Read the classics Seventy five years ago astronomers knew only of the Milky Way. To them our galaxy was the universe. Edwin Hubble in a paper entitled "A relation Between Distance and Radial Velocity Among Extra-Galactic Nebulae" published in January 1929 changed all this and in the process gave birth to the entire branch of astronomy known as cosmology. His famous paper proved with observational evidence that galaxies are moving away from us with a speed proportional to their distance and expanded our knowledge of the universe from one galaxy to billions of galaxies.