Big Think
2026-09-07 06:00 en
Back in 1923, an unprecedented scientific revolution occurred. Hubble’s discovery of a Cepheid variable in the Andromeda galaxy, M31, opened up the Universe to us, giving us the observational evidence we needed for galaxies beyond the Milky Way and leading us, in short order, to the discovery of the expanding Universe. Credits : NASA, ESA and the Hubble Heritage Team (STScI/AURA); Illustration via NASA, ESA, and Z. Levay (STScI) Distances to individual stars were measured beyond the Milky Way. Edwin Hubble’s original plot of galaxy distances, from 1929, versus redshift (left), establishing…