The second key was the work of Vesto Slipher, who had investigated the spiral nebulae, before Hubble's Andromeda discovery. These bodies emit light which can be split into its component colors on ...

The first solid paper demonstrating cosmic expansion was published by Edwin Hubble in 1929, based on observations made by Vesto Slipher, Milton Humason, and Henrietta Leavitt. Because of this ...

The second key was the work of Vesto Slipher, who had investigated the spiral nebulae, before Hubble's Andromeda discovery. These bodies emit light which can be split into its component colors on ...