Edwin Hubble invented a system in 1925 that classified galaxies according to their various shapes, such as spiral, elliptical and irregular. His research in astronomy also helped to prove the theory of the expanding universe. For his contribution to the fields of astronomy and astrophysics, the Hubble Space Telescope was named after him.
Another of Hubble's discoveries was showing that there were other galaxies outside the Milk Way. Edwin Hubble and Milton Humason also did research on the spectral shifts and emissions of galaxies that demonstrated that galaxies were moving away from each other. This led to proving the theory of the expanding universe.