The Hubble Constant measures how fast the universe is expanding. Scientist estimates of the Hubble Constant have varied since its development in 1929 by astronomer, Edwin Hubble. Astrophysicists from Clemson University recently used state-of-the-art technologies and techniques to estimate the Hubble Constant to be 67.5 kilometers per second per megaparsec. A megaparsec equals 3.26 million light years.