Whakaotihia te rerenga kōrero e whai ake nei: I te tau 1920,
i tū te Kōrero Nui i waenganui i a Harlow Shapley rāua ko Curtis, e pā ana ki te āhua o te Milky Way, ngā nebulae kōaro, me ngā āhuatanga o te Ao. Hei tautoko i tana kerēme ko te Great Andromeda Nebula (M31) he tupuni o waho, i kite hoki a Curtis i te ahua o nga ara pouri e rite ana ki nga kapua puehu i roto i to tatou ake tupuni, me te nekehanga Doppler nui. I te tau 1922 i whakaatuhia e Ernst Öpik he tikanga astrophysical huatau me te ngawari ki te whakatau i te tawhiti o M31. Ko tāna kitenga i whakatakoto i te Andromeda Nebula ki waho rawa o to tatou aorangi i te tawhiti e pā ana ki te 450,000 parsec, e pā ana ki te 1,500,000 ly. I whakatauhia e Edwin Hubble te tautohetohe mo te mea kei kona ano etahi atu tupuni i te tau 1925 i tana kitenga i nga whetu rereke rereke o Cepheid mo te wa tuatahi i runga i nga whakaahua aorangi o M31. I hangaia enei ma te whakamahi i te 2.5 mita (100 inihi) Hooker telescope, a ka taea e raatau te whakatau i te tawhiti o te Great Andromeda Nebula. I tino kitea e tana ine, ehara i te kohinga whetu me te hau i roto i to tatou tupuni, engari he tupuni motuhake kei tawhiti atu i to tatou. I whakamatau tēnei i te tīariatanga o ētahi atu tupuni.