See soorce fer Neptune

[[File:Neptune Voyager2 color calibrated.png|thumb|right|Neptune]]

'''Neptune''' is the aicht an farthest [[planet]] frae the [[Sun]] in the [[Solar Seestem]]. It is the fowert-lairgest planet bi diameter an the third-lairgest bi mass. Amang the gaseous planets in the solar seestem, Neptune is the maist dense. Neptune is 17 times the mass o [[Yird]] an is slichtly mair massive than its near-twin [[Uranus]], which is 15 times the mass o Yird but nae as dense.<ref group=lower-alpha name="mass">The mass of the Earth is 5.9736{{e|24}}&nbsp;kg, giving a mass ratio of:
: <math>\begin{smallmatrix}\frac{M_{Neptune}}{M_{Earth}} \ =\ \frac{1.02 \times 10^{26}}{5.97 \times 10^{24}} \ =\ 17.09\end{smallmatrix}</math>
The mass of Uranus is 8.6810{{e|25}}&nbsp;kg, giving a mass ratio of:
: <math>\begin{smallmatrix}\frac{M_{Uranus}}{M_{Earth}} \ =\ \frac{8.68 \times 10^{25}}{5.97 \times 10^{24}}\ =\ 14.54\end{smallmatrix}</math>
The mass of Jupiter is 1.8986{{e|27}}&nbsp;kg, giving a mass ratio of:
: <math>\begin{smallmatrix}\frac{M_{Jupiter}}{M_{Neptune}} \ =\ \frac{1.90 \times 10^{27}}{1.02 \times 10^{26}}\ =\ 18.63\end{smallmatrix}</math>
Mass values from {{cite web
| last = Williams|first = David R.
| date = 29 November 2007
| url = http://nssdc.gsfc.nasa.gov/planetary/factsheet/
| title = Planetary Fact Sheet&nbsp;– Metric|publisher=NASA
| accessdate = 13 March 2008
}}</ref> On average, Neptune orbits the Sun at a distance o 30.1 [[Astronomical Unit|AU]], approximately 30 times the Yird–Sun distance. Named for the Roman god o the sea, its astronomical seembol is [[File:Neptune symbol (fixed width).svg|16px|♆]], a stylised version o the god Neptune's trident.

Neptune wis the first planet foond bi mathematical prediction rather than bi empirical observation. Unexpectit chynges in the orbit o [[Uranus]] led Alexis Bouvard tae deduce that its orbit wis subject tae [[gravitation]]al perturbation bi an unkent planet. Neptune wis subsequently observed on 23 September 1846<ref name="Hamilton">
{{cite web
|first = Calvin J.|last = Hamilton
|date = 4 August 2001
|url = http://www.solarviews.com/eng/neptune.htm
|title = Neptune
|publisher = Views of the Solar System
|accessdate = 13 August 2007
}}</ref> bi [[Johann Galle]] within a degree o the poseetion predictit bi [[Urbain Le Verrier]], an its lairgest muin, [[Triton (muin)|Triton]], wis discovered shortly thareefter, tho none o the planet's remainin 13 muins wur locatit telescopically till the 20t century. Neptune haes been visited bi anly ane spacecraft, ''[[Voyager 2]]'', which flew bi the planet on 25 August 1989.

Neptune is seemilar in composeetion tae [[Uranus]], an baith hae composeetions which differ frae those o the lairger gas giants, [[Jupiter]], an [[Saturn]]. Neptune's atmosphere, while seemilar tae Jupiter's an Saturn's in that it is componed primarily o [[hydrogen]] an [[helium]], alang wi traces o [[hydrocarbon]]s an possibly [[nitrogen]], contains a heicher proportion o "ices" sic as watter, [[ammonia]], an [[methane]]. Astronomers whiles categorise Uranus an Neptune as "ice giants" in order tae emphasise thir distinctions.<ref name="Lunine 1993">{{cite journal| doi = 10.1146/annurev.aa.31.090193.001245| last = Lunine| first = Jonathan I.| date=September 1993 | title = The Atmospheres of Uranus and Neptune| journal = Annual Review of Astronomy and Astrophysics| volume = 31| pages = 217–263| bibcode = 1993ARA&A..31..217L| ref = harv}}</ref> The interior o Neptune, lik that o Uranus, is primarily componed o ices an rock.<ref name="Podolak Weizman et al. 1995">
{{cite journal| doi = 10.1016/0032-0633(95)00061-5| last1 = Podolak| first1 = M.| last2 = Weizman| first2 = A.| last3 = Marley| first3 = M.| date=December 1995 | title = Comparative models of Uranus and Neptune| url = https://archive.org/details/sim_planetary-and-space-science_1995-12_43_12/page/1517| journal = Planetary and Space Science| volume = 43| issue = 12| pages = 1517–1522| pmid = | pmc = | bibcode = 1995P&SS...43.1517P| ref = {{sfnRef|Podolak Weizman et al.|1995}}}}
</ref> It is possible that the cor haes a solit surface, but the temperatur wad be thoosands o degrees an the atmospheric pressur crushin.<ref>[http://www.universetoday.com/22070/surface-of-neptune/ Upper Surface of Neptune]. Universetoday.com (2008-12-09). Retrieved on 2013-07-28.</ref> Traces o methane in the ootermaist regions in pairt accoont for the planet's blue appearance.<ref name="bluecolour">{{cite web|last=Munsell|first=Kirk|last2=Smith|first2=Harman|last3=Harvey|first3=Samantha|date=13 November 2007|title=Neptune overview|url=http://solarsystem.nasa.gov/planets/profile.cfm?Object=Neptune&Display=OverviewLong|url-status=dead|archive-url=https://web.archive.org/web/20080303045911/http://solarsystem.nasa.gov/planets/profile.cfm?Object=Neptune&Display=OverviewLong|archive-date=2008-03-03|accessdate=20 February 2008|work=Solar System Exploration|publisher=NASA}}</ref>

In contrast tae the hazy, relatively featureless atmosphere o Uranus, Neptune's atmosphere is notable for its active an veesible wather patterns. For example, at the time o the 1989 ''Voyager 2'' flyby, the planet's soothren hemisphere possessed a Great Dark Spot comparable tae the Great Red Spot on [[Jupiter]]. Thir wather patterns are driven bi the strangest sustained winds o ony planet in the Solar Seestem, wi recordit wind speeds as heich as {{convert|2100|kph|mph}}.<ref name="Suomi1991">
{{cite journal|last=Suomi|first=V. E.|last2=Limaye|first2=S.S|last3=Johnson|first3=D.R|year=1991|title=High Winds of Neptune: A possible mechanism|journal=[[Science (journal)|Science]]|volume=251|issue=4996|pages=929–932|bibcode=1991Sci...251..929S|doi=10.1126/science.251.4996.929|pmid=17847386}}</ref> Acause o its great distance frae the Sun, Neptune's ooter atmosphere is ane o the cauldest places in the Solar Seestem, wi temperaturs at its clood taps approachin {{convert|55|K|C|0|lk=on}}<!--note that the template is no good, abbr=off has no effect-->. Temperaturs at the planet's centre are approximately {{convert|5400|K|C|-3}}.<ref name=hubbard>{{cite journal
|last=Hubbard|first=W. B.
|title=Neptune's Deep Chemistry
|journal=Science|year=1997
|volume=275|issue=5304|pages=1279–1280
|doi=10.1126/science.275.5304.1279
|pmid=9064785}}</ref><ref name="nettelmann">{{cite web|last=Nettelmann|first=N.|last2=French|first2=M|last3=Holst|first3=B|last4=Redmer|first4=R.|title=Interior Models of Jupiter, Saturn and Neptune|url=https://www.gsi.de/informationen/wti/library/plasma2006/PAPERS/TT-11.pdf|url-status=dead|archive-url=https://web.archive.org/web/20110718120920/https://www.gsi.de/informationen/wti/library/plasma2006/PAPERS/TT-11.pdf|archive-date=2011-07-18|accessdate=25 February 2008|publisher=University of Rostock|format=PDF}}</ref> Neptune haes a faunt an fragmented ring seestem (labeled 'arcs'), which mey hae been detectit durin the 1960s but wis anly indisputably confirmed in 1989 bi ''Voyager 2''.<ref name=ring1>{{cite news
|last=Wilford|first=John N.|date=10 June 1982
|title=Data Shows 2 Rings Circling Neptune
|work=The New York Times
|url=http://query.nytimes.com/gst/fullpage.html?sec=technology&res=950DE3D71F38F933A25755C0A964948260&n=Top/News/Science/Topics/Space
|accessdate=29 February 2008}}</ref>

==Notes==
<references group="lower-alpha"/>

==References==
{{Reflist}}

==Freemit airtins==
{{Sister project links|Neptune}}
* [http://nssdc.gsfc.nasa.gov/planetary/factsheet/neptunefact.html NASA's Neptune fact sheet]
* [http://www.nineplanets.org/neptune.html Neptune] frae Bill Arnett's nineplanets.org
* [http://www.astronomycast.com/astronomy/episode-63-neptune/ Neptune] Astronomy Cast episode No. 63, includes full transcript.
* [http://solarsystem.nasa.gov/planets/profile.cfm?Object=Neptune Neptune Profile] {{Webarchive|url=https://web.archive.org/web/20061213204351/http://solarsystem.nasa.gov/planets/profile.cfm?Object=Neptune |date=2006-12-13 }} at [http://solarsystem.nasa.gov NASA's Solar Seestem Exploration steid]
* [http://www.projectshum.org/Planets/neptune.html Planets&nbsp;– Neptune] {{Webarchive|url=https://web.archive.org/web/20110606055326/http://www.projectshum.org/Planets/neptune.html |date=2011-06-06 }} A childer's guide tae Neptune.

{{Neptune}}
{{Solar Seestem}}
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[[Category:Neptune| ]]
[[Category:Astronomical objects discovered in 1846]]
[[Category:Gas giants]]
[[Category:Planets o the Solar Seestem]]