Kwenzeka Ntoni Kwizirhubuluzi Zamandulo?

“IZIFUNDO ngezidalwa zamandulo zikukuhlolisisa iifosili, ibe iifosili zamathambo aseleyo ezidalwa zeminyaka edluleyo.” Kodwa njengokuba esinye isazinzulu ngezidalwa zamandulo satshoyo, “yinzululwazi esekelwe kwizibakala ezisengqiqweni nakuluvo ngendlela ephakame gqitha.” Ubungqina boku sibubona kwizirhubuluzi zamandulo (dinosaurs). Sidwelisa ezinye izimvo ngoko kwenzekayo kuzo, isazinzulu sasePrinceton uG. L. Jepson sachaza sisithi:

“Ababhali abanobuchule obahlukahlukeneyo baye babonisa ukuba izirhubuluzi zamandulo zathi shwaka ngenxa yokonakala kwemozulu . . . okanye ukuphela kokutya. . . . Abanye ababhali baye ityala balibeka kwizifo, kwizinambuzane ezitya igazi, . . . kwiinguqulelo ezibekho kuxinzeleleko okanye kwindlela osebenza ngayo umoya ojikeleza umhlaba, kwiigesi ezinetyhefu, kuthuli olubangelwa yintabamlilo, kwioksijini eninzi ngokugqithiseleyo evela kwizityalo, kumatye awa esibhakabhakeni, kwiintshakatsholo, kukutshatyalaliswa kwemizila yemfuza zizilwanyana ezincinane ezanyisayo nezidla amaqanda, . . . kwimitha yelanga, kukutshintsha kokujikeleza koMhlaba, kwizikhukula, kukukhukuliswa kwamazwekazi, . . . kukutsha kwamanzi emigxobhozweni nakumachibi amakhulu, nakwithinzi elisitha ukukhanya kwelanga.”​—⁠The Riddle of the Dinosaur.

Kuyabonakala ngokusuka kwizimvo ezinjalo ukuba izazinzulu azinako, ngako nakuphi na ukuqiniseka, ukuphendula umbuzo othi: Kwenzeka ntoni kwizirhubuluzi zamandulo?

Ingcamango Yokuphela Kwazo Ngequbuliso

Le ngcamango yakutshanje yaveliswa ngubawo nonyana wakhe ababesebenza kunye, uLuis noWalter Alvarez. UWalter Alvarez wafumana, ngaphandle kwedolophu yaseGubbio kumbindi weItali, ucamba lodongwe olungaqhelekanga, olusicaba nolubomvu oluphakathi kweengcamba ezimbini zamatye entlenga yomhlaba. Ucamba olungezantsi lwelitye lentlenga lwaluneefosili ezininzi. Ucamba olungasentla lwaluphantse lungabi nazo iifosili, nto leyo eyakhokelela ekubeni izazinzulu ngokubumbeka komhlaba zigqibe kwelokuba ubomi bathi shwaka ngequbuliso nokuba ucamba lodongwe olusicaba nolubomvu lwalunokuthanani noku kuphela.

Uhlolisiso luye lwatyhila ukuba olu dongwe lwaluneiridium eninzi (isinyithi esithile), eninzi kangangezihlandlo eziphindwe ngama-30 kunaleyo ngokuqhelekileyo ifumaneka ematyeni. Babesazi ukuba umlinganiselo ophakame ngolo hlobo wesinyithi usisiqalelo esinqabileyo esinokuvela embilinini womhlaba kuphela okanye kwimithombo engaphandle komhlaba. Bagqiba ngelithi i-iridium yayishiywe sisijikelezi-langa esincinane esabetheka emhlabeni, sibangela ukuphela ngequbuliso kwezirhubuluzi zamandulo.

Emva kokufunyaniswa kodongwe oluneiridium eninzi eGubbio, iintsalela ezifanayo zafunyanwa kwamanye amacandelo ehlabathi. Ngaba oku kuyayixhasa ingcamango engesi sijikelezi-langa sincinane? Zimbi iinzululwazi aziqinisekanga. Kodwa njengokuba incwadi ethi The Riddle of the Dinosaur ivuma, ingcamango ka-Alvarez “yaluphembelela ngakumbi uhlolisiso lokuphela kwezidalwa ezithile nokuhlolisiswa kwemfundiso yendaleko.” Ibe isazinzulu ngezidalwa zamandulo uStephen Jay Gould siyavuma ukuba oku kunokukuphelisa “ukubaluleka kokhuphiswano phakathi kweentlobo zezinto eziphilayo.”

Egqabaza ngale ngcamango intsha noko kubonakala ikukuphela ngequbuliso kwezirhubuluzi zamandulo, omnye umbhali wenzululwazi uyavuma ukuba: “Banokusigungqisa isiseko sebhayoloji yendaleko baze bavuse imbambano ngengcamango yanamhlanje engendlela esebenza ngayo indalo.”

Isazinzulu uDavid Jablonski weYunivesithi yaseArizona uqukumbela ngelokuba ‘kwizityalo nezilwanyana ezininzi, oku kuphela kwakukokwequbuliso ibe kwakukhethekile ngandlel’ ithile. Azizange ziphele kuba zisifa ngokuthe ngcembe. Kwenzeka into ethile engaqhelekanga.’ Oku kukwayinto efanayo nangezirhubuluzi zamandulo. Ukuvela nokuthi shwaka kwazo ngequbuliso kuyangqubana nembono eqhelekileyo neyamkelwayo yendaleko yokuvela kwezidalwa eziphilileyo ngokuthe ngcembe.

Ixesha Lokuvela Kwezirhubuluzi Zamandulo

Amathambo ezirhubuluzi zamandulo afunyanwa ngokuthe rhoqo kwiingcamba zomhlaba ezingaphantsi kwezo zazinamathambo omntu, nto leyo ekhokelela ekubeni abaninzi bagqibe ngelithi zazikho ngexesha elingaphambi kwelomntu. Izazinzulu ngokubumbeka komhlaba zalibiza eli xesha ngokuba lithuba leMesozoic yaye kwakhona ziyalahlula libe lithuba leCretaceous, leJurassic neleTriassic. Ixesha lala mathuba likumashumi ezigidi eminyaka. Kodwa ngaba oku kuye kwasekwa ngako nakuphi na ukuqiniseka?

Enye inkqubo eye yasetyenziselwa ukulinganisela iminyaka yeefosili ibizwa ngokuba yiradiocarbon dating. Le nkqubo ilinganisela umlinganiselo wokubola kweradioactive carbon ukususela ekufeni kwaloo nto. IScience and Technology Illustrated ithi, “Yakuba ifile into, ayisayifunxi icarbon dioxide kuloo mmandla uyingqongileyo, ibe umlinganiselo othile wamandla eatom xa uthelekiswa noweisotope uyaphela ekuhambeni kwexesha njengoko loo nto ibola.”

Noko ke, kukho iingxaki ezinzulu ngale nkqubo. Okokuqala, xa ifosili igqalwa imalunga neminyaka engama-50 000 ubudala, umlinganiselo wayo weradioactivity uye uwele kowona mlinganiselo uphantsi ngokokude kube nzima gqitha ukuwubona. Okwesibini, nkqu nakwiintlobo zakutshanje, lo mlinganiselo uye wehlela ezantsi kangangokuba kusenzima ngokugqithiseleyo ukulinganiselwa kwawo ngokuchanileyo. Okwesithathu, izazinzulu zinokulinganisela umlinganiselo wale mihla weradioactive carbon kodwa azinayo indlela yokulinganisela ubungakanani becarbon yeminyaka eyadlulayo.

Ngoko enoba zisebenzisa inkqubo yeradiocarbon ekuhlolisiseni ixesha ezavela ngalo iifosili okanye ezinye iinkqubo, njengokusebenzisa iradioactive potassium, iuranium, okanye ithorium, ekuhlolisiseni ukuvela kwamatye athile, izazinzulu azinakukwazi ukumisela ixesha ezaqalisa ngalo ukuvela izidalwa zaloo minyaka. Ngaloo ndlela, unjingalwazi ngesinyithi uMelvin A. Cook uthi: “Ubani usenokuwuthelekelela nje umlinganiselo [weradioactive], ibe iziphumo zeminyaka azinakuba bhetele kolu qikelelo.” Oku kwakuya kuba njalo ngokukhethekileyo ukuba besiqwalasela ukuba uMkhukula womhla kaNowa owawukho kwithuba elingaphezu kweminyaka engama-4 300 eyadlulayo wezisa iinguqulelo ezinkulu gqitha kumoya ojikelezayo nasemhlabeni.

Izazinzulu ngokubumbeka komhlaba ezikwiKholeji yaseDartmouth uCharles Officer noCharles Drake bongezelela amathandabuzo ngokubhekele phaya malunga nokuchana kweradioactive dating. Zithi: “Sigqiba kwelokuba i-iridium nezinye iziqalelo ezinxulumene nayo azizange zishiywe ngequbuliso . . . kodwa kunoko kwakukho ukungena okunamandla nokuguquguqukayo kwezi ziqalelo ebudeni bexesha elifutshane leminyaka eli-10 000 ukuya kweli-100 000.” Zaphikisa ngelokuba ukwahlukana nokulwa kwamazwekazi kwaye kwaphazamisa ihlabathi lonke, kubangela ugqabhuko-dubulo lweentabamlilo, ukusithwa kokukhanya kwelanga nokungcoliswa komoya ojikeleza umhlaba. Ngokuqinisekileyo, iziganeko eziphazamisa ngolo hlobo zazinokuwuguqula umlinganiselo weradioactivity, ngaloo ndlela ziphazamisa imiphumo yokuhlolisiswa kwexesha lokuvela kwezinto ngenkqubo yeradioactive yanamhlanje.

Ingxelo YeGenesis Nezirhubuluzi Zamandulo

Ngoxa ukuhlolisiswa kwexesha lokuvela kwezinto ngenkqubo yeradioactive kutyhila ulwazi olutsha isasekelwe kwingqikelelo nokungaqiniseki. Ngokwahlukileyo koko, ingxelo yeBhayibhile kwisahluko sokuqala seGenesis ngokulula nje ichaza indlela elungeleleneyo neqhelekileyo yendalo. Ibiza iminyaka engamawaka ezigidi ekunokwenzeka ukuba yachithwa ekwenziweni komhlaba namanye amawakawaka ngokuthi ngamaxesha, okanye “yimihla” emithandathu yokudala, ukulungiselela abantu ukuba bawume umhlaba.

Ezinye izirhubuluzi zamandulo (neepterosaurs) eneneni zisenokuba zadalwa ngomhla wesihlanu odweliswe kwiGenesis, xa iBhayibhile isithi uThixo wenza ‘iintaka eziphaphazelayo neminenga emikhulu.’ Mhlawumbi ezinye iintlobo zezirhubuluzi zamandulo zadalwa kusuku lwesithandathu. Uluhlu olukhulukazi lwezirhubuluzi zamandulo nokuthanda kwazo ukutya kakhulu kwakukokufanelekileyo xa kuqwalaselwa utyani obuninzi ngokucacileyo obabukho ngexesha lazo.​—⁠Genesis 1:​20-⁠24.

Xa izirhubuluzi zamandulo zayiphumezayo injongo yazo, uThixo wabuphelisa ubomi bazo. Kodwa iBhayibhile ayiyixeli indlela awakwenza ngayo okanye ixesha awakwenza ngalo oko. Sinokuqiniseka ukuba izirhubuluzi zamandulo zadalwa nguYehova ezidalela injongo, nakuba singayazi ngokupheleleyo loo njongo okwangoku. Azizange zibekho ngamabona-ndenzile, zingeyomveliso yendaleko. Into yokuba zithe ngequbuliso zavela kwingxelo yeefosili zinganxulumananga nayo nayiphi na ingxelo yeefosili ezingaphambi kwazo, nokuthi shwaka kwazo ngaphandle kokushiya iifosili ezinokunxulunyaniswa nazo, ibubungqina obunxamnye nembono yokuba ezo zilwanyana zavela ngokuthe ngcembe ukutyhubela ixesha leminyaka ezizigidi. Ngaloo ndlela, ingxelo yeefosili ayiyixhasi ingcamango yendaleko. Kunoko, ivisisana nembono yeBhayibhile yemisebenzi kaThixo yokudala.

[Amagama acatshulweyo akwiphepha 10]

Ingxelo yeefosili yezirhubuluzi zamandulo ayiyixhasi indaleko kodwa ixhasa indalo