Knowledge about aliens might be as dangerous as the aliens themselves.
Imagine that you’ve lived your entire life in a small village deep within a continental wilderness. For centuries this community has been isolated from the rest of the world. One day you go out exploring, skirting the edges of known territory. Suddenly, and against all expectations, you stumble across a signpost embedded in the ground. The script is highly unusual, foreign, but the text is clear enough. It says, simply, “We Are Here.”
The question is: What happens next?
There might be happiness and celebration to mark the end of isolation, or the news might be met with a shrug. But human nature suggests it’s more probable that this discovery triggers a chain of events that lead to utter disaster.
Suddenly your safe haven is threatened by an unknown “them.” Your time-tested principles of governance and social order are put under pressure. Gossip, rumor, and conjecture will gnaw away at your stable home. Barricades and armed forces will be raised at enormous cost, crops and repairs will be forgotten. A community will lurch toward its own collapse. Yet there is little more than a half-realized idea represented by this impersonal signpost, a whispered implication that infects the world with its ambiguity.
This tale is not the opening sequence of a B-grade movie, but an allegorical version of what might, just possibly, happen after we solve one of the oldest scientific and philosophical puzzles—whether or not we have neighbors “out there” in the wilderness of the cosmos.
For the rest of the story: http://nautil.us/issue/17/big-bangs/can-you-ever-really-know-an-extraterrestrial