“If the universe would just sit still, then light from a galaxy 33.8 billion light-years away would take 33.8 billion years to reach us, and that would be that. But, in the early 1900s, Edwin Hubble found that distant galaxies appeared to be receding away from each other, and the further apart they were, the faster they were going. In other words, the universe isn’t static; it is expanding”