Edwin Hubble

The man who best exploited the power of the Mount Wilson telescopes was Edwin Hubble, whose first great discovery was to show in 1923 that the faint smudges that populated the heavens were in fact remote galaxies, each one consisting of billions of stars. Mount Wilson became famous and Hubble became a celebrity.

Tourists began to trek up to the mountaintop; the Hollywood glitterati would spend nights gazing at the sky and Hubble became a much sought after guest on the Los Angeles party circuit.

In 1929, Hubble made an even greater discovery while working with his assistant Milton Humason, who had been promoted from mule driver to the most accomplished astronomical photographer in the world. They showed that the red shift of the light from galaxies was greater if the galaxy was fainter (further away). Assuming that the red shift was due to a Doppler effect the speeds of recession were consistent with what would be expected if the Universe had started in the one place with a "Big Bang".