Milky Way Galaxy

The Milky Way is a galaxy that contains our Solar System. Its name "milky" is derived from its appearance as a dim glowing band arching across the night sky whose individual stars cannot be distinguished by the naked eye. From Earth the Milky Way appears as a band because its disk-shaped structure is viewed from within. Galileo Galilei first resolved the band of light into individual stars with his telescope in 1610. Until the early 1920s most astronomers thought that the Milky Way contained all the stars in the Universe. Following the 1920 Great Debate between the astronomers Harlow Shapley and Heber Curtis, observations by Edwin Hubble showed that the Milky Way is just one of many galaxies—now known to number in the billions.