Perhaps asking if we are alone in the universe is the wrong question. Maybe the right question is, were we always alone in the universe? Most of us know that the universe is vast, but so is the span of time. So not only do we hope that we can find co-existing life somewhere in our universe, but we also hope to find it at the very moment that we happen to be looking for it. So the question is no longer, What are the odds of finding life? but it’s also What are the odds of finding life at this single point in time, across the billions of years that the Universe has existed?
Suddenly, the vastness of space isn’t the only factor in the equation. We now must factor in time, whether or not civilizations could have come and gone long before humans ever existed. Maybe some alien civilization, many years ago had already examined Earth for signs of life, and maybe the results were negative because quite frankly, life didn’t exist at that time. To turn the tables, we may study that very same world that studied us for life, only to find that there is no life on that world…at this time, even though life existed there in the past and they even examined Earth for signs of life at one point in history. Each of our species was looking in the right place at the wrong time.
Artists impression of a world outside our solar system.
Mars is a good example, as life could have existed there at one time even if it doesn’t now. Though it is unlikely to contain any intelligent life at the moment, it may have in the past. We have already found evidence of water in the form on vast oceans that existed previously, but even if we find evidence of life in the past there for certain, it may not improve the chances that we may visit or be visited be ET within the time frame of our existence.
What Mars may have looked like in the past.
The odds of probability tell us that it is in fact likely that life has existed elsewhere in the universe. This is supported by the amount of exo-planets that we seem to be discovering at a steady rate each year. It is also supported by the fact that with of stars out there circled with planets, life has had to exist on at least a handful of them at some point in time. The odds of finding life within reach, living concurrently with our own species however, may seem less likely. Compared to how long the universe has been here, the existence of humans and even Earth for that matter, is barely noticeable on the time-line. Not to mention that it wasn’t until recent years that humans have gained the ability to even search for extraterrestrial life outside of the solar system.
There is also the belief that throughout time, many intelligent species have came to be but are only able to evolve to a certain point before they become extinct. Even if a type of long range but short term method of communication or transportation is even possible, few if any extraterrestrials may not be able to evolve to the point of making this discovery. This may be why SETI has yet to confirm any radio signals from such a civilization. It also brings into the realm of possibility that even if they have been able to invent such a method to communicate, it may be in the form of something totally different than any thing we could possibility identify. Therefore, we would not be able to decode such messages with no understanding of how the medium works in which they are being transmitted.
Timeline of the Universe.
Then again, there are an awful lot of stars out there. In fact, there could be thousands of aliens that are co-existing with us at this very moment, with the only limitation being the vastness of space between us, which prevents communication with one another. They could also be up there right now, watching an waiting for us to prove our readiness to join a vast interstellar community.
The truth of the matter, for now anyway, is that we just don’t know. Keep in mind though that we just started looking, so anything is possible.