The Edge of Everything Seen

Point a powerful enough telescope at the dark between stars, hold it there, and the emptiness fills with galaxies — thousands of them, in a scrap of sky you could hide behind a grain of sand held at arm's length. And because their light has travelled so far, you see them not as they are but as they were, billions of years ago: young galaxies, still forming, caught in the act of being born.

To look far into space is to look far back into time. The deepest images we have are baby photos of the universe. Push to the very limit and you approach the first galaxies ever to light up, emerging out of the darkness after the Big Bang.

But the looking has an edge. Light from beyond a certain distance has not had time, in the whole age of the universe, to reach us yet — and because space itself is stretching, some of it never will.

And if there is more universe than we can ever see — how much is lost beyond the edge forever?