do aliens exist or not?

I think that aliens do exist but a lot of people don't believe that they do unless they are able to see them with there own eyes.

I believe that there are aliens out there and God knows what else. I saw a UFO many years ago. We (my family and I) were heading out to visit my grandparents when up in the sky hovering about a rock cliff was a UFO. The multicolored lights were flashing around it's circular form and it was just sitting there. We sat in the car and gazed from our windows and then all of a sudden it decided to take off so my dad stepped on it and tried to keep up but it was impossible. It sped away and then stopped and did a 90 degree turn and then continued off into the distance. It was so cool. I wish that I could see them more often. My dad has seen UFO's back in the 70's when he worked the graveyard shift and those incidents are all documented in a book that was published. I haven't seen the book in years though so I'm not sure what it was called. I wish there were more. Too bad there wasn't more insight on Area 51, that would be even cooler to check out as I'm sure there is lots going on in there.

Soemwhere out there, probably not at all what we imagine though. There is a possibilty of lichen, a type of moss, on mars, that could be considered alien.