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{{Featured Article2|Year Featured=24|Month Featured=Jan}}{{Moon|image1=<gallery>
Titan.jpg|True Color
Titan False Color.jpeg|False Color
</gallery>|DiscoveredOn=March 25, 1655|Diameter=5,150 kilometers|DiscoveredBy=Christiaan Huygens|PlanetofOrigin=[[Saturn]]|Semi-MajorAxis=1,221,870 km|periapsis=1,186,680 km|apoapsis=1,257,060 km|atmospheric_composition=98.4% nitrogen<br>1.6% trace gases (ethane, propane, carbon dioxide, and argon)|Mass=0.0225 Earth's|Albedo=0.22|Volume=0.066 Earth's|Density=1.88 g/cm3|EscapeVeloc-=2.641 km/s|orbital_motion=Prograde|temperature=93.7 K|eccentricity=0.0288|orbital_period=16 days|radius=2,575 km}}

'''Titan''', also known as '''Saturn VI''', is a prograde moon and is the largest natural satellite of the outer planet, [[Saturn]]. Is is also the second largest moon in the Solar System, just behind [[Ganymede]],<ref>https://web.archive.org/web/20200212021254/https://pdfs.semanticscholar.org/7ec3/29458f5dabfa6c370476df8236779941f93f.pdf</ref> one of the Galilean moons belonging to the outer planet, [[Jupiter]]. This however is the only moon known in the Solar System to have a dense atmosphere and is even believed to have surface water,<ref>Robert Brown; Jean Pierre Lebreton; Hunter Waite, eds. (2009). ''Titan from Cassini-Huygens''. Springer Science & Business Media. p. 69.ISBN 
</ref> the only other body to have received this classification after our own [[Earth]]. Titan was discovered on March 25, 1655 by the Dutch astronomer [[wikipedia:Christiaan_Huygens|Christiaan Huygens]].<ref>"Lifting Titan's Veil" (PDF). Cambridge. p. 4. Archived from the original (pdf) on February 22, 2005.
</ref><ref>"Titan". ''Astronomy Picture of the Day''. NASA. Archived from the original on March 27, 2005.
</ref> It was the sixth moon ever discovered, after Earth's [[Moon]] and the [[Galilean moons]] of [[Jupiter]].

== Discovery ==
Titan was discovered on March 25, 1655, by the Dutch astronomer Christiaan Huygens. Huygens was inspired by Galileo's discovery of Jupiter's four [[Galilean moons|largest moons]] in 1610 and his improvements in telescope technology. Christiaan, with the help of his elder brother Constantijn Huygens Jr., began building telescopes around 1650 and was able to discover the first observed moon orbiting Saturn with one of the telescopes that they built.

== Name ==
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). The International Astronomical Union numbers Titan as '''Saturn VI'''.

The name ''Titan'', and the names of all seven satellites of Saturn then known, came from John Herschel (son of William Herschel, discoverer of two other Saturnian moons, 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''. Numerous small moons have been discovered around Saturn since then. Saturnian moons are named after mythological giants. The name Titan comes from the Titans, a race of immortals in Greek mythology.

==Formation==
Since Saturn is so close to the [[Asteroid belt]], it is believed Titan was a stray [[Asteroid belt#Composition|carbonaceous]], or C-type, asteroid, the most populous of the asteroids in the Asteroid belt. Since they were (and still are) so populous, it is believed that many of these asteroids collided and created friction, which generated heat that fused these asteroids together. Once the later-to-be-named Titan became large enough - in fact large enough to maintain hydrostatic equilibrium - it could not collect any more and was pushed into deep space through other impacts. It is not completely clear how it escaped Jupiter's strong gravitational pull, but it is believed to be due to the amount of perturbation caused by the existing moons causing the gravitational pull to be slowed and keeping Titan from staying with Jupiter and instead traveling to Saturn, where it was soon captured.<sup>''[citation needed]''</sup>

Titan may have also been formed by a co-accretion. According from the source material, this would explain it’s high eccentricity and the icy materials of other of Saturn’s large moons.<ref>https://www.spacedaily.com/reports/Giant_impact_scenario_may_explain_the_unusual_moons_of_Saturn_999.html</ref>

==Surface Features==
The surface of Titan can only be seen through high-tech radar telescopes, for it is completely covered by a dense, orange atmosphere. The surface of Titan is in many ways similar to Earth's, and in some places even [[Moon|Earth's moon]]. There have been reported sand dunes on Titan's surface, which are very similar to the likes of those seen on Earth - the lining of sand is, in comparison, similar to those of the Namib Desert. The [http://en.wikipedia.org/wiki/Shangri-la Shangri-la] of Titan, a long and extremely dark surface feature (referred to as a ''dark albedo feature''), can be compared to the mares of Earth's moon. There are many faculae on the surface of Titan including the [http://en.wikipedia.org/wiki/Shikoku_Facula Shikoku Facula] and the [http://en.wikipedia.org/wiki/Sotra_Facula Sotra Facula].
{{Geology of Titan}}[[File:0E274172-A00A-48FB-8071-F28A4B1044CF.jpg|thumb]]

==Atmosphere==
The atmosphere of Titan is the only fully developed atmosphere of any moon in the Solar System, and is also the densest of any moon. The atmosphere's presence was first discovered by Spanish astronomer Josep Comas Solà in 1903. The atmosphere is composed of 98.4% nitrogen, which makes it ~1.2 times more massive than Earth's atmosphere. The rest of the atmosphere is composed of trace gases including ethane, propane, carbon dioxide, and argon.<ref>https://web.archive.org/web/20051202030828/https://saturn.jpl.nasa.gov/news/features/saturn-story/moons.cfm</ref>

==Composition==
The composition of Titan makes it more massive than any other moon belonging to Saturn (aka the ''Saturnian moons''). The uppermost layer is the crust which is mostly covered in water-ice. There's an ocean located just beneath the ice. Oceans and lakes are found on the crust. Titan is so cold that the gas changes state and becomes a liquid. Under the crust is the upper mantle. It's unknown what is under the upper mantle.

At the south pole of Titan is a permanent hurricane that continues to expand today. It pushes matter into the atmosphere, making itself denser as it expands. Since clouds typically cover about 0.9% of Titan's surface, this hurricane is unique, for it covers quite a distance.
Titan might have life, or it might not - but it does have rivers and rocks.
[[File:Titan’s Night Side.jpeg|thumb|The night side of Titan, taken by Voyager.]]

== Structure ==
Titan’s internal structure isn’t entirely known, but one model based on data from the Cassini-Huygens mission suggests Titan has five primary layers. The innermost layer is a core of rock (specifically, water-bearing silicate rock) about 2,500 miles (4,000 kilometers) in diameter. Surrounding the core is a shell of water ice—a special type called ice-VI that is only found at extremely high-pressures. The high-pressure ice is surrounded by a layer of salty liquid water, on top of which sits an outer crust of water ice. This surface is coated with organic molecules that have rained or otherwise settled out of the atmosphere in the form of sands and liquids. The surface is hugged by a dense atmosphere. 

== Exploration ==
Titan was a mysterious moon before it was first explored by [[Pioneer 11]] and [[Voyager 1]]. Pioneer 11 data showed that Titan was probably too cold to support life, and Voyager 1 was able to discoverer key details about the atmosphere, like its density. If Voyager 1 didn’t target Titan, it is possible it could have gone to [[Pluto]].

Cassini-Huygens visited Saturn in 2004, and started orbiting around Titan, and landed a probe on Titan, called Huygens. Huygens lasted a few hours on the surface, observing and conducting research. Cassini also made multiple flybys of Titan during its main and extended missions.

=== Flybys ===
{| class="fandom-table"
!Probe
!Closest Approach
!Date
|-
|Pioneer 11
|362,962 km
|September 2, 1979
|-
|Voyager 1
|6,490 km
|November 11, 1980
|-
|Cassini-Huygens
|Multiple Flybys
|Multiple Flybys
|}

=== Landers ===
{| class="fandom-table"
!Name
!Date Landed
|-
|Huygens titan Lander
|January 14, 2005
|}

== Atmospheric Composition ==
[[File:2048px-Titan poster.svg -1200x800.jpg|thumb|180x180px|Structure:
Atmosphere
* Upper atmosphere
* Thick tholin haze
* Lower atmosphere
Normal ice (1<sub>h</sub>)

Liquid water ocean

Ice-six (tetragonal crystals)

Hydrous silicate core
]]
{| class="article-table"
|Molecule
|Symbol
|%  (stratosphere)
|% (lower troposphere)
|-
|Nitrogen
|N<sub>2</sub>
|98.4
|95.0
97
|-
|Methane
|CH<sub>4</sub>
|1.4
|4.9
2.7±0.1
|-
|Hydrogen
|H<sub>2</sub>
|0.2
|0.1-0.2
|}

==Gallery==
{{GalleryRedirect|Object Name=Titan}}

== Bibliography ==
<references />{{Moons of Saturn}}

[[Category:Moons]]
[[Category:Moons Belonging to Outer Planets]]
[[Category:Moons Belonging to Gaseous Planets]]
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[[Category:Moons Belonging to Saturn]]
[[Category:Inner Moons of Saturn]]
[[Category:Objects Maintaining Hydrostatic Equilibrium]]
[[Category:Atmospheres]]
[[Category:Major Moon]]
[[Category:Regular Satellites]]
[[Category:Regular Satellites Of Saturn]]
[[Category:Prograde Moons]]
[[Category:Prograde Moons Of Saturn]]
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