Ukuzama ukulinganisa iSantya sokuKhanya

NguCarlos I. Calle

Ingcamango kaJames Clerk Maxwell ye-electromagnetism isixelela ukuba ukukhanya ngumbane wombane ohamba ngeekhilomitha ezingama-300,000 ngomzuzwana (kps). Amanani kaMaxwell asixelela ukuba ukutshintsha amandla ombane kunye nemagnethi kuyadala kwaye kugcinana nakwimimandla apho kungekho zintlawulo zombane zokukhawulezisa okanye iimagnethi ukuhamba. UMaxwell ubonise ukuba la macandelo mabini, angenelelene kumdaniso, enza umboniso wokukhanya. Amasimi asasazeka esithubeni njengokukhanya okanye njengalo naliphi na elinye igagasi lombane.



Kodwa ngaphambi kukaMaxwell, ezinye izazinzulu zazenza amalinge okuchonga ukukhanya kunye nokubala isantya.



UGalileo: Izibane ezijingayo

Ukukhanya kuhamba ngokukhawuleza kangakanani emajukujukwini? Ixabiso langoku lesantya sokukhanya ngama-300,000 kps (186,000 mps). Ngokwenyani, zii-299,792.458 kps, kodwa lelo linombolo elinzima ukukhumbula. Umjikelo womhlaba umalunga ne-40,000 km (25,000 mi), ke kungathatha ukukhanya ixesha elide kancinci kuneshumi lomzuzwana ukuhamba ujikeleze umhlaba.

Izilonda esifubeni ezingaphilanga

Ngezixhobo zale mihla, ixabiso elikhulu kakhulu lesantya sokukhanya linokulinganiswa. Kodwa umntu wayilinganisa njani ngaphambi kokuba zenziwe ezo zixhobo?



UGalileo ngumntu wokuqala owazama. Wayenabantu ababini abema kwiinduli ezikude ezibengezelayo. Ngokucacileyo, ulingo lukaGalileo aluzange lusebenze - wayengakwazi nokulinganisa imizuzwana ngokuchanekileyo, ngokungaphantsi iqhezu elincinci lomzuzwana elithathe ukukhanya ukuhamba phakathi kweenduli ezimbini.

Kodwa uGalileo wayenguGalileo, kwaye ngendlela yakhe ekrwada kolu vavanyo lunzima kakhulu, wayesenakho ukubonisa ukuba isantya sokukhanya siphelile. Isithandi sobulumko esasiphila ngeloxesha, isiFrentshi, uRené Descartes, wayesithi ayinakuphela.

Roemer: Ixesha lesathelayithi

Kwiminyaka engama-70 emva kovavanyo lukaGalileo, isazi ngeenkwenkwezi saseDenmark u-Olaus Roemer wakwazi ukufumana ixabiso lokuqala lesantya sokukhanya. Kodwa kwafuneka ukuba aye kude kunenduli ekude ukuze ayifumane. Wasebenzisa iisathelayithi zeJupiter endaweni yoko. Kwaye kwafuneka alwe nomphathi wakhe - isazi ngeenkwenkwezi esidumileyo uJean-Dominique Cassini, lowo kuthiwe ngoku amakhonkco eSaturn.



Ukujongana nokungangqinelani

URoemer wayeneminyaka eli-21 eqaqambileyo waqeshwa ngomnye wabancedisi bakaCassini ukuba ancede eParis Observatory, eyayikhokelwa nguCassini. Kodwa uRoemer akazange ancede nje; Uye wajongana nenye yeengxaki eziphambili zokujonga.

Ukuqwalaselwa kukaCassini kwakubonisa ingxaki ngesindululo sesinye isathelayithi zikaJupiter, esi sinegama Mna (emva komnye wabathandi bakaZeus, obizwa ngokuba nguJupiter kwiintsomi zamaRoma). Kwakubonakala ngathi i-Io's orbit yayingaqikeleleki. Amaxesha apho isathelayithi yaphuma ngasemva kweplanethi yatshintsha ngokungachazekiyo. UCassini wayalela abancedisi bakhe ukuba baqwalasele ngcono kwaye benze ngakumbi ukubala.

URoemer uyathandabuza ukuba ukuqaphela okanye ukubala yingxaki. Ingxaki yayikukuba akukho mntu wawuthathela ingqalelo umgama olinganayo woMhlaba kunye neJupiter njengoko iiplanethi ezimbini zazijikeleza ilanga. Kwiindawo ezahlukeneyo kwiindawo zabo, iiplanethi ngamanye amaxesha zisondele kwaye ngamanye amaxesha ziqelelene. Xa u-Io ephuma ngasemva kweJupiter, umgama ohamba ukukhanya ukusuka kwisathelayithi ukuya eMhlabeni kuxhomekeke ekwahlulweni kweeplanethi ngelo xesha.

UCassini akazange avumelane nomncedisi wakhe. Wayekholelwa ukuba ukukhanya kuhamba ukusuka kwenye indawo ukuya kwenye ngephanyazo, ngaphandle kokulibaziseka. Kwakungakhathaliseki ukuba kude kangakanani iJupiter.

URoemer wanamathela kumbono wakhe. Ubuyele umva wajonga kwakhona iminyaka emininzi yedatha ethathwe kwindawo yokugcina izinto kaCassini. Ngale datha, wakwazi ukubala utshintsho kumaxesha okusithwa kwelanga ngu-Io njengoko wayejikeleza kumjikelo wawo. Wayeqinisekile ukuba wayenyanisile kwaye wayefuna ukuya esidlangalaleni.

Ukujikeleza umphathi

Kwenziwe ntoni? Ngokwesiqhelo, umlawuli welebhu wayenokwenza inkcazo yoluntu ngeziphumo ezitsha, kunye nomphandi owenza ukufumanisa. Kodwa uCassini akazange avumelane nomsebenzi kaRoemer, ke uRoemer wagqiba kwelokuba ahambe yedwa. Wayekwi-Cassini's Observatory iminyaka emihlanu kwaye waziva eyi-cocky. Uvele phambi kweAkhademi yeSayensi eParis kwaye wabhengeza ukuba u-Io uza kuphuma emva kweJupiter kanye emva kwemizuzu elishumi emva kokuba uCassini ethe kuyakuba njalo.

i-hydrocodone pol cpm 10 8 5ml engamanzi

UCassini wayebala ukuba u-Io wayeza kuphuma ekusithekeni ngo-Novemba 9, 1676, ngo-5: 25: 45. Izazi ngeenkwenkwezi zaphuma zaya kujonga ngobo busuku. 5:25:45 yeza yahamba, kwaye u-Io wayengekho. Ngo-5: 30, kwakungabikho zimpawu zawo. Kodwa ngo-5: 35: 45, ndaphinda ndavela. URoemer wayenyanisile.

Umhlobo kaRoemer uChristian Huygens wasebenzisa le datha ukuza nexabiso lokuqala elilinganisiweyo kwisantya sokukhanya. Inani lakhe laliyi-227,000 km (140,000 mi) ngomzuzwana, malunga neepesenti ezingama-24 ezantsi kunexabiso lanamhlanje.

UCassini akazange ayivume impazamo yakhe. Uninzi lweenkwenkwezi zeYurophu lwalulandela uCassini kwaye zange bakholelwe ukuba isantya sokukhanya sasiphelile. Kwiminyaka engama-50 kamva, ezinye iindlela zokulinganisa isantya sokukhanya zabonisa ukuba uRoemer wayenyanisile.

Ngexesha u-Einstein wayesesikolweni, isantya sokukhanya sasilinganiswe ngokuchanekileyo ngokuchanekileyo. Esi santya, simelwe ngumsebenzi ka-Einstein yileta c, waphela kwisiseko sethiyori yakhe ekhethekileyo yolwalamano.