Editing Titan (moon) (section)

== Climate ==
{{Main|Climate of Titan}}
[[File:Vortex on saturn's moon titan.png|thumb|left|Atmospheric [[polar vortex]] over Titan's south pole|text-top]]
Titan's surface temperature is about {{convert|94|K|°C}}. At this temperature, water ice has an extremely low [[vapor pressure]], so the little [[water vapor]] present appears limited to the stratosphere.<ref name="CottiniNixon2012">{{cite journal |display-authors=8 |last1=Cottini |first1=V. |last2=Nixon |first2=C.A. |last3=Jennings |first3=D.E. |last4=Anderson |first4=C.M. |last5=Gorius |first5=N. |last6=Bjoraker |first6=G.L. |last7=Coustenis |first7=A. |last8=Teanby |first8=N.A. |last9=Achterberg |first9=R.K. |last10=Bézard |first10=B. |last11=de Kok |first11=R. |last12=Lellouch |first12=E. |last13=Irwin |first13=P.G.J. |last14=Flasar |first14=F.M. |last15=Bampasidis |first15=G. |title=Water vapor in Titan's stratosphere from Cassini CIRS far-infrared spectra |journal=Icarus |volume=220 |issue=2 |date=2012 |pages=855–862 |issn=0019-1035 |doi=10.1016/j.icarus.2012.06.014 |bibcode = 2012Icar..220..855C |hdl=2060/20120013575|s2cid=46722419 |hdl-access=free }}</ref> Titan receives about 1% as much sunlight as Earth.<ref>{{cite web |url=https://www.space.com/7103-titan-world-earth.html |title=Titan: A World Much Like Earth |publisher=Space.com |date=August 6, 2009 |access-date=April 2, 2012 |url-status=live |archive-url=https://web.archive.org/web/20121012005030/https://www.space.com/7103-titan-world-earth.html |archive-date=October 12, 2012 }}</ref> Before sunlight reaches the surface, about 90% has been absorbed by the thick atmosphere, leaving only 0.1% of the amount of light [[Earth]] receives.<ref>[https://arstechnica.com/science/2012/01/like-ogres-titans-atmosphere-may-have-layers/ Faint sunlight enough to drive weather, clouds on Saturn's moon Titan] {{webarchive|url=https://web.archive.org/web/20170403194843/https://arstechnica.com/science/2012/01/like-ogres-titans-atmosphere-may-have-layers/ |date=April 3, 2017 }} Between the large distance from the Sun and the thick atmosphere, Titan's surface receives about 0.1 percent of the solar energy that Earth does.</ref>

Atmospheric methane creates a [[greenhouse effect]] on Titan's surface, without which Titan would be much colder.<ref name="oil">{{cite web |url=https://www.space.com/4968-titan-oil-earth.html |title=Titan Has More Oil Than Earth |website=[[Space.com]] |date=February 13, 2008 |access-date=February 13, 2008 |url-status=live |archive-url=https://web.archive.org/web/20120708055735/https://www.space.com/4968-titan-oil-earth.html |archive-date=July 8, 2012 }}</ref> Conversely, [[haze]] in Titan's atmosphere contributes to an [[anti-greenhouse effect]] by absorbing sunlight, canceling a portion of the greenhouse effect and making its surface significantly colder than its upper atmosphere.<ref>{{cite journal |doi=10.1126/science.11538492 |first1=C.P. |last1=McKay |first2=J. B. |last2=Pollack |first3=R. |last3=Courtin |date=1991 |title=The greenhouse and antigreenhouse effects on Titan |journal=Science |volume=253 |issue=5024 |pages=1118–1121 |pmid=11538492 |url=https://pdfs.semanticscholar.org/55b1/69bd4d31772da8c5e7ad17586baff4389481.pdf |archive-url=https://web.archive.org/web/20200412143944/https://pdfs.semanticscholar.org/55b1/69bd4d31772da8c5e7ad17586baff4389481.pdf |url-status=dead |archive-date=April 12, 2020 |bibcode=1991Sci...253.1118M |s2cid=10384331 }}</ref>

{{listen |filename=Titan_haze_sound.ogg |title=The Winds of Titan |description=A recording of winds of Titan}}
[[File:PIA18420-Titan-MethaneClouds-20140722.gif|thumb|upright|Methane clouds (animated; July 2014).<ref name="NASA-20140812">{{cite web |last=Dyches |first=Preston |title=Cassini Tracks Clouds Developing Over a Titan Sea |url=https://www.jpl.nasa.gov/news/news.php?release=2014-274 |date=August 12, 2014 |work=[[NASA]] |access-date=August 13, 2014 |url-status=live |archive-url=https://web.archive.org/web/20140813004912/https://www.jpl.nasa.gov/news/news.php?release=2014-274 |archive-date=August 13, 2014 }}</ref>]]
Titan's clouds, probably composed of methane, ethane or other simple organics, are scattered and variable, punctuating the overall haze.<ref name="nineplanets" /> The findings of the ''Huygens'' probe indicate that Titan's atmosphere periodically rains liquid methane and other organic compounds onto its surface.<ref name="planetary-Arizona_Icebox">{{cite news |url=https://planetary.org/news/2005/0121_Titan_Arizona_in_an_Icebox.html |title=Titan: Arizona in an Icebox? |last=Lakdawalla |first=Emily |author-link=Emily Lakdawalla |publisher=The Planetary Society |date=January 21, 2004 |archive-date=February 12, 2010 |archive-url=https://web.archive.org/web/20100212062535/https://planetary.org/news/2005/0121_Titan_Arizona_in_an_Icebox.html |access-date=March 28, 2005 }}</ref>

Clouds typically cover 1% of Titan's disk, though outburst events have been observed in which the cloud cover rapidly expands to as much as 8%. One hypothesis asserts that the southern clouds are formed when heightened [[insolation|levels of sunlight]] during the southern summer generate uplift in the atmosphere, resulting in [[convection]]. This explanation is complicated by the fact that cloud formation has been observed not only after the southern summer solstice but also during mid-spring. Increased methane humidity at the south pole possibly contributes to the rapid increases in cloud size.<ref>{{cite journal |last1=Emily L. |first1=Schaller |last2=Brouwn |first2=Michael E. |last3=Roe |first3=Henry G. |last4=Bouchez |first4=Antonin H. |date=2006 |title=A large cloud outburst at Titan's south pole |doi=10.1016/j.icarus.2005.12.021 |journal=Icarus |issue=1 |pages=224–229 |url=https://www.gps.caltech.edu/~mbrown/papers/ps/largecloud.pdf |volume=182 |bibcode=2006Icar..182..224S |access-date=August 23, 2007 |url-status=live |archive-url=https://web.archive.org/web/20070926102541/https://www.gps.caltech.edu/~mbrown/papers/ps/largecloud.pdf |archive-date=September 26, 2007 }}</ref> It was summer in Titan's southern hemisphere until 2010, when Saturn's orbit, which governs Titan's motion, moved Titan's northern hemisphere into the sunlight.<ref name="Titan wind">{{cite news|title=The Way the Wind Blows on Titan |date=June 1, 2007 |url=https://saturn.jpl.nasa.gov/news/cassinifeatures/feature20070601f/ |access-date=June 2, 2007 |publisher=Jet Propulsion Laboratory |url-status=dead |archive-url=https://web.archive.org/web/20090427110242/https://saturn.jpl.nasa.gov/news/cassinifeatures/feature20070601f/ |archive-date=April 27, 2009 }}</ref> When the seasons switch, it is expected that ethane will begin to condense over the south pole.<ref>{{cite journal |title=Huge ethane cloud discovered on Titan |last=Shiga |first=David |journal=New Scientist |volume=313 |page=1620 |date=2006 |url=https://www.newscientist.com/article/dn10073-huge-ethane-cloud-discovered-on-titan.html |access-date=August 7, 2007 |url-status=live |archive-url=https://web.archive.org/web/20081220030748/https://www.newscientist.com/article/dn10073-huge-ethane-cloud-discovered-on-titan.html |archive-date=December 20, 2008 }}</ref>