How Much Of The Unobservable Universe Will We Someday Be Able To See?
As more time passes since the Big Bang, more of the Universe comes into view. But how much?
Even though it’s been billions of years since the Big Bang, there’s a cosmic limit to how far we can observe the objects that occupy our Universe. The Universe has been expanding all this time, but that expansion rate is both finite and well-measured. If we were to calculate how far a photon emitted at the instant the Big Bang occurred could have traveled by today, we come up with the upper limit to how far we can see in any direction: 46 billion light-years.
That’s the size of our observable Universe, which contains an estimated two trillion galaxies in various stages of evolutionary development. But beyond that, there ought to be much more Universe beyond the limits of what we can presently see: the unobservable Universe. Thanks to our best measurements of the part we can see, we’re finally figuring out what lies beyond, and how much of it we’ll someday be able to perceive and explore.