Umkhathi Wethu Omangalisayo—Ingabe Wazivelela?
ABANYE abantu bathi: ‘Yebo, umkhathi wethu wazivelela.’ Abanye, ikakhulukazi abathanda inkolo, bayaphika. Abanye abaqiniseki. Wena yini oyikholelwayo?
Kungakhathaliseki ukuthi uyini umbono wakho, akungabazeki ukuthi uzovuma ukuthi umkhathi wethu uyamangalisa. Cabangela imithala. Kulinganiselwa ukuthi kunemithala eyizigidi eziyizinkulungwane eziyikhulu emkhathini obonakalayo. Ngamunye uyiqoqo lezinkanyezi ezisukela kwezingaphansi kwezigidi eziyinkulungwane kuya kwezingaphezu kwezigidi eziyisigidi.
Imithala eminingi ingamaqoqo asukela emithaleni eyidlanzana kuya kweyizinkulungwane. Ngokwesibonelo, umthala ongumakhelwane wethu i-Andromeda uchazwa njengewele lomthala wethu i-Milky Way. Amandla adonsela phansi azigcina zindawonye lezi zimiso ezimbili ezinkulu zezinkanyezi. Zona kanye nedlanzana leminye imithala engomakhelwane, kwakha iqoqo.
Umkhathi wakhiwe yinani elingenakubalwa lamaqoqo emithala. Amandla adonsela phansi agcina amanye amaqoqo endawonye, bese kwakheka amaqoqo amakhulu. Kodwa ukusuka kulelo zinga kuya phambili, amandla adonsela phansi ayaxegisa. Ososayensi bathola ukuthi amaqoqo amakhulu emithala ayaqhelelana. Ngamanye amazwi, umkhathi uyanda. Ukutholakala kwaleli qiniso elimangalisayo kusikisela ukuthi kunesiqalo lapho umkhathi wawumncane futhi uminyene khona. Ukuqala komkhathi kuvame ukubhekiselwa kukho njengokuqhuma okukhulu.
Abanye ososayensi bayangabaza ngempela ukuthi umuntu uyoke akwazi ukuthola ukuthi umkhathi waqala kanjani. Abanye baqagela izindlela okungenzeka ukuthi umkhathi waba khona ngazo ngaphandle komuntu ohlakaniphile. Umagazini i-Scientific American ka-January 1999, wakhuluma ngesihloko esithi “Waqala Kanjani Umkhathi?” Ezinye zezinkolelo-mbono zososayensi kakade ziye zatholakala zingagculisi. Lo magazini uthi: “Ngeshwa, kungase kube nzima kakhulu ngezazi zezinkanyezi . . . ukuhlola noma imuphi wale mibono.”
Umbono wokuthi umkhathi wazivelela udinga ukuba ukholelwe kulokho ososayensi abakubiza ngokuthi “izenzakalo zenhlanhla” noma “ukuqondana” kwezinto eziningi. Ngokwesibonelo, umkhathi wenziwe ngama-athomu alula amaningi—i-hydrogen ne-helium. Nokho, ukuphila akudingi i-hydrogen nje kuphela kodwa namanye ama-athomu amaningi ayinkimbinkimbi, ikakhulukazi isikhutha nomoya-mpilo. Ososayensi babevame ukuzibuza ukuthi avelaphi la ma-athomu ayigugu.
Ingabe kwamane kwaqondana nje ukuthi ama-athomu ayinkimbinkimbi adingekayo ukuze asekele ukuphila akheka ngaphakathi kwezinkanyezi ezithile ezinkulu? Ingabe kwamane kwazenzekela ukuthi ezinye zalezi zinkanyezi ezinkulu ziqhume, zikhiphe amagugu azo angama-athomu ayivelakancane? USir Fred Hoyle, owayenengxenye kulolu cwaningo, wathi: “Angikholwa ukuthi noma imuphi usosayensi owahlola ubufakazi akanakuphetha ngokuthi imithetho yesayensi yenuzi iye yaklanywa ngenhloso.”
Khona-ke, ake sihlolisise izinto owenziwe ngazo umkhathi wethu.
[Ibhokisi/Isithombe ekhasini 4]
INKOLELO-MBONO YE-INFLATION
Abanye ososayensi bakholelwa ukuthi izici ezithile zomkhathi lapho usaqala, njengezinga elithe ngqó lokukhula kwawo, zingase zichazwe ngaphandle kokuba kudingeke umuntu ohlakaniphile. Babambelela kuyinkolelo-mbono noma izinkolelo-mbono ezibizwa ngokuthi i-inflation (ukufutheka komkhathi). Nokho, inkolelo-mbono ye-inflation ayiyixazululi indaba yokuthi waqala kanjani. Kudingeka ukukholelwa entweni eyayivele ikhona ngaphambili, umkhathi wethu owavela kuyo ngengozi.
Ngokwale nkolelo-mbono, umkhathi wakhula usuka ekubeni ngaphansi kwe-athomu waba ngaphezu komthala wethu ngesikhathi esingaphansi komzuzwana. Kuthiwa kusukela lapho kuqhubeke, umkhathi waqhubeka ukhula kancane kancane ngezinga elivamile. Namuhla, ingxenye ebonakalayo yomkhathi wethu kuthiwa iyingxenye encane kakhulu uma kuqhathaniswa nawo wonke umkhathi. Ososayensi bale nkolelo-mbono bathi nakuba umkhathi obonakalayo ubukeka uhleleke ngokufanayo nxazonke, ingxenye enkulu engabonakali kungenzeka ihlukile futhi ayihlelekile. Isazi sokwakheka kwezinto ezisemkhathini uGeoffrey Burbidge sithi: “Ayikho indlela yokuhlola ebonisa ukufutheka komkhathi.” Eqinisweni, inkolelo-mbono ye-inflation iphikisana nemibono emisha yobufakazi obubonakalayo. Manje sekuyabonakala ukuthi ukube le nkolelo-mbono ibiyiqiniso, bekuyodingeka ukuba kuthiwe kukhona amandla amasha aphikisana nadonsela phansi. Omunye usosayensi, uHoward Georgi, waseHarvard University, wachaza ukufutheka komkhathi ngokuthi “uhlobo oluyisimanga lwenganekwane yesayensi, okungenani efana nezinye izinganekwane zendalo engake ngazizwa.”
[Isithombe ekhasini 3]
Cishe yonke into ekulo mfanekiso we-Hubble Space Telescope iwumthala
[Umthombo]
Pages 3 and 4 (blurred): Robert Williams and the Hubble Deep Field Team (STScI) and NASA
[Izithombe ekhasini 4]
“Imithetho yesayensi yenuzi iye yaklanywa ngenhloso.”—USir Fred Hoyle, ovezwe lapha nenkanyezi enkulu eqhumayo i-1987A
[Imithombo]
Dr. Christopher Burrows, ESA/STScI and NASA
Photo courtesy of N. C. Wickramasinghe