In addition to the insightful answers already provided, we know that the first or proto-stars were born shortly after the Big Bang, approximately 14 billions (ba) of years ago. We are only able to see, either visually or with telescopes that detect electromagnetic waves of different kinds (microwave), so far at least, galaxies of stars formed about 13 billion years ago. The Hubble Deep Field (HDF), using the Hubble space based telescope has detected a galaxy nearly 13.7 billion years old. So, there are theorized galaxies that are older of which the light has simply not reached Earth (or, more correctly, our telescopes) yet. (Some astrohysicists estimate the age of the Universe at near 20 billion years)...