Light horizon

Light horizon is the furthest distance one can see light until there is nothing left to see. While observing a celestial body in space, light can only show what an object used to look like so many years ago. In the Light horizon, however, objects that are furthest away may not exist anymore or may be in a completely different state. The concept of the light horizon relates to the Observable universe. In the Observable universe, there are only objects that are visible to the viewer and everything past the light horizon is unknown to the viewer.