“Titan”的概念、定义、翻译、参考文献-科学参考

Titan

Astronomy

The largest satellite of Saturn, and the second-largest satellite in the Solar System, diameter 5150 km; also known as Saturn VI. Titan orbits Saturn in 15.95 days at a distance of 1 221 865 km. Its axial rotation period is the same as its orbital period. At opposition it is magnitude 8.3. It was discovered in 1655 by C. Huygens. Titan is probably composed of rock and ice in about equal parts. It is the only satellite in the Solar System to have a substantial atmosphere, the surface atmospheric pressure being higher than on Earth. The atmosphere is mainly nitrogen, with 2–10% methane, 0.2% hydrogen (molecular percentages), and traces of ethane, propane, ethyne, hydrogen cyanide, and carbon monoxide. The atmospheric pressure at Titan’s surface is 1.5 bar and the temperature about −180°C. Photochemical reactions have generated dense orange clouds of hydrocarbons at a height of 200 km, while layers of atmospheric haze exist up to 500 km. The Voyager probes showed a north polar cap in the clouds of Titan with a slightly darker collar around it. Also, the northern hemisphere was distinctly darker than the southern. These are probably both seasonal effects. The satellite was closely studied by the Cassini–Huygens mission. Radar and spectroscopy revealed a complex surface of hilly terrain and extensive darker fields of dunes. There are a few raised regions, one called Xanadu which appears to show weathering and layered deposits, perhaps of organic matter. The Huygens probe successfully landed on Titan in 2005 in a region of high ground known as Adiri, east of which is a dark lower-lying area called Shangri-la. Adiri is etched by river valleys, fed perhaps by sporadic liquid methane rain. Weathering on Titan is not restricted to fluid erosion. Radar observations by the Cassini craft show what appear to be thousand-kilometre-long dune fields of an unknown material, as well as lakes of liquid methane and other hydrocarbons in the polar regions; the largest of these is Kraken Mare, nearly 1200 km across. One potential source of methane is volcanic activity but this is yet to be confirmed. The Cassini mission also found evidence that Titan has a global subsurface ocean of liquid water and ammonia.
http://photojournal.jpl.nasa.gov/catalog/PIA08398

Space Exploration

The largest moon of the planet Saturn, with a diameter of 5 150 km and a mean distance from Saturn of 1 222 000 km. It was discovered in 1655 by Dutch mathematician and astronomer Christiaan Huygens, and is the second-largest moon in the Solar System (only Ganymede, a moon of Jupiter, is larger).
Titan is the only moon in the Solar System with a substantial atmosphere (mostly nitrogen), topped with smoggy orange clouds that obscure the surface, which may be covered with liquid ethane lakes. Its surface atmospheric pressure is greater than Earth's. Radar signals suggest that Titan has dry land as well as oceans (among the planets, only Earth has both in the Solar System).
The Huygens probe carried aboard NASA's Cassini spacecraft landed on Titan on 14 January 2005.

Geology and Earth Sciences

One of the major satellites of Saturn, with a radius of 2575 km; mass 1345.5 × 10²⁰ kg; mean density 1881 kg/m³; visual albedo 0.21. It was discovered in 1655 by C. Huygens. Titan has a dense atmosphere, with a surface pressure of 0.15 MPa. The atmosphere consists primarily of nitrogen, with up to 6% argon and a small amount of methane. The surface temperature is about 94 K. The Cassini mission reached Titan in 2004 and launched the Huygens lander in 2005. Huygens photographed a landscape marked by features resembling river channels and the shoreline of a dry lake. It is thought that from time to time liquid methane falls to the surface as rain, forming slushy areas and perhaps filling lakes. Data from Cassini also suggests there is an extensive ocean of liquid water beneath the surface shell.

单词	Titan
释义	Titan Astronomy The largest satellite of Saturn, and the second-largest satellite in the Solar System, diameter 5150 km; also known as Saturn VI. Titan orbits Saturn in 15.95 days at a distance of 1 221 865 km. Its axial rotation period is the same as its orbital period. At opposition it is magnitude 8.3. It was discovered in 1655 by C. Huygens. Titan is probably composed of rock and ice in about equal parts. It is the only satellite in the Solar System to have a substantial atmosphere, the surface atmospheric pressure being higher than on Earth. The atmosphere is mainly nitrogen, with 2–10% methane, 0.2% hydrogen (molecular percentages), and traces of ethane, propane, ethyne, hydrogen cyanide, and carbon monoxide. The atmospheric pressure at Titan’s surface is 1.5 bar and the temperature about −180°C. Photochemical reactions have generated dense orange clouds of hydrocarbons at a height of 200 km, while layers of atmospheric haze exist up to 500 km. The Voyager probes showed a north polar cap in the clouds of Titan with a slightly darker collar around it. Also, the northern hemisphere was distinctly darker than the southern. These are probably both seasonal effects. The satellite was closely studied by the Cassini–Huygens mission. Radar and spectroscopy revealed a complex surface of hilly terrain and extensive darker fields of dunes. There are a few raised regions, one called Xanadu which appears to show weathering and layered deposits, perhaps of organic matter. The Huygens probe successfully landed on Titan in 2005 in a region of high ground known as Adiri, east of which is a dark lower-lying area called Shangri-la. Adiri is etched by river valleys, fed perhaps by sporadic liquid methane rain. Weathering on Titan is not restricted to fluid erosion. Radar observations by the Cassini craft show what appear to be thousand-kilometre-long dune fields of an unknown material, as well as lakes of liquid methane and other hydrocarbons in the polar regions; the largest of these is Kraken Mare, nearly 1200 km across. One potential source of methane is volcanic activity but this is yet to be confirmed. The Cassini mission also found evidence that Titan has a global subsurface ocean of liquid water and ammonia. http://photojournal.jpl.nasa.gov/catalog/PIA08398 Space Exploration The largest moon of the planet Saturn, with a diameter of 5 150 km and a mean distance from Saturn of 1 222 000 km. It was discovered in 1655 by Dutch mathematician and astronomer Christiaan Huygens, and is the second-largest moon in the Solar System (only Ganymede, a moon of Jupiter, is larger). Titan is the only moon in the Solar System with a substantial atmosphere (mostly nitrogen), topped with smoggy orange clouds that obscure the surface, which may be covered with liquid ethane lakes. Its surface atmospheric pressure is greater than Earth's. Radar signals suggest that Titan has dry land as well as oceans (among the planets, only Earth has both in the Solar System). The Huygens probe carried aboard NASA's Cassini spacecraft landed on Titan on 14 January 2005. Geology and Earth Sciences One of the major satellites of Saturn, with a radius of 2575 km; mass 1345.5 × 10²⁰ kg; mean density 1881 kg/m³; visual albedo 0.21. It was discovered in 1655 by C. Huygens. Titan has a dense atmosphere, with a surface pressure of 0.15 MPa. The atmosphere consists primarily of nitrogen, with up to 6% argon and a small amount of methane. The surface temperature is about 94 K. The Cassini mission reached Titan in 2004 and launched the Huygens lander in 2005. Huygens photographed a landscape marked by features resembling river channels and the shoreline of a dry lake. It is thought that from time to time liquid methane falls to the surface as rain, forming slushy areas and perhaps filling lakes. Data from Cassini also suggests there is an extensive ocean of liquid water beneath the surface shell.
随便看	secant secant method secant(of a curve) Secchi classification Secchi disc Secchi, Pietro Angelo Secchi, (Pietro) Angelo (1818–78) SECDED secession sech second second(angular measure) second arrival secondary air mass secondary alcohol secondary amine secondary blasting secondary cell secondary cell wall secondary colour secondary consumer secondary cosmic ray secondary crater secondary creep Haller, Albrecht von