The visible universe is approximately 40 billion light years across. This means the furthest starlight we can see from earth is about twenty billion light years away from us in whichever direction the star is. This also means—since a light year is the distance light travels in the span of a year—that the light from the furthest stars is extremely old, possibly from close to the beginning of the universe.
The idea of a horizon immediately begs the question: what is beyond the veil? What is it that is being hidden from sight? Were we to travel twenty billion light years to the edge of the universe would we be able to see stars that were invisible from earth? The question of what is beyond the universe is abstract and to a large degree unanswerable, partly because if the universe is infinite, the question poses a contradiction. Since the universe is all of existence, if there were anything outside of it, that would be part of the universe, too. From this angle, the question falls to pieces as nonsense—it seems silly to ask, “What exists that doesn’t exist?â€
So is the universe all there is? Some physicists want to talk about parallel universes and multiverses where our universe would be merely one bubble in a possibly infinite ocean of bubbles. Do you think science will ever be able to tell us for certain if the universe is infinite?
