The universe could be infinitely large. And even if it isn’t, it’s probably so big it might as well be infinite. But we see only a tiny fraction of that expanse: a bubble known as the observable universe.
What we see is limited by the speed of light: 670 million miles per hour. This is fast. But it is not infinite. So light can only travel so far in a year, or a century, or a billion years. Since the universe was born 13.8 billion years ago, we cannot see further than light can travel in that time: 13.8 billion light years. The most distant galaxies and quasars we’ve seen are almost that far away.
Or were they that far. We see these objects as they looked more than 13 billion light years away. But keep in mind that the universe is expanding. So today there is much more space between us and the first objects. In fact, today the edge of the observable universe is about 46 billion light years away.
Assuming Earth was still around, tens of billions of years from now, we’ll see what these objects look like today. And the limits of the observable universe could reach about 60 billion light years. But the universe is expanding so rapidly that we would never be able to see further, limiting ourselves to a bubble of space and time within a possibly infinite universe.
Tomorrow we will have more information about the observable universe.
Screenplay by Damond Benningfield