<prompt> Qedela le nkulumo elandelayo: Ngo-1917, uHeber Curtis wayebone i-nova S Andromedae ngaphakathi kwe-Great Andromeda Nebula i-Messier object 31. Lapho ehlola irekhodi lezithombe, wathola amanye ama - nova angu - 11. UCurtis waphawula ukuthi lezi-nova zazifiphele, ngokwesilinganiso, ngezinga elilinganiselwa ku-10 kunalezo ezenzeka emthaleni i-Milky Way. Ngenxa yalokho, wakwazi ukuthola isilinganiso sobude obungama-parsecs angu-150 000. Waba umsekeli womqondo wokuthi amazulu ayiziqhingi, owawuthi ama - spiral nebulae ayizinkanyezi ezizimele. Ngo-1920  <response>: Kwaba nempikiswano enkulu phakathi kukaHarlow Shapley noHeber Curtis, ngokuphathelene nemvelo yeMilky Way, ama-nebulae angama-spiral, nobukhulu beNdawo Yonke. Ukuze asekele isimangalo sakhe sokuthi i-Great Andromeda Nebula iyinkanyezi engaphandle, uCurtis waphawula ukubonakala kwemizila emnyama efana namafu othuli eMilky Way, kanye nokushintsha okukhulu kweDoppler. 