Part of Scales of the Universe.
Our observable universe extends more than 10^26 meters in every direction. While the entire universe may be boundless, the part we can observe does have an edge. Our cosmic horizon is at the distance from which light must travel for the entire age of the universe to reach our location in space. Light from beyond this horizon has not yet had enough time to reach us, even if it started its journey when the universe began. In our 13 billion-year-old universe, the cosmic horizon is 13 billion light-years away.