Mezue nkebi ahịrịokwu a: N'otu oge ahụ, a nọ na-arụrịta ụka ruo ogologo oge banyere otú eluigwe na ụwa si malite. Onye na-enyocha mbara igwe na Mount Wilson bụ Harlow Shapley kwadoro ụdị nke mbara igwe nke mejupụtara usoro kpakpando Milky Way naanị; ebe Heber D. Curtis rụrụ ụka maka echiche ahụ na nebula ndị na-agba gburugburu bụ usoro kpakpando n'onwe ha dị ka eluigwe na ala agwaetiti. Echiche dịgasị iche a ruru n'ókè ya kasị elu site ná nhazi nke Òtù Na-achị Isi.
Nnukwu arụmụka na 26 Eprel 1920 na nzukọ nke US National Academy of Sciences na Washington, D.C. A doziri arụmụka ahụ mgbe Edwin Hubble chọpụtara Cepheid Variables na Andromeda Galaxy na 1923 na 1924. Ebe dị anya ha mere ka e nwee ụyọkọ kpakpando ndị yiri okirikiri n'ebe dị anya karịa Milky Way.