Our Universe 2: Redshift, Expansion & Dark Energy

This book continues our exploration of cosmology, the science of the universe as a whole.

One of the most profound questions in cosmology is: Has our universe existed forever, or did it have a beginning? Philosophers, theologians, and scientists have argued both sides of this debate, for millennia. The first observational evidence came in 1929 when American astronomer Edwin Hubble announced his discovery that the universe was expanding, and therefore had a beginning. This was one of the m…