Umqondo we unyaka wokukhanya ivame ukudukisa. Ubukhona begama elithi unyaka buye benza abaningi bahlobanisa le nkulumo neyunithi yesikhashana. Kodwa-ke, iyunithi yokulinganisa ye-longitude esetshenziswa emkhakheni wesayensi yezinkanyezi, ngakho-ke esikhundleni sokuthi "thatha unyaka okhanyayo", abantu bathi "kube unyaka okhanyayo".
Kulesi sihloko sizokutshela ukuthi uyini unyaka wokukhanya, ukuthi ulinganiswa kanjani, izibonelo nokunye okuningi.
Yini unyaka wokukhanya
Lo mqondo usebenza njengeyunithi yokulinganisa kusayensi yezinkanyezi elinganisa ibanga elingahanjwa yi-photon noma ingxenyana yokukhanya phakathi nesithuba esingangonyaka owodwa. Ngokwezinombolo, Unyaka owodwa wokukhanya ulingana no-9,46 x 1012 km noma 9.460.730.472.580,8 km. Le yunithi yayiklanyelwe ngokukhethekile ukukala amabanga amakhulu asemaceleni anwebeka ngaphezu kwezigidigidi zamakhilomitha. La mabanga adinga isilinganiso esithile sokuwaveza ngendlela eqondakala kalula.
I-International Astronomical Union ihlinzeka ngencazelo enembayo yonyaka okhanyayo, efushanisiwe ngokuthi qamba noma ly ngesiNgisi. Ukuze kulinganiswe, kufanele kucatshangelwe ikhalenda likaJulian (esikhundleni sikaGregory) kanye nejubane lokukhanya (elibalwa ngamamitha angu-299.792.458 XNUMX XNUMX ngomzuzwana). Ngakho-ke, ubude bonyaka lapho ukukhanya kuhamba khona ibanga emkhathini lilingana nezinsuku ezingama-365,25, esikhundleni sezinsuku ezingama-365,2425 njengasekhalendeni likaGregory.
Njengamanye amayunithi okulinganisa ibanga, lesi silinganiso singanwetshwa sibe yiziphindaphinda eziphezulu ngokungeza isiqalo senani lezinombolo. Isibonelo, ibanga leminyaka engu-1.000 yokukhanya lingachazwa njenge-kilo-light-year, noma i-kly, kuyilapho ibanga leminyaka yokukhanya engu-1.000.000 lingavezwa njenge-mega-light-year, noma i-gly.
Umsuka womqondo
Maphakathi nekhulu le-61, uFriedrich Bessel, isazi sezinkanyezi saseJalimane nesazi sezibalo, wasungula umqondo wonyaka wokukhanya njengeyunithi yokulinganisa. Impumelelo eyinhloko ka-Bessel kwaba ukubala okunembile kwebanga ukusuka eMhlabeni kuya enkanyezini ngaphandle kweLanga, ikakhulukazi inkanyezi engu-XNUMX Cygni etholakala kumlaza i-Cygnus. Leli banga lalimangalisa inani lamakhilomitha angu-98.734.594.662 noma amamayela angu-61.350.985.287,1, Lezo kwakuyizinombolo ezinzima kakhulu ukuzibamba. Ukuze agweme le nkinga, uBessel wakhetha ukuveza leli banga ngokwenani lesikhathi esisithathayo ukuze ukukhanya kulihambe leli banga, okuyiminyaka engaba ngu-10,3.
Phakathi nesikhathi u-Bessel asebenza ngaso, ijubane lokukhanya lalingakanqunywa ngokunembile, okwamholela ekubeni agweme ukusebenzisa igama elithi “light year” ezibalweni zakhe. U-Otto Ule, umbhali wesayensi odumile waseJalimane, wethula umqondo "wonyaka wokukhanya" ngo-1851 futhi wahlongoza ukuba usetshenziswe ngendlela efanayo "nehora likamashi."
Le yunithi yokulinganisa ekuqaleni yayibhekwa njengeyunithi yezinkanyezi yi-German academy, nakuba abanye, njengesazi sezinkanyezi saseBrithani u-Arthur Eddington, babemelene nokutholwa kwayo, bekubheka njengento enzima, engenakwenzeka, futhi eyifanele kangcono isayensi ethandwayo.
Izibonelo zamabanga akalwa ngeminyaka yokukhanya
Uma kulinganiswa ngeminyaka yokukhanya, ibanga elithile lendawo libaluleka kakhulu. Ake sibone ezinye zezibonelo ezimele kakhulu lapho ososayensi basebenzisa le yunithi yokulinganisa:
- Indlela yobisi, umthala wethu siqu, unobubanzi obungama-light-year angaba ngu-150.000 240.000. Uma kuqhathaniswa, i-Andromeda, umthala ongumakhelwane wawo, inobubanzi obungama-light-year angaba ngu-2.500.000 XNUMX. Imithala emibili ihlukaniswe ibanga leminyaka engu-XNUMX yokukhanya.
- Emaphethelweni angaphandle Isimiso sethu sonozungezilanga sitholakala e-Oort Cloud., futhi ibanga phakathi kwaleli fu neLanga lingaba unyaka ongu-1 wokukhanya.
- U-Proxima Centauri, inkanyezi eseduze kakhulu neLanga, ikude ngeminyaka engu-4,22 ukukhanya.
- Umthala omncanyana i-Canis Major, oseduze kakhulu ne-Milky Way, uhlukaniswa nawo ngebanga elingama-light years angu-25.000 XNUMX.
- Iqembu lendawo lemithala, kuhlanganise ne-Milky Way, Inobubanzi obulinganiselwa ku-10.000.000 weminyaka yokukhanya.
- I-Virgo Supercluster, ehlanganisa i-Local Group of galaxies, inobubanzi obulinganiselwa ku-200 weminyaka yokukhanya.
- I-Pisces-Cetus supercluster complex, okuhlanganisa i-Virgo Supercluster, inobubanzi obulinganiselwa ku-1.000.000.000 weminyaka yokukhanya.
- La I-Great Wall of Hercules-Corona Borealis, isakhiwo sezinkanyezi esikhulu kunazo zonke esibonakala endaweni yonke, sinobubanzi obucishe bube yiminyaka yokukhanya engaphezu kuka-10.000.000.000.
Amanye amayunithi wokulinganisa wezinkanyezi
Ngaphandle kwaleli yunithi yokulinganisa eyaziwa kakhulu yezinkanyezi, kunamanye amayunithi okulinganisa asetshenziselwa ukumelela amabanga amakhulu phakathi kwendikimba yasezulwini nokubunjwa komkhathi. Amayunithi amaningana alawa athathwe onyakeni wokukhanya, okuhlanganisa inyanga yokukhanya, usuku lokukhanya, ihora lokukhanya, umzuzu wokukhanya, nesekhondi elikhanyayo. Lawa mayunithi asebenza ngomgomo ofanayo futhi avame ukusetshenziswa kusayensi edumile, ezokuxhumana, kanye ne-relativistic physics.
Ochwepheshe bezinkanyezi bavame ukuvumela ukusetshenziswa kwamayunithi ezinkanyezi angaphezu konyaka owodwa wokukhanya. Izibonelo zamayunithi anjalo zifaka:
- Iqanjwe nge-parallax yesiNgisi yomzuzwana owodwa we-arc, I-parsec (i-pc) iyiyunithi yokulinganisa elingana neminyaka yokukhanya engu-3,2616.
- Ngokubala isilinganiso sebanga phakathi koMhlaba neLanga, ososayensi basungula iyunithi yezinkanyezi (AU) njengelingana nemizuzu engu-8 yokukhanya.
Abafundi besayensi yezinkanyezi bavame ukukhetha iyunithi yezinkanyezi njengeyunithi yokulinganisa abayikhethayo ngenxa yenani layo elilinganiselwe elilinganiselwe, elingavezwa ngamagama alula. Ngakolunye uhlangothi, inani lonyaka wokukhanya lingaphansi kokucatshangelwa komongo, njengokuthi ingabe isilinganiso sithathwa endaweni engenalutho noma ukuthi ikhalenda likaJulian noma likaGregory liyasetshenziswa.
Unyaka wokukhanya uyiyunithi yokulinganisa enganembe kakhulu futhi eyinkimbinkimbi kunezinye. Nokho, inenzuzo yokuba umfanekiso ochazayo kakhulu wamabanga amakhulu phakathi kwezinto zasezulwini. Lokhu kungenxa yokuthi ukukhanya, okuyingxenye eshesha kunazo zonke endaweni yonke, kusetshenziswa njengendawo okubhekisela kuyo ukukala la mabanga.
Ngithemba ukuthi ngalolu lwazi ungafunda kabanzi mayelana nokuthi unyaka wokukhanya uyini nokuthi ulinganiswa kanjani.