Iplanethi yethu uMhlaba ibingakaze ibe njalo njengoba injalo manje. Ngesikhathi sezigidigidi zeminyaka selokhu kwakhiwa uMhlaba, kube neziqephu zeminyaka yeqhwa, ukuqothulwa, izinguquko, ukubuyela emuva, imijikelezo, njll. Ayikaze ilungiswe futhi izinze kangako.
Enye yezinto eguqukile futhi ebingakaze ibe kanjena impilo yethu yonke yisibalo somazibuthe soMhlaba. Cishe eminyakeni engama-41.000 edlule, umhlaba wawune-polarity eguqulwayo, okungukuthi, isigxobo esisenyakatho sasiyiseningizimu futhi okuphambene nalokho. Ngabe ufuna ukwazi ukuthi kungani lokhu kwenzeka nokuthi ososayensi bazi kanjani?
Ukuguqulwa kwesigxobo sikazibuthe soMhlaba
Kuwo wonke umlando woMhlaba, izinguquko ezigxotsheni zikazibuthe zenzeke kaninginingi, zahlala amakhulu ezinkulungwane zeminyaka. Ukuze bakwazi lokhu, ososayensi bathembele ezivivinyweni nge amaminerali aphendula amandla kazibuthe. Okusho ukuthi, ngokuhlaziya ukuhleleka kwamaminerali kazibuthe, singakwazi ukwazi ukuthi izigxobo kazibuthe zomhlaba zazibheke kuphi ezigidini zeminyaka edlule, njengoba kuphawulwe ocwaningweni amatshe kazibuthe.
Kepha akusabalulekanga nje kuphela ukukhombisa ukuthi izingongolo zikaMazibuthe zomhlaba ziguqukile kuwo wonke umlando, kepha kungani bakwenzile lokho. Ososayensi bathole amalambu amakhulu omlilo anezindawo zamadwala ezikhuphuka ngezikhathi ezithile futhi ziwele zijule emhlabeni wethu. Ukwenziwa kwala matshe kungabangela izinguquko ezigxotsheni Zomhlaba futhi kubangele ukuthi ziphenduke. Ukuthola lokhu, ososayensi basekela izifundo zabo ezimpawini ezishiywe ezinye ze ukuzamazama komhlaba okubhubhisa kakhulu we planethi.
Cishe emaphethelweni omgogodla woMhlaba, kukhona izinga lokushisa elingu-4000° C, ngakho-ke idwala eliqinile ligeleza kancane kancane eminyakeni eyizigidi. Le convection current esembathweni ibangela ukuthi amazwekazi anyakaze futhi ashintshe ukuma. Ngenxa yensimbi eyakhiwe futhi igcinwe enkabeni yoMhlaba, uMhlaba ugcina insimu yawo kazibuthe esivikela emisebeni yelanga, njengoba kuchazwe esihlokweni esithi. insimu kazibuthe yomhlaba.
Ukuphela kwendlela ososayensi abazi ngayo le ngxenye yoMhlaba ukutadisha izimpawu zokuzamazama komhlaba ezikhiqizwa ukuzamazama komhlaba. Ngolwazi lwejubane namandla egagasi lokuzamazama komhlaba bangakwazi ukuthi yini esinayo ngaphansi kwezinyawo zethu nokuthi kunjani ukwakheka.
Ingabe kukhona imodeli entsha yoMhlaba?
Ngale ndlela yokufunda uMhlaba kungaziwa ukuthi kunezifunda ezimbili ezinkulu engxenyeni engenhla yengqikithi yoMhlaba lapho amagagasi enyikima ahamba kancane. Lezi zifunda zihambisana kakhulu ne- ukuthi zithinta kanjani yonke inguquko yezingubo, ngaphezu kwesimo indlela umnyombo ophola ngayo.
Sibonga u ukuzamazama komhlaba okuqine kakhulu emashumini eminyaka amuva nje okwenza kube nokwenzeka ukufundwa kwala magagasi ahamba eduze komngcele phakathi komnyombo woMhlaba nesiphuku. Ucwaningo lwakamuva kakhulu ngalezi zindawo zengaphakathi lomhlaba lubonisa ukuthi ingxenye engezansi yenkaba inokuminyana okuphezulu (ngakho-ke ukuminyana kwayo okuphansi) kanti ingxenye engaphezulu inomthamo ophansi kakhulu. Lokhu kusikisela okuthile okubaluleke kakhulu. Futhi izinto zokwakha ziyanda phezulu, okungukuthi, zihambela phezulu.
Izifunda zingancipha kakhulu ngoba zifudumele. Njengabantu abaningi (okushisa kakhulu kuvame ukukhuphuka), kwenzeka into efanayo ngaphakathi kwengubo nengqikithi yoMhlaba. Kodwa-ke, kungenzeka ukuthi ukwakheka kwamakhemikhali kwezingxenye zesembatho kuziphatha njengamaconsi avela kusibani se-lava. Okusho ukuthi, baqale bafudumale bese bavuka. Uma usukhuphukile, ungenakho ukuxhumana nomnyombo woMhlaba, uqala ukuphola futhi ube mkhulu, ngakho-ke wehla kancane uye emuva emgodini.
Lokhu kuziphatha okufana nesibani somlilo kungashintsha indlela ososayensi abachaza ngayo ukukhipha ukushisa ebusweni bendawo. Ngaphezu kwalokho, ingasebenza kahle ukuchaza ukuthi kungani, kuwo wonke umlando woMhlaba, izigxobo zikazibuthe zibuyiselwe emuva.
Umthombo
Ukutadisha okugcwele: http://www.sciencedirect.com/science/article/pii/S0012821X15000345
