Usemkhulu umsebenzi ohlalele osonkanyezi
KUBUKEKA usemkhulu umsebenzi okumele wenziwe emshikashikeni wokuthola izingamhlaba ( asteroids) ezingaba yingozi eMhlabeni. Okwamanje osonkanyezi ( astronomers) basathole ezingaphezu kwezi-8 000, ezilinganiselwa e-140m umugqankaba ( diameter) - okuwubukhulu obanele ukuba isingamhlaba singabhubhisa isifundazwe sonke.
Nokho lezi zingamhlaba eziyizi-8 000 (ezili-140 umugqankaba), zibukeka ziyimbijana kakhulu uma kuqhathaniswa neziyizi-25 000 osonkanyezi abacabanga ukuthi zingomakhelwane boMhlaba.
“Kunezingamhlaba ezilinganiselwa kweziyizi-16 000 zalolu hlobo okusamele zitholakale,” kusho uMnu Lindley Johnson oyisikhulu sohlelo lokuvikelwa komhlaba ( planetary defence programme) enhlokohhovisi yeNational Aeronautics Space Administration (Nasa), eWashington D.C, e-United States of America (USA). Uma kukhulunywa ngezakhiwomkhathi ( celestial bodies) eziseduze koMhlaba, kusuke kukhulunywa ngento esebangeni elilinganiselwa ezi-50 million km ukusuka lapho kuzungeza khona uMhlaba.
Isibalo sazo zonke izingamhlaba eziseduze koMhlaba, kuvela ukuthi kasiqondakali kahle ubuningi baso; kungenzeka ukuthi ezilinganiselwa phakathi kwe10-20m umugqankaba, zibalelwa ezigidini ezingamashumi ngamashumi, ngokusho kukaMnu Johnson.
Lezi-ke zingenza umonakalo omncane nje; isibonelo yileso esishayisane noMhlaba edolobheni iChelyabinsk, eRussia ngoNhlolanja (February) wezi-2013.
Besilinganiselwa e-19m umugqankaba. Kulesi sehlakalo kuphihlike amawindi ezakhiweni kwalimala abantu abangaphezu kwe-1 200. Eminyakeni ye-1990, kunengqungquthela (yoso- nkanyezi) ejube iNasa ukuba ithungathe, ithole ama-90% ezingamhlaba eziseduze noMhlaba, ezilinganiselwa kwi1km, okuyinto le nhlangano ephumelele ukuyenza ngowezi-2010. Njengamanje zingama-887 lezi zinkunzimalanga zamadwala ezaziwayo, kanti kucatshangelwa ukuthi zilinganiselwa ema-50 okubhekwe ukuba zitholakale, ngokusho kukaMnu Johnson.
Ngowezi-2005, iNasa ithole omunye umyalelo kubashayimthetho base-USA ukuba kushaye unyaka wezi-2020 isithole ama-90% azo zonke izakhiwomhlaba eziseduze koMhlaba, ezili-140m nangaphezulu umugqankaba.
Ngokosonkanyezi, kuyacaca ukuthi iNasa izowukhomba lo mnqamulajuqu. Embikweni weNasa oshicilelwe ngoMandulo (September) wezi-2017, le nhlangano ithe ukuthola lolu hlobo lwezingamhlaba kudinga ukuba kusetshenzwe ngamandla athe xaxa.
Umabonemajukujukwini ( telescope) ongasetshenziswa ukwenza lolu cwaningo ungabekwa endaweni ebizwa ngesun-Earth Langrange point 1 (L1), okuyindawo lapho amandla kantandozibuthe (gravity) ezikile ( stable). Le ndawo itholakala ebangeni eliyi-1.5 million km ukusuka eMhlabeni.
Lolu hlobo locwaningo, luhlanganiswe noluzokwenziwa kusetshenziswa omabonemajukujukwini ababekwe eMhlabeni, lungaba yimpumelelo - kutholakale lezi zingamhlaba ezidingekayo eminyakeni eli-10 ezayo, ngokusho kukaMnu Johnson.
Kuyimanje iNasa iphezu komshikashika wokuqala lolu cwaningo ngokwenza iprojekthi ezosiza ukuthola lezi zingamhlaba, ibizwa ngeNear-Earth Object Camera (NEOCam). INEOCam le, ngenye yamaprojekthi ayisihlanu abesemzuliswaneni wamanqamu kwabevivinywa yiNasa ukulungiselela uhlelo lwayo olubizwa ngeDiscovery Program.
Nokho iNEOCam igcine ikhale ngaphansi, iNasa yaqoka amaprojekthi amabili okucubungula izingamhlaba, okuyiLucy nePsche.
UMnu Johnson uthi lisekhona ithemba lokuthi iNEOCam iyobonakala emkhathini ngelinye ilanga. Uthi ukuvikelwa koMhlaba kulezi zakhiwomhlaba eziseduze kwawo - njengazo nje izingamhlaba - kakudingi ukuba zitholakale nje kuphela kodwa kudingeka abantu babe namaqhinga okuthi bazozigudluza kanjani endleleni ebheke eMhlabeni.