From an astronomical point of view the existence of other intelligent life in the universe is a virtual certainty. The more important question is whether the technology exists or ever will exist that will allow life to bridge the incredible distances between stars. What if however our current understanding of the fabric of the universe is not complete and it is indeed possible to travel through "worm-holes" to distant parts unreachable otherwise. Perhaps we even need to think beyond the standard 4 dimensions of space-time that we are so familiar with in our everyday existence. Perhaps our essence, or soul, can indeed exist without its physical shell and travel just like any other form of energy at the speed of light.
All that being said, there are certain pieces of evidence from history and from my personal experience that lead me to believe that the souls of human beings are alien in origin, and are in continual contact with their home base of operations. I believe the dawn of civilization on earth was triggered when an alien race found our human bodies to be a suitable host for them to experience physical reality. In that sense our sole purpose in life is to try to maximize whatever potential we are born with to help our species evolve. Every night when we experience REM sleep we are transmitting our latest experiences back to the home base for analysis. Depending on the resources dedicated to each individual, suggestions for how to optimize one's existence are relayed back to the individual in the form of intuitions to be used in the days ahead.
The problem with this hypothesis is that it is very difficult to prove, but once you develop a trust in your intuition the results can be documented. Of course it is impossible to see the outcome of two decisions, but after time passes the action stemming from intuition has almost always to preferable outcome.
Since I am a scientist even I get quite skeptical reading over these statements, however I believe we will eventually be able to prove the hypothesis scientifically by monitoring energy fluctuations before and after the time of death, and also monitoring the sleeping. One form of energy that is incredibly abundant in the universe, yet goes virtually undetected by human instruments, is that of neutrinos. Electrically neutral, and nearly massless, these particles travel near the speed of light and can pass through virtually all material. Despite the fact that our own Sun emits billions of neutrinos everyday, we on earth are only able to detect a handful every year. Perhaps the parts of our brains that are supposedly not being used are adept at receiving and transmitting information by manipulating neutrinos. The prime example from everyday life would be the feeling one gets when one is being stared at. How do we really know that somebody is looking at us? Before we understood the principles of optics, philosophers hypothesized that our eyes emitted something and we saw by reabsorbing the reflected particles, similar to the way some animals use echolocation. Perhaps when we focus our attention on someone we really are directing part of our energy field towards the person, which interacts with their field, and is thereby felt.
In any case this hypothesis will have to wait a few more decades to be proven, because our current neutrino detection capability is almost nonexistent. Nevertheless, with a little faith, and trust in one's intuition it is possible to live a synchronistic life that in its most pure form can turn into a heaven on earth experience. Literally all your dreams come true, you just have to follow the directions, work hard and base your decisions on love and compassion.