### Umbono Wokwakheka Kwesistimu Yelanga
I-Pendahuluan
Ukwakheka kweSistimu Yelanga kungenye yezihloko ezithakazelisa kakhulu ku-astrophysics kanye ne-astronomy. Kuye kwaphakanyiswa imibono eminingi namamodeli ukuchaza ukuthi iSistimu yethu Yelanga yakhiwa kanjani eminyakeni ecishe ibe yizigidi eziyizinkulungwane ezingu-4,6 edlule. Lesi sihloko sihlose ukuhlola eminye yemibono eyinhloko echaza le nqubo, ngokugcizelela kakhulu i-Nebular Theory, okwamanje eyimodeli eyamukelwa kabanzi emphakathini wesayensi.
Imibono Yokuqala
Umlando wokuthuthukiswa kwemibono ngokwakhiwa kweSistimu Yelanga uqala ngemibono ehlukahlukene kanye nemibono kusukela ezikhathini zasendulo kuya enkathini yanamuhla. Eminye imibono yokuqala ivela kwifilosofi yemvelo yasendulo yamaGreki, evame ukuba nokuqagela futhi engenasisekelo sesayensi.
Ngekhulu le-18, kwavela imibono emibili emikhulu. Eyokuqala kwakuyi-Catastrophism Theory, eyaphakanyiswa yisazi sezinkanyezi saseFrance uGeorges-Louis Leclerc, uComte de Buffon. Ngokwale mbono, iSistimu Yelanga eyakhiwa ngezinto ezikhishwe njengoba inkanyezi enkulu isondela eLangeni elincane.
Ithiyori yesibili, eyaziwa kakhulu yiLaplace's Theory (Nebular Hypothesis), eyathandwa kakhulu nguPierre-Simon Laplace. Le thiyori ithi iSolar System yakhiwa ngefu elijikelezayo legesi nothuli, elabe seliwa ngaphansi kwamandla alo adonsela phansi lakha idiski yeprotoplanetary.
Ithiyori ye-Nebular (I-Nebular Hypothesis)
I-Nebular Theory iyona mbono eyamukelwa kabanzi ukuchaza ukwakheka kweSolar System. Le mbono yaqala ukuphakanyiswa ngu-Immanuel Kant ngo-1755 futhi yathuthukiswa nguLaplace ngasekupheleni kwekhulu le-18. Le mbono ithi iSolar System yakhiwa ngefu elikhulu legesi elibizwa ngokuthi i-nebula, elakhiwe ngokuyinhloko yi-hydrogen, i-helium, kanye nezinto eziphakathi kwezinkanyezi.
Le nqubo yokwakheka ingahlukaniswa ngezigaba eziningana:
1. Ukuwa kweNebula:
I-nebula yancipha ngamandla adonsela phansi, okwabangela ukuba kwakheke umongo oqinile. Le nqubo cishe yabangelwa amagagasi okushaqeka avela ku-supernova eseduze, okwabangela ingcindezi eyengeziwe ku-nebula.
2. Ukwakheka kwe-Protoplanetary Disc:
Njengoba i-nebula iwa, iqala ukujikeleza ngokushesha ngenxa yokulondolozwa komfutho we-angular. Igesi nothuli kugxila enkabeni exinene, kwakheka idiski ye-protoplanetary ezungeze i-protostar esanda kwakheka.
3. Ukwakheka Kwelanga:
Enkabeni yediski, izinto zazilokhu ziqongelela futhi zifudumala ngaphansi kwengcindezi yamandla adonsela phansi, okwabangela ukuhlangana kwenuzi okwagcina kudala iLanga. Le nqubo yathatha amashumi ezigidi zeminyaka.
4. Ukwakheka Kwamaplanethi:
Izinhlayiya zothuli neqhwa kudiski zaqala ukuhlangana ngenqubo ebizwa ngokuthi i-accretion, zakha ama-planetesimals. La ma-planetesimals abe eseshayisana futhi ahlangana ukuze akhe ama-protoplanets, agcina eseba amaplanethi. Izinto eziseduze neLanga, njengezinsimbi namatshe, zakha amaplanethi asemhlabeni: iMercury, iVenus, uMhlaba, neMars. Engxenyeni engaphandle yediski, izinto ezibandayo namagesi kwakubusa, kwakha amaplanethi amakhulu egesi: iJupiter, iSaturn, i-Uranus, neNeptune.
5. Ukwakheka KweNyanga Nesistimu Yesathelayithi:
Ngokufanayo nenqubo yokwakheka kwamaplanethi, amasathelayithi nezinyanga nakho kwakhiwe ngamadiski ezinto ezizungeze amaplanethi amakhulu.
6. Ukuhlanzwa Kwesistimu Yelanga:
Ekupheleni kwenqubo yokwakheka, umoya wezinkanyezi ovela eLangeni elincane waphephula igesi esele kanye nothuli, washiya amaplanethi, izinyanga, ama-asteroid, kanye nama-comet esiwaziyo namuhla.
Enye Ithiyori:
Ngaphandle kwe-Nebula Theory, kunezinye izinkolelo-mbono eziningana eziye zahlongozwa ukuchaza ukwakheka kweSistimu Yelanga.
1. Ithiyori Yeplanethi:
Njengoba iphakanyiswe nguThomas Chrowder Chamberlin noForest Ray Moulton ngasekupheleni kwekhulu le-19, le mbono ithi amaplanethi akheka kusukela kumaplanethi amancane ahlangana ngokukhula. Nakuba ifana neNebular Theory, le mbono igcizelela indima yamaplanethi ekwakhekeni kwamaplanethi.
2. I-Tidal Hypothesis:
I-Tidal Hypothesis, eyaphakanyiswa nguJames Jeans noHarold Jeffreys ngo-1919, ithi iSistimu Yelanga yakhiwa kusukela ekusebenzelaneni eduze kweLanga nenye inkanyezi. Amandla e-Tidal avela enkanyezini eseduze abangela ukuba izinto ezivela eLangeni zikhishwe, zakha amaplanethi ngenqubo yokwanda.
3. Ithiyori Yokuthwebula:
Kulo mbono, iSistimu Yelanga yavela eLangeni elibamba izinto efwini elidlula phakathi kwezinkanyezi. Lokhu okubanjwe kwabe sekwakha amaplanethi. Kodwa-ke, lo mbono ubhekene nezinselele eziningi ekuchazeni ukusatshalaliswa kwamaplanethi nokwakheka kwawo.
Ubufakazi Bokubuka
Kusukela maphakathi nekhulu lama-20, intuthuko kwezobuchwepheshe bethelesikopu kanye nemisebenzi yasemkhathini inikeze ulwazi olusha oluningi mayelana nokwakheka kweSistimu Yelanga. Ezinye zezingxenye ezibalulekile zobufakazi obusekela iNebular Theory zifaka:
1. I-Dust Ring Disc Ezungeze Izinkanyezi Ezincane:
Ukubonwa kwamadiski azungeza izinkanyezi ezincane noma amadiski azungeza izinkanyezi ezincane ezinezibonakude ezifana neHubble Space Telescope kufana kakhulu nezibikezelo zeNebular Theory.
2. Ama-Isotopes Anemisebe:
Izifundo ze-meteorite zembula ukwakheka kwe-isotopic okusekela ukuba khona kwezinto ezisindayo ezakhiwe ezizukulwaneni zangaphambili zezinkanyezi, okusekela isimo sokuthi i-nebula yangcoliswa yi-supernova eseduze.
3. Ukuhlukahluka Kwamaplanethi Angaphandle Kwelanga:
Ukutholakala kwezinkulungwane zamaplanethi angaphandle kwelanga kanye nezinhlelo zelanga ezahlukahlukene kubonisa ukuthi ukwakheka kwamaplanethi kuyinto evamile kulo lonke igalari yethu futhi kuhambisana nezimiso zeNebular Theory.
4. Ukusatshalaliswa Kwemizimba Yasezulwini:
Ukuhlelwa kwamaplanethi ku-Solar System kanye nokuba khona kwebhande le-asteroid kanye nebhande le-Kuiper kuyahambisana nemiphumela ye-dynamical kanye ne-gravitational ebikezelwe yizinkolelo-mbono zokwakheka kwamaplanethi.
Isiphetho
Emakhulwini eminyaka ambalwa edlule, ukuqonda kwethu ukuthi iSistimu Yelanga yakheke kanjani kuthuthuke kakhulu. Nakuba kusenezimfihlakalo eziningi, iNebular Theory okwamanje inikeza incazelo ephelele kakhulu, esekelwa kokubili ukubonwa kanye nokulingisa kwekhompyutha. Ngokuthuthuka kwesayensi nobuchwepheshe, siyaqhubeka nokuthola ukuqonda okusha ngezinqubo eziyinkimbinkimbi ezibumba indawo yethu yasemkhathini.
Ngakho-ke, ucwaningo lokwakheka kweSistimu Yelanga alugcini nje ngokusisiza siqonde imvelaphi yamaplanethi ohlelweni lwethu, kodwa futhi lunikeza izinkomba ezibalulekile mayelana nokwakheka kanye nokuvela kwezinhlelo zamaplanethi kulo lonke i-galaxy, okucebisa ukuqonda kwethu indawo yethu endaweni yonke.
