Milton Humason, a high-school dropout who worked as a mule driver and then a janitor at the Mount Wilson Observatory in California, worked his way up to become the assistant of Edwin Hubble, whom he helped to study the spectral redshift of hundreds of galaxies.
Scientists have found that dark energy, the force thought to be accelerating the expansion of the universe, may be doing the same thing to local groups of galaxies. That bolsters Einstein's idea of a 'cosmological constant.'
New Hubble telescope images provide a look at the cosmos when it was just 600 to 800 million years old. Galaxies from this period might have helped transform the universe from dark to light.