There are roughly 70 sextillion stars in the visible universe. This number is a little hard to fathom as is the understanding that the universe is 13.7 billion years old. Yet these two facts lead to an important question. With a universe so old and so vast why don’t we see evidence of alien life?
Consider a species like ours that is only 5 million years ahead of our own. Not a long time on the cosmic scale, but assuming that this species didn’t die out, even if they were unable to find a way around the speed of light they should have left signs behind. In five million years probes, signals and more should have been littered across the galaxy and it seems likely that we would have discovered some of them and it shouldn’t be a single species. With 70,000,000,000,000,000,000,000 stars it seems likely that there would be multiple civilizations, so where are they.
This is the heart of the Fermi Paradox and once that scientists have been trying to answer ever since. Even at the slow rate of sub light speeds it should only take about 5 million years to colonize the entire galaxy.
One of the most important attempts to understand where aliens are in the universe is the Drake Equation which allows for variables that include star formation, planet formation, life bearing planets, life bearing planets that bear intelligence and finally and perhaps most important the length of time that intelligent civilizations can exist.
It is this last question that make the Fermi paradox so scary. Is it possible that the reason that the galaxy hasn’t been colonized and we haven’t been contacted by beings from other worlds is that the advances in technology or some other disaster continually befalls these creatures. That through some type of cosmic joke every time a civilization reaches the point where they are able to reach out into the galaxy the very power that allows them to do so allows them to destroy themselves leaving the galaxy a barren land.
If this is true then the Fermi paradox is part of the great question are we alone? Is this universe a cold and dead place, or are there others like us on some distant world waiting for us to grow up enough to become part of a galactic community?
The universe is bigger and older than anything humans can imagine. Yet, after decades of searching we have yet to find a single conclusive piece of evidence that there is intelligent life anywhere in it and while we hold out hope that we simply haven’t looked in the right place or in the right way it becomes difficult each day to simply explain away the lack of evidence as nothing.
