Transcript: In the big bang model the universe does not necessarily have an edge in space, but it does have an edge in time. The age is measured to be about eleven or twelve billion years. There is a distance, therefore, beyond which light could not have reached us in the time since the big bang. This is called a cosmic horizon. We can’t see beyond it. The observable universe grows slightly everyday as light from more and more distant regions reaches us for the first time. Early in the cosmic expansion, the expansion rate was actually faster than the speed of light, so there are points in space that early on were moving away faster than the speed of light from each other but have since slowed down and could communicate with light signals. We know therefore in the big bang model that the physical universe, all that there is, is larger than the observable universe, all that we can see.