Wax ka sii qor faqradan - Sanadkii 1920, Dooddii Weyneyd
dhexmaray Harlow Shapley iyo Curtis, oo ku saabsanaa dabeecada Wadada Caanaha, Nebulae-yada loo yaqaano "Spiral Nebulae", iyo cabirka caalamka. Si uu u taageero sheegashadiisa ah in Nebula weyn ee Andromeda (M31) uu ahaa galaxy dibadeed, Curtis wuxuu sidoo kale xusay muuqaalka wadooyinka mugdiga ah ee u eg daruuraha boodhka ee galaxy-keena, iyo sidoo kale wareejinta Doppler ee muhiimka ah. Sannadkii 1922 Ernst Öpik wuxuu soo bandhigay qaab fudud oo astrofisikal ah si loo qiyaaso masaafada M31. Natiijadiisa waxay gelisay Nebula Andromeda meel aad uga fog xidigaheena meel u jirta 450,000 parsecs, taasoo u dhiganta 1,500,000 oo malyuun oo ilbiriqsi. Edwin Hubble wuxuu xaliyay dooda ku saabsan in galaxyada kale ay jiraan 1925 markii uu aqoonsaday xiddigaha cepheid variable ee ka baxsan galaxyada markii ugu horeysay sawirada astronomical ee M31. Sawiradan waxaa lagu sameeyay 2.5 mitir (100 inches) Hooker telescope, waxayna u suurtagelisay in la ogaado masaafada Nebula Great Andromeda. Cabiritaankiisa wuxuu si cad u muujiyay in muuqaalkan uusan aheyn koox xiddigood iyo gaas oo galakeena ku jira, laakin gabi ahaanba galaxy gooni ah oo ku taala meel aad uga fog mida aan ku noolnahay. Tani waxay cadeysay jiritaanka xidigaha kale.