Titan (moon)

Titan
Titan in true color.jpg
Titan in natural color. The thick atmosphere is orange due to a dense organonitrogen haze.
Discovery
Discovered by Christiaan Huygens
Discovery date March 25, 1655
Designations
Pronunciation ən/ ( About this sound  listen)
Saturn VI
Adjectives Titanean, Titanian [1]
Orbital characteristics [2]
Periapsis 1186680 km
Apoapsis 1257060 km
1221870 km
Eccentricity 0.0288
15.945 d
5.57 km/s (calculated)
Inclination 0.34854° (to Saturn's equator)
Satellite of Saturn
Physical characteristics
Mean radius
2575.5±2.0 km (0.404 Earths) [3] (1.480 Moons)
8.3×107 km2 (0.163 Earths) (2.188 Moons)
Volume 7.16×1010 km3 (0.066 Earths) (3.3 Moons)
Mass (1.3452±0.0002)×1023 kg
(0.0225 Earths) [3] (1.829 Moons)
Mean density
1.8798±0.0044 g/cm3 [3]
1.352 m/s2 (0.14  g) (0.85 Moons)
0.3414±0.0005 [4] (estimate)
2.639 km/s (0.236 Earths) (1.11 Moons)
Synchronous
Zero
Albedo 0.22 [5]
Temperature 93.7 K (−179.5 °C) [6]
8.2 [7] to 9.0
Atmosphere
Surface pressure
146.7  kPa (1.45  atm)
Composition by volume Variable [8] [9]
Stratosphere:
98.4% nitrogen (N2),
1.4% methane (CH4),
0.2% hydrogen (H2);
Lower troposphere:
95.0% N2, 4.9% CH4

Titan is the largest moon of Saturn. It is the only moon known to have a dense atmosphere, and the only object in space other than Earth where clear evidence of stable bodies of surface liquid has been found.

Titan is the sixth ellipsoidal moon from Saturn. Frequently described as a planet-like moon, Titan is 50% larger than Earth's Moon, and it is 80% more massive. It is the second-largest moon in the Solar System, after Jupiter's moon Ganymede, and is larger than the smallest planet, Mercury, but only 40% as massive. Discovered in 1655 by the Dutch astronomer Christiaan Huygens, Titan was the first known moon of Saturn, and the sixth known planetary satellite (after Earth's Moon and the four Galilean moons of Jupiter). Titan orbits Saturn at 20 Saturn radii. From Titan's surface, Saturn subtends an arc of 5.09 degrees and would appear 11.4 times larger in the sky than the Moon from Earth.

Titan is primarily composed of water ice and rocky material. Much as with Venus before the Space Age, the dense opaque atmosphere prevented understanding of Titan's surface until new information from the Cassini–Huygens mission in 2004, including the discovery of liquid hydrocarbon lakes in Titan's polar regions. The geologically young surface is generally smooth, with few impact craters, although mountains and several possible cryovolcanoes have been found.

The atmosphere of Titan is largely nitrogen; minor components lead to the formation of methane and ethane clouds and nitrogen-rich organic smog. The climate—including wind and rain—creates surface features similar to those of Earth, such as dunes, rivers, lakes, seas (probably of liquid methane and ethane), and deltas, and is dominated by seasonal weather patterns as on Earth. With its liquids (both surface and subsurface) and robust nitrogen atmosphere, Titan's methane cycle is analogous to Earth's water cycle, at the much lower temperature of about 94 K (−179.2 °C).

History

Discovery

Christiaan Huygens discovered Titan in 1655.

Titan was discovered on March 25, 1655 by the Dutch astronomer Christiaan Huygens. [10] [11] Huygens was inspired by Galileo's discovery of Jupiter's four largest moons in 1610 and his improvements in telescope technology. Christiaan, with the help of his brother Constantijn Huygens, Jr., began building telescopes around 1650 and discovered the first observed moon orbiting Saturn with one of the telescopes they built. [12] It was the sixth moon to be discovered, after Earth's Moon and the Galilean moons of Jupiter. [13]

Naming

Huygens named his discovery Saturni Luna (or Luna Saturni, Latin for "Saturn's moon"), publishing in the 1655 tract De Saturni Luna Observatio Nova (A New Observation of Saturn's Moon). After Giovanni Domenico Cassini published his discoveries of four more moons of Saturn between 1673 and 1686, astronomers fell into the habit of referring to these and Titan as Saturn I through V (with Titan then in fourth position). Other early epithets for Titan include "Saturn's ordinary satellite". [14] Titan is officially numbered Saturn VI because after the 1789 discoveries the numbering scheme was frozen to avoid causing any more confusion (Titan having borne the numbers II and IV as well as VI). Numerous small moons have been discovered closer to Saturn since then.

The name Titan, and the names of all seven satellites of Saturn then known, came from John Herschel (son of William Herschel, discoverer of Mimas and Enceladus) in his 1847 publication Results of Astronomical Observations Made during the Years 1834, 5, 6, 7, 8, at the Cape of Good Hope. [15] [16] He suggested the names of the mythological Titans ( Ancient Greek: Τῑτάν), brothers and sisters of Cronus, the Greek Saturn. In Greek mythology, the Titans were a race of powerful deities, descendants of Gaia and Uranus, that ruled during the legendary Golden Age.

Other Languages
Afrikaans: Titan (maan)
Alemannisch: Titan (Mond)
العربية: تيتان (قمر)
azərbaycanca: Titan (peyk)
বাংলা: টাইটান
Bân-lâm-gú: Titan (oē-chheⁿ)
български: Титан (спътник)
bosanski: Titan (mjesec)
brezhoneg: Titan (loarenn)
čeština: Titan (měsíc)
Deutsch: Titan (Mond)
eesti: Titan
Esperanto: Titano (luno)
فارسی: تیتان
français: Titan (lune)
ગુજરાતી: ટાઇટન (ચંદ્ર)
hrvatski: Titan (mjesec)
Ido: Titano
Bahasa Indonesia: Titan (satelit)
íslenska: Títan (tungl)
қазақша: Титан (серік)
Kiswahili: Titan (Zohali)
Lëtzebuergesch: Titan (Mound)
македонски: Титан (месечина)
Bahasa Melayu: Titan (bulan)
Mìng-dĕ̤ng-ngṳ̄: Titan (ôi-sĭng)
монгол: Титан (сар)
မြန်မာဘာသာ: တိုက်တန် (လ)
Nederlands: Titan (maan)
norsk nynorsk: Saturnmånen Titan
occitan: Titan (luna)
oʻzbekcha/ўзбекча: Titan (yoʻldosh)
ਪੰਜਾਬੀ: ਟਾਈਟਨ
português: Titã (satélite)
română: Titan (satelit)
sicilianu: Titanu
Simple English: Titan (moon)
slovenčina: Titan (mesiac)
slovenščina: Titan (luna)
کوردی: تیتان
српски / srpski: Титан (сателит)
srpskohrvatski / српскохрватски: Titan (mjesec)
svenska: Titan (måne)
Tagalog: Titan (buwan)
татарча/tatarça: Титан (иярчен)
Türkçe: Titan (uydu)
українська: Титан (супутник)
Tiếng Việt: Titan (vệ tinh)
文言: 土衛六
Winaray: Titan (bulan)
粵語: 土衞六
中文: 土卫六