Neptun

*Neptun*' bi di eiht and planet wey fa pas from di Sun. E bi di foht-lajes planet for di Sola System bai diameta, di thord-mos-masiv planet, and di densest jaiant planet. E bi 17&nbsp;taims di mass of Earth, and dey slaihtli moh masiv than felo ice jaiant Uranus. Neptun dey densa and fisikali smola than Uranus bekaus e great mass dey kaus moh gravitashonal kompresion of e atmosfe. Wey dey komposd praimarili of gasis and liquids, e no get wel-defaind solid surfais. Di planet dey obit di Sun wons evri 164.8&nbsp;years for an orbital distans of 30.1AU|e9km e9mi. E nem kom from di Roman god of di sea and get di astronomikal simbol  wey dey represent Neptun traident.

Neptun no dey visibul to unaided ai and bi di onli planet for di Sola System wey wi faind bai matematikal predishons rada than bai empirikal obsavashon. Unexpeted chenjis for di obit of Uranus lead Alexis Bouvard to hypotesaiz say e obit dey subjet to gravitashonal petobashon bai a planet wey wi neva sabi abaut. Afta Bouvard kpai, di posishon of Neptun kom dey predited from e obsavashons, independentli, bai John Kouch Adams and Urbain Le Verrier. Neptun kom dey subsequentli obsavd wit teleskop on 23&nbsp;September 1846 bai Johann Gottfried Galle widin a degree of di posishon wey Le Verrier predit. E lajes moon, Triton, dey diskovad shortli diarafta, though non of di planet remainin 13 moons dey teleskopikali obsavd until di 20th&nbsp;century. Di planet distans from Earth dey giv am a smol aparent saiz, mekin am dey chalenjin to stodi am wit Earth-bayzd teleskops. *[[Voyaija 2|Voyaija&nbsp;2]]* been visit Neptun, wen e flai ova di planet on 25&nbsp;August 1989; *Voyaija&nbsp;2* remain di onli spaiskraft wey don visit am. Di advent of di Hobul Spais Teleskop and laj graund-bayzd teleskops wit adaptiv optiks don alau for adishonal detaild obsavashons from afa.

Laik di gas jaiants (Jupita and Saturn), Neptun atmosfe dey komposd praimarili of hydrojen and helium, along wit traces of hydrokarbons and posibli naitrojen, but kontain a haia proporshon of *[[Volatile (astrojeoloji)|ices]]* such as wota, ammonia and methaen. Simila to Uranus, e interior dey praimarili komposd of ices and rok; both planets nomali dey konsidad as "ice jaiants" to distinguish dem. Along wit Rayleih skatarin, traces of methaen for di autamos rejions mek Neptun to apia faintli blue.

In kontras to di strongli seasonal atmosfe of Uranus, wey fit dey feachorles for long periods of taim, Neptun atmosfe get ativ and konsistentli visibul weda patans. As at di taim of di *Voyaija&nbsp;2* flaibai for 1989, di planet sautan hemisfe get a Great Dak Spot wey dey komparabul to di Great Red Spot for Jupita. For 2018, a niua main dak spot and smola dak spot kom dey identifaid and stodid. Diz weda patans dey driven bai di stronges sustaind winds of eni planet for di Sola System, as hai as 2100km/h|m/s mph. Bekaus of e great distans from di Sun, Neptun auta atmosfe bi wan of di koldes plaesis for di Sola System, wit temperechors for e kloud tops dey aproach 55K|C F. Temperechots for di centa of di planet bi aproximateli 5400K|C F. Neptun get a faint and fragmented ring system (wey dey labeld as "arks"), wey wi diskova for 1984 and wey *Voyaija 2* konfam.

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