http://arstechnica.com/science/2014/0
6/why-havent-we-encountered-aliens-yet-the-answer-could-be-climate-change/
Seems to me the odds are alot higher that we have always been visited by advanced non human and advanced human intellegences.... The hatchet cover up worked so well cause humans only care about how there team are doing or whats going on in there favorite soap...sad to say but accurate....