<prompt> Bhala okuqhubekayo kwalesi sigaba - Ngaphambi kokuba kuqondwe ukuthi kunezinkanyezi eziyindilinga ezingaphandle komthala wethu i-Milky Way, ngokuvamile zazibizwa ngokuthi ama-nebulae ayindilinga. Umbuzo wokuthi ingabe izinto ezinjalo zazingama-galaxy ahlukene angaxhunyiwe eMilky Way, noma uhlobo lwe-nebula olukhona emthaleni wethu, wawuyisihloko se-Great Debate  <response>: Ngo-1920, phakathi kukaHeber Curtis waseLick Observatory noHarlow Shapley waseMt. Indawo Yokubuka Izinkanyezi iWilson. Kusukela ngo-1923, u-Edwin Hubble waqaphela izinto eziguquguqukayo ze-Cephid ezinama-nebula amaningana avundlile, kuhlanganise nalawo abizwa ngokuthi i-Andromeda Nebula, okufakazela ukuthi empeleni, ayizinkanyezi eziphelele ezingaphandle kwezethu. Igama elithi spiral nebula selingasasetshenziswa. 