In general relativity, an event horizon is a boundary in spacetime beyond which events cannot affect an outside observer. In layman's terms, it is defined as "the point of no return", i.e., the point at which the gravitational pull becomes so great as to make escape impossible. An event horizon is most commonly associated with black holes. Light emitted from beyond the event horizon can never reach the outside observer. Likewise, any object approaching the horizon from the observer's side appears to slow down and never quite pass through the horizon.

All there matters in this situation is information. If we had enough of it we could reconstruct various episodes that happened throughout the history of the universe itself. Since all the information we could get from an event horizon is all mixed up and blurry, the only pictures we could get would be overlapping, and since we can only see certain frequencies of the spectrum of light it makes it more difficult to tell fition from reality. Our eyes decieve us so what we see in a precise moment could be everything else we never thought of.

Immagine staring at a landscape and suddenly see the presence of someone above you, you would assume right away it's a hallucination, but what if it is not?