Sep 26 2011 56 mins 7
Before we get all the way back to the Big Bang, there may have been a time when stars like our Sun and galaxies like our Milky Way did not exist, because the Universe was denser than it is now. Harvard professor Abraham (Avi) Loeb explores how and when the first stars and galaxies formed. Series: "Scientific Horizons" [Science] [Show ID: 22628]
