
If you could travel in a spaceship as fast as you wanted, could you ever reach the edge of the universe? The answer is "no". According to Bryson, "space curves, in a way that allows it to be boundless but finite. "
He then continues to explain using an analogy: Assume there is a man in this world that has never seen a round object in his life, and therefore also doesn't know that the world is round. If you had him walk in one direction forever, we all know that he would eventually return to the exact spot he started. Chances are he would be absolutely astonished -- he wouldn't get it at all.
I guess that is what it is like when it comes to space. If you

We've never seen any physical thing like it, and the average person surely doesn't study such theories, so we just simply don't understand.