Actually, there is a TON of evidence than aliens have been here and perhaps still are.
- I personally witnessed craft in the 1960s which violated every physical law known to man. Either the USA has secret technology from the 27th century it is sitting on, or it was taken from aliens. Either way, such technology exists because I've seen it.
- A close friend I knew for 35 years told me on his death bed that he had been abducted by aliens in his youth, and he was the most grounded person I've ever known in my life.
- I have background in astronomy (I've even taught it), and if you knew the odds of us being totally alone, it is a literal impossibility.
The real problem is time. Our civilization has only had radio for 1 century. For all we know, there are far better ways for advanced civilizations to communicate. After all, radio was discovered by people using 19th century technology with vacuum tubes and carbon pads. If people centuries ahead of us technologically don't have anything better, I'd be shocked.
We have been probing space for signals for about 40 years. That is about 0.000000355% of the age of the universe or about 1/2,500,000th the time that the universe has been around, and our radio signals have only traveled out about 100 light years by now, our own backyard, astronomically speaking.
That makes it highly likely that we have not even begun to look at a tiny fraction of the universe in a minuscule period of time it has existed, or that they are already here but realize we are far too backward and primitive yet to risk revealing their presence to us on any grand scale.
Then again, maybe the easiest way to conquer someone is to do it clandestinely and quietly before they even realize it.
Not saying we are alone in the entire universe, because we don't know the extent of it.
But we are alone in our sector.
And I deal strictly in logic and cold facts.
My 6th grade history teacher was an ex-military Colonel I think, they wanted to make him big name General, but he said no.
He told us he was tired of the lies, backstabbing, and of the goverment and military using the average American as a guineapig.
During the week, we would read history from our history books, then he would tell us what REALLY happened. Blew our minds away.
The one thing we came away with from that class, was learning his motto...........history is not what happened, it is what was written by the winners, who want you to believe they won for being "good" people.
On Fridays, we got to ask him questions about anything, and he promised to tell us the absolute truth about it.
Someone asked about UFO's, since it was the 70's and the UFO craze was beginning to take off in all directions.
He told us that the government is AT LEAST 100 years past any current technology being used that the public may know about.
He said that ALL governments around the world hold on very tightly to future tech they design and build, as they want to be in full control of how socieities on this planet evolve. Governments want to be IN CONTROL, PERIOD. And the best way to control the masses, is with technology.
Big Foot, aliens, etc.........all government created conspiracies and ghost stories to keep the sheeples fascinated and at each others throats, squabbling on "is there or isn't there", while government secretly trogs ahead with more future tech to be released when the government feels sufficient enough it will effect the masses they way THEY WANT IT TO.
What ever you may see in the sky that cannot remotely be defined by nature or science, is more than likely the government testing out new tech, new theories, or new ways of covering up what they are doing.
And realizing this, along with using logic in everything in my life, has resulted in me being able to decypher most of what I've seen, heard, or witnessed myself. And none of it has been extraterrestrial in nature.