The average field at the surface is 0.23 gauss (23 µT).  Ethane and acetylene tend to condense in the colder lower part of stratosphere and tropopause (below 10 mBar level) forming haze layers, which may be partly responsible for the bland appearance of Uranus. , The middle layer of the Uranian atmosphere is the stratosphere, where temperature generally increases with altitude from 53 K (−220 °C; −364 °F) in the tropopause to between 800 and 850 K (527 and 577 °C; 980 and 1,070 °F) at the base of the thermosphere.  Uranus's 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. made of 2/3 water. © 1996-2015 National Geographic Society, © 2015- , One of the hypotheses for this discrepancy suggests that when Uranus was hit by a supermassive impactor, which caused it to expel most of its primordial heat, it was left with a depleted core temperature.  This information implies that the visible pole brightens some time before the solstice and darkens after the equinox. In total, Saturn has a system of 12 rings with 2 divisions.  The Uranian ionosphere is denser than that of either Saturn or Neptune, which may arise from the low concentration of hydrocarbons in the stratosphere. Before the arrival of Voyager 2, no measurements of the Uranian magnetosphere had been taken, so its nature remained a mystery.  In larger amateur telescopes with an objective diameter of between 15 and 23 cm, Uranus appears as a pale cyan disk with distinct limb darkening. The title of is axis is 97.77 degrees (compared to Earth's with is 23.45 degrees.)  The earliest definite sighting was in 1690, when John Flamsteed observed it at least six times, cataloguing it as 34 Tauri. The matter in the rings may once have been part of a moon (or moons) that was shattered by high-speed impacts. All except two rings of Uranus are extremely narrow – they are usually a few kilometres wide. Answered Planet with sideways axis… Uranus. ", Herschel recorded in his journal: "In the quartile near ζ Tauri ... either [a] Nebulous star or perhaps a comet.  The density of low-energy (below 1 kiloelectronvolt) ions in the inner magnetosphere is about 2 cm−3. The French astronomer Pierre Charles Le Monnier observed Uranus at least twelve times between 1750 and 1769, including on four consecutive nights. 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. Our neighboring planet Venus is an oddball in many ways. Jupiter is tilted by 3 degrees, for example, and Earth by 23 degrees. , In December 2005, the Hubble Space Telescope detected a pair of previously unknown rings. The discovery was serendipitous; they planned to use the occultation of the star SAO 158687 (also known as HD 128598) by Uranus to study its atmosphere. Its name is a reference to the Greek god of the sky, Uranus, who, according to Greek mythology, was the grandfather of Zeus (Jupiter) and father of Cronus (Saturn). Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. Before 1986, scientists had expected the magnetic field of Uranus to be in line with the solar wind, because it would then align with Uranus's poles that lie in the ecliptic. To put it in simple terms, momentum is ‘mass in motion’, or the ‘quantity’ of motion that a body possesses. The planet discovered by Herschel (1781) Uranus. As on all the giant planets, its upper atmosphere experiences strong winds in the direction of rotation. Log in. Although the model considered above is reasonably standard, it is not unique; other models also satisfy observations.  The Solar System is hypothesised to have formed from a giant rotating ball of gas and dust known as the presolar nebula.  Swedish astronomer Erik Prosperin proposed the name Neptune, which was supported by other astronomers who liked the idea to commemorate the victories of the British Royal Naval fleet in the course of the American Revolutionary War by calling the new planet even Neptune George III or Neptune Great Britain. No other planet has anywhere near such a tilt.  It is called a southern "collar".  Their boundary is located at about −45° of latitude. heat) part of the spectrum is 1.06±0.08 times the solar energy absorbed in its atmosphere.  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 (47 °C; 116 °F). And would it then still rotate?  For the sake of convenience, a revolving oblate spheroid set at the point at which atmospheric pressure equals 1 bar (100 kPa) is conditionally designated as a "surface". Like the classical planets, Uranus is visible to the naked eye, but it was never recognised as a planet by ancient observers because of its dimness and slow orbit.  A later proposal, ⛢,[h] 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.  Its effects include a drag on small particles orbiting Uranus, causing a general depletion of dust in the Uranian rings.  The intensity of sunlight varies inversely with the square of distance, and so on Uranus (at about 20 times the distance from the Sun compared to Earth) it is about 1/400 the intensity of light on Earth. This article is about the planet.  Methane has prominent absorption bands in the visible and near-infrared (IR), making Uranus aquamarine or cyan in colour.  Near the summer and winter solstices, Uranus's hemispheres lie alternately either in full glare of the Sun's rays or facing deep space.  One hypothesis is that, unlike the magnetic fields of the terrestrial and gas giants, 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. In Chinese, Japanese, Korean, and Vietnamese, its name is literally translated as the "sky king star" (天王星). The new rings bring the total number of Uranian rings to 13. The mixing ratio of carbon monoxide is similar at these altitudes. From numerous pieces of debris that formed as a result of those impacts, only a few particles survived, in stable zones corresponding to the locations of the present rings. The Uranian system has a unique configuration because its axis of rotation is tilted sideways, nearly into the plane of its solar orbit.  Observations show that the ionosphere occupies altitudes from 2,000 to 10,000 km (1,200 to 6,200 mi).  The pronunciation of the name Uranus preferred among astronomers is /ˈjʊərənəs/, with stress on the first syllable as in Latin Ūranus, in contrast to /jʊˈreɪnəs/, with stress on the second syllable and a long a, though both are considered acceptable. , At ultraviolet and visible wavelengths, Uranus's atmosphere is bland in comparison to the other giant planets, even to Neptune, which it otherwise closely resembles. Uranus is a real oddball in our solar system. Uranus reached its most recent equinox on 7 December 2007.  In 1986, images from Voyager 2 showed Uranus as an almost featureless planet in visible light, without the cloud bands or storms associated with the other giant planets. Uranus is the celestial black sheep of our small cosmic family. Mars. , There are some indications that physical seasonal changes are happening in Uranus. [f], Consensus on the name was not reached until almost 70 years after the planet's discovery. 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.  In April 2006, images of the new rings from the Keck Observatory yielded the colours of the outer rings: the outermost is blue and the other one red.  This indeed happened in 2007 when it passed an equinox: a faint northern polar collar arose, and the southern collar became nearly invisible, although the zonal wind profile remained slightly asymmetric, with northern winds being somewhat slower than southern. 1.  This surface is used throughout this article as a zero point for altitudes.  Now that the spring and autumn equinoxes are arriving on Uranus, the dynamics are changing and convection can occur again. Based on the volume within the level of 1 bar atmospheric pressure. You have wandered far from the sun. At some point early in Uranus's history something, perhaps a large impact, probably tipped the planet onto its side, since most planets spin with their axes of …  The lifetime of clouds spans several orders of magnitude.  Voyager 2 also discovered two additional faint rings, bringing the total number to eleven.  In fact the magnetic dipole is shifted from Uranus's centre towards the south rotational pole by as much as one third of the planetary radius. 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".  This impact hypothesis is also used in some attempts to explain the planet's axial tilt. , The tracking of numerous cloud features allowed determination of zonal winds blowing in the upper troposphere of Uranus. The north pole is locked in more than 20 years of darkness in the winter and just as much sunlight in the summer, yet the temperature varies little here on the solar system’s coldest planet. Uranus' axis is tilted at an angle of 98 degrees! Mixing ratio is defined as the number of molecules of a compound per a molecule of hydrogen. At the beginning of the 21st century, when the northern polar region came into view, the Hubble Space Telescope (HST) and Keck telescope initially observed neither a collar nor a polar cap in the northern hemisphere.  Recent simulations of planetary migration have suggested that both ice giants formed closer to the Sun than their present positions, and moved outwards after formation (the Nice model). The rings are probably quite young; the dynamics considerations indicate that they did not form with Uranus. You can’t help but tilt your head as you watch Uranus creep closer on your spaceship’s view screen. If it spun horizontally, extreme winters and summers would doom life as we know it. No other planet has anywhere near such a tilt. closest planet to the Sun. I don't really feel like teaching how to get equations for angles but I'm sure there are many video tutorials on youtube. The total power radiated by Uranus in the far infrared (i.e.  The rings were directly imaged when Voyager 2 passed Uranus in 1986.  Uranus's south pole was pointed almost directly at the Sun at the time of Voyager 2's flyby in 1986. , The outermost layer of the Uranian atmosphere is the thermosphere and corona, which has a uniform temperature around 800 to 850 K. The heat sources necessary to sustain such a high level are not understood, as neither the solar UV nor the auroral activity can provide the necessary energy to maintain these temperatures. , The name of Uranus references the ancient Greek deity of the sky Uranus (Ancient Greek: Οὐρανός), the father of Cronus (Saturn) and grandfather of Zeus (Jupiter), which in Latin became Ūranus (IPA: [ˈuːranʊs]).  Closer to the poles, the winds shift to a prograde direction, flowing with Uranus's rotation.  Ultimately, Bode's suggestion became the most widely used, and became universal in 1850 when HM Nautical Almanac Office, the final holdout, switched from using Georgium Sidus to Uranus.  Besides the large-scale banded structure, Voyager 2 observed ten small bright clouds, most lying several degrees to the north from the collar.  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.  The heating of the stratosphere is caused by absorption of solar UV and IR radiation by methane and other hydrocarbons, which form in this part of the atmosphere as a result of methane photolysis.  A Uranus orbiter and probe was recommended by the 2013–2022 Planetary Science Decadal Survey published in 2011; the proposal envisages launch during 2020–2023 and a 13-year cruise to Uranus. In Mongolian, its name is Tengeriin Van (Тэнгэрийн ван), translated as 'King of the Sky', reflecting its namesake god's role as the ruler of the heavens. Uranus's satellites have relatively low albedos; ranging from 0.20 for Umbriel to 0.35 for Ariel (in green light). Scientists suspect that a planet-size object knocked Uranus sideways in the early days of its formation. The title of is axis is 97.77 degrees (compared to Earth's with is23.45 degrees.)  This value indicates that it is made primarily of various ices, such as water, ammonia, and methane. You can easily improve your search by specifying the number of letters in the answer.  Research by Jacob Kegerreis of Durham University suggests that the tilt resulted from a rock larger than the Earth crashing into the planet 3 to 4 billion years ago. , In English language popular culture, humor is often derived from the common pronunciation of Uranus's name, which resembles that of the phrase "your anus"..  It has the coldest planetary atmosphere in the Solar System, with a minimum temperature of 49 K (−224 °C; −371 °F), and has a complex, layered cloud structure with water thought to make up the lowest clouds and methane the uppermost layer of clouds. Only a narrow strip around the equator experiences a rapid day–night cycle, but with the Sun low over the horizon. It has equatorial and polar radii of 25,559 ± 4 km (15,881.6 ± 2.5 mi) and 24,973 ± 20 km (15,518 ± 12 mi), respectively. Conversely, a direction or plane is said to be horizontal if it is perpendicular to the vertical direction.  Many of these particles probably derive from the thermosphere. The planet with an axis that tilts nearly sideways is Uranus. Uranus is similar in composition to Neptune, and both have bulk chemical compositions which differ from that of the larger gas giants Jupiter and Saturn. The Earth already spins on a slight tilt, causing the seasons.  Such a mission is aided by the ease with which a relatively big mass can be sent to the system—over 1500 kg with an Atlas 521 and 12-year journey.  In 1789, Bode's Royal Academy colleague Martin Klaproth named his newly discovered element uranium in support of Bode's choice. The northern clouds are smaller, sharper and brighter. Its north and south poles, therefore, lie where most other planets have their equators.  The ESA evaluated a "medium-class" mission called Uranus Pathfinder. Journal of the Royal Society and Royal Astronomical Society 1, 30, quoted in, Royal Astronomical Society MSS W.2/1.2, 23; quoted in, Johann Elert Bode, Berliner Astronomisches Jahrbuch, p. 210, 1781, quoted in, Formation and evolution of the Solar System, Timeline of discovery of Solar System planets and their natural satellites, Southern Illinois University Edwardsville, "NASA: Solar System Exploration: Planets: Uranus: Facts & Figures", "The MeanPlane (Invariable plane) of the Solar System passing through the barycenter", JPL Horizons for Uranus (mb=799) and Observer Location: @Sun, "Detection of hydrogen sulfide above the clouds in Uranus's atmosphere", "Voyager 2 in the Uranian System: Imaging Science Results", "MIRA's Field Trips to the Stars Internet Education Program", "Uranus – About Saying, Finding, and Describing It", "Ice Giants: The Discovery of Nepture and Uranus", "The Annual RPI and Average Earnings for Britain, 1209 to Present (New Series)", "Hawaiian Dictionary, Mary Kawena Pukui, Samuel H. Elbert", "Hubble captures rare, fleeting shadow on Uranus", "Hubble Discovers Dark Cloud in the Atmosphere of Uranus", "Science Says: A big space crash likely made Uranus lopsided", "Report of the IAU/IAG working group on cartographic coordinates and rotational elements of the planets and satellites: 2000", Large brightness variations of Uranus at red and near-IR wavelengths, "Twelve Year Planetary Ephemeris: 1995–2006", "Further investigations of random models of Uranus and Neptune", "Water-ammonia ionic ocean on Uranus and Neptune?  In contrast, in the northern hemisphere maximum speeds as high as 860 km/h (540 mph) are observed near +50° latitude.  The majority of this variability is thought to occur owing to changes in the viewing geometry.  The speculation is that Uranus is becoming more Neptune-like during its equinoctial season. Another hypothesis is that some form of barrier exists in Uranus's upper layers that prevents the core's heat from reaching the surface. They are probably also higher than solar values.