Ndlela leyi ti Meteors ti Khumbhaka misava Hikona

© David Fleminger

Interplanetary Projectiles

Loko u languta e mapapeni exikarhi ka vusiku lebyingana vunyama, hinkwaswo swilanguteka swihorile. Tinyeleti titshame kahle no vangama exibakabakeni xa ntima xikan’we na kupfuleka ka ndzhawu leyi ehenhla ka nhloko ya wena. Kambe ntiyiso iku swihambanile swinene. Misava yitshama yirikarhi yi cheriwa swilo leswihumaka eka space, leswi swotala swa kona swisukaka eka bandi rati asteroid letinga exikarhi ka Mars na Jupiter. Nhlaselo lowu awu tshamisekaka naswona, loko swaha hleketiwa leswawaku nhlayo yati interplanetary projectiles yile hansi swinene namuntlha loko ku pimanyisiwa na leswi aswiri xiswona loko misava yaha kuvumbiwa, ku ehleketeleriwa leswaku kwalomu ka 30 000 wati ton ta thyaka ra interplanetary raha nghena eka xibakabaka lembe na lembe.

Thyaka leri rotala ratshwa loko riri karhi ringhena exibakabakeni, rihisiwa ku kondza ri nwoka hikokwalaho ka ku ala ka moya. Rivoningo leri tlunyaka leri humesiwaka hi swilo leswi ri endla swivonaka tani hiti meteors, kumbe tinyeleti leti balekaka. Loko kuriku meteor yikule ngopfu, swivula leswaku, xiphemu xinwana xa yona xinga pona kuhisa loku kutani yi hetelela yifikile emisaveni tani hi meteorite. FYI, meteorite leyikulu swinene leyinga kumeka kufikela sweswi hileyi vange i Hoba meteorite, yikumeke hi 1920. Yifike yiwela emisaveni ekusuhi nale Grootfontein, en’walungwini wa Namibia, kutlula kwalomu ka 80 000 wa malembe lawa yanga hundza naswona ayise susiwa kusukela yi wile. Hoba i xiphemu xa nsimbi xa iron na nickel, lexinga pimiwa kufikela ka timitara tinharhu yitlhela yiva mitara yin’we hikuya ehenhla.

Ntshikelelo lowukulu

Kambe akuta humelela yini loko ko tshuka kuve na xilo xikulu swinene lexi sukaka exibakabakeni xita laha misaveni? Xana kunga humelela yini loko bolide leyi pimiweke 10 kumbe 100 wati kilomitara yo humelela kutani yiwela ehansi? Vulavisisi bya ku chayisiwa ka misava lokunga hundza abyi hlamuseli xivumbeko xa kahle.

Kutlumbiwa lokukulu kulanguteka kuve na ku onha lokukulu swinene hambi kungari eka ndzhawu yale kusuhi ntsena kambe eka misava hinkwayo. Ku dzinginika ka misava lokukulu, titanic nati tsunami xikan’we na mikhukhula ya volcano leyingava kona kusukela eka ku chayisiwa loku swiherisa vutomi emisaveni yoleyo. Kuyisa emahlweni, nhlayo leyikulu ya ritshuri na thyaka rotala swihangalasiwile exibakabakeni naswona swinga siva kuvoninga ka dyambu, leswinga endlaka leswaku kuva xixika eka planet leswinga tekaka tinhweti kumbe malembe. Hiku komisa, ku tshembiwa leswaku kuchayisiwa loku kunga vanga kumbe ku herisa misava.

Kunyamalala

Kunyamalala i xiphemu xa ntumbuluko xaku antswisa. Eka mabiliyoni wa malembe lawa yanga hundza, kuna swotala leswinga lahlekela hi vutomi hikokwalaho ka kucinca ka timheho, makhobo ya ntumbuluko xikanwe na mphikizano wa swivumbiwa swinwana. Leswi switekiwa swinga hoxekangi helo hikuva i maheriselo ya ntumbuluko naswona swahaya emahlweni na namuntlha – leswi pfunetiwaka manguva lawa hi vanhu loko vaya vakari vafamba famba eka planet. Ku pimanyisiwe leswaku, e hansi ka xiyimo xa ntolovelo, exikarhi ka mindyangu yimbirhi kumbe ntlhanu ya taxonomic yita nyamalala endzhaku ka miliyoni wa malembe kambe, xikan’we na nhlayo nyana ya kuthyakisiwa, hinga kota ku pimanyisa nhlayo kambe swingaka swinga olovi.

Hambi swiritano, ntsariso wa ti fossil wukomba leswakua, eka minkarhi yinwana eka nkarhi lowu hundzeke, kuherisiwe ngopfu vutomi hi nhlayo yale henhla emisaveni leyinga nyamalala swinga languteriwanga. Leswi minkarhi yinwana swivuriwa boundary events naswona switikomba hiku nyamalala ka maribye nati fossils, laha muxaka wunwe wa vutomi wu siviwaka hi wunwana swinga languteriwanga. Ti boundary events leti tivonaka eka tileyara ta maribye ya manguva lawa lawa ya kumekaka planet hinkwayo.

Kunyamalala Lokukulu

Sweswi hingo tshembela eka ntsariso wati fossil kukuma mindzelekano, kuya emahlweni ka mintirho yaku nyamalala swivonaka ntsena endzhaku ka kuhangalaka kumbe kukula ka vutomi eka nkarhi wa Cambrian, kwalomu ka 550 wa mamiliyoni ya malembe lawa yanga hundza(Ma). Kusukela kwalano, kuvile na kuherisiwa hixitalo koringana ka ntlhanu: ku hundza ka End-Ordovician (444 Ma: 84% vutomi lebyi lahlekeke), Late Devonian (360 Ma: 79% vutomi lebyi lahlekeke), End-Permian (250 Ma, 95% vutomi lebyi lahlekeke – kunyamalala ko chavisa ka laha misaveni), End-Triassic (200 Ma, 79% vutomi lebyi lahlekeke) xikan’we na End-Cretaceous (65 Ma, 70% vutomi lebyi lahlekeke).

Valavisisi vanwana vamanguva lawa vaya emahlweni vavula leswaku sweswi hilekusuhi naku langutana nakunyamalala lokukulu swinene, lokunga ka xihatla swinene lokunga tsarisiwa. Hiku pfuniwa hileswi hina hinga khomisa xiswona mbango wa hina, leswi vange i kunyamalala hi Holocene swinga vula leswaku kufika eka hafu ya vutomi byebyo emisaveni byita hela eka malembe ya 100 lawa landzelaka (kuya hi mutivi wa sayense wa ndhuma).

Translated by Ike Ngobeni