Leyomigqa Engabonakali Ewusizo

NGUMLOBELI WE-PHAPHAMA! EBRITHANI

AKE ubuke ibalazwe noma isiyingi somhlaba. Ingabe uyayiqaphela inxanxathela yemigqa eyehlayo nevundlayo edwetshwe kulo lonke? Ngokungangabazeki ngokushesha uqaphela ukuthi umugqa ovundla phakathi nebalazwe uyinkabazwe. Kodwa kuthiwani ngeminye imigqa? Iyini?

Lemigqa ibizwa ngokuthi imigqa ye-latitude ne-longitude. Imigqa ye-latitude, noma evundlayo, ebalazweni lakho, ihlanganisa izingxenye zomhlaba ezisebangeni elifanayo ukusuka enkabazwe. Ngakolunye uhlangothi, imigqa ye-longitude, noma eyehlayo idwetshwa kusuka enyakatho kuya eningizimu, kusuka phezulu kuya phansi. Lokho ungase ukukhumbule ezifundweni zakho zesayensi yokuma komhlaba esikoleni. Kodwa iyini injongo yalesisimiso semigqa? Sisebenza kanjani? Futhi sasungulwa kanjani?

Ukuyikhomba Ngokuqondile Indawo Okuyo

Njengoba kunalenxanxathela yemigqa ye-latitude ne-longitude, zingakhonjwa ngokunembile zonke izingxenye zomhlaba ngokusebenzisa ukulinganisa okubili, okubizwa ngokuthi ama-coordinate. Ngokwesibonelo, ungathola iNew York City ebalazweni ngokubheka ku-lat. 40°42’ eNyakatho no-long. 74°0’ eNtshonalanga, okusho ukuthi lelidolobha lisendaweni engama-degree angu-40 nemizuzu engu-42 enyakatho nenkabazwe nama-degree angu-74 entshonalanga yomugqa owehlayo oyinhloko osetshenziswa emhlabeni wonke, umugqa we-longitude onqamula eGreenwich, idolobhana likahulumeni eLondon, eNgilandi.a Uma kunezelwa imizuzwana kulama-coordinate, kungakhonjwa ngisho nezakhiwo ezisedolobheni. Ngokwesibonelo, ihholo ledolobha laseNew York City liku-lat. 40°42’45” eNyakatho naku-long. 74°0’23” eNtshonalanga.

Amabanga nawo alinganiswa ngokubhekisela kulemigqa. Ngokwesibonelo, ubude bemayela elisetshenziswa amatilosi buwumzuzu owodwa we-latitude olinganiswa uqondane nomugqa owehlayo. Njengoba indawo ebandayo esenyakatho noma eningizimu ikuma-degree angu-90, noma imizuzu engu-5 400 (90 x 60 = 5 400) kuyi-latitude ukusuka enkabazwe, imayela elilodwa elisetshenziswa amatilosi liyibanga elingu-1/5 400 kusukela kuleyondawo kuya enkabazwe. Ngakho, imayela elivamile elisetshenziswa amatilosi lingamakhilomitha angu-1,8532.

Ikhono lokukhomba noma iyiphi indawo ngokunembile ngokuqinisekile liyinzuzo enkulu, ikakhulukazi kumatilosi. Nokho, ukuze isimiso esinjalo sisebenze, kumelwe sibe nezizinda ezithile. Inkabazwe iyindawo efanelekayo njengesisekelo okuthathelwa kuso izilinganiso ze-latitude. Kodwa kungani kwakhethwa iGreenwich njengendawo yomugqa owehlayo oyinhloko, isizinda sezilinganiso zama-longitude empumalanga nentshonalanga? Eqinisweni, wavela kanjani lomqondo walemigqa engabonakali eyabekwa umuntu ebalazweni lakhe?

Imigqa Enomlando

Ekuqaleni kwekhulu lesibili B.C.E., isazi sezinkanyezi esingumGreki uHipparchus sasebenzisa umqondo wemigqa engabonakali ukuze sikhombe izindawo ezisemhlabeni. Sakhetha umugqa onqamula esiqhingini saseGreece iRhodes njengesizinda sokubala izindawo ngasempumalanga nangasentshonalanga. Isazi sezinkanyezi esingumGreki uClaudius Ptolemy sekhulu lesibili C.E. ngokuvamile kuthiwa singumuntu wokuqala owasungula isimiso esifana naleso esisetshenziswa namuhla. Imigqa yaso ye-latitude yayihambisana nenkabazwe. Ukuze senze ama-longitude, into esaqala ngayo kwakuwumugqa onqamula emaphethelweni asentshonalanga omhlaba wosuku lwaso, eFortunate Isles, njengoba iCanary Islands yayibizwa kanjalo ngalesosikhathi.

Kwaze kwaba ngo-1884 lapho kwafinyelelwa khona isivumelwano somhlaba wonke sokukhetha umugqa oyinhloko we-longitude okungalinganiselwa kuwo izindawo ngasempumalanga nangasentshonalanga. Ngalowonyaka i-International Meridian Conference eWashington, D.C., yahlanganisa izihambeli ezingu-41 zasemazweni angu-25. Ukuze kwenziwe ukucwaninga okudingekayo ngezinkanyezi emgqeni oyinhloko owehlayo, lezizihambeli zakhetha umugqa onqamula esikhungweni sokucwaninga esifanelekayo. Ngazwi-linye, zakhetha umugqa onqamula eGreenwich, eNgilandi.

Ukuhamba Nezigaba Zesikhathi

Ukukhethwa kweGreenwich njengendawo yomugqa oyinhloko owehlayo kwakungenzekanga ngengozi. Kusukela ekhulwini le-18, okaputeni bemikhumbi abasukela ethekwini elimatasa laseLondon babelokhu bephawula ukuthi njengoba beya ngasentshonalanga benqamula e-Atlantic, ilanga lalihlaba okhakhayini ngokuhamba kwesikhathi usuku ngalunye. Babazi ukuthi ngenxa yokuthi umhlaba uphenduka ngokuphelele njalo emahoreni angu-24, umehluko wehora elilodwa esikhathini wawumelela ama-degree angu-15 e-longitude ukusuka eGreenwich. Ngakho, besebenzisa amawashi ahambisana nelikhulu elisesikhungweni sokucwaninga eGreenwich, babengabala indawo abakuyo olwandle ngokumane baphawule umehluko phakathi kwesikhathi saseGreenwich nesikhathi abasiphethe. Ngokwesibonelo, uma babesendaweni lapho ilanga lihlaba okhakhayini (ngo-12:00 emini bebade ngesikhathi sethu) ngo-3:30 ntambama ngokwesikhathi saseGreenwich, khona-ke ngokubala okulula, babenganquma ukuthi indawo abakuyo ingama-degree angu-52,5 (15 x 3,5) entshonalanga yaseGreenwich, okuwukuthi, ngasogwini lwasempumalanga lwaseNewfoundland, uma nje beye baba semgqeni ofanayo we-latitude.

Ukuhlala emgqeni owodwa we-latitude, noma ukuhamba ngomkhumbi uqonde, kwakuwumsebenzi olula. Amakhulu amaningi eminyaka amatilosi aseNyakatho Nenkabazwe aphawula ukuthi i-polestar, noma i-Polaris, yayibonakala cishe imile lapho iqhathaniswa nezinye izinkanyezi eziningi ezihamba ebusuku. Aqala ukulinganisa ukuthi ayesenyakatho naseningizimu kangakanani ngokulinganisa ukuphakama kwaleyonkanyezi ngaphezu komkhathi-zwe. Lapho esolwandle, ayazi ukuthi ayeya ngasempumalanga noma ngasentshonalanga uma nje leyonkanyezi ihlala endaweni efanayo.

Ukukhethwa kweGreenwich njengesizinda kwakunezinye izinzuzo eNgilandi. Lapho kusungulwa ukuhamba ngezitimela kuleyondawo, kwakudingeka isimiso sokuvumelanisa isikhathi kulo lonke izwe. Yeka indlela okwakudabukisa ngayo ngesihambi esasithi lapho sifika esiteshini sesitimela e-Exeter sizobamba isitimela sika-11:33 sithole ukuthi sasihambe emizuzwini engaba ngu-14 ngaphambi kwalokho! Yayiyini inkinga? Isihambi sasisebenzise isikhathi sase-Exeter; isimiso sikaloliwe sasisebenzisa isikhathi saseLondon. Ukwamukelwa kwesikhathi saseGreenwich kulo lonke izwe kwaziqeda lezozinkinga.

E-United States kwakunezinkinga ezinkulu ngisho nakakhulu. Imizila ehlukene yezitimela yayisebenzisa izikhathi ezingafani. Lesisimo saholela kuyi-General Time Convention yemizila yesitimela, eyaqhutshwa ngo-1883. Kwasetshenziswa izigaba ezine zesikhathi, ngasinye esasihlanganisa ama-degree e-longitude angu-15, noma ihora, futhi sihlanganisa izwekazi lase-United States. Wonke amadolobhana asesigabeni esisodwa kwakumelwe agcine isikhathi esifanayo.

Ekugcineni lelilungiselelo lokuhlukanisa ngokwezigaba lamukelwa emhlabeni wonke. Umhlaba wahlukaniswa waba izigaba zesikhathi ezingu-24. Indawo ephakathi kulesisimiso kwakuyi-Zone 0, eyayithatha ama-degree angu-7 1/2 ohlangothini ngalunye lomugqa waseGreenwich. Lapho umuntu eya ngasempumalanga, wayehlehlisa iwashi lakhe ngehora elilodwa njengoba edlula esigabeni ngasinye. Lapho eya ngasentshonalanga wayebeka iwashi lakhe phambili ngehora elilodwa.

Phakathi nendawo uma uzungeza umhlaba usuka eGreenwich, kuvela isimo esithakazelisayo. Lapha, emgqeni we-longitude ongama-degree angu-180, kunomehluko wesikhathi samahora angu-24 kusuka ohlangothini olulodwa lwalomugqa kuya kolunye. Ngenxa yalokho, umugqa we-longitude ongama-degree angu-180, ngokuguquguquka okuncane nje ukuze kufakwe nemingcele yamazwe, waba umugqa wokubala izinsuku emhlabeni wonke. Uma enqamula lomugqa eya ngasentshonalanga, osohambweni ulahlekelwa usuku olulodwa. Ngokuphambene, uma enqamula lomugqa eya ngasempumalanga, uzuza usuku olulodwa.

Isabalulekile

Izinsuku zokuhlola amawashi eGreenwich bese eyiswa olwandle ukuze kubalwe imigqa ye-longitude zidlulile. Ubuchwepheshe banamuhla buye bakuqeda konke lokho. Ama-radio beacon, i-radar, nokuxhumana kwamazwe omhlaba kunikeza ukwaziswa okunembe kakhudlwana. Nokho, ukuyikhomba ngokuqondile indawo okuyo eshadini noma ebalazweni kusaxhomeke kuleyomigqa engabonakali ye-latitude ne-longitude. Singabonga ngaleyomigqa engabonakali ewusizo kakhulu.

[Umbhalo waphansi]

[Ibhokisi/Izithombe ekhasini 20]

ISIKHATHI SENDAWO SASEGREENWICH

Ngo-1675, iNkosi uCharles II yaseNgilandi yayala ukuba kwakhiwe “isikhungo esincane sokucwaninga” endaweni manje eyidolobhana likahulumeni iGreenwich eLondon “ukuze kubalwe ibanga lezindawo ukuze kuqinisekiswe uhambo lwemikhumbi nesayensi yezinkanyezi.” Kwafakwa amawashi amabili amasha, anezimpondo ezingamamitha amane ubude, ukuze kubalwe ngokunembile ukuphenduka komhlaba.

Ososayensi baseRoyal Observatory ngokushesha baqaphela ukuthi ukuphenduka komhlaba kunesivinini esishintshashintshayo. Lokhu kwenziwa ukuthi ukuzungeza komhlaba ilanga akusona isiyingi esiphelele futhi i-axis yawo itshekile. Ngakho, usuku—isikhathi kusukela emini bebade kuya emini bebade—lunobude obuhlukahlukene phakathi nawo wonke unyaka. Njengoba amawashi aseGreenwich esebenza, kwenzeka ukuba kubalwe ukuthi ubude bosuku obuvamile bungakanani.

Isikhathi saseGreenwich lapho kusemini bebade yisikhathi lapho ilanga lishaya okhakhayini kunoma iyiphi ingxenye esemgqeni we-longitude waseGreenwich (ngesiLatini, meridianus, phakathi nosuku). Ngokusekelwe kuleligama lesiLatini, isikhathi esingaphambi kwasemini bebade saziwa ngokuthi i-ante meridiem (a.m.), noma ekuseni; isikhathi santambama sabizwa ngokuthi i-post meridiem (p.m.).

[Izithombe]

Ngenhla: IRoyal Observatory yaseGreenwich. Kwesokudla: Umugqa oyinhloko we-“longitude” egcekeni eligandayiwe

[Ibalazwe ekhasini 18]

(Ukuze ubone ukuthi indaba ihlelwe kanjani, bheka encwadini)

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