@Taurisk , @whereu , There is much we don't know. Each to his/her own about invisible presences. We're dealing with both known and unknown unknowns here. I agree that there is much that we don't know and/or understand. which is the reason that we have so much debate.
As far as extraterrestrials visiting Earth is concerned, I'm of the opinion that this is an extraordinary claim which requires extraordinary evidence. In spite of the many claims and wide availability of technology, we are pretty much short of good quality images and DNA or equivalent testing.
It is possible that we are or have been visited by extraterrestrials but being a person who is fascinated by the unusual while being a septic I'm disappointed by what to me is a low low level of evidence for extraterrestrial visits.
