Ukuhlola Lokho Okungabonakali—Kwembulani?

YINI efezwayo lapho abantu besebenzisa izinto ezintsha abazisungulile ukuze babone lokho ababengenakukubona ngaphambili, njengokungathi kususwe inkungu? Ukwenza kanjalo kungasiza ekutholeni ngokuqiniseka lokho okwakungaziwa ngaphambili.—Bheka ibhokisi ngezansi.

Kwake kwaba inkolelo evamile ukuthi umhlaba uphakathi nendawo emkhathini. Kodwa ngaleso sikhathi ukusetshenziswa kwesibonakude kwabonisa ukuthi amaplanethi, kuhlanganise nomhlaba, azungeza ilanga endaweni yawo. Muva nje, ngokusungulwa kwesibonakhulu esinamandla, abantu baye bahlola i-athomu ngokwayo futhi babona ukuthi izinhlobo ezithile zama-athomu zihlangana kanjani nezinye ukuze zenze lokho okubizwa ngokuthi ama-molecule.

Cabanga ngokwakheka kwe-molecule yamanzi, into ebalulekile ekuphileni. Ngenxa yendlela aklanywe ngayo, ama-athomu amabili e-hydrogen ahlangana ne-athomu eyodwa ye-oxygen ngendlela eyinqaba abese enza i-molecule yamanzi—kunezinkulungwane zezigidi zawo econsini ngalinye! Yini esingayifunda ngokuhlola i-molecule yamanzi bese sicabangela imikhuba yayo ngaphansi kwezimo ezihlukahlukene?

Isimangaliso Samanzi

Nakuba amaconsi angawodwa amanzi ebonakala eyinto engelutho, amanzi ayinto eyinkimbinkimbi kakhulu. Eqinisweni, uDkt. John Emsley, umlobi wezesayensi e-Imperial College, eLondon, eNgilandi, wathi “angamanye amakhemikhali ahlolwa kakhulu kunawo wonke, kodwa asaqondwa kancane kunawo wonke.” Umagazini i-New Scientist wathi: “Amanzi awuketshezi olujwayeleke kunalo lonke eMhlabeni, kodwa futhi oluyimfihlakalo kunalo lonke.”

UDkt. Emsley wachaza ukuthi naphezu kokwakheka kwamanzi okulula, “ayikho into eyinkimbinkimbi njengemikhuba yawo.” Ngokwesibonelo, wathi: “I-H₂0 kufanele ibe umoya, . . . kodwa iwuketshezi. Ngaphezu kwalokho lapho iqina . . . iba yiqhwa, intante esikhundleni sokuzika,” njengoba bekungalindeleka ngokuvamile. Mayelana nalo mkhuba ongavamile, uDkt. Paul E. Klopsteg, owayengumongameli we-American Association for the Advancement of Science, waphawula:

“Lokhu kubonakala kungumklamo omangalisayo wokusekela ukuphila kwasemanzini njengezinhlanzi. Cabanga ukuthi bekuyokwenzekani ukube amanzi lapho ebanda eba yiqhwa, abengenzi lokho okuchaziwe. Iqhwa beliyokwakheka futhi liqhubeke lakheka lize lithathe indawo yalo lonke idamu, liqothule zonke noma eziningi zezinto eziphila emanzini.” UDkt. Klopsteg wathi lo mkhuba wamanzi oyinqaba “uwubufakazi bokuthi endaweni yonke kunomuntu okhaliphile nonenjongo.”

Ngokwe-New Scientist, abacwaningi manje bacabanga ukuthi bayasazi isizathu salo mkhuba wamanzi ongavamile. Baye basungula isimiso sokuqala senkolelo-mbono ebikezela ngokunembile ukwanda kwamanzi. Abacwaningi baphawula ukuthi: “Isihluthulelo sale mfihlakalo sisezikhaleni ezikhona phakathi kwama-athomu omoya-mpilo angaphakathi kula ma-molecule.”

Ingabe lokhu akumangalisi? I-molecule ebonakala ilula kangaka ibekela ukuqonda komuntu inselele. Ingasaphathwa eyokuthi amanzi akha ingxenye enkulu yesisindo somzimba wethu! Ingabe nawe uyabubona ubufakazi “bokusebenza komuntu ohlakaniphile nonenjongo” ezimangalisweni zale molecule yama-athomu amathathu kuphela ezakhi ezimbili? Nokho, i-molecule yamanzi incane kakhulu futhi ayiyona inkimbinkimbi njengamanye ama-molecule.

Ama-molecule Ayinkimbinkimbi Kakhulu

Amanye ama-molecule enziwe izinkulungwane zama-athomu ezakhi eziningi kwezingu-88 ezingokwemvelo emhlabeni. Ngokwesibonelo, i-molecule ye-DNA (isifushaniso se-deoxyribonucleic acid), equkethe ukwaziswa kwesimiso sezakhi zofuzo zayo yonke into ephilayo, ingaba nezigidi zama-athomu ezakhi eziningana!

Naphezu kokuba yinkimbinkimbi kwayo okungakholeki, i-molecule ye-DNA ingamamilimitha angu-0,0000025 kuphela ububanzi, incane kakhulu ukuba ingabonakala ngaphandle kosizo lwesibonakhulu esinamandla. Ososayensi baze bathola ngo-1944 ukuthi iDNA iyona enquma ufuzo lomuntu. Lokhu okwatholakala kwaqala ucwaningo olunzulu ngale molecule eyinkimbinkimbi kakhulu kangaka.

Nokho, iDNA namanzi kumane nje kuyizinto ezimbili ezinhlotsheni eziningi zama-molecule akha izinto. Futhi njengoba kunama-molecule amaningi atholakala kokubili kokuphilayo nokungaphili, ingabe kufanele siphethe ngokuthi ngandlela-thile kukhona isinyathelo noma ushintsho oluncane nje phakathi kokuphilayo nokungaphili?

Sekuyisikhathi eside abantu abaningi bekholelwa kanjalo. Isazi samagciwane uMichael Denton sachaza: “Izikhulu eziningi ngawo-1920 nawo-1930 zathi zinethemba lokuthi ulwazi olwengeziwe ngokulumbana kwamakhemikhali luzovala igebe.” Nokho, yini ngempela eyatholakala ngokuhamba kwesikhathi?

Ukuphila Kukhethekile Futhi Kuvelele

Nakuba ososayensi babelindele ukuthola ushintsho oluxhumanisayo, noma uchungechunge lwezinyathelo ezenzeka kancane kancane phakathi kokuphilayo nokungaphili, uDenton waphawula ukuthi ukuba khona kwegebe eliphelele “kwagcina kuqinisekisiwe ngemva kokusungulwa kwesayensi yamangqamuzana ezinto eziphilayo okwaletha ushintsho ngasekuqaleni kwawo-1950.” Elandisa ngeqiniso eliphawulekayo manje eselisobala kososayensi, uDenton waqhubeka echaza:

“Manje asisazi nje kuphela ukuthi kunegebe phakathi kwezinto eziphilayo nezingaphili, kodwa nokuthi liyigebe elikhulu neliyisisekelo kunawo wonke ezintweni zemvelo. Kunegebe elikhulu nelisobala ngokucacile phakathi kwengqamuzana ephilayo nesimiso sezinto ezingaphili esinokuhleleka okukhulu, njengekristalu noma ukukhithika kweqhwa.”

Lokhu akusho ukuthi ukwenza i-molecule kulula. Incwadi ethi Molecules to Living Cells ichaza ukuthi “ukuhlanganiswa kwezici ezakha i-molecule encane kuyinkimbinkimbi ngokwako.” Nokho, inezela ngokuthi ukwenza ama-molecule anjalo “kuwubala uma kuqhathaniswa nalokho okumelwe ukuba kwalandela ukuze kwenziwe ingqamuzana ephilayo yokuqala.”

Amangqamuzana angase aziphilele ngawodwa abe yizinto eziphilayo, njengama-bacterium, noma angase abe yingxenye yento ephilayo enamangqamuzana amaningi, njengomuntu. Kungathatha amangqamuzana avamile angu-500 ukuba alingane nongqi osekupheleni kwalo musho. Yingakho nje kungesona isimanga ukuthi imisebenzi yengqamuzana ayibonakali ngehlo lenyama. Pho, yini eyembulwa isibonakhulu lapho kuhlolwa ingqamuzana eyodwa yomzimba womuntu?

Ingqamuzana—Yazivelela Noma Yaklanywa?

Okokuqala nje, umuntu ngeke ahlale angamangazwa ubunkimbinkimbi bamangqamuzana aphilayo. Omunye umbhali wesayensi waphawula: “Ngisho nokukhula okuvamile kwengqamuzana ephilayo encane kudinga amashumi ezinkulungwane zokuguquka kwamakhemikhali okwenzeka ngokuvumelana.” Wabuza: “Kungenzeka kanjani ukuba phakathi kwengqamuzana eyodwa encane, kube nezinguquko ezingu-20 000 zonke eziqondiswa ngesikhathi esisodwa?”

UMichael Denton waqhathanisa ngisho nengqamuzana encane kunawo wonke “nefektri enokwethenjelwa yezinto ezincane kakhulu enezinkulungwane zezingxenye eziklanywe ngokumangalisayo zomshini wama-molecule oyinkimbinkimbi, owenziwe ngokuphelele ngama-athomu ayizigidi eziyizinkulungwane eziyikhulu, oyinkimbinkimbi kakhulu ngaphezu kwanoma yimuphi umshini owenziwe umuntu futhi ngokuqinisekile ongenakufaniswa nalutho ezintweni ezingaphili.”

Ososayensi basala bekhungathekile ngenxa yokuba yinkimbinkimbi kwengqamuzana, njengoba i-New York Times ka-February 15, 2000, yaphawula: “Lapho ososayensi bezinto eziphilayo beqonda okwengeziwe ngamangqamuzana aphilayo, kulapho ubathena amandla kakhulu umsebenzi wokuqonda yonke into ayenzayo. Ingqamuzana yomuntu evamile incane kakhulu ukuba ingabonakala, kodwa nganoma yisiphi isikhathi izakhi zayo zofuzo ezingafika ku-30 000 kwezingu-100 000 zingase ziqale noma zimise okuthile, zenza imisebenzi edingwa ingqamuzana noma zisabela emiyalezweni evela kwamanye amangqamuzana.”

I-Times yabuza: “Ungahlaziywa kanjani umshini omncane noyinkimbinkimbi kangaka? Ngisho noma kungenzeka ukuba ngomzamo omkhulu ingqamuzana yomuntu eyodwa iqondwe, okungenani kunezinhlobo ezingu-200 emzimbeni womuntu.”

Umagazini i-Nature, esihlokweni esithi “Imishini Yangempela Yendalo,” wabika ngokutholakala kwama-motor amancane ngaphakathi kwengqamuzana ngayinye yomzimba. Lawa ayazungeza akhe i-adenosine triphosphate, umthombo wamandla amangqamuzana. Omunye usosayensi wacabanga: “Yini esingayifeza uma singafunda ukuklama futhi sakhe izimiso zomshini wama-molecule ezifana nezimiso zama-molecule esizithola engqamuzaneni?”

Cabanga nje ngamandla engqamuzana okusungula izinto! Inani lokwaziswa okuqukethwe yi-DNA yengqamuzana eyodwa nje yomzimba wethu lingagcwala amakhasi ayisigidi angangaleli! Ngaphezu kwalokho, njalo lapho ingqamuzana ihlukana ukuze yakhe entsha, ukwaziswa okufanayo kudluliselwa engqamuzaneni entsha. Ucabanga ukuthi kwenzeka kanjani ukuba ingqamuzana ngayinye—njengoba kunayizigidi eziyizigidi ezingu-100 emzimbeni wakho—ibe nalokhu kwaziswa? Ingabe kwamane kwazenzekela, noma kwenziwa uMklami Omkhulu?

Mhlawumbe ufinyelele isiphetho esifanayo nesesazi sezinto eziphilayo uRussell Charles Artist. Wathi: “Sibhekene nengwadla esingenakuyinqoba ekuzameni ukuchaza isiqalo [sengqamuzana], ingasaphathwa eyokuqhubeka kwayo isebenza, uma singavumi ngesizathu esihle nesinengqondo ukuthi umuntu ohlakaniphile wenza ukuba ibe khona.”

Ukuhleleka Kwezinto Okumangalisayo

Eminyakeni ethile edlule, ngesikhathi uKirtley F. Mather, ayesenguprofesa wesayensi yokwakheka komhlaba eHarvard University, waphetha kanje: “Siphila endaweni yoMthetho noHlelo, hhayi ezenzakalele noma evele yaba khona. Ukulawulwa kwayo kunengqondo ngokuphelele futhi kuyakufanelekela ukuhlonishwa kakhulu. Cabangela ukuklanywa kwemvelo ngokumangalisayo nangokunembile okusivumela ukuba sikwazi ukunikeza isakhi sento ngasinye inombolo yama-athomu.”

Ake sicabangele kafushane lokho “kuklanywa kwemvelo okumangalisayo nokunembile.” Phakathi kwezakhia ezazaziwa endulo kukhona igolide, isiliva, ithusi, ithini nensimbi. I-arsenic, i-bismuth ne-antimony kwatholwa izazi ze-alchemy phakathi neNkathi Ephakathi, futhi kamuva ngawo-1700, kwatholakala ezinye izakhi eziningi. Ngo-1863, i-spectroscope, esingahlukanisa imibala evelele ekhishwa yisakhi ngasinye, sasetshenziswa ukuze sihlole i-indium, eyayiyisakhi sama-63 esatholakala.

Ngaleso sikhathi isazi sokuthakwa kwemithi saseRussia uDmitry Ivanovich Mendeleyev saphetha ngokuthi lezi zakhi zazingadalwanga ngobudlabha. Ekugcineni, ngo-March 18, 1869, umbiko wakhe othi “Uhlaka Lwesimiso Sezakhi” wafundelwa i-Russian Chemical Society. Kuwo wathi: ‘Ngifisa ukusungula uhlobo oluthile lwesimiso esingazenzakaleli kodwa esiqondiswa uhlobo oluthile lomthetho oqondile.’

Kuleli phephandaba elidumile, uMendeleyev wabikezela: “Kusafanele silindele ukuthola izakhi eziningi ezingaziwa ezilula; ngokwesibonelo, lezo ezifana ne-aluminum ne-silicon, izakhi ezinesisindo sama-athomu angu-65 kuya kwangu-75.” UMendeleyev washiya isikhala esingabhalwe lutho sezinye izakhi ezingu-16. Lapho kuthiwa akakhiphe ubufakazi besibikezelo sakhe, waphendula: “Asikho isidingo sobufakazi. Emithethweni yemvelo, ngokungafani nasemithethweni yolimi, ayikho into okuthiwa ihlukile.” Wanezela: “Ngicabanga ukuthi uma izakhi zami ezingaziwa zitholakala, baningi abantu abayosilalela.”

Yilokho kanye okwenzeka! I-Encyclopedia Americana iyachaza: “Eminyakeni engu-15 eyalandela, ukutholakala kwe-gallium, scandium ne-germanium, izici zayo ezazifana nalezo ezabikezelwa uMendeleyev zaveza ubuqiniso beshadi lezakhi futhi zabangela ukuba adume umsunguli walo.” Ngasekuqaleni kwekhulu lama-20 leminyaka, zonke izakhi ezikhona zase zitholakele.

Ngokusobala, njengoba umcwaningi wokuthakwa kwemithi u-Elmer W. Maurer aphawula, “leli lungiselelo elihle akunakwenzeka ukuba lazenzekela.” Ukuthi akhona yini amathuba okuthi uhlelo oluvumelanayo lwezakhi kube ukuthi lwazenzekela, uprofesa wokuthakwa kwemithi uJohn Cleveland Cothran waphawula: “Ukutholakala kwezakhi okwalandela isibikezelo esenziwa [uMendeleyev], nokuba kwazo nezinto ayezibikezele kwawaqeda nyá lawo mathuba. Isimiso sakhe esikhulu akushiwo ukuthi ‘Ukuzivelela Kwezakhi.’ Kunalokho, kuthiwa ‘UMthetho Wezakhi.’”

Ukuhlolisisa ngokuseduze izakhi nendlela ezihlangana ngayo ndawonye ukuze zenze yonke into esemkhathini kwabangela isazi se-physics esidumile uP. A. M. Dirac, owayenguprofesa wezibalo eCambridge University, ukuba athi: “Mhlawumbe umuntu angachaza isimo ngokuthi uNkulunkulu ungungqondongqondo wezibalo, futhi wasebenzisa izibalo zezinga eliphezulu kakhulu ekwakheni umkhathi.”

Kuyathakazelisa ngempela ukuhlola izinto ezingabonakali kokubili ama-athomu amancane kakhulu, ama-molecule namangqamuzana aphilayo kanye nemithala emikhulu yezinkanyezi ekudlulela kude lokho okungabonakala ngamehlo enyama! Ukuhlola lokhu kuyathobisa. Kukuthinta kanjani wena ngokwakho? Yini ekukhanyelayo kulezi zinto? Ingabe ubona okungaphezu kwalokho amehlo akho enyama angakubona?

[Umbhalo waphansi]

[Ibhokisi/Izithombe ekhasini 5]

Kushesha Kakhulu Ukuba Ihlo Lingakubona

Njengoba ukugabavula kwehhashi kushesha kangaka, abantu bangekhulu le-19 babephikisana ngokuthi sike sibe khona yini isikhathi lapho yonke imilenze yalo ingathinti phansi. Ekugcineni, ngo-1872, u-Eadweard Muybridge waqala ukuhlola ngokuthatha izithombe okwaxazulula inkinga kamuva. Wasungula icebo lokuthatha izithombe zejubane eliphezulu lokuqala.

UMuybridge wabeka ndawonye amakhamera angu-24 ethe ukugqagqana kancane. Kusukela endaweni yokuthatha isithombe yekhamera ngayinye, kwakubekwe intambo yavundla endleleni, ukuze kuthi lapho ihhashi lidlula, linyathele intambo bese kuthinteka amakhamera athathe isithombe. Ukuhlaziywa kwezithombe ezaphuma kwembula ukuthi kuyenzeka ngezinye izikhathi yonke imilenze yehhashi ibe semoyeni.

[Umthombo]

Courtesy George Eastman House

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Kungani amanzi ayiqhwa entanta esikhundleni sokuba azike?

[Isithombe ekhasini 7]

I-“molecule” ye-DNA ingamamilimitha angu-0,0000025 ububanzi, kodwa iqukethe ukwaziswa okungagcwala amakhasi ayisigidi

[Umthombo]

Computerized model of DNA: Donald Struthers/Tony Stone Images

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Engqamuzaneni yomzimba ngayinye—njengoba kunayizigidi eziyizigidi eziyikhulu zawo—kwenzeka izingu-quko zamakhemikhali ezingamashumi ayizinkulungwane ngokuvumelana

[Umthombo]

Copyright Dennis Kunkel, University of Hawaii

[Izithombe ekhasini 9]

Usokhemisi waseRussia uMendeleyev waphetha ngokuthi izakhi azidalwanga ngobudlabha

[Umthombo]

Courtesy National Library of Medicine