Throughout history, theories have come and gone. One of the most popular and scientifically accepted is the Big Bang theory. Knowing that the universe is constantly expanding, Lemaitre proposed the idea that, at some point in time, the entire universe was conceived at a single point. From this point the universe expanded and stretched to the magnitudes we know. It was not until years later that the astronomer Edwin Hubble was inspired by the priest's idea. He discovered, moreover, that there are galaxies moving away from us, and that the farther away these galaxies are the faster they move.