Izvi zvinorevei: "Murangariro wenyika yakatsiga"?
Mu cosmology, chimiro chenguva dzose, kana kuti dzidziso yenguva dzose, inotsiva dzidziso yeBig Bang yokushanduka-shanduka kwechisiko chose. Mumuenzaniso wenguva dzose, uwandu hwezvinhu zviri muchadenga chiri kuwedzera hunoramba hwakangofanana nokuti zvinhu zvinogara zvichiumbwa. Izvi zvinowirirana nomutemo wakakwana wenyika yose, uyo unoti zvinhu zvose zvakasikwa zvatinogona kuona zvakafanana kwose kwose uye panguva ipi neipi.  Zvinetso ne steady-state model zvakatanga kubuda muma1950 nema1960, apo kucherekedza kwakatanga kutsigira pfungwa yokuti zvinhu zvose zvaitove zvichichinja: manyuko anopenya eradio (quasars uye radio galaxies) akawanikwa chete kure kure (saka angadai akavapo chete munguva yakapfuura iri kure nekuda kwemigumisiro yekumhanya kwechiedza pakuongorora nyeredzi), kwete mumapoka enyeredzi ari pedyo.  Kuwanwa kwe cosmic microwave background radiation muna 1964, iyo dzidziso yeBig Bang yakanga yafanotaura, yakapa ruzhinji rwevanoongorora nyeredzi nenzvimbo chinetso chinogumisa kumugariro wenguva dzose.