UMkhathilibe

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uMkhathilibe uyikho konke okomkhathi nesikhathi nakho konke okuqukethwe yikho,  okungahlanisa imiZulane, iziNkanyezi, iMikhathinga, kanye nazo zonke izinhlobo zoTho neMpekumpeku. Umbono wokuQhuma okuKhulu uyincazelo edlu'bhedu engokomkhathi yokwakheka koMkhathilibe. Ngokwalombono, umkhathi nesikhathi kwavela ndawonye eminyakeni engaba izigidigudi ezingama-13.787 ±0.020 ezidlule, futhi umkhathilibe ubulokhu ulwiza kusuka lapho. Nakuba isilinganiso esiphelele somkhathilibe wonke singaziwa, kuyinto engenzeka ukuba kulinganiswe ubungako bomkhathilibe esingawubuka, okungenzeka ungukukhanyabanga  okuyizigidigidi ezingama-93 ngebangandilinga namuhla.

Unongo lokuma komkhathi lwangaphambili olwaziwayo lomkhathilibe lwenziwa osonjulalwazi bamaGreki namaNdiya futhi lwaluthi umhlaba ungumnyombo wozungezohlelo. Emakhulwini eminyaka eyalandela, iziqapho zezulu ezinembile ezenziwa ziholwa uNicolaus Copernicus, ezaziyizinongo zomnyombo welanga ohlelweni lukaNozubgezilanga, zakuphikisa lokho. Ekuthuthukiseni umthetho womnyondo wajikelele, u-Isaac Newton wakhela phezu komsebenzi ka-Copernicus nasemthethweni womdiki wemizulane kaJohannes Keppler kanye naseziqaphweni zikaTycho Brahe.

Iziqapho eziqhubekayo ezithuthukile zaholela ekuqapheleni ukuthi ilanga lingenye yezinkanyezi eziyizigidigidi ezingamakhulu ambalwa kumzilafasimbe, okungumthalakazi owodwa kweyizigidigidi zamakhulu ambalwa kumkhathilibe. Iningi lezinkanyezi kumthalakazi zinemizulane. Ngokomlinganiso omkhulu, imithalakazi esabalaliswe ngokufanayo futhi iyefana nhkangothi zonke, okusho ukuthi umkhathilibe awunamnyombo noma umkhawulo. Ngokwemilinganiso emincane, imithalakazi isabalaliswe njengezixheke nezixhekekazi (superclusters) ezakha izinkosa ezínkulu ezifana namangqola (foam-like)  kanye namaze(voids) emkhathingeni, kanjalo zidala izinhlaka ezifana nengqola. Izivubukulo kmekhulwini lama-20 zisikisele ukuthi umkhathilibe wawunesiqalo nokuthi umkhathi ubulokhu ulwiza kusuka kuso ngezinga elikhuphukayo.

Ngokombono wokuqhuma okukhulu, impekumpeku notho ezazikhona ekuqaleni sezibe siluthe kancane njengoba umkhathilibe ulwiza. Emva kokulwiza okuphangisayo kwakuqala okubizwa (inflationary epoch) kwemizuzwana engaba i-10−32, kanye nokuhlukaniswa kweziphoqi eziyisiseko ezine ezaziwayo, umkhathilibe waphola kancane futhi waqhubeka nokulwiza, okwavumela izinhlayiyana zechwe zokuqala kanye namachwe alula kwakheke. Injelwane yaqala ukubutheleka kancane, ngokwakha izinhlaka ezifana namangqola zezinkosa kanye namaze(voids) ngaphansi kwethonya lomnyondo. Amafu ayisiqhamela ehwanzi kanye nehwelanga ahosheka kancane kancane ezindaweni lapho injelwane yayisiluthe khona, futhi zakha imithalakazi yokuqala, izinkanyezi nakho konke esikubonayo namuhla.

Ngokucwaninga umdiki wemithalakazi, sekuvubukulwe ukuthi umkhathilibe uqukethe okungaphezu kotho olungaphezu kwesikubonayo; izinkanyezi, imithalakazi, imiqongo nothunqathunqa lwenqeke. Lolutho olungabonakali lwaziwa ngokuthi injelwane (dark means that there is a wide range of strong indirect evidence that it exists, but we have not yet detected it directly). Unongo lwe-ΛCDM luwunongo olwamukelwa kabanzi lonongo lomkhatgilibe. Lusikisela ukuthi isisindo nempekumpeku okungama-69.2%±1.2% [2015] kumkhathilibe buyi-(cosmological constant) (noma, injijo ye-ΛCDM, ezinye izimo zesidlakalasi esimpisholo, ezifana scalar field) okuyizo ezibangela ukulwiza komkhathi okwenzeka manje, kanye nenjelwane engama-25.8%±1.1% [2015]. Ngalokho utho ('lwenkindisi') oluvamile ludla umkhathilibe ongaba inani-4.84%±0.1% [2015]. Izinkanyezi, imizulane, kanye nthunqathunqa lohowo lwakha inani 6% lotho oluvamile.

Kunezihlawumbiselo ezincintisanayo ngokuphathelene nesigcino esinqunyelwe umkhathilibe futhi nangokuphathelene nokuthi yini eyandulela ukuqhuma okukhulu, kuyilapho abanye abafundindalo nabosonjululwazi benqaba ukuqagela, bethandabuza ukuba ukwaziswa ngokuphathelene nezimo ezandulele kuzofikelelwa. Abanye abafundindalo sebasikisele ízihlawumbiselo zemikhathilibe eminingi engafani, lapho umkhathilibe wethu uyingxenye yeminye imikhathilibe ekhona njengawo.

 Incasiselo 

Umkhathilibe ongokoqobo uchasiswa njengawo wonke umkhathi nesikhathi. Iziqikili ezifana nalezinzihlanganisa sonke isidlakathi ngezinhlobo zazo, kuhlanganisa imiyonzi yenzubawonga kanye noTho, kuhlanganise nemizulane, amaduna wemvelo (natural satellites), izinkanyezi, imithalakazo, kanye neziqikili ezisemkhathingeni ongaphandle. Umkhathilibe ubuye uhlanganise nayo yonke imithetho yemvelo ethonya isidlakathi noTho, efana nemithetho yokonga, kanye  nobucakatho (relativity).

Umkhathilibe uvame ukuchasiswa "njengesamba sobukhona", noma konke okukhona , konke okwake kwaba khona, nakho konke okusazoba khona.

 Umsukagama 
Ibizo lesizulu elithi umkhathilibe liyinhlanganisela yamabizo amabili, elithi 'umkhathi' kanye nelithi 'umlibe'. Elithi umlibe lisho ukugoduka unomphela noma ukuhamba uhambo olungabuyeli emuva',  ngakho liyafaneleka ngoba ngenxa yobukhulu bomkhathi, uhambo lokuwunqamula kuzoba uhambo lwamlibe. Ngakho lona umkhathi ongenaqhathaniswa, umkhathilibe.

 Izenzakalo zokuqhuma okukhulu 

Unongo oluseqhulwini lwemvelo yomkhathilibe lwaziwa ngokuthi ukuqhuma okukhulu. Lolu nongo luveza ukuthi ubunjalo bokuqala bomkhathilibe babusiyisigagadu futhi buyisiluthe, futhi umkhathilibe kamuva wanwebeka futhi waqala ukuphola.


 Imithombo