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Encyclopedia > Titan (moon)
Titan

Titan seen from the Cassini–Huygens spacecraft.
Discovery
Discovered by: Christiaan Huygens
Discovery date: March 25, 1655
Orbital characteristics[1]
Semi-major axis: 1,221,870 km
Eccentricity: 0.0288
Orbital period: 15.94542 days
Inclination: 0.34854° (to Saturn's equator)
Satellite of: Saturn
Physical characteristics
Mean radius: 2575.50 ± 2.00 km (0.404 Earths) [2]
Surface area: 8.3×107 km²
Mass: 1.34520029 ± 0.00020155×1023 kg (0.0225 Earths)[2]
Mean density: 1.8798 ± 0.0044 g/cm³[2]
Equatorial surface gravity: 1.352 m/s2 (0.14 g)
Escape velocity: 2.639 km/s
Rotation period: (synchronous)
Axial tilt: zero
Albedo: 0.21
Temperature: 90 K (−297°F)
Atmosphere
Surface pressure: 146.7 kPa
Composition: 98.4% nitrogen
1.6% methane

Titan (/ˈtaɪ.tən/, from Ancient Greek Τῑτάν) or Saturn VI is the largest moon of Saturn and the only moon known to have a dense atmosphere.[3] It is the twentieth most distant moon of Saturn and sixth farthest among those large enough to assume a spheroid shape. Roughly 50% larger than Earth's moon by diameter and 80% more massive , Titan is the second largest moon in the Solar System, after Jupiter's moon Ganymede.[3] It is larger by diameter than the smallest planet Mercury and about half as massive; it is frequently described as a satellite with planet-like characteristics. It was the first known moon of Saturn, discovered on March 25, 1655, by the Dutch astronomer Christiaan Huygens.[4] Titan reaches an angular distance of about 20 Saturn radii (just over 1.2 million kilometers) from Saturn and subtends a disk 0.8 arcseconds in diameter. Image File history File linksMetadata Titan_in_natural_color_Cassini. ... Cassini–Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ... Christiaan Huygens (pronounced in English (IPA): ; in Dutch: ) (April 14, 1629 – July 8, 1695), was a Dutch mathematician, astronomer and physicist; born in The Hague as the son of Constantijn Huygens. ... is the 84th day of the year (85th in leap years) in the Gregorian calendar. ... Events March 25 - Saturns largest moon, Titan, is discovered by Christian Huygens. ... Two bodies with a slight difference in mass orbiting around a common barycenter. ... 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. ... 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). ... (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. ... Inclination in general is the angle between a reference plane and another plane or axis of direction. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Atmospheric characteristics Atmospheric pressure 140 kPa Hydrogen >93% Helium >5% Methane 0. ... In mathematics, a spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. ... Square kilometre (U.S. spelling: square kilometer), symbol km², is a decimal multiple of SI unit of surface area square metre, one of the SI derived units. ... This article or section is in need of attention from an expert on the subject. ... The kilogram or kilogramme (symbol: kg) is the SI base unit of mass. ... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... BIC pen cap, about 1 gram. ... A cubic centimetre (cm3) is an SI derived unit of volume, equal to the volume of a cube with side length of 1 centimetre. ... 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 at any point on a velocity-time graph, it is given by the slope of the tangent to that point basicly. ... 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. ... Due to synchronous rotation of their moon, the inhabitants of the central body will never be able to see its green side. ... In astronomy, Axial tilt is the inclination angle of a planets rotational axis in relation to a perpendicular to its orbital plane. ... Albedo is the ratio of reflected to incident electromagnetic radiation. ... This article includes a list of works cited or a list of external links, but its sources remain unclear because it lacks in-text citations. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ... Diurnal (daily) rhythm of air pressure in northern Germany (black curve is air pressure) Atmospheric pressure is the pressure at any point in the Earths atmosphere. ... The pascal (symbol: Pa) is the SI derived unit of pressure or stress (also: Youngs modulus and tensile strength). ... General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Methane is a chemical compound with the molecular formula CH4. ... Note: This article contains special characters. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Adjectives: Saturnian Atmosphere [3] Scale height: 59. ... Atmosphere is the general name for a layer of gases that may surround a material body of sufficient mass. ... In mathematics, a spheroid is a quadric surface in three dimensions obtained by rotating an ellipse about one of its principal axes. ... Apparent magnitude: up to -12. ... This article or section is in need of attention from an expert on the subject. ... This is a list of natural satellites in the solar system, ordered from largest to smallest by average diameter. ... Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ... Adjectives: Jovian Atmosphere [4] Surface pressure: 20–200 kPa[9] (cloud layer) Scale height: 27 km Composition: Jupiter (IPA: or ) is the fifth planet from the Sun and the largest planet within the solar system. ... This article or section does not adequately cite its references or sources. ... This article is about the planet. ... is the 84th day of the year (85th in leap years) in the Gregorian calendar. ... Events March 25 - Saturns largest moon, Titan, is discovered by Christian Huygens. ... Christiaan Huygens (pronounced in English (IPA): ; in Dutch: ) (April 14, 1629 – July 8, 1695), was a Dutch mathematician, astronomer and physicist; born in The Hague as the son of Constantijn Huygens. ... A second of arc or arcsecond is a unit of angular measurement which comprises one-sixtieth of an arcminute, or 1/3600 of a degree of arc or 1/1296000 ≈ 7. ...


Titan is primarily composed of water ice and rocky material. The dense atmosphere prevented understanding of Titan's surface until new information accumulated with the arrival of the Cassini–Huygens mission in 2004, including the discovery of liquid hydrocarbon lakes near the satellite's north pole. These are the only large, stable bodies of surface liquid known to exist anywhere other than Earth. The surface is geologically young; although mountains and cryovolcanoes have been discovered, it is relatively smooth and few impact craters have been discovered. Cassini–Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... This article is about Earth as a planet. ... Ganesa Macula, a dark feature on Saturns moon Titan, might be a cryovolcanic dome. ...


The atmosphere of Titan is largely composed of nitrogen and its climate includes methane and ethane clouds. The climate—including wind and rain—creates surface features that are similar to those on Earth, such as sand dunes and shorelines. With its solvents (both surface and subsurface) and robust nitrogen atmosphere, Titan is viewed as analoguous to the early Earth, although at much lower temperature. The satellite has thus been cited as a possible host for microbial extraterrestrial life or, at least, as a prebiotic environment revealing of complex organic chemistry. Researchers have suggested possible underground liquid oceans might serve as a biotic environment.[5][6] General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Methane is a chemical compound with the molecular formula CH4. ... Ethane is a chemical compound with chemical formula C2H6. ... A microorganism or microbe is an organism that is so small that it is microscopic (invisible to the naked eye). ... “Green people” redirects here. ...

Contents

Discovery and naming

Christiaan Huygens, discoverer of Titan
Christiaan Huygens, discoverer of Titan

Following from Galileo's discovery of Jupiter's four largest moons in 1610, and his improvements on telescope technology, other astronomers actively sought their own discoveries.[7] Huygens himself worked on improvements to the technology and his discovery of Titan owed "partly to the quality of his telescope and partly to luck."[8] He named it simply Saturni Luna (or Luna Saturni, Latin for "Saturn's moon"), publishing in the 1655 tract De Saturni Luna Observatio Nova. Later, Giovanni Domenico Cassini named the four moons of Saturn he discovered (Tethys, Dione, Rhea and Iapetus) the Sidera Lodoicea ("the stars of Louis") to honour king Louis XIV. Astronomers fell into the habit of referring to these and Titan as Saturn I through Saturn V. Other epithets that have been used include "Saturn's ordinary satellite",[9] the "Huygenian satellite of Saturn" (or "Huyghenian"), or the "sixth satellite of Saturn" (Saturn VI, still in use); Titan was discovered to be sixth in order of distance from Saturn, once Mimas and Enceladus were found in 1789. Image File history File links Christiaan_Huygens-painting. ... Image File history File links Christiaan_Huygens-painting. ... Galileo can refer to: Galileo Galilei, astronomer, philosopher, and physicist (1564 - 1642) the Galileo spacecraft, a NASA space probe that visited Jupiter and its moons the Galileo positioning system Life of Galileo, a play by Bertolt Brecht Galileo (1975) - screen adaptation of the play Life of Galileo by Bertolt Brecht... Jupiters 4 Galilean moons, in a composite image comparing their sizes and the size of Jupiter (Great Red Spot visible). ... This article does not cite any references or sources. ... Giovanni Domenico (Jean-Dominique) Cassini Portrait Giovanni Domenico Cassini (June 8, 1625–September 14, 1712) was an Italian astronomer, engineer, and astrologer. ... Atmosphere none Tethys (tee-thÉ™s or teth-É™s, IPA , Greek Τηθύς) is a moon of Saturn that was discovered by Giovanni Domenico Cassini in 1684. ... Atmosphere none Dione (dye-oe-nee, Greek Διώνη) is a moon of Saturn discovered by Giovanni Cassini in 1684. ... Atmosphere none Rhea (ree-a, Greek ‘Ρέα) is the second largest moon of Saturn and was discovered in 1672 by Giovanni Domenico Cassini. ... Iapetus (eye-ap-É™-tÉ™s, IPA , Greek Ιαπετός) is the third-largest moon of Saturn, discovered by Giovanni Domenico Cassini in 1671. ... Cassini Sidera Lodoicea (IPA ˈsɪdÉ™rÉ™ ËŒlÉ’dəʊˈɪʃə) is the name given by the astronomer Giovanni Domenico Cassini to the four moons of Saturn discovered by him in the years 1671, 1672, and 1684 and published in the Journal des sçavans in 1673 and 1686. ... “Sun King” redirects here. ... Mimas (mee-mÉ™s or mye-mÉ™s, IPA: , Greek Μίμᾱς, rarely Μίμανς) is a moon of Saturn that was discovered in 1789 by William Herschel. ... [5] Atmospheric characteristics Pressure trace, significant spatial variability [6], [7] Water vapour 91% [8] Carbon dioxide 3. ...


The name "Titan," and the names of all seven satellites of Saturn then known, come from John Herschel (son of William Herschel, discoverer of Mimas and Enceladus) in his 1847 publication Results of Astronomical Observations made at the Cape of Good Hope.[10] He suggested the names of the mythological Titans, sisters and brothers of Cronos, the Greek Saturn. John Herschel Sir John Frederick William Herschel (7 March 1792 – 11 May 1871) was an English mathematician and astronomer. ... William Herschel Sir Frederick William Herschel, FRS KH (15 November 1738-25 August 1822) was a German-born British astronomer and composer who became famous for discovering the planet Uranus. ... In Greek mythology, the Titans (Greek: Titan; plural: Titanes) were a race of powerful deities that ruled during the legendary Golden Age. ... This article needs additional references or sources for verification. ...


Physical characteristics

Titan's internal structure.
Titan's internal structure.

Titan is 5,150 km across, compared to 4879 km for the planet Mercury and 3474 km for Earth's moon. Prior to the arrival of Voyager 1 in 1980, Titan was thought to be slightly larger than Ganymede (diameter 5262 km) and thus the largest moon in the Solar System; its dense, hazy atmosphere had led to overestimates upon observation.[11] Titan's diameter and mass (and thus its density) are similar to Jovian moons Ganymede and Callisto.[12] Based on its bulk density of 1.88 g/cm³, Titan's bulk composition is half water ice and half rocky material. It is probably differentiated into several layers with a 3400 km (2,040 mi) rocky center surrounded by several layers composed of different crystal forms of ice.[13] Its interior may still be hot and there may be a liquid layer consisting of water and ammonia between the ice crust and the rocky core. Though similar in composition to Rhea and the rest of Saturn's moons, it is denser due to gravitational compression. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... Trajectory of Voyager 1 using Celestia The Voyager 1 spacecraft is a 733-kilogram robotic space probe of the outer solar system and beyond, launched September 5, 1977, and is currently operational. ... This article or section does not adequately cite its references or sources. ... There is also an asteroid named 204 Kallisto. ... Ammonia is a compound with the formula NH3. ... Atmosphere none Rhea (ree-a, Greek ‘Ρέα) is the second largest moon of Saturn and was discovered in 1672 by Giovanni Domenico Cassini. ... This is a process whereby the self-gravity of an object increases the density of the object and reduces its size. ...


Atmosphere

True-color image of layers of haze in Titan's atmosphere.
True-color image of layers of haze in Titan's atmosphere.

Titan is the only known moon with a fully developed atmosphere that consists of more than just trace gases. Atmosphere thickness has been suggested between 400 km[14] and 880 km.[15] The atmosphere is opaque at many wavelengths and a complete reflectance spectrum is impossible through outside observation;[16] it was this haziness that led to errors in diameter estimates. Image File history File links Download high-resolution version (972x1004, 26 KB) Original Caption Released with Image: This natural color image shows Titans upper atmosphere -- an active place where methane molecules are being broken apart by solar ultraviolet light and the byproducts combine to form compounds like ethane and... Image File history File links Download high-resolution version (972x1004, 26 KB) Original Caption Released with Image: This natural color image shows Titans upper atmosphere -- an active place where methane molecules are being broken apart by solar ultraviolet light and the byproducts combine to form compounds like ethane and... View of Jupiters active atmosphere, including the Great Red Spot. ... The term trace gas refers to a gas or gasses which make up less than 1% of the earths atmosphere. ... The wavelength is the distance between repeating units of a wave pattern. ...


The presence of a significant atmosphere was first discovered by Gerard P. Kuiper in 1944 using a spectroscopic technique that yielded an estimate of an atmospheric partial pressure of methane of the order of 100 millibars (10 kPa).[17] Observations from the Voyager space probes have shown that the Titanian atmosphere is denser than Earth's, with a surface pressure more than one and a half times that of our planet. It supports an opaque cloud layer that blocks most visible wavelength light from the Sun and other sources and renders Titan's surface features obscure. The haze that can be seen in the picture to the right contributes to the moon's anti-greenhouse effect and lowers the temperature by reflecting sunlight away from the satellite. It is so thick and the gravity so low, that humans could fly through it by flapping "wings" attached to their arms.[18] The Huygens probe was unable to detect the direction of the Sun during its descent, and although it was able to take images from the surface, scientists say the process was like photographing asphalt at dusk.[19] Gerard Peter Kuiper, born Gerrit Pieter Kuiper (December 7, 1905 – December 23, 1973) was a Dutch-American astronomer. ... Extremely high resolution spectrogram of the Sun showing thousands of elemental absorption lines (fraunhofer lines) Spectroscopy is the study of the interaction between radiation (electromagnetic radiation, or light, as well as particle radiation) and matter. ... In a mixture of ideal gases, each gas has a partial pressure which is the pressure which the gas would have if it alone occupied the volume. ... Methane is a chemical compound with the molecular formula CH4. ... Voyager Project redirects here. ... This article is about Earth as a planet. ... Haze is an atmospheric phenomenon where dust, smoke and other pollutant particles obscure the normal clarity of the sky. ... The Anti-Greenhouse Effect describes the cooling effect an atmosphere has on the ambient temperature of the planet. ... The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ... Asphalt is a sticky, black and highly viscous liquid or semi-solid that is present in most crude petroleums and in some natural deposits. ...


The atmosphere is 98.4% nitrogen—the only dense nitrogen-rich atmosphere in the solar system aside from the Earth's—with the remaining 1.6% composed of methane and trace amounts of other gases such as hydrocarbons (including ethane, diacetylene, methylacetylene, cyanoacetylene, acetylene, propane), argon, carbon dioxide, carbon monoxide, cyanogen, hydrogen cyanide and helium.[20] The hydrocarbons are thought to form in Titan's upper atmosphere in reactions resulting from the breakup of methane by the Sun's ultraviolet light, producing a thick orange smog. Titan has no magnetic field and sometimes orbits outside Saturn's magnetosphere, directly exposing it to the solar wind. This may ionize and carry away some molecules from the top of the atmosphere. General Name, Symbol, Number nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... Ethane is a chemical compound with chemical formula C2H6. ... Diacetylene is an unsaturated hydrocarbon with chemical formula HCCCCH. Categories: Stub ... 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. ... Cyanoacetylene, chemical formula C3HN, is also known as 2-Propynenitrile. ... Acetylene (systematic name: ethyne) is the simplest alkyne hydrocarbon, consisting of two hydrogen atoms and two carbon atoms connected by a triple bond. ... Propane is a three-carbon alkane, normally a gas, but compressible to a liquid that is transportable. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Standard atomic weight 39. ... In order to meet Wikipedias quality standards, this article requires cleanup. ... Carbon monoxide, with the chemical formula CO, is a colorless, odorless, and tasteless gas. ... Cyanogen is a chemical compound (CN)2. ... Hydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid. ... General Name, Symbol, Number helium, He, 2 Chemical series noble gases Group, Period, Block 18, 1, s Appearance colorless Standard atomic weight 4. ... “UV” redirects here. ... Magnetic field lines shown by iron filings In physics, a magnetic field is a solenoidal vector field in the space surrounding moving electric charges and magnetic dipoles, such as those in electric currents and magnets. ... 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. ... An electrostatic potential map of the nitrate ion (NO3−). Areas coloured red are lower in energy than areas colored yellow An ion is an atom or group of atoms which have lost or gained one or more electrons, making them negatively or positively charged. ...


The nitrogen ratio of 14N to 15N is 183, compared with the Earth's average of 272.[20] The methane isotope ratio 12C/13C is 82.3 on Titan and 89.9 on Earth.[20] An H/D isotope ratio of 3.6×103 compares with 3.0×103 on Earth. The depletion of the lighter isotope of nitrogen indicates atmospheric escapes whereas the carbon and the hydrogen are far less depleted. The ratio of argon to nitrogen is 100 times less than in Earth's atmosphere.[20]

Layers of haze seen in a colorized ultraviolet image of Titan's night-side limb
Layers of haze seen in a colorized ultraviolet image of Titan's night-side limb

The most recent Cassini flyby has suggested the existence of a large cloud over Titan's north pole, at a height of 40 km. Although methane is known to condense in Titan's atmosphere, this cloud is more likely to be ethane, as the detected size of the particles is only 1-3 microns and ethane can also freeze at these altitudes. The downdrafts at high northern latitudes are strong enough to drive these particles towards the surface. A theory is that it is currently raining (or, if cool enough, snowing) on the north pole. When the seasons switch, ethane will begin to condense over the south pole.[21] It is currently summer in Titan's southern hemisphere and will remain so until 2010, when Saturn's orbit, which governs the moon's motion, will tilt the northern hemisphere towards the Sun.[22] Image File history File links Download high-resolution version (1024x1024, 53 KB) Original Caption Released with Image: Cassini has found Titans upper atmosphere to consist of a surprising number of layers of haze, as shown in this ultraviolet image of Titans night side limb, colorized to look like... Image File history File links Download high-resolution version (1024x1024, 53 KB) Original Caption Released with Image: Cassini has found Titans upper atmosphere to consist of a surprising number of layers of haze, as shown in this ultraviolet image of Titans night side limb, colorized to look like...


Simulations of global wind patterns based on wind speed data taken by Huygens during its descent have suggested that Titan's atmosphere circulates in a single enormous Hadley cell. Warm air rises in Titan's southern hemisphere—which was experiencing summer during Huygens' descent—and sinks in the northern hemisphere, resulting in high-altitude air flow from south to north and low-altitude airflow from north to south. Such a large Hadley cell is only possible on a slowly rotating world such as Titan. There was also a pattern of air circulation flowing in the direction of Titan's rotation, from west to east.[22] The Hadley cell is a circulation pattern that dominates the tropical atmosphere, with rising motion near the equator, poleward flow 10-15 kilometers above the surface, descending motion in the subtropics, and equatorward flow near the surface. ...


Natural extremely low frequency (ELF) radio waves have been tentatively identified by Cassini in Titan's atmosphere. Titan's surface is thought to be a poor reflector of ELF waves, so they may instead be reflecting off the liquid-ice boundary of a subsurface ocean of water and ammonia predicted by some theoretical models. Titan's ionosphere is also more complex than Earth's, with the main ionosphere at an altitude of 1200 km but with an additional layer of charged particles at 63 km. This splits Titan's atmosphere to some extent into two separate resonating chambers. The source of natural ELF waves on Titan is unclear as there does not appear to be extensive lightning activity.[23] Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ...


Climate

Possible cloud of ethane (red) over Titan's north pole (marked NP)

At the surface, Titan's temperature is about 94 K (−179 °C, or −290.2 °F). At this temperature water ice does not sublimate from solid to gas, so the atmosphere is nearly free of water vapor. The clouds on Titan, probably composed of methane, ethane or other simple organics, are scattered and variable, punctuating the overall haze.[11] The orange color as seen from space must be produced by other more complex chemicals in small quantities, possibly tholins, a tar-like organic precipitate.[24] Image File history File links Titan-ethane. ... Image File history File links Titan-ethane. ... Ethane is a chemical compound with chemical formula C2H6. ... Sublimation of an element or compound is the change from a solid directly to a gas with no intermediate liquid stage. ... Tholin is a heteropolymer formed by solar ultraviolet irradiation of simple organic compounds such as methane or ethane. ...


Ground-based observations show that Titan's climate changes with the seasons. Over the course of Saturn's 30-year orbit, Titan's cloud systems appear to manifest for 25 years, and then fade for four to five years, before reappearing again.[25]


The findings of the Huygens probe indicate that Titan's atmosphere periodically rains liquid methane and other organic compounds onto the moon's surface.[26] It is possible that areas of Titan's surface may be coated in a layer of tholins, but this has not been confirmed. The presence of argon 40 was also discovered in the atmosphere, evidence of cryovolcanism producing a "lava" of water ice and ammonia.[27] Later, a methane-spewing volcano was spotted in close-up images, and Titanian volcanism is now believed to be a significant source of the methane in the atmosphere. As of early 2007, liquid methane oceans appear to be present (see section below). This is a departure from the previously accepted theory that such oceans were all but entirely absent.[28] General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Standard atomic weight 39. ... Ganesa Macula, a dark feature on Saturns moon Titan, might be a cryovolcanic dome. ...


The October 2004 Cassini flyby photographed bright, high clouds at Titan's south pole, but they do not appear to be methane, as had been expected. This discovery has baffled scientists and studies are currently underway to determine the composition of the clouds and decide whether our understanding of Titan's atmosphere needs to be revised.[29] Observations by Cassini of the atmosphere made in 2004 suggest that Titan is a "super rotator," like Venus, with an atmosphere that rotates much faster than its surface. (*min temperature refers to cloud tops only) Atmospheric characteristics Atmospheric pressure 9. ...

A methane cloud imaged in false colour over Titan's north pole
A methane cloud imaged in false colour over Titan's north pole

In December 2006, Cassini imaged a large cloud of methane, ethane and other organics over the moon's north pole. The cloud is over 2400 km in diameter and was still visible during a following flyby a month later. This cloud likely formed from evaporation from methane lakes recently observed at that pole, which were in turn likely formed by methane rains from the cloud. (see below). This is the strongest evidence yet for the long hypothesised "methanological" cycle (analogous to Earth's hydrological cycle) on Titan.[25] Image File history File linksMetadata No higher resolution available. ... Image File history File linksMetadata No higher resolution available. ... The water cycle is known scientifically as the hydrologic cycle. ...


Surface features

See also: list of geological features on Titan

The surface of Titan has been described as "complex, fluid-processed, [and] geologically young."[30] The Cassini mission has revealed it to be relatively smooth; the few objects that seem to be impact craters appeared to have been filled in, perhaps by raining hydrocarbons or volcanoes. The area mapped so far appears to have no height variation greater than 50 meters (165 feet);[31] however, radar altimetry has so far only covered part of the north polar region. This is a list of the informal names given to surface features of Saturns moon Titan. ... Tycho crater on Earths moon. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll. ...

Titan in false color showing surface details and atmosphere. "Xanadu" is the bright region at the centre-right
Titan in false color showing surface details and atmosphere. "Xanadu" is the bright region at the centre-right

Titan's surface is marked by broad regions of bright and dark terrain. These include a large, highly reflective area about the size of Australia identified in infrared images from the Hubble Space Telescope and the Cassini spacecraft. This region is named Xanadu and appears to represent an area of relatively high ground. There are dark areas of similar size elsewhere on the moon, observed from the ground and by Cassini; it had been speculated that these are methane or ethane seas, but Cassini observations seem to indicate otherwise (see below). Cassini has also spotted some enigmatic linear markings, which some scientists have suggested may indicate tectonic activity, as well as regions of bright material cross cut by dark lineaments within the dark terrain. Original Caption Released with Image: This image shows Titan in ultraviolet and infrared wavelengths. ... Original Caption Released with Image: This image shows Titan in ultraviolet and infrared wavelengths. ... The reflection of a bridge in Indianapolis, Indianas Central Canal. ... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... The Hubble Space Telescope (HST) is a telescope in orbit around the Earth, named after astronomer Edwin Hubble. ... Xanadu is the bright area at the centre-right of this image Xanadu (often called Xanadu Regio, though this is not its official name) is a highly reflective area on the leading hemisphere of Saturns moon Titan. ... ...


In order to understand Titanian surface features better, the Cassini spacecraft is currently using radar altimetry and synthetic aperture radar (SAR) imaging to map portions of Titan during its close fly-bys of the moon. The first images have revealed a complex, diverse geology with both rough and smooth areas. There are features that seem volcanic in origin, which probably disgorge water mixed with ammonia. There are also streaky features that appear to be caused by windblown particles. The surface of Venus, as imaged by the Magellan probe using SAR Synthetic aperture radar (SAR) is a form of radar in which sophisticated post-processing of radar data is used to produce a very narrow effective beam. ... Image of the south pole of Triton taken by Voyager 2 in 1989. ...


Liquids

Pseudo-colored radar imaging data from a Cassini flyby of northern lattitudes, published in the journal Nature to illustrate the convincing evidence for large bodies of liquid. The false blue coloring indicates low radar reflectivity areas, likely caused by liquid.

It has long been believed that lakes or even seas of methane might exist on Titan's surface, but until recently, conclusive evidence had proven elusive.[32] When the Cassini probe arrived in the Saturnian system, it was hoped that hydrocarbon lakes or oceans might be detectable by reflected sunlight from the surface of any liquid bodies, but no specular reflections were initially observed. Cassini observed surface features that could be explained as the products of flowing liquids, but again, there were few conclusive observations. Image File history File links Download high-resolution version (2600x3400, 1149 KB) source: http://photojournal. ... Image File history File links Download high-resolution version (2600x3400, 1149 KB) source: http://photojournal. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... Oil refineries are key to obtaining hydrocarbons; crude oil is processed through several stages to form desirable hydrocarbons, used in fuel and other commercial products. ... Diagram of specular reflection Specular reflection is the perfect, mirror-like reflection of light from a surface, in which light from a single incoming direction is reflected onto a single outgoing direction. ...


The first indication of the presence of a lake was observed at Titan's south pole, where clouds have been observed to cluster, and where an enigmatic dark feature at the pole, named Ontario Lacus was identified as a possible lake created by precipitation from them.[33] A possible shoreline has also been identified at the pole via radar imagery.[34] Then, on January 3, 2007, it was announced that scientists have "definitive evidence of lakes filled with methane on Saturn's moon Titan."[35][36] The high relative humidity of methane in Titan’s lower atmosphere could be maintained by evaporation from lakes covering only 0.002–0.02 of the whole surface.[37] Ontario Lacus is the dark feature at centre-left of this image of Titans south pole Ontario Lacus is a dark feature near the south pole of Saturns moon Titan. ... Blowdown Lake in the mountains near Pemberton, British Columbia A lake (from Latin lacus) is a body of water or other liquid of considerable size contained on a body of land. ... is the 3rd day of the year in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ...


Following a flyby on July 22, 2006, in which the Cassini spacecraft's radar imaged the northern latitudes (which are currently in winter), a number of large, smooth (and thus dark to radar) patches were seen dotting the surface near the pole.[38] The Cassini–Huygens team have now concluded that these features are almost certainly the long sought hydrocarbon lakes of Titan. Some of the lakes appear to have channels running in or out of them, which are just as smooth. Ethane and methane may be liquids near Titan's poles, which are cold enough for these gases to condense. Repeated coverage of these areas should prove whether they are truly liquid, as any changes that correspond with wind blowing on the surface of the liquid would alter the roughness of the surface and be visible in the radar. The National Aeronautics and Space Administration (NASA) recently confirmed that there is ice from hydrocarbon rain at the north polar area. is the 203rd day of the year (204th in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday (link displays full 2006 calendar) of the Gregorian calendar. ... NASA Logo Listen to this article · (info) This audio file was created from the revision dated 2005-09-01, and does not reflect subsequent edits to the article. ...

NASA image comparing a body of liquid on Titan with Lake Superior.
Image of Titan taken during Huygens' descent, showing hills and topographical features that resemble a shoreline and drainage channels.

The strongest evidence yet of lakes on Titan came during a Cassini flyby in late February 2007, as observations by the radar and camera instruments revealed several large features in the north polar region that may be large expanses of liquid methane and/or ethane, including one sea with an area of over 100,000 square kilometers (larger than Lake Superior), and another (though less definite) region potentially the size of the Caspian Sea.[39] Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Lake Superior, bounded by Ontario, Canada and Minnesota, USA, to the north and Wisconsin and Michigan, USA, to the south, is the largest of North Americas Great Lakes. ... Descent image of Titan taken during Huygens landing, showing an apparent shoreline with hills and drainage channels Credit: ESA/NASA/Univ. ... Descent image of Titan taken during Huygens landing, showing an apparent shoreline with hills and drainage channels Credit: ESA/NASA/Univ. ... The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ... Lake Superior, bounded by Ontario, Canada and Minnesota, USA, to the north and Wisconsin and Michigan, USA, to the south, is the largest of North Americas Great Lakes. ... The Caspian Sea (Russian: Каспийское море; Kazakh: Каспий теңізі; Turkmen: Hazar deňizi; Azeri: XÉ™zÉ™r dÉ™nizi; Persian: دریای خزر Daryā-ye Khazar) is the largest lake on Earth by area[2], with a surface area of 371,000 square kilometers (143,244 sq mi) and a volume of 78,200 cubic kilometers (18...


The discoveries at the poles contrast with the findings of the Huygens probe, which landed near Titan's equator on January 14, 2005. The images taken by the probe during its descent show no open areas of liquid, but strongly indicate the presence of liquids in the recent past, showing pale hills crisscrossed with dark drainage channels that lead into a wide, flat, darker region. It was initially thought that the dark region might be a lake of a fluid or at least tar-like substance, but it is now clear that Huygens landed on the dark region, and that it is solid without any indication of liquids. A penetrometer studied the composition of the surface as the craft impacted it, and it was initially reported that the surface was similar to loose sand, wet clay, or perhaps crème brûlée (that is, a hard crust covering a sticky material). However, subsequent analysis of the data suggests that this reading was likely caused by Huygens displacing a large pebble as it landed, and that the surface is better described as a 'sand' made of ice grains.[40] The images taken after the probe's landing show a flat plain covered in pebbles. The pebbles, which may be made of water ice, are somewhat rounded, which may indicate the action of fluids on them.[41] The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ... is the 14th day of the year in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ... The Cone Penetrometer apparatus is an alternative method to the Casagrande Device in measuring the Liquid Limit of a soil sample (See:Atterberg Limits). ... Patterns in the sand Sand is a granular material made up of fine rock particles. ... The Gay Head cliffs in Marthas Vineyard are made almost entirely of clay. ... Crème brûlée Crème brûlée (French for burnt cream; IPA: in English, in French) is a dessert consisting of a rich custard base topped with a layer of hard caramel, created by burning sugar under a grill or other intense heat source. ...

A view of Titan centered on the large lake-like feature in Titan's north polar region, which lies just below the day-night line in this image.
A view of Titan centered on the large lake-like feature in Titan's north polar region, which lies just below the day-night line in this image.

Since the existence of lakes on Titan has only been recently confirmed, and the hypothesized vast methane oceans have not been found, some scientists now believe that many of the moon's features are caused by cryovolcanism rather than running liquids. Alternatively, it has been hypothesized that Huygens landed during a dry season on Titan, and that periods of heavy methane rain could form lakes that subsequently evaporate. The length of the intervals between rainy periods on Titan are unknown, and scientists stress that Huygens sampled only one small site on this planet-sized moon, which is insufficient for evaluating the entire body.[26] Image File history File links Size of this preview: 600 × 600 pixel Image in higher resolution (1024 × 1024 pixel, file size: 42 KB, MIME type: image/jpeg) This view of Titan taken on Feb. ... Image File history File links Size of this preview: 600 × 600 pixel Image in higher resolution (1024 × 1024 pixel, file size: 42 KB, MIME type: image/jpeg) This view of Titan taken on Feb. ... Image of the south pole of Triton taken by Voyager 2 in 1989. ...


Impact craters

Radar SAR and imaging data from Cassini have revealed a relative paucity of impact craters on Titan's surface, suggesting a youthful surface. To date, only three impact craters have been confirmed, which includes a 440 km wide multi-ring impact basin named Menrva (seen by Cassini's ISS as a bright-dark concentric pattern),[42] a smaller 80 km wide flat-floored crater named Sinlap,[43] and a 30 km crater with a central peak and dark floor named Ksa.[44] RADAR and Cassini imaging have also revealed a number of "crateriforms", circular features on the surface of Titan that may be impact related, but lack certain features that would make identification certain. For example, a 90 km wide ring of bright, rough material known as Guabonito has been observed by Cassini.[45] This feature is thought to be an impact crater filled-in by dark, windblown sediment. Several other similar features have been observed in the dark Shangri-la and Aaru regions. RADAR observed several circular features that may be craters in the bright region Xanadu during Cassini's April 30, 2006 flyby of Titan.[46] Cassini view of Guabonito Guabonito is ring of bright features on Saturns moon Titan. ... is the 120th day of the year (121st in leap years) in the Gregorian calendar. ... Year 2006 (MMVI) was a common year starting on Sunday (link displays full 2006 calendar) of the Gregorian calendar. ...


Cryovolcanism and mountains

See also: Cryovolcano
One of the first radar images of Titan's complex surface. The circular feature at left, Ganesa Macula, is thought to be a cryovolcanic dome.
One of the first radar images of Titan's complex surface. The circular feature at left, Ganesa Macula, is thought to be a cryovolcanic dome.

Scientists have speculated that conditions on Titan resemble those of early Earth, though at a much lower temperature. Evidence of volcanic activity from the latest Cassini mission suggests that temperatures are probably much higher in hotbeds, enough for liquid water to exist. Argon 40 detection in the atmosphere indicates that volcanoes spew plumes of water and ammonia.[47] Ganesa Macula, a dark feature on Saturns moon Titan, might be a cryovolcanic dome. ... One of the first radar images of Titans surface, released October 28, 2004. ... One of the first radar images of Titans surface, released October 28, 2004. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll. ... Ganesa Macula imaged by Cassini radar. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18, 3, p Appearance colorless Standard atomic weight 39. ...


A mountain range measuring 150 km (93 miles) long, 30 km (19 miles) wide and 1.5 km (1 mile) high was discovered by Cassini in 2006. This range lies in the southern hemisphere and is thought to be composed of icy material and covered in methane snow. The movement of tectonic plates, perhaps influenced by a nearby impact basin, could have opened a gap through which the mountain's material upwelled.[48]


Dark terrain

Sand dunes on Earth (top), compared with dunes on Titan's surface.

In the first images of Titan's surface taken by Earth-based telescopes in the early 2000s, large regions of dark terrain were revealed straddling Titan's equator.[49] Prior to the arrival of Cassini, these regions were thought to be seas of organic matter like tar or seas of liquid hydrocarbons.[50] However, radar images captured by the Cassini spacecraft have instead revealed some of these regions to be extensive plains covered in longitudinal sand dunes. The sand dunes are believed to be formed by wind generated as a result of tidal forces from Saturn on Titan's atmosphere, which are 400 times stronger than the tidal forces of the Moon on Earth. The tidal winds cause dunes to build up in long parallel lines, with Titan's zonal winds aligning the dunes west-to-east. The dunes break this pattern around mountains, where the wind direction is shifted. Image File history File links Titan_dunes. ... Image File history File links Titan_dunes. ... A diagram showing the formation of a dune with a slipface. ... Apparent magnitude: up to -12. ... In geography, geophysics, and meteorology, zonal usually means along a latitude circle, i. ...


Widespread evidence has also recently been found to support the claim that lakes of hydrocarbons do in fact exist on Titan's North pole during the second of several planned Cassini spacecraft flybys.[51]


The sand on Titan might have formed when liquid methane rained and eroded the ice bedrock, possibly in the form of flash floods. Alternatively, the sand could also have come from organic solids produced by photochemical reactions in Titan's atmosphere.[52][53][54]


Observation and exploration

Cassini image of Epimetheus and Titan

Titan is never visible to the naked eye, but can be observed through small telescopes (diameter greater than 5 cm) or strong binoculars. It has a maximum magnitude of +7.9, and is outshone by six asteroids (Vesta, Pallas, Iris, Hebe, Juno, Melpomene) and the dwarf planet Ceres.[citation needed] Image File history File links Epimetheus_Titan_Saturn_Rings_Cassini_Photo. ... Image File history File links Epimetheus_Titan_Saturn_Rings_Cassini_Photo. ... Epimetheus (ep-i-mee-thee-us, Greek Επιμηθεύς) is a moon of Saturn. ... 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. ... 253 Mathilde, a C-type asteroid. ... 4 Vesta (ves-ta) is the second most massive asteroid in the asteroid belt, with a mean diameter of about 530 km and an estimated mass 12% the mass of the entire asteroid belt. ... 2 Pallas (pal-us, Greek Παλλάς) was the first asteroid discovered after 1 Ceres. ... 7 Iris (eye-ris) is one of the largest main belt asteroids. ... 6 Hebe (hee-bee, Greek ‘Ήβη) is a very large Main belt asteroid. ... Juno (IPA: ), designated 3 Juno in the Minor Planet Center catalogue system, was the third asteroid to be discovered and is one of the largest main belt asteroids, being the second heaviest of the stony S-type. ... 18 Melpomene (mel-pom-a-nee) is a large, bright Main belt asteroid. ... Spectral type: G[8] Absolute magnitude: 3. ...


Observations of Titan prior to the space age were limited. In 1907 Spanish astronomer Jose Comas Sola suggested that he had observed darkening near the edges of Titan's disk and two round white patches in its center. The deduction of an atmosphere by Kuiper in the 1940s was the next major observational event.[55] Josep Comas Solá (or José Comas Solá) (December 19, 1868 – December 2, 1937) was a Spanish astronomer. ...


The first probe to visit the Saturnian system was Pioneer 11 in 1979, which determined that Titan was likely too cold to support life.[56] The craft took the first images of the moon (including some of it and Saturn together) but these were of low quality; the first ever close-up of Titan was taken on September 2, 1979.[57] Position of Pioneer 10 and 11 Pioneer 11 was the second mission to investigate Jupiter and the outer solar system and the first to explore the planet Saturn and its main rings. ... September 2 is the 245th day of the year (246th in leap years) in the Gregorian calendar. ... Also: 1979 by Smashing Pumpkins. ...


Titan was examined by both Voyager 1 and Voyager 2 in 1980 and 1981, respectively. Voyager 1's course was diverted specifically to make a closer pass of Titan. Unfortunately, the craft did not possess any instruments that could penetrate Titan's haze, an unforeseen factor. Many years later, intensive digital processing of images taken through Voyager 1''s orange filter did reveal hints of the light and dark features now known as Xanadu and the Sickle,[58] but by then they had already been observed in the infrared by the Hubble Space Telescope. Voyager 2 took only a cursory look at Titan. The Voyager 2 team had the option of steering the spacecraft to take a detailed look at Titan or to use another trajectory which would allow it to visit Uranus and Neptune. Given the lack of surface features seen by Voyager 1, the latter plan was implemented. Trajectory Voyager 2 is an unmanned interplanetary spacecraft, launched on August 20, 1977. ...


Cassini-Huygens

Main articles: Cassini–Huygens and Huygens probe

Even with the data provided by the Voyagers, Titan remained a body of mystery—a planet-like satellite, which is shrouded in an atmosphere that makes detailed observation difficult. The intrigue that had surrounded Titan since the 17th century observations of Christiaan Huygens and Giovanni Cassini was finally gratified by the spacecraft named in their honor. Cassini–Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ... The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ...


The Cassini–Huygens spacecraft reached Saturn on July 1, 2004 and has begun the process of mapping Titan's surface by radar. A joint project of the European Space Agency (ESA) and NASA, Cassini-Huygens has proved a very successful mission. The Cassini probe flew by Titan on October 26, 2004[59] and took the highest-resolution images ever of the moon's surface, at only 1,200 kilometers,[59] discerning patches of light and dark that would be invisible to the human eye from the Earth. Huygens landed on Titan on January 14, 2005,[60] discovering that many of the moon's surface features seem to have been formed by flowing fluids at some point in the past. Present liquid on the surface may be found near the north pole, in the form of many lakes that were recently discovered by Cassini.[38] Titan is the most distant body from Earth that has seen a space probe landing.[61] is the 182nd day of the year (183rd in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... This long range radar antenna, known as ALTAIR, is used to detect and track space objects in conjunction with ABM testing at the Ronald Reagan Test Site on the Kwajalein atoll. ... Paris headquarters The ESA control room in Darmstadt, Germany The European Space Agency (ESA), established in 1974, is an inter-governmental organisation dedicated to the exploration of space, currently with 17 member states. ... is the 299th day of the year (300th in leap years) in the Gregorian calendar. ... Year 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... 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). ... is the 14th day of the year in the Gregorian calendar. ... Year 2005 (MMV) was a common year starting on Saturday (link displays full calendar) of the Gregorian calendar. ...


Huygens landing site

Huygens image from Titan's surface

The Huygens probe landed just off the easternmost tip of a bright region now called Adiri, and photographed pale hills with dark 'rivers' running down to a dark plain. Current understanding is that the hills (also referred to as highlands) are composed mainly of water ice. Dark organic compounds, created in the upper atmosphere by the ultraviolet radiation of the Sun, may rain from Titan's atmosphere. They are washed down the hills with the methane rain and are deposited on the plains over geological time scales.[27] Download high resolution version (316x630, 38 KB)Image of Titans surface taken by the Huygens lander on January 14, 2005; the simulated colour is based on spectral measurements taken by the probe. ... Download high resolution version (316x630, 38 KB)Image of Titans surface taken by the Huygens lander on January 14, 2005; the simulated colour is based on spectral measurements taken by the probe. ... The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ... Adiri as seen by Huygens Adiri is a bright albedo feature on Saturns moon Titan. ...


Huygens landed on a dark plain covered in small rocks and pebbles, which are composed of water ice.[27] The two rocks just below the middle of the image on the right are smaller than they may appear. The left-hand one is 15 centimeters (6 inches) across, and the one in the center is 4 centimeters (about 1.5 inches) across, at a distance of about 85 centimeters (about 33 inches) from Huygens. There is evidence of erosion at the base of the rocks, indicating possible fluvial activity. The surface is darker than originally expected, consisting of a mixture of water and hydrocarbon ice. It is believed that the 'soil' visible in the images is precipitation from the hydrocarbon haze above. The word fluvial is used in geography and earth science to refer to all topics related to flowing water. ...


In March of 2007, NASA, ESA, and COSPAR decided to name the Huygens landing site as Hubert Curiel Memorial Station in memory of a president of the European Space Agency.[62] COSPAR, the Comittee for Outer SPAce Research was founded in 1958. ...


Prebiotic conditions and possible life

See also: Planetary habitability

Scientists believe that the atmosphere of early Earth was similar in composition to the current atmosphere on Titan. Many hypotheses have developed that attempt to bridge the step from chemical to biological evolution. The Miller-Urey experiment and several following experiments have shown that with an atmosphere similar to that of Titan and the addition of UV radiation, complex molecules and polymer substances like tholins can be generated. The reaction starts with dissociation of nitrogen and methane forming hydrocyan and ethyne. Further reactions have been studied extensively.[63] Understanding planetary habitability is partly an extrapolation of the Earths conditions, as it is the only planet currently known to support life. ... The experiment The Miller-Urey experiment (or Urey-Miller experiment) was an experiment that simulated hypothetical conditions present on the early Earth and tested for the occurrence of chemical evolution. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Tholin is a heteropolymer formed by solar ultraviolet irradiation of simple organic compounds such as methane or ethane. ... Dissociation is a psychological state or condition in which certain thoughts, emotions, sensations, or memories are separated from the rest of the psyche. ... Hydrogen cyanide is a chemical compound with chemical formula HCN. A solution of hydrogen cyanide in water is called hydrocyanic acid. ... The chemical compound acetylene, also called ethyne, was discovered in 1836 by Edmund Davy, in England; its chemical formula is C2H2 and its structure is: Acetylene is a colorless and extremely flammable gas at standard temperature and pressure and has a pleasantly sweet ethereal odor. ...


All of these experiments have led to the suggestion that enough organic material exists on Titan to start a chemical evolution analogous to what is thought to have started life on Earth. While the analogy assumes the presence of liquid water for longer periods than is currently observable, several theories suggest that liquid water from an impact could be preserved under a frozen isolation layer.[64] It has also been observed that liquid ammonia oceans could exist deep below the surface;[5] one model suggests an ammonia-water solution as much as 200 km deep beneath a water ice crust, conditions that "while extreme by terrestrial standards, are such that life could indeed survive."[6] Heat transfer between the interior and upper layers would be critical in sustaining any sub-surface oceanic life.[5] In thermal physics, heat transfer is the passage of thermal energy from a hot to a cold body. ...


Detection of microbial life on Titan would depend on its biogenic effects. That the atmospheric methane and nitrogen are of biological origin has been examined, for example.[6] Hydrogen has been cited as one molecule suitable to test for life on Titan: if methanogenic life is consuming atmospheric hydrogen in sufficient volume it will have a measurable effect on the mixing ratio in the troposphere.[65] Atmosphere diagram showing the mesosphere and other layers. ...


Despite these biological possibilities, there are formidable obstacles to life on Titan and any analogy to Earth is inexact. At a vast distance from the Sun, Titan is frigid (a fact excaserbated by the anti-greenhouse effect of its cloud cover), and its atmosphere lacks CO2. Given these difficulties, the topic of life on Titan may be best described as an experiment for examining theories on conditions necessary prior to flourishing life's on Earth.[66] While life itself may not exist, the prebiotic conditions of the Titanian environment, and the possible presence of organic chemistry, remain of great interest in understanding the early history of the terrestrial biosphere.[67] Using Titan as a prebiotic experiment involves not only observation through spacecraft, but laboratory experiment, and chemical and photochemical modelling on Earth.[63] The Sun (Latin: ) is the star at the center of the Solar System. ... The Anti-Greenhouse Effect describes the cooling effect an atmosphere has on the ambient temperature of the planet. ...


An alternate explanation for life's hypothetical existence on Titan has been proposed: if life were to be found on Titan, it would be statistically more likely to have originated from Earth than to have appeared independently, a process known as panspermia. It is theorized that large asteroid and cometary impacts on Earth's surface have caused hundreds of millions of fragments of microbe-laden rock to escape Earth's gravity. Calculations indicate that a number of these would encounter many of the bodies in the solar system, including Titan.[68][69] Panspermia is a proven process (based on the principles of Biology, Microbiology, Physics, Chemistry, Astronomy, and assumption that life existed already in the universe) that explains how all life in the universe and/or solar system comes from a seed of life. ...


While the Cassini–Huygens mission was not equipped to provide evidence for biology or complex organics, it did support the theory of an environment on Titan that is similar, in some ways, to that of the primordial Earth. Future missions are not currently being planned to research the issue, and considering the time required for executing a voyage, further scientific data may be decades away.[67] Cassini–Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ...


See also

The Huygens probe, supplied by the European Space Agency (ESA) and named after the Dutch 17th century astronomer Christiaan Huygens, is an atmospheric entry probe carried to Saturns moon Titan as part of the Cassini-Huygens mission. ... No solid plans or studies have been made regarding manned missions to Titan, or colonization of that world, at least not outside of science fiction. ... Titan is the largest moon of Saturn. ...

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The National Aeronautics and Space Administration (NASA) is an agency of the United States government, responsible for the nations public space program. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 231st day of the year (232nd 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) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... January 8 is the 8th day of the year in the Gregorian calendar. ... The National Aeronautics and Space Administration (NASA) is an agency of the United States government, responsible for the nations public space program. ... 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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. ... Year 2006 (MMVI) was a common year starting on Sunday (link displays full 2006 calendar) of the Gregorian calendar. ... is the 287th day of the year (288th 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. ... Space. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 218th day of the year (219th 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. ... University of Helsinki is not to be confused with Helsinki University of Technology. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 231st day of the year (232nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 231st day of the year (232nd in leap years) in the Gregorian calendar. ... Year 2007 (MMVII) is the current year, a common year starting on Monday of the Gregorian calendar and the AD/CE era. ... is the 231st day of the year (232nd in leap years) in the Gregorian calendar. ... 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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. ... 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 2004 (MMIV) was a leap year starting on Thursday of the Gregorian calendar. ... is the 223rd day of the year (224th in leap years) in the Gregorian calendar. ... 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Further reading

  • Lorenz, Ralph; Jacqueline Mitton (May 2002). Lifting Titan's Veil: Exploring the Giant Moon of Saturn. Cambridge University Press. ISBN 0-521-79348-3. 

External links

Wikimedia Commons has media related to:
... · Rhea · Titan · Hyperion · ...

The Gallic group is made up of moons of Saturn which share similar orbits. ... Albiorix (al-bee-or-iks) is a natural satellite of Saturn. ... Bebhionn, or Saturn XXXVII (provisional designation S/2004 S 11) is a natural satellite of Saturn. ... Erriapo (air-ee-ap-oe?, Latin Erriapō or Erriappō) (Saturn XXVIII) is a natural satellite of Saturn. ... Tarvos (tar-vus) (Saturn XXI) is a natural satellite of Saturn. ... The full set of rings, as photographed by the Cassini spacecraft on September 15, 2006 (brightness has been exaggerated in this image). ... Cassini-Huygens is a joint NASA/ESA/ASI unmanned space mission intended to study Saturn and its moons. ... On April 28, 1905, William H. Pickering, who had seven years earlier discovered PhÅ“be, announced the discovery of a tenth satellite of Saturn, which he promptly named Themis. ... A natural satellite is an object that orbits a planet or other body larger than itself and which is not man-made. ... Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ... Apparent magnitude: up to -12. ... The relative sizes of and distance between Mars, Phobos, and Deimos, to scale. ... Jupiters outer moons and their highly inclined orbits. ... The Saturnian system (photographic montage) Saturn has fifty-six confirmed natural satellites, plus three unconfirmed moons. ... Uranus has 27 known moons. ... Neptune (top) and Triton (bottom), 3 days after the Voyager 2 flyby. ... Image File history File links Download high resolution version (604x602, 23 KB)Cassini color image of Rhea taken Jan. ... The planet Pluto has three known moons. ... Dysnomia (officially designated (136199) Eris I Dysnomia) is a moon of the dwarf planet Eris. ... 243 Ida and its moon Dactyl An asteroid moon is an asteroid that orbits another asteroid. ... This article or section does not adequately cite its references or sources. ... There is also an asteroid named 204 Kallisto. ... Atmosphere Surface pressure: trace Composition: 90% sulfur dioxide Io (eye-oe, IPA: , Greek Ῑώ) is the innermost of the four Galilean moons of Jupiter and, with a diameter of 3,642 kilometers, is the fourth largest moon in the Solar System. ... Apparent magnitude: up to -12. ... Apparent magnitude: 5. ... Triton (trye-tÉ™n, IPA: , Greek Τρίτων), or Neptune I, is the planet Neptunes largest moon. ... Atmospheric pressure   Titania (ti-taan-ee-É™ or tye-tan-ee-É™) is the largest moon of Uranus. ... Atmosphere none Rhea (ree-a, Greek ‘Ρέα) is the second largest moon of Saturn and was discovered in 1672 by Giovanni Domenico Cassini. ... Atmospheric pressure 0 kPa Oberon (oe-bur-on) is the outermost of the major moons of the planet Uranus. ... Iapetus (eye-ap-É™-tÉ™s, IPA , Greek Ιαπετός) is the third-largest moon of Saturn, discovered by Giovanni Domenico Cassini in 1671. ... Charon (shair-É™n or kair-É™n (key), IPA , Greek Χάρων), discovered in 1978, is, depending on the definition employed, either the largest moon of Pluto or one member of a double dwarf planet with Pluto being the other member. ... 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. ... Atmosphere none Dione (dye-oe-nee, Greek Διώνη) is a moon of Saturn discovered by Giovanni Cassini in 1684. ... Atmosphere none Tethys (tee-thÉ™s or teth-É™s, IPA , Greek Τηθύς) is a moon of Saturn that was discovered by Giovanni Domenico Cassini in 1684. ... [5] Atmospheric characteristics Pressure trace, significant spatial variability [6], [7] Water vapour 91% [8] Carbon dioxide 3. ... Miranda (IPA: ) is the smallest and innermost of Uranus major moons. ... Atmospheric pressure 0 kPa Proteus (proe-tee-us, Greek Πρωτέας) is one of Neptunes moons. ... Mimas (mee-mÉ™s or mye-mÉ™s, IPA: , Greek Μίμᾱς, rarely Μίμανς) is a moon of Saturn that was discovered in 1789 by William Herschel. ... In astronomy, an inner satellite is a natural satellite following a prograde, low inclination orbit inwards of the large satellites of the parent planet. ... A Trojan moon is a natural satellite of a planet occupying the L4 or L5 equilateral Lagrangian points of a primary-moon system. ... In astronomy, an irregular satellite is a natural satellite following a distant, inclined, often retrograde orbit and believed to be captured as opposed to a regular satellite, formed in situ. ... This is a list of natural satellites in the solar system: Mercury: none Venus: none Earth: Moon Mars: Phobos Deimos Jupiter: see Jupiters natural satellites Saturn: see Saturns natural satellites Uranus: see Uranus natural satellites Neptune: see Neptunes natural satellites Pluto: Charon In addition, various asteroids are... This is a list of natural satellites in the solar system, ordered from largest to smallest by average diameter. ... This timeline of discovery of Solar System planets and their natural satellites charts the progress of the discovery of new bodies over history. ... The naming of natural satellites has been the responsibility of the IAUs committee for Planetary System Nomenclature since 1973. ...


  Results from FactBites:
 
Titan (moon) - Wikipedia, the free encyclopedia (3643 words)
Titan's diameter and mass (and thus its density) are similar to Jovian moons Ganymede and Callisto.
Titan is the only known moon with a fully developed atmosphere that consists of more than just trace gases.
Titan is one of the most popular extraterrestrial settings in science fiction other than Earth's Moon and the planets.
Wikinfo | Titan (moon) (568 words)
Titan was discovered on March 25, 1655 by the Dutch astronomer Christian Huygens, making it one of the first non-terrestrial moons to be discovered.
Titan is the only known moon with a fully developed atmosphere that consists of more than just trace gases; in fact, Titan's atmosphere is denser than Earth's, with a surface pressure more than one and a half times that of Earth.
These hydrocarbons are thought to form in Titan's upper atmosphere in reactions resulting from the breakup of methane by the Sun's ultraviolet light, producing a thick orange smog, and Titan's surface may be coated in a tar-like layer of organic precipitate.
  More results at FactBites »

 
 

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