Bigenda bite ngo Abahanga bamenye imyaka ikintu cya kera kimaze ku isi

Mu mateka y’ubushakashatsi ku bisigaratongo, hari inkuru izwi cyane yabaye mu 1822 mu gace ka Whiteman’s Quarry mu Bwongereza.

Muri icyo gihe, umushakashatsi w’Umwongereza Gideon Mantell yagaragaje amagufa yari yarabonye agaragaza inyamaswa nini itari isanzwe. Yagaragaje ko amenyo n’imiterere yayo bitandukanye n’iby’inyamaswa z’ubu, bigaragaza ko yari inyamaswa yaryaga ibimera.

Nyuma byaje kumenyekana ko ayo magufa yari ay’inyamaswa ya kera cyane yo mu bwoko bwa dinosaur izwi nka Iguanodon. Ubu bushakashatsi bwafunguye inzira yo gusobanukirwa amateka y’ubuzima ku isi mbere y’uko habaho abantu, ariko ikibazo cy’ingenzi cyari ugusobanura imyaka ibyo bintu bimaze. Aha ni ho haje uburyo bwa siyansi buzwi nka Radiocarbon Dating.

Ubu buryo bwatangiye mu mpera z’imyaka ya 1940 muri University of Chicago, bukozwe n’umuhanga Willard Libby. Mu 1949 yerekanye ko bishoboka kumenya imyaka y’ibintu bikomoka ku binyabuzima hifashishijwe ikinyabutabire cya Carbon-14, maze mu 1960 ahabwa igihembo cy’amahoro kitiriwe Nobel mu gice cy’Ubutabire (Nobel Prize in Chemistry) kubera uwo musanzu.

Carbon-14 ni ubwoko bwa karubone bukorwa mu kirere iyo imirasire iva mu isanzure ihuye na azote. Iyo ibayeho, yivanga na ogisijeni igakora dioxyde de carbone (CO₂). Iyi gaz ifatwa n’ibimera mu gihe cya fotosinteze(photosynthesis), hanyuma inyamaswa zikayibona zirya ibyo bimera. Bityo, Carbon-14 ikagera mu binyabuzima byose.

Iyo igihingwa cyangwa inyamaswa ipfuye, ihagarika guhererekanya karubone n’ibidukikije. Icyo gihe Carbon-14 yari irimo itangira kugabanuka buhoro buhoro. Igice cy’ubuzima (half-life) cyayo kingana n’imyaka 5,730, bivuze ko nyuma y’iyo myaka igabanukaho 50%.

Abashakashatsi bapima ingano ya Carbon-14 isigaye mu igufa, mu giti cyangwa mu kindi kinyabuzima, bakayigereranya n’igipimo cyari gihari igihe cyari kikiri kizima. Uko isigaye ari nke, nibwo byerekana ko icyo kintu kimaze igihe kirekire cyarapfuye.

Kuva mu myaka ya 1970, hifashishwaga cyane ikoranabuhanga rigezweho rya Accelerator Mass Spectrometry (AMS), ribasha gupima uduce duto cyane tw’ikintu rikamenya neza umubare wa Carbon-14 urimo.

Radiocarbon dating yahinduye cyane ubushakashatsi ku mateka y’isi. Yafashije abashakashatsi gusobanukirwa ibihe by’ingenzi mu mateka y’abantu n’ibidukikije, nko kumenya iherezo ry’igihe cy’urubura n’itangiriro ry’igihe abantu batangiye guhinga no korora.

Muri rusange, iri koranabuhanga ryagaragaje ko siyansi ishobora guhuza ubumenyi bw’ikirere, ubuzima n’amateka kugira ngo isobanure ibyabaye mu myaka ibihumbi ishize. Ni yo mpamvu uyu munsi abahanga bashobora kuvuga neza imyaka ibintu bya kera bimaze ku isi.

KWIZERA Fiston/TheKaminuzaStar