In this article I will try to introduce one of the more controversial and interesting to the general public questions in Astrobiology. This is the Fermi Paradox.
Enrico Fermi was a very prominent scientist of the 20th century. He was not very involved in the field of astrobiology (exobiology, as it was called back then), but still had an enormous impact on science in general and his opinion was widely acclaimed in the scientific circles, with very good reasons for that of course. He put into words a question that had been on the minds of many scientists who were involved in Astrobiology and in SETI in particular at that time.
Very well described in a good book that I recommend reading (Bennet, 2008) this question can be clarified only by spending some time on pondering on what we know of civilizations and their [putative] occurrence throughout the Cosmos. Of course, one might very well say that we cannot say much since, after all, we are the only civilization we know of, so we don’t have really too much material to work with in the first place. But still, try we must and try we will.
By using the Drake equation (which I have briefly explained in this post) and emerging data about some of the previously dubious variables in it, namely exoplanet and habitable exoplanet count, we can state that there must be around 100 000 intelligent civilizations currently in our Galaxy. The interesting bit is that statistically the youngest one of these should be the human civilization, and the next one after that should be 50 000 years older than us (remember this part, we will come to this later).
So there are at least three possible answers to this paradox:
- We are indeed alone. One of the key variables in the Drake equation defines life as a one-time event, a galactic stroke of fortune. As of now a good candidate for such a variable in the equation would be the ability of life to originate, since despite the numerous experiments done after those of Stanley Miller, we are no closer to discovering how life on Earth emerged than 50 years ago, and this despite all the advancements in science, especially those in molecular and cell biology.
- All civilizations that have developed technocratically have eventually destroyed themselves.
- There are many intelligent civilizations in the Cosmos, but we cannot detect them at present with our technology since they are vastly superior to us and we cannot even define them as living. Here ideas about the Galactic engineering concepts in Contact (my review on the book here) come to mind. If a civilization is 50 000 years older (and some could be much older than that, in the order of billions of years) than us, how would it look like? In the moment we can’t (and have failed before, in most of the science fiction books of the 20th century) predict the future even 50 years from now, let alone tens of thousands, or even billions… A civilization that is that much older (read advanced) than us might be able to be completely invisible to the primitive (comparatively) biology of the human senses, both physical and mental. They can be everywhere and we might not know. For all we know that part of the Cosmos which is visible by the Hubble Space Telescope might be just a tiny pebble on a beach of their world.
There are many implications of the Fermi paradox and it sure made many people think about the possibilities. The second answer is perhaps the most gloomy one. It reminds me of many of the things that the late Carl Sagan devoted his life to explaining to the public. Or ability to destroy not only our own civilization, but even life on Earth (although this would be also disputable, taking into account the ability of extremophilic organisms to thrive in such diverse niches in the biosphere, but still the development of intelligence might be rare, as I said beforehand, so we should not risk it).
We can indeed be alone, it is possible. In the mind of an informed scientist, highly unlikely, but still possible. But determining this might take forever. Literally. As Carl Sagan said, atheists and believers alike know far more than an agnostic. The proof of in-existence will mean searching the entire Cosmos in every possible way imaginable, and even then we won’t be sure of the credibility of our results. The absence of evidence is not evidence of absence.
It is simply inexcusable, taking in mind the military budget of the wealthy nations of the world, not to spend at least a respectable amount of that for SETI research. It is a cliche, but we are born to explore. The sky is no longer the limit.
1. Bennet, J. (2008). Beyond UFO’s. The Search for Extraterrestrial Life and its Astonishing Implications for Our Future. Princeton University Press, New Jersey, USA.
If you wish to read more on the matter, the best place to go will be SETI institute’s website. Don’t forget that they are a privately funded institution and your support can mean a lot. Any contribution you make can prove useful in of humanity’s most noble and age defining endeavors, that give purpose to our existence.
Also Carl Sagan’s Cosmos is indeed a masterpiece of science shared to the world. It is a must-see for any aspiring scientist. His other books, most notably the “Dragons of Eden” consider different topics, but still relevant to humanity in more than one way.