Umkhathi ungqimba lwegesi ezungeza indikimba yasezulwini, njengoMhlaba, okhangwa amandla adonsela phansi. Ivikela emisebeni ye-ultraviolet yelanga, ilawula izinga lokushisa futhi ivimbele ukungena kwama-meteorite. Ukube umkhathi ubungenazo izici onazo njengamanje, iplanethi engumhlaba ibingeke ikusekele ukuphila. Nokho, abantu abaningi bayazibuza ukuthi iyini ukwakheka komkhathi.
Ngenxa yalesi sizathu, sizonikezela lesi sihloko ukukutshela mayelana nokwakheka komkhathi, ukuthi wadalwa nini nokuthi wakhiwa kanjani.
Ukwakheka komkhathi
Umkhathi ungqimba lwegesi oluzungeza iplanethi yethu, futhi ukuba khona kwawo kubangelwa amandla adonsela phansi oMhlaba. Yaqala ukwakheka ngemvelaphi yoMhlaba eminyakeni eyizigidi eziyizinkulungwane ezingu-4.600 edlule. Phakathi neminyaka yokuqala eyizigidi ezingu-500, umkhathi waqala ukuguquguquka; Njengoba ingaphakathi leplanethi yethu encane laliqhubeka lizivumelanisa nezimo, laba minyene ngokungavamile ngenxa yomusi namagesi aphumile. Amagesi aqambayo angaba yi-hydrogen (H2), umhwamuko wamanzi, i-methane (CH4), i-helium (He) nama-carbon oxides. Leso isimo sakudala ngoba umkhathi ophelele wawungeke ube khona eminyakeni eyizigidi ezingama-200 edlule. Umhlaba wawusashisa kakhulu ngaleso sikhathi, okwakukhuthaza ukuphuma kwamagesi alula.
Amandla adonsela phansi omhlaba aphansi kancane kunanamuhla, avimbela uMhlaba ekugcineni ama-molecule endaweni yawo; i-magnetosphere namanje ayikakhi futhi umoya welanga uvunguza ngqo phezulu. Konke lokhu kwabangela ukuba umkhathi omningi wakudala unyamalale emkhathini.
Iplanethi yethu, ngenxa yezinga lokushisa layo, ubukhulu kanye nesisindo esijwayelekile, ayikwazi ukugcina amagesi alula kakhulu njenge-hydrogen ne-helium, abalekela emkhathini futhi adonswe umoya welanga. Ngisho nesisindo somhlaba samanje, akunakwenzeka ukugcina amagesi afana ne-helium ne-hydrogen, ngokungafani namaplanethi amakhulu njenge-Jupiter ne-Saturn, anomoya ocebile ngegesi. Amadwala akha iplanethi yethu aqhubeka ekhipha amagesi amasha nomhwamuko wamanzi isikhathi eside kwaze kwaba cishe eminyakeni eyizigidi eziyizinkulungwane ezine edlule, lapho umkhathi waqala ukwakhiwa ama-molecule ekhabhoni. i-carbon dioxide (CO2), i-carbon monoxide (CO), amanzi (H2O), i-nitrogen (N2), ne-hydrogen (H).
Origen
Ukuba khona kwalezi zinhlanganisela kanye nokwehla kwezinga lokushisa eMhlabeni ngaphansi kuka-100 ° C kwaholela ekuthuthukisweni kwe-hydrosphere yaqala ukwakheka eminyakeni engaba yizigidi eziyizinkulungwane ezine edlule.
Iminyaka eminingi yokufingqa komhwamuko wamanzi yaholela ekwakhekeni kwamanzi amaningi avumela inqubo yokubeka. Ukuba khona kwamanzi kuthanda ukuchithwa kwamagesi afana ne-sulphur dioxide, i-hydrochloric acid noma i-carbon dioxide, ukwakheka kwama-acids nokusabela kwawo nge-lithosphere, okuholela ekunciphiseni komkhathi. Amagesi afana ne-methane ne-ammonia. Ngawo-1950, umcwaningi waseMelika uStanley Miller waklama isilingo sakudala ukuze afakazele lokho ngesenzo samandla athile angaphandle. wasebenzisa ukukhishwa kukagesi ukuthola ingxube yama-amino acid kuleyo ndawo.
Ngokwenza kanjalo, uhlose ukwenza kabusha izimo ezihlanzekile zomkhathi ezingase ziveze umsuka wokuphila. Kuyavunywa ukuthi kunezimo ezintathu eziyisisekelo zokuphila njengoba sikuqonda: umkhathi ozinzile ocebile ngezakhi ezifana nomoya-mpilo ne-hydrogen, umthombo waphakade wamandla angaphandle, namanzi awuketshezi. Njengoba sesibonile, izimo zokuphila sezicishe zaqiniswa. Noma kunjalo, ngaphandle komoyampilo wamahhala, ukuphila ngokwako kungase kuqhele ngezigidi zeminyaka. Ukwakheka kwamadwala okuqukethe amanani amancane ezakhi ezifana ne-uranium nensimbi kuwubufakazi bomkhathi we-anaerobic. Ngakho-ke, lezi zakhi azitholakali emadwaleni asuka ku-Precambrian ephakathi noma okungenani eminyakeni eyizigidi eziyizinkulungwane ezingu-3 kamuva.
Ukubaluleka komoyampilo
Ezintweni eziphilayo ezinjengathi, inqubo ebaluleke kakhulu yasemkhathini ukwakheka komoyampilo. Izinqubo zamakhemikhali eziqondile noma izinqubo ze-geological ezifana nokusebenza kwentaba-mlilo azikhiqizi umoya-mpilo. Ngakho-ke, kunenkolelo yokuthi ukwakheka i-hydrosphere, umkhathi ozinzile namandla elanga yizimo ukwakhiwa kwamaprotheni olwandle kanye nenqubo ye-amino acid condensation kanye nokuhlanganiswa. we-nucleic acids ephethe ikhodi yofuzo, eminyakeni eyizigidi eziyi-1.500 Kamuva, izinto eziphilayo ze-anaerobic unicellular zivela olwandle. Eminyakeni eyinkulungwane nje edlule, izinto eziphilayo zasemanzini okuthiwa ama-cyanobacteria zaqala ukusebenzisa amandla elanga ukuze zihlukanise ama-molecule.
Amanzi (H2O) kanye ne-carbon dioxide (CO2) aphinde ahlanganiswe abe yizinhlanganisela eziphilayo kanye nomoya-mpilo wamahhala (O2), okungukuthi, lapho isibopho samakhemikhali phakathi kwe-hydrogen nomoya-mpilo siphulwa, lesi sakamuva sikhululwa endaweni ezungezile sisuka kumoya-mpilo. i-photosynthesis ihlangana ne-organic carbon ukwakha ama-molecule e-CO2. Inqubo yokuguqula amandla elanga abe yi-oxygen yamahhala ngokusebenzisa i-molecular dissociation ibizwa ngokuthi i-photosynthesis futhi yenzeka ezitshalweni kuphela, nakuba kuyisinyathelo esikhulu esibheke emkhathini woMhlaba esinawo namuhla. Lena inhlekelele enkulu yezinto eziphilayo eziphefumulayo, ngoba uma umoya-mpilo osemkhathini ukhula, i-CO2 iyancipha.
Ukwakhiwa komkhathi namagesi
Ngaleso sikhathi, amanye amangqamuzana omoya-mpilo osemkhathini amunca amandla emisebeni ye-ultraviolet ekhishwa ilanga bese ehlukana akhe ama-athomu omoya-mpilo. Lawa ma-athomu ahlangana nomoya-mpilo osele akhe amangqamuzana e-ozone ( O3 ), adonsa ukukhanya kwe-ultraviolet elangeni. Eminyakeni eyizigidi eziyizinkulungwane ezingu-4, inani le-ozone lalinganele ukuvimba ukungena kokukhanya kwe-ultraviolet, lokhu bekungeke kuvumele ukuphila kube khona ngaphandle kwezilwandle. Cishe eminyakeni eyizigidi ezingu-600 edlule, ngenxa yempilo yasolwandle, umkhathi woMhlaba wafinyelela amazinga e-ozone aphezulu ngokwanele ukumunca ukukhanya okuyingozi kwe-ultraviolet, okwaholela ekuqhamukeni kwempilo emazwenikazi. Kuleli qophelo, izinga le-oxygen cishe li-10% yenani lamanje. Yingakho, ngaphambi kwalokhu, ukuphila kwakulinganiselwe olwandle. Nokho, ukuba khona kwe-ozone kubangela ukuba izinto eziphilayo zasolwandle zifudukele ezweni.
Ukusebenzelana okuqhubekayo nezimo ezihlukahlukene zomhlaba kwaqhubeka kwenzeka emkhathini kwaze kwaba yilapho kufinyelela ekwakhiweni okumanje okungamaphesenti angama-99 e-hydrogen, umoya-mpilo, ne-argon. Njengamanje, umkhathi awusebenzi nje kuphela ukuvikela izenzakalo ezihlukahlukene ezibonakalayo ezenzeka emkhathini, kodwa futhi usebenza njengomlawuli ongavamile wezinqubo ze-thermodynamic, zamakhemikhali kanye ne-biological ezitholakala ekuziphendukeleni kwemvelo kanye nemvelo. Izenzakalo zomhlaba, ngaphandle kwalokho ukuphila bekungeke kube njengoba sikwazi. Lokho kuhlangana njalo kwamazinga okushisa olwandle, ukuvikelwa kwe-ozone emisebeni yelanga eyingozi, nesimo sezulu esizolile kwavumela ukuphila ukuba kuqhubeke kuguquguquka.
Ngithemba ukuthi ngalolu lwazi ungafunda kabanzi mayelana nokwakheka komkhathi nokuthi wenziwa kanjani.