Retrieved on 2007-08-05. 
  91. ^ a b c d e f Krimigis, S.M.; Armstrong, T.P.; Axford, W.I.; et.al. (1986). "The Magnetosphere of Uranus: Hot Plasma and radiation Environment". Science 233: 97-102. 
  92. ^ Voyager: Uranus: Magnetosphere. NASA (2003). Retrieved on 2007-06-13.
  93. ^ Bridge, H.S.; Belcher, J.W.; Coppi, B.; et.al. (1986). "Plasma Observations Near Uranus: Initial Results from Voyager 2". Science 233: 89-93. 
  94. ^ a b c d e Emily Lakdawalla (2004). No Longer Boring: 'Fireworks' and Other Surprises at Uranus Spotted Through Adaptive Optics. The Planetary Society. Retrieved on 2007-06-13.
  95. ^ a b c d e Hammel, H.B.; de Pater, I.; Gibbard, S.; et.al. (2005). "Uranus in 2003: Zonal winds, banded structure, and discrete features" (pdf). Icarus 175: 534-545. doi:10.1016/j.icarus.2004.11.012. 
  96. ^ a b c d e Rages, K.A.; Hammel, H.B.; Friedson, A.J. (2004). "Evidence for temporal change at Uranus’ south pole". Icarus 172: 548–554. doi:10.1016/j.icarus.2004.07.009. 
  97. ^ a b Karkoschka, Erich (2001). "Uranus’ Apparent Seasonal Variability in 25 HST Filters". Icarus 151: 84–92. doi:10.1006/icar.2001.6599. 
  98. ^ a b c d Hammel, H.B.; de Pater, I.; Gibbard, S.G.; et.al. (2005). "New cloud activity on Uranus in 2004: First detection of a southern feature at 2.2 µm" (pdf) 175: 284–288. doi:10.1016/j.icarus.2004.11.016. 
  99. ^ a b Sromovsky, L.; Fry, P.;Hammel, H.;Rages, K. Hubble Discovers a Dark Cloud in the Atmosphere of Uranus (pdf). physorg.com. Retrieved on 2007-08-22.
  100. ^ Hammel, H.B.; Rages, K.; Lockwood, G.W.; et.al. (2001). "New Measurements of the Winds of Uranus". Icarus 153: 229-235. doi:10.1006/icar.2001.6689. 
  101. ^ Devitt, Terry (2004). Keck zooms in on the weird weather of Uranus. University of Wisconsin-Madison. Retrieved on 2006-12-24.
  102. ^ a b c d e Hammel, H.B.; Lockwood, G.W. (2007). "Long-term atmospheric variability on Uranus and Neptune". Icarus 186: 291–301. doi:10.1016/j.icarus.2006.08.027. 
  103. ^ a b Lockwood, G.W.; Jerzykiewicz, Mikołaj (2006). "Photometric variability of Uranus and Neptune, 1950–2004". Icarus 180: 442–452. doi:10.1016/j.icarus.2005.09.009. 
  104. ^ Klein, M.J.; Hofstadter, M.D. (2006). "Long-term variations in the microwave brightness temperature of the Uranus atmosphere". Icarus 184: 170–180. doi:10.1016/j.icarus.2006.04.012. 
  105. ^ a b Hofstadter, Mark D.; and Butler, Bryan J. (2003). "Seasonal change in the deep atmosphere of Uranus". Icarus 165: 168–180. doi:10.1016/S0019-1035(03)00174-X. 
  106. ^ a b c d e Thommes, Edward W.; Duncan, Martin J.; Levison, Harold F. (1999). "The formation of Uranus and Neptune in the Jupiter-Saturn region of the Solar System" (pdf). Nature 402: 635-638. doi:10.1038/45185. 
  107. ^ a b c d e Brunini, Adrian; Fernandez, Julio A. (1999). "Numerical simulations of the accretion of Uranus and Neptune". Plan. Space Sci. 47: 591-605. doi:10.1016/S0032-0633(98)00140-8. 
  108. ^ a b Sheppard, Scott S.; Jewitt, David; Kleyna, Jan (2006). "An Ultradeep Survey for Irregular Satellites of Uranus: Limits to Completeness" (PDF). The Astronomical Journal 129: 518-525. doi:10.1086/426329. 
  109. ^ Uranus. nineplanets.org. Retrieved on 2007-07-03.
  110. ^ Hussmann, Hauke; Sohl, Frank; Spohn, Tilman (2006). "Subsurface oceans and deep interiors of medium-sized outer planet satellites and large trans-neptunian objects". Icarus 185: 258-273. doi:10.1016/j.icarus.2006.06.005. 
  111. ^ Tittemore, W. C.; Wisdom, J. (June 1990). "Tidal evolution of the Uranian satellites III. Evolution through the Miranda-Umbriel 3:1, Miranda-Ariel 5:3, and Ariel-Umbriel 2:1 mean-motion commensurabilities". Icarus 85 (2): 394–443. Elsevier Science. doi:10.1016/0019-1035(90)90125-S. 
  112. ^ Pappalardo, R. T.; Reynolds, S. J., Greeley, R. (1997-06-25). "Extensional tilt blocks on Miranda: Evidence for an upwelling origin of Arden Corona". Journal of Geophysical Research 102 (E6): 13,369–13,380. Elsevier Science. 
  113. ^ Chaikin, Andrew (2001-10-16). Birth of Uranus' Provocative Moon Still Puzzles Scientists. Space.Com. Imaginova Corp.. Retrieved on 2007-12-07.
  114. ^ Tittemore, W. C. (1990). "Tidal Heating of Ariel". Icarus 87: 110-139. doi:10.1016/0019-1035(90)90024-4. 
  115. ^ Voyager: The Interstellar Mission: Uranus. JPL (2004). Retrieved on 2007-06-09.

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Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 164th day of the year (165th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 164th day of the year (165th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 165th day of the year (166th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... 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A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Larry W. Esposito is a Professor at the Laboratory for Atmospheric and Space Physics, University of Colorado. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 160th day of the year (161st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 160th day of the year (161st in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 160th day of the year (161st in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 96th day of the year (97th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 276th day of the year (277th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 160th day of the year (161st in leap years) in the Gregorian calendar. ... is the 109th day of the year (110th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 109th day of the year (110th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 171st day of the year (172nd in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 217th day of the year (218th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 164th day of the year (165th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 164th day of the year (165th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 234th day of the year (235th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 358th day of the year (359th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 184th day of the year (185th in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Andrew Chaikin is an author, speaker and space journalist. ... This article is about the year. ... is the 289th day of the year (290th in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 341st day of the year (342nd in leap years) in the Gregorian calendar. ... A digital object identifier (or DOI) is a standard for persistently identifying a piece of intellectual property on a digital network and associating it with related data, the metadata, in a structured extensible way. ... Year 2007 (MMVII) was a common year starting on Monday of the Gregorian calendar in the 21st century. ... is the 160th day of the year (161st in leap years) in the Gregorian calendar. ...

External links

Find more about Uranus on Wikipedia's sister projects:
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  • Edge On! ESO Press Release
  • NASA's Uranus fact sheet
  • Uranus Profile by NASA's Solar System Exploration
  • Keck pictures of Uranus show best view from the ground—Press release with some photographs showing rings, satellites and clouds
  • News reports of December 22, 2005 rings and moons discovery
    • New Moons and Rings found at Uranus, SPACE.com
    • Two more rings discovered around Uranus, MSNBC
  • Planets—Uranus A kid's guide to Uranus.
  • Uranus at Jet Propulsion Laboratory's planetary photojournal.
  • Spring Has Sprung on Uranus
  • Astronomy Cast: Uranus

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Because of technical limitations, some web browsers may not display these glyphs properly. More info… Wikipedia does not have an article with this exact name. ... Image File history File links Wikibooks-logo. ... Image File history File links Wikiquote-logo. ... Image File history File links Wikisource-logo. ... Image File history File links Commons-logo. ... Image File history File links WikiNews-Logo. ... Image File history File links Wikiversity-logo-Snorky. ... is the 356th day of the year (357th in leap years) in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... Space. ... For the news website, see msnbc. ... For the singer/songwriter, see Jon Peter Lewis. ... Uranus has twenty-seven known moons. ... Atmospheric pressure 0 kPa Ariel (air-ee-É™l, IPA ) is a moon of Uranus discovered on 24 October 1851 by William Lassell. ... Miranda (IPA: ) is the smallest and innermost of Uranus five major moons. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Not to be confused with the Saturnian moon Titan or the asteroid 593 Titania. ... Atmospheric pressure 0 kPa Umbriel (um-bree-É™l, IPA ) is a moon of Uranus discovered on 1851-10-24 by William Lassell. ... Image File history File linksMetadata Download high-resolution version (1724x1716, 89 KB) A photo of Uranus taken by Voyager 2. ... The bland face of Uranus, as imaged by Voyager 2 in 1986. ... This is a list of the named planetary rings of Uranus. ... Uranus has twenty-seven known moons. ... For other persons named William Herschel, see William Herschel (disambiguation). ... William Lassell (June 18, 1799 – October 5, 1880) was a British astronomer, born in Bolton, Lancashire, England. ... Uranus viewed from 18 million kilometers. ... Voyager Project redirects here. ... Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ... 15 Orionis has the distinction of being the southern pole star of Uranus. ... An Uranus-crosser asteroid is an asteroid whose orbit crosses that of Uranus. ... The planet Uranus has appeared in various forms of fiction: // Mr. ... This article is about the Solar System. ... Sol redirects here. ... This article is about the planet. ... For other uses, see Venus (disambiguation). ... This article is about Earth as a planet. ... Adjectives: Martian Atmosphere Surface pressure: 0. ... Spectral type: G[8] Absolute magnitude: 3. ... For other uses, see Jupiter (disambiguation). ... This article is about the planet. ... For other uses, see Neptune (disambiguation). ... For other uses, see Pluto (disambiguation). ... Absolute magnitude: −1. ... This article is about the astronomical term. ... Artists impression of Pluto (background) and Charon (foreground). ... A natural satellite or moon is a celestial body that orbits a planet or smaller body, which is called the primary. ... This article is about Earths moon. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale : Phobos (top) and Deimos (bottom). ... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... The Saturnian system (photographic montage) Moons of Saturn (photographic montage) Saturn has 60 confirmed natural satellites, plus three hypothetical moons. ... Uranus has twenty-seven known moons. ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... Hubble image of the Plutonian system Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... A Small Solar System Body (SSSB) is a term defined in 2006 by the International Astronomical Union to describe objects in the Solar System that are neither planets nor dwarf planets: [1] This encompasses: all minor planets apart from the dwarf planets, : the classical asteroids, (except for 1 Ceres, the... Meteor redirects here. ... For other uses, see Asteroid (disambiguation). ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... For other uses, see Asteroid (disambiguation). ... The centaurs are a class of icy planetoids that orbit the Sun between Jupiter and Neptune, named after the mythical race of centaurs. ... A trans-Neptunian object (TNO) is any object in the solar system that orbits the sun at a greater distance on average than Neptune. ... The Kuiper belt, derived from data from the Minor Planet Center. ... Eris, the largest known scattered disc object (center), and its moon Dysnomia (left of center). ... Comet Hale-Bopp Comet West For other uses, see Comet (disambiguation). ... Artists rendering of the Oort cloud and the Kuiper Belt. ... Astronomical objects are significant physical entities, associations or structures which current science has confirmed to exist in space. ... Below is a list of solar system objects with diameter >500km: The Sun, a spectral class G2 star Mercury Venus Earth Moon Mars Jupiter Io Europa Ganymede Callisto complete list of Jupiters natural satellites Saturn Tethys Dione Rhea Titan Iapetus complete list of Saturns natural satellites Uranus Ariel... It has been suggested that Planetary-size comparison be merged into this article or section. ... This is a list of solar system objects by mass, in decreasing order. ... An example of a Web browser (Mozilla Firefox) A web browser is a software application that enables a user to display and interact with text, images, videos, music and other information typically located on a Web page at a website on the World Wide Web or a local area network. ... variant glyphs representing the character a (allographs of a) in the Zapfino typeface. ...


  Results from FactBites:
 
Uranus - Wikipedia, the free encyclopedia (1623 words)
Uranus was the first planet to be discovered that was not known in ancient times; although it had been observed on many previous occasions, it was always mistakenly identified as a star.
Uranus' cyan color is due to the absorption of red light by atmospheric methane.
Uranus' magnetic field is peculiar since it is not originating from the geometric center of the planet and is tilted almost 60° from the axis of rotation.
  More results at FactBites »

 
 

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