See I find it interesting that so many dismiss the potential of life in our galaxy let alone the universe. Even if there where 50 billion potentially inhabitable planets the distances between many means that until enough time has passed for any species to become extremely advanced we'd never find them. Many argue about radio waves why aren't we detecting any? Well there are 2 reasons 1) any species advanced enough to leave their home planet and wander the galaxy wouldn't use a method that's so slow while radio waves travel at near light speed that's pretty much useless to speak to your home planet or even send out a burst to show 'we are here' the signal just takes to long to travel from point A to point B. 2) radio waves despite continuing on for a good distance the actually fade out at around 1AU's distance that and they are distorted by solid objects or clusters of smaller ones. Also we always assume that evolutions end game is for the creation of 'intelligent' life there's no basis for this in the entirety of earths history there's only one species in hundreds of millions of years that evolved from a suitable species to allow it to manipulate the environment (us just incase anyone wondered...) so out of all that time and all the other species that have had far longer to evolve and become dominate yet we are the only ones to do so shows that evolution and perhaps life itself cares very little for intelligent life. The most adaptable life form is the one that survives and thrives after all.