It's been bugging me. We've looked 13.5 billion years into the past, supposedly only about 500 million years short of the big bang, at objects 46.5 billion light years away. What were the limiting factors? What stops us so close from the finish line from peeking into the very beginning? If it's limitations on the Hubble, couldn't we build another telescope with just a smidge more accuracy to get that glimpse? I mean.. it can't be because there was no light, I'd assume with all the heat generated at some point pre 13.5 billion light years there must have been a lot of photons being thrown about. Thanks! ------ Edit - This is what I found on Wiki, so shouldn't we be able to "theoretically" look back to +10 seconds given the best circumstances? Photon epoch Between 10 seconds and 380,000 years after the Big Bang Main article: Photon epoch After most leptons and anti-leptons are annihilated at the end of the lepton epoch the energy of the universe is dominated by photons. These photons are still interacting frequently with charged protons, electrons and (eventually) nuclei, and continue to do so for the next 380,000 years.