>>12038568If you're (which is short for you are, by the way, not a possessive) talking about a massively advanced spacefaring civilisation which has decided to visit earth, there is absolutely zero reason to doubt that they'd be sufficiently advanced to completely avoid any detection.
Even an advance of one hundred years gave us the concept of a nuclear reactor, a concept completely beyond the grasp of those who would have been alive prior. Their only perception of radioactivity would have been an invisible thing that kills people which they can't currently explain, because they haven't mastered the concept of the atom yet. You're now proposing that an alien civilisation would be incapable of avoiding our sensors. Completely ridiculous when you're talking about such an overwhelming gap in technology.
Secondly, suppose we do detect one. We detect UFOs all the time. There are tons of USAF and Navy reports on them by now. Those were quite easily kept secret by those agencies until they chose to reveal them. So that argument that it would leak instantly is a total failure, because we know for a fact that they do encounter anomalies like that and successfully keep them secret.
Supposing they even confirmed these UFOs were alien in origin and even got their hands on one. Would that leak? Even then it's uncertain because the potentially enormous amount of value that would be is certainly plausible motivation to keep it top secret while it's studied. And even if someone does leak, what happens then?
Someone just says "hey guys we were contacted by aliens" and then he gets dismissed as insane or lying. Easy.
