<prompt> Bheka isigaba esingezansi bese uphendula umbuzo emva kwalokho ngolimi olufanayo nesigaba: Ukudlula: I-90377 Sedna iyiplanethi enkulu encane ekufinyeleleni kwangaphandle kohlelo lwelanga, kusukela ngo-2015, ebangeni elingama-86 amayunithi wezinkanyezi 1.29×1010 km; 8.0×109 mi ukusuka elangeni, cishe kathathu kude neNeptune. I-spectroscopy iveze ukuthi ukwakheka kobuso be-Sedna kufana nokwezinye izinto ze-trans-Neptunian, okuyingxube enkulu yamanzi, i-methane, ne-nitrogen ice ene-tholins. Indawo yayo ingenye yezinto ezibomvu kakhulu phakathi kwezinto eziseSimisweni Sokujikeleza Kwelanga. Cishe liyiplanethi emincane. Phakathi kwezinto eziyisishiyagalombili ezinkulu ze-trans-Neptunian, iSedna iyona kuphela engaziwa ukuthi inenyanga. Ngokuhamba kwesikhathi, ikude kakhulu neLanga kunamanje, ne-aphelion yayo elinganiselwa ku-937 AU izikhathi ezingama-31 ibanga le-Neptune, okwenza kube enye yezinto ezikude kakhulu ezaziwayo eSolar System ngaphandle kwama-comets wesikhathi eside. ISedna inendlela ehlukile ende futhi ende, ethatha cishe iminyaka engu-11,400 ukuqedela futhi iphuzu elikude lokusondela kakhulu elangeni ku-76 AU. La maqiniso aye aholela ekucabangeni okuningi ngemvelaphi yayo. I-Minor Planet Center njengamanje ibeka iSedna kuyi-disc ehlakazekile, iqembu lezinto ezithunyelwa emzileni omude kakhulu ngenxa yethonya likaNeptune. Lokhu kuhlukaniswa kuye kwaphikiswa ngoba iSedna ayikaze isondele ngokwanele kuNeptune ukuze isakazwe yiyo, okuholela abanye izazi zezinkanyezi ukuba ziyibize ngokungahleliwe njengelungu lokuqala elaziwayo lefu langaphakathi le-Oort. Abanye bacabanga ukuthi kungenzeka ukuthi lalikhishwa yinkanyezi edlulayo, mhlawumbe eyayiyingxenye yeqoqo lezinkanyezi elizala iLanga iqoqo lezinkanyezi elivulekile, layiswa emzileni walo wamanje, noma ngisho nokuthi lathathwa kwenye isimiso sezinkanyezi. Omunye umbono uthi umjikelezo wayo ungaba ubufakazi bokuthi kuneplanethi enkulu engaphandle komjikelezo weNeptune. Isazi sezinkanyezi uMichael E. Brown, owathola i-Sedna namaplanethi amancane u-Eris, Haumea, noMakemake, ucabanga ukuthi iyinto ebaluleke kakhulu kwezesayensi etholakala kuze kube manje, ngoba ukuqonda umjikelezo wayo ongajwayelekile kungenzeka kunikeze imininingwane ebalulekile mayelana... Umbuzo: Unjani umbala wobuso beplanethi iSedna?  <response>: obomvu 