I'm with RC here, I mean the universe is so huge and beyond our capacity to imagine or discover it's entire length.We would've discovered and researched bearly 1% of what's present in this Universe.The basic ingrediants for life is Energy,Matter and Space,everything we know about is a combination or a permutation of these three combinations.Alternatively, it's a very naive concept to believe that we are the only living creatures in this Universe.I mean come on it's like an ant claiming that the earth is flat.All it see's is what is in it's immediate surroundings,it doesn't know that there are organisms smaller than it neither does it realize the existence of the sun,stars or the meteorites.