Ukulinganisa Umhlaba Ngoluthi

NGABA wakha weva ngosozibalo ongumGrike nesazi ngeenkwenkwezi uEratosthenes? Kusenokwenzeka ukuba igama lakhe laziwa kakhulu zizazi ngeenkwenkwezi. Kutheni zimhlonela kangaka nje?

UEratosthenes wazalwa malunga nowama-276 B.C.E. yaye wafunda eAthene, eGrisi. Noko ke, kubomi bakhe ixesha elininzi walichitha eAlexandria, eYiputa ngoko eyayilawulwa ngamaGrike. Malunga nowama-200 B.C.E., uEratosthenes wazama ukulinganisa ubukhulu bomhlaba ngoluthi. Usenokuba uthi ‘akunakwenzeka oko.’ Wakwenza njani?

Kwisixeko saseSiyene (ngoku ekuthiwa yiAswân), uEratosthenes waqonda ukuba emini emaqanda kusuku lokuqala ehlotyeni, ilanga liba sesazulwini kanye sesibhakabhaka. Oku wakuqonda ngokuba kungekho sithunzi xa imitha yelanga ihlab’ umhlaba. Noko ke, kwangolo suku emini emaqanda kwisixeko saseAlexandria, esasikumgama wezitadiyaa ezingama-5 000 kumantla eSiyene, kwakubakho isithunzi. Oko kwabangela ukuba uEratosthenes ajije qhinga lithile.

UEratosthenes wamisa uluthi nkqo. Lathi xa ilanga lisesazulwini sesibhakabhaka emini emaqanda, walinganisa iengile yesithunzi soluthi olwaluseAlexandria. Wafumanisa ukuba loo engile ilingana needegrees ezisi-7.2 ukusuka kwintloko yolo luthi.

Oku kwenza uEratosthenes wakholelwa ukuba umhlaba ungqukuva, yaye wayesazi ukuba isazinge silingana needegrees ezingama-360. Ngoko wahlula ama-360 ngalo engile isisi-7.2 wayeyifumene. Wafumanisa ntoni? Wafumanisa ukuba le engile inokuphindaphindwa ngama-50 ukuze yenze isazinge esipheleleyo. Emva koko wafikelela kwisigqibo sokuba, umgama osuka eSiyene ukuya kutsho eAlexandria okanye izitadiya ezingama-5 000, zilingana nama-50 kwisazinge somhlaba. Ngokuphindaphinda ama-50 ngama-5 000, uEratosthenes wafumanisa ukuba isazinge somhlaba silingana nezitadiya ezingama-250 000.

Elo nani lichane kangakanani xa lithelekiswa neendlela zokubala zanamhlanje? Izitadiya ezingama-250 000 zilingana neekhilomitha ezingama-40 000 ukusa kwezingama-46 000 ngokweendlela zokubala zanamhlanje. Zisebenzisa isiphekepheke esijikeleza umhlaba, izazi ngeenkwenkwezi zafumanisa ukuba isazinge somhlaba ukusuka emazantsi ukusa emantla silingana neekhilomitha ezingama-40 008. Ngoko ke, kwiminyaka engaphezu kwama-2 000 eyadlulayo, kwaba kancinane ukuba uEratosthenes angafikeleli kwinani lanamhlanje. Ukuchana kwakhe kuphawuleka gqitha xa ucinga ukuba wasebenzisa uluthi kuphela nolwazi lwakhe lwegeometry! Namhlanje, izazi ngeenkwenkwezi zisebenzisa le migaqo yokuma komhlaba ukuze zibale umgama ongaphaya kommandla wezijikelezi-langa zethu.

Abanye basenokuhlatywa umxhelo yinto yokuba uEratosthenes wayesazi ukuba umhlaba ungqukuva. Kaloku, kwade kwaba kumakhulu ambalwa eminyaka adluleyo nezilumko ezithile ezazisazi inzululwazi zikholelwa ukuba umhlaba uthe tyaba. AmaGrike amandulo akufumanisa ukuma komhlaba esebenzisa inzululwazi yawo. Noko ke, malunga neminyaka engama-500 ngaphambi kukaEratosthenes, ephefumlelwe omnye umprofeti ongumHebhere wabhala wathi: “Kukho Lowo [uThixo] uhlala phezu kwesazinge somhlaba.” (Isaya 40:22) UIsaya wayengesiso isazinzulu. Wayazi njani into yokuba umhlaba usisazinge? Waphefumlelwa nguThixo ukuze ayazi le nyaniso.

[Umbhalo osemazantsi]

[Umzobo okwiphepha 10]

(Ukuba ufuna inkcazelo ehlahlelwe kakuhle, yiya kwimpapasho)

Umtha welanga

ISiyene

7.2°

IAlexandria

7.2°