Question: What's the furthest galaxy we have discovered in the universe?

Sara Imari Walker answered on 17 Jun 2011:

Hi Rachel. The Hubble Ultra Deep Field is the deepest image of the universe ever taken. The light from the galaxies in the HUDF have taken 13 billion years to reach us. That’s right, that light from those galaxies has taken 13 billion years to get here!! (Typically we talk about time in cosmology rather than distance because of the cosmic expansion.) You should definitely google it and take a look at that image. It is one of the most amazing things you will every see – peering 13 billion years into the past! Interesting factoid for when you look at the HUDF – there are about 10,000 galaxies in the photo. To gauge how much of our night sky is covered – take a pencil and hold it at arms length. The tip of that pencil is about the size of the HUDF on our night sky. AMAZING!