Ku dhammee weedha soo socota: Sanadkii 1920 waxaa loo magacaabay agaasimaha Allegheny Observatory. Isla sanadkaas wuxuu ka qeyb galay
Dood weyn oo lala yeeshay Harlow Shapley (oo sidoo kale loo yaqaan Shapley <unk> Curtis Debate) oo ku saabsan dabeecadda nebulae iyo galaxies, iyo cabirka caalamka. Curtis wuxuu taageeray aragtida hada la aqbalo ee ah in galaxyada kale ay jiraan marka laga reebo Milky Way.