On first glance, it seems as though the universe is so big there simply must be other life out there. And that may be the case. But is it possible that life is as common as portrayed in the scifis? Most likely, the answer is no. The truth is, if life were that common, it would be plainly visible. It doesn't take a huge knowledge of statistics to understand. If an extraterrestrial civilization had existed before us, they should have had something close to half the galaxy's lifetime to collonize it. Collonizing the galaxy seems like a monumental task, especially when you take into account that it is unlikely superluminal velocity is possible. However, in comparison to the age of the galaxy, its size is quite small. It's easy to forget that the galaxy has rotated several times (at much slower than lightspeed) since life got started on EARTH. It's rotated once since the dinosaurs. So if one extraterrestrial intelligence had existed before us, they had plenty of time to collonize the galaxy. And if they had done so, we would see something. Structure in the galaxy. Mined stars. Artifacts. Radio signals. Does this mean there is no extraterrestrial intelligence? No. But it does mean it is almost certainly rare. Unless by some freak of coincidence another intellligent race emmerged within a few million years of ours, we are the only intelligent race in our galaxy. If extraterrestrial intelligence exists, there are two options. They exist in distant galaxies, or they exist in the future. On a sidenote, it at least seems highly unlikely that only 1 intelligent race would ever form in our galaxy, considering how long it has left to live. A likely time for another one to pop up would be somewhere around twice the age of the present Milky Way's age, assuming intelligent races pop up on a regular basis. Any thoughts?