It'll be something that is either profoundly disappointing and soul crushing, such as a realization that the level of violence, blood lust, and overall stupidity is truly a part of them, or something profoundly groundbreaking, such as testing other dimensions of reality, black matter, or other things that we are just learning about, or things we don't even know of. Maybe those fading lights off in the distant universe are just the aliens, god, or whatever/whoever, pulling the plug on our expirement?