Hey! I randomly came accross your question on AronRa's page about aliens and decided to randomly give you my personal opinion about it since its something I think a lot about sometime =p

It is very unlikely that aliens or extra-terrestrial visited earth like many people claimed they did. Also, we can tell that the probability of life forming on a planet is very slim since we have been looking for other life-forms for years and were not able to find any yet. However, our universe is the host of billions of billions of galaxy which too hold billions and billions of solar system which hosts billions and billions of planets.

Based on these numbers, it is not unreasonable to assume that there are very likely many planets hosting life, maybe even intelligent life as well. Are they within our reach? Will we be ever able to interact with them? that we will only know once we find one of these planets.