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Atmosphere Of Uranus
The atmosphere of Uranus is composed primarily of hydrogen and helium. At depth it is significantly enriched in volatiles (dubbed "ices") such as water, ammonia and methane. The opposite is true for the upper atmosphere, which contains very few gases heavier than hydrogen and helium due to its low temperature. Uranus's atmosphere is the coldest of all the planets, with its temperature reaching as low as 49 K. The Uranian atmosphere can be divided into five main layers: the troposphere, between altitudes of −300 and 50 km and pressures from 100 to 0.1 bar; the stratosphere, spanning altitudes between 50 and 4000 km and pressures of between and the hot thermosphere (and exosphere) extending from an altitude of 4,056 km to several Uranian radii from the nominal surface at 1 bar pressure. Unlike Earth's, Uranus's atmosphere has no mesosphere. The troposphere hosts four cloud layers: methane clouds at about 1.2 bar, hydrogen sulfide and ammonia clou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranus As Seen By NASA's Voyager 2 (remastered)
Uranus is the seventh planet from the Sun. Its name is a reference to the Greek god of the sky, Uranus (Caelus), who, according to Greek mythology, was the great-grandfather of Ares (Mars), grandfather of Zeus (Jupiter) and father of Cronus (Saturn). It has the third-largest planetary radius and fourth-largest planetary mass in the Solar System. 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. For this reason, scientists often classify Uranus and Neptune as "ice giants" to distinguish them from the other giant planets. As with gas giants, ice giants also lack a well defined "solid surface." Uranus's atmosphere is similar to Jupiter's and Saturn's in its primary composition of hydrogen and helium, but it contains more " ices" such as water, ammonia, and methane, along with traces of other hydrocarbons. It has the coldest planetary atmosphere in the Solar System, with a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Hydrosulfide
Ammonium hydrosulfide is the chemical compound with the formula . Composition It is the salt derived from the ammonium cation and the hydrosulfide anion. The salt exists as colourless, water-soluble, micaceous crystals. On Earth the compound is encountered mainly as a solution, not as the solid, but ice is believed to be a substantial component of the cloud decks of the gas-giant planets Jupiter and Saturn, with sulfur produced by its photolysis responsible for the color of some of those planets' clouds. It can be generated by mixing hydrogen sulfide and ammonia. Preparation Solutions of ammonium hydrosulfide can be prepared by passing hydrogen sulfide gas through concentrated ammonia solution. According to a detailed 1895 report, hydrogen sulfide reacts with concentrated aqueous ammonia solution at room temperature to give . When this species is cooled to 0 °C and treated with additional hydrogen sulfide, one obtains . An ice-cold solution of this substance kept a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rupert Wildt
Rupert Wildt (; June 25, 1905 – January 9, 1976) was a Germany, German-United States, American astronomer. He was born in Munich, German Empire, Germany, and grew up in that country during World War I and its aftermath. In 1927 he was awarded a Ph.D. from the University of Berlin. He joined the University of Göttingen, specializing in the properties of Celestial body atmosphere, atmospheres. In 1932 he studied the Astronomical spectroscopy, spectra of Jupiter, and other outer planets, and identified certain absorption bands as belonging to the hydrogen-rich compounds of methane and ammonia. The composition appeared consistent with a composition similar to the sun and other stars. Assuming that the atmosphere was composed of these gases, during the 1940s and 1950s he constructed a model of the structure of these planets. He believed the core of the planets is solid and composed of a mixture of rock and metal, covered by a thick outer shell of ice, overlaid by a dense atmosp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Charles Trépied
Charles is a masculine given name predominantly found in English and French speaking countries. It is from the French form ''Charles'' of the Proto-Germanic name (in runic alphabet) or ''*karilaz'' (in Latin alphabet), whose meaning was "free man". The Old English descendant of this word was '' Ċearl'' or ''Ċeorl'', as the name of King Cearl of Mercia, that disappeared after the Norman conquest of England. The name was notably borne by Charlemagne (Charles the Great), and was at the time Latinized as ''Karolus'' (as in ''Vita Karoli Magni''), later also as '' Carolus''. Some Germanic languages, for example Dutch and German, have retained the word in two separate senses. In the particular case of Dutch, ''Karel'' refers to the given name, whereas the noun ''kerel'' means "a bloke, fellow, man". Etymology The name's etymology is a Common Germanic noun ''*karilaz'' meaning "free man", which survives in English as churl (< Old English ''ċeorl''), which developed its depr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Henri Joseph Perrotin
Henri Joseph Anastase Perrotin (December 19, 1845 – February 29, 1904) was a French astronomer and a discoverer of minor planets. Some sources give his middle name as Athanase. In his early career, he and Guillaume Bigourdan were assistants of Félix Tisserand at Toulouse Observatory. Later, he was the first director of the Nice Observatory in Nice, France from 1884 until his death. He made observations of Mars and attempted to determine the rotation period of Venus. He also calculated perturbations in the orbit of 4 Vesta. In the literature, he is sometimes referred to as Henri Perrotin and sometimes as Joseph Perrotin (this is indeed one and the same person). He is also referenced in H.G Well's novel "The War of The Worlds" as "Perrotin of Nice". His 6 asteroid discoveries are credited by the Minor Planet Center to "J. Perrotin". He won the Prix Lalande in 1875 and 1883. The Martian crater '' Perrotin'' and the inner main-belt asteroid 1515 Perrotin were name ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Norman Lockyer
Sir Joseph Norman Lockyer (17 May 1836 – 16 August 1920) was an English scientist and astronomer. Along with the French scientist Pierre Janssen, he is credited with discovering the gas helium. Lockyer also is remembered for being the founder and first editor of the influential journal ''Nature''. Biography Lockyer was born in Rugby, Warwickshire. His early introduction to science was through his father, who was a pioneer of the electric telegraph. After a conventional schooling supplemented by travel in Switzerland and France, he worked for some years as a civil servant in the British War Office. He settled in Wimbledon, South London after marrying Winifred James, who helped translate at least four French scientific works into English. He was a keen amateur astronomer with a particular interest in the Sun. In 1885 he became the world's first professor of astronomical physics at the Royal College of Science, South Kensington, now part of Imperial College. At the college ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fraunhofer Lines
In physics and optics, the Fraunhofer lines are a set of spectral absorption lines named after the German physicist Joseph von Fraunhofer (1787–1826). The lines were originally observed as dark features (absorption lines) in the optical spectrum of the Sun (white light) . Discovery In 1802, the English chemist William Hyde WollastonMelvyn C. UsselmanWilliam Hyde WollastonEncyclopædia Britannica, retrieved 31 March 2013 was the first person to note the appearance of a number of dark features in the solar spectrum. In 1814, Fraunhofer independently rediscovered the lines and began to systematically study and measure the wavelengths where these features are observed. He mapped over 570 lines, designating the principal features (lines) with the letters A through K and weaker lines with other letters. Modern observations of sunlight can detect many thousands of lines. About 45 years later, Kirchhoff and Bunsen noticed that several Fraunhofer lines coincide with characteristic em ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Huggins
Sir William Huggins (7 February 1824 – 12 May 1910) was an English astronomer best known for his pioneering work in astronomical spectroscopy together with his wife, Margaret. Biography William Huggins was born at Cornhill, Middlesex, in 1824. In 1875, he married Margaret Lindsay, daughter of John Murray of Dublin, who also had an interest in astronomy and scientific research. She encouraged her husband's photography and helped to put their research on a systematic footing. Huggins built a private observatory at 90 Upper Tulse Hill, London, from where he and his wife carried out extensive observations of the spectral emission lines and absorption lines of various celestial objects. On 29 August 1864, Huggins was the first to take the spectrum of a planetary nebula when he analysed NGC 6543. He was also the first to distinguish between nebulae and galaxies by showing that some (like the Orion Nebula) had pure emission spectra characteristic of gas, while others ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angelo Secchi
Angelo Secchi (; 28 June 1818 – 26 February 1878) was an Italian Catholic priest, astronomer from the Italian region of Emilia. He was director of the observatory at the Pontifical Gregorian University (then called the Roman College) for 28 years. He was a pioneer in astronomical spectroscopy, and was one of the first scientists to state authoritatively that the Sun is a star. Biography Secchi was born in Reggio Emilia, where he studied at the Jesuit gymnasium. At the age of 16, he entered the Jesuit Order in Rome. He continued his studies at the Roman College, and demonstrated great scientific ability. In 1839, he was appointed tutor of mathematics and physics at the college. In 1841, he became professor of physics at the Jesuit College in Loreto. In 1844, he began theological studies in Rome, and was ordained a priest on 12 September 1847. In 1848, due to the Roman Revolution, the Jesuits were ordered to leave Rome. Angelo Secchi spent the next two years in the United Ki ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kelvin (unit)
The kelvin, symbol K, is the primary unit of temperature in the International System of Units (SI), used alongside its prefixed forms and the degree Celsius. It is named after the Belfast-born and University of Glasgow-based engineer and physicist William Thomson, 1st Baron Kelvin (1824–1907). The Kelvin scale is an absolute thermodynamic temperature scale, meaning it uses absolute zero as its null (zero) point. Historically, the Kelvin scale was developed by shifting the starting point of the much-older Celsius scale down from the melting point of water to absolute zero, and its increments still closely approximate the historic definition of a degree Celsius, but since 2019 the scale has been defined by fixing the Boltzmann constant to be exactly . Hence, one kelvin is equal to a change in the thermodynamic temperature that results in a change of thermal energy by . The temperature in degree Celsius is now defined as the temperature in kelvins minus 273.15, meaning ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmosphere
An atmosphere () is a layer of gas or layers of gases that envelop a planet, and is held in place by the gravity of the planetary body. A planet retains an atmosphere when the gravity is great and the temperature of the atmosphere is low. A stellar atmosphere is the outer region of a star, which includes the layers above the opaque photosphere; stars of low temperature might have outer atmospheres containing compound molecules. The atmosphere of Earth is composed of nitrogen (78%), oxygen (21%), argon (0.9%), carbon dioxide (0.04%) and trace gases. Most organisms use oxygen for respiration; lightning and bacteria perform nitrogen fixation to produce ammonia that is used to make nucleotides and amino acids; plants, algae, and cyanobacteria use carbon dioxide for photosynthesis. The layered composition of the atmosphere minimises the harmful effects of sunlight, ultraviolet radiation, the solar wind, and cosmic rays to protect organisms from genetic damage. The current comp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Adding To Uranus's Legacy
Addition (usually signified by the plus symbol ) is one of the four basic operations of arithmetic, the other three being subtraction, multiplication and division. The addition of two whole numbers results in the total amount or '' sum'' of those values combined. The example in the adjacent image shows a combination of three apples and two apples, making a total of five apples. This observation is equivalent to the mathematical expression (that is, "3 ''plus'' 2 is equal to 5"). Besides counting items, addition can also be defined and executed without referring to concrete objects, using abstractions called numbers instead, such as integers, real numbers and complex numbers. Addition belongs to arithmetic, a branch of mathematics. In algebra, another area of mathematics, addition can also be performed on abstract objects such as vectors, matrices, subspaces and subgroups. Addition has several important properties. It is commutative, meaning that the order of the operands ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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