All conspiracy theories aside, there's now a NASA scientific paper that suggests that aliens might have already visited Earth -- without us knowing, because we are looking for all the wrong signs of alien life.
This questions the very fundamental nature of what we claim to know about life in the universe.
In a detailed research paper, a computer scientist at NASA Ames Research Centre, Professor Silvano P Colombano has suggested that aliens may vastly differ than what humans expect them to be.
For example, Prof Colombano suggests that alien life may not be carbon-based, which would allow them to remain undetected by humans so far -- even on our very own earth.
Writing in his scientific paper from March 2018 which just became public, NASA researcher Colombano says "I simply want to point out the fact that the intelligence we might find and that might choose to find us (if it hasn’t already) might not be at all produced by carbon-based organisms like us."
For this super intelligence alien life form, interstellar travel will just be a hop, skip and jump. If you stretch that thought, it could very well mean that non-carbon based aliens might be here on Earth right now.
But how will you find it? How will you identify it? No one knows what a non-carbon life form looks like, so here we go again doing more guess work.