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Venus Snow
Venus snow is a brightening of the radar reflection from the surface of Venus at high elevations. The "snow" appears to be a mineral condensate of lead(II) sulfide and bismuth sulfide precipitated from the atmosphere at altitudes above . The nature of the "snow" was initially unknown. In radar images, smooth surfaces such as lava plains generally appear dark, while rough surfaces such as impact debris appear bright. The composition of the rock also alters the radar return: conductive material, or material with a high dielectric constant, appears brighter. It was therefore initially difficult to determine whether the high-altitude areas of Venus were different from the lowlands in chemical composition or in texture. Possible explanations included loose soil, different rates of weathering at high and low elevations, and chemical deposition at high elevation. It could not be water ice, which cannot exist in the extremely hot, dry conditions of the Venusian surface. Data from the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxwell Montes Of Planet Venus
Maxwell may refer to: People * Maxwell (surname), including a list of people and fictional characters with the name ** James Clerk Maxwell, mathematician and physicist * Justice Maxwell (other) * Maxwell baronets, in the Baronetage of Nova Scotia * Maxwell (footballer, born 1979), Brazilian forward * Maxwell (footballer, born 1981), Brazilian left-back * Maxwell (footballer, born 1986), Brazilian striker * Maxwell (footballer, born 1989), Brazilian left-back * Maxwell (footballer, born 1995), Brazilian forward * Maxwell (musician) (born 1973), American R&B and neo-soul singer * Maxwell (rapper) (born 1993), German rapper, member of rap band 187 Strassenbande * Maxwell Jacob Friedman (born 1996), American professional wrestler * Maxwell Silva (born 1953), Sri Lankan Sinhala Catholic cleric, Archdiocese of Colombo, Auxiliary Bishop of Colombo Places United States * Maxwell, California * Maxwell, Indiana * Maxwell, Iowa * Maxwell, Nebraska * Maxwell, New Mexico * Maxwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Venus
Venus is the second planet from the Sun. It is often called Earth's "twin" or "sister" planet for having almost the same size and mass, and the closest orbit to Earth's. While both are rocky planets, Venus has an atmosphere much thicker and denser than Earth and any other rocky body in the Solar System. Its atmosphere is composed of mostly carbon dioxide (), with a global sulfuric acid cloud cover and no liquid water. At the mean surface level the atmosphere reaches a temperature of and a pressure 92 times greater than Earth's at sea level, turning the lowest layer of the atmosphere into a supercritical fluid. Venus is the third brightest object in Earth's sky, after the Moon and the Sun, and, like Mercury, appears always relatively close to the Sun, either as a "morning star" or an "evening star", resulting from orbiting closer ( inferior) to the Sun than Earth. The orbits of Venus and Earth make the two planets approach each other in synodic periods of 1.6 years ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead(II) Sulfide
Lead(II) sulfide (also spelled '' sulphide'') is an inorganic compound with the formula Pb S. Galena is the principal ore and the most important compound of lead. It is a semiconducting material with niche uses. Formation, basic properties, related materials Addition of hydrogen sulfide or sulfide salts to a solution containing a lead salt, such as PbCl2, gives a black precipitate of lead sulfide. : Pb2+ + H2S → PbS↓ + 2 H+ This reaction is used in qualitative inorganic analysis. The presence of hydrogen sulfide or sulfide ions may be tested using "lead acetate paper." Like the related materials PbSe and PbTe, PbS is a semiconductor. In fact, lead sulfide was one of the earliest materials to be used as a semiconductor. Lead sulfide crystallizes in the sodium chloride motif, unlike many other IV-VI semiconductors. Since PbS is the main ore of lead, much effort has focused on its conversion. A major process involves smelting of PbS followed by reduction of the re ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bismuth Sulfide
Bismuth(III) sulfide () is a chemical compound of bismuth and sulfur. It occurs in nature as the mineral bismuthinite. Synthesis Bismuth(III) sulfide can be prepared by reacting a bismuth(III) salt with hydrogen sulfide: : Bismuth (III) sulfide can also be prepared by the reaction of elemental bismuth and elemental sulfur in an evacuated silica tube at 500 °C for 96 hours. : Properties Bismuth(III) sulfide is isostructural with stibnite (stibnite is one of the forms of antimony(III) sulfide). Bismuth atoms are in two different environments, both of which have 7 coordinate Bismuth atoms, 4 in a near planar rectangle and three more distant making an irregular 7-coordination group. It can react with acids to produce the odoriferous hydrogen sulfide gas. Bismuth(III) sulfide may be produced in the body by the reaction of the common gastrointestinal drug bismuth subsalicylate Bismuth subsalicylate, sold generically as pink bismuth and under brand names including Pepto-B ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Washington University In St
Washington most commonly refers to: * George Washington (1732–1799), the first president of the United States * Washington (state), a state in the Pacific Northwest of the United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on Washington, D.C. Washington may also refer to: Places England * Washington Old Hall, ancestral home of the family of George Washington * Washington, Tyne and Wear, a town in the City of Sunderland metropolitan borough * Washington, West Sussex, a village and civil parish Greenland * Cape Washington, Greenland * Washington Land Philippines *New Washington, Aklan, a municipality *Washington, a barangay in Catarman, Northern Samar *Washington, a barangay in Escalante, Negros Occidental *Washington, a barangay in San Jacinto, Masbate *Washington, a barangay in Surigao City United States * Fort Washington (disambiguati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
BBC News
BBC News is an operational business division of the British Broadcasting Corporation (BBC) responsible for the gathering and broadcasting of news and current affairs in the UK and around the world. The department is the world's largest broadcast news organisation and generates about 120 hours of radio and television output each day, as well as online news coverage. The service has over 5,500 journalists working across its output including in 50 foreign news bureaus where more than 250 foreign correspondents are stationed. Deborah Turness has been the CEO of news and current affairs since September 2022. In 2019, it was reported in an Ofcom report that the BBC spent £136m on news during the period April 2018 to March 2019. BBC News' domestic, global and online news divisions are housed within the largest live newsroom in Europe, in Broadcasting House in central London. Parliamentary coverage is produced and broadcast from studios in London. Through BBC English Regions, th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dielectric Constant
The relative permittivity (in older texts, dielectric constant) is the permittivity of a material expressed as a ratio with the electric permittivity of a vacuum. A dielectric is an insulating material, and the dielectric constant of an insulator measures the ability of the insulator to store electric energy in an electrical field. Permittivity is a material's property that affects the Coulomb force between two point charges in the material. Relative permittivity is the factor by which the electric field between the charges is decreased relative to vacuum. Likewise, relative permittivity is the ratio of the capacitance of a capacitor using that material as a dielectric, compared with a similar capacitor that has vacuum as its dielectric. Relative permittivity is also commonly known as the dielectric constant, a term still used but deprecated by standards organizations in engineering as well as in chemistry. Definition Relative permittivity is typically denoted as (som ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pioneer Venus Project
The Pioneer Venus project was part of the Pioneer program consisting of two spacecraft, the Pioneer Venus Orbiter and the Pioneer Venus Multiprobe, launched to Venus in 1978. The program was managed by NASA's Ames Research Center. The Pioneer Venus Orbiter entered orbit around Venus on December 4, 1978, and performed observations to characterize the atmosphere and surface of Venus. It continued to transmit data until October 1992. The Pioneer Venus Multiprobe deployed four small probes into the Venusian atmosphere on December 9, 1978. All four probes transmitted data throughout their descent to the surface. One probe survived the landing and transmitted data from the surface for over an hour. Overview The Pioneer mission consisted of two components, launched separately: an orbiter and a multiprobe. Orbiter The orbiter was launched on May 20, 1978 on an Atlas-Centaur rocket. The orbiter's mass was . The Pioneer Venus Orbiter was inserted into an elliptical orbit around V ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Iron Pyrite
The mineral pyrite ( ), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of ''fool's gold''. The color has also led to the nicknames ''brass'', ''brazzle'', and ''brazil'', primarily used to refer to pyrite found in coal. The name ''pyrite'' is derived from the Greek (), 'stone or mineral which strikes fire', in turn from (), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what is now called pyrite. By Georgius Agricola's time, , the term had become a generic term for all of the sulfide minerals. Pyrite is usually found associated with other sulfides or oxides in q ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Weathering
Weathering is the deterioration of rocks, soils and minerals (as well as wood and artificial materials) through contact with water, atmospheric gases, sunlight, and biological organisms. It occurs '' in situ'' (on-site, with little or no movement), and so is distinct from erosion, which involves the transport of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity. Weathering processes are either physical or chemical. The former involves the breakdown of rocks and soils through such mechanical effects as heat, water, ice and wind. The latter covers reactions to water, atmospheric gases and biologically produced chemicals with rocks and soils. Water is the principal agent behind both kinds, though atmospheric oxygen and carbon dioxide and the activities of biological organisms are also important. Biological chemical weathering is also called biological weathering. The materials left after the rock breaks down combine with organic material to create so ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magellan Probe
The ''Magellan'' spacecraft was a robotic space probe launched by NASA on May 4, 1989. Its mission objectives were to map the surface of Venus by using synthetic-aperture radar and to measure the planetary gravitational field. The ''Magellan'' probe was the first interplanetary mission to be launched from the Space Shuttle, the first one to use the Inertial Upper Stage booster, and the first spacecraft to test aerobraking as a method for circularizing its orbit. ''Magellan'' was the fifth successful NASA mission to Venus, and it ended an eleven-year gap in U.S. interplanetary probe launches. History Beginning in the late 1970s, scientists advocated for a radar mapping mission to Venus. They first sought to construct a spacecraft named the '' Venus Orbiting Imaging Radar'' (VOIR), but it became clear that the mission would be beyond the budget constraints during the ensuing years. The VOIR mission was canceled in 1982. A simplified radar mission proposal was recommended by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tellurium
Tellurium is a chemical element; it has symbol Te and atomic number 52. It is a brittle, mildly toxic, rare, silver-white metalloid. Tellurium is chemically related to selenium and sulfur, all three of which are chalcogens. It is occasionally found in its native form as elemental crystals. Tellurium is far more common in the Universe as a whole than on Earth. Its extreme rarity in the Earth's crust, comparable to that of platinum, is due partly to its formation of a volatile hydride that caused tellurium to be lost to space as a gas during the hot nebular formation of Earth. Tellurium-bearing compounds were first discovered in 1782 in a gold mine in Kleinschlatten, Transylvania (now Zlatna, Romania) by Austrian mineralogist Franz-Joseph Müller von Reichenstein, although it was Martin Heinrich Klaproth who named the new element in 1798 after the Latin 'earth'. Gold telluride minerals are the most notable natural gold compounds. However, they are not a commercially signif ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
