Ku dhammee oraahdan:
Hubble iyo Slipher waxay ogaadeen balaadhinta caalamka sanadihii 1920kii iyagoo cabirayay isbedelka cas ee Doppler spectra ee galactic nebulae. Lemaître iyo Gamow waxay soo saareen waxa loo yaqaano aragtida 'big bang theory' ayagoo adeegsanaya Einstein's general relativity. Mid kale oo la mid ah, oo loo yaqaano aragtida gobolka joogtada ah waxaa soo saaray Hoyle, Gold, Narlikar iyo Bondi.