The Alpha Road

The Science of Life

Tag: SETI

The Fermi Paradox

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.

Why have we not yet come into contact with intelligent alien civilizations when there are billions and billions of stars [and possibly worlds] in the Universe?

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.

Reference: 

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.

Further Reading:

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.

 www.seti.org

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.

Carl Sagan – Contact (book review)

I still remember watching the film when I was a kid. I am not sure that I completely grasped the ideas behind the script at the time, but I was definitely captivated by the magical story of the first contact with an extraterrestrial civilization. It is often not so interesting to read a book after one has watched a movie based on it, but Sagan’s “Contact” is definitely an exception. Being in the field of astrobiology, there is a lot about SETI that I read every day, thus I had plenty of material to satisfy my thirst for knowledge and I was not sure whether I would really need to read that book. I already saw the movie and knew the ending. Nevertheless, being an avid follower of Carl Sagan’s legacy I decided that it is high time that I read it, hoping that it will surprise me with something. And it sure did.

I was expecting the eloquence of Sagan’s words. Many people marvel at his ability to speak in such free-flowing, comprehensive and easily accessible to everyone manner. He used this in all of his works (mainly in the Cosmos series) in order to reach for the masses, where inspiration is always welcome. A scientist with such charisma and ability to effectively communicate ideas across to his/her audience is a rare breed indeed (a similar topic is discussed in a great blog about astrobiology, link here). The first few chapters I remembered well from the movie, but I was still captured with the story straightaway. There were too many details in the script that reminded me of my own childhood and my own sources of inspiration (which I guess are very common among scientists, astrobiologists especially). Since I do not want to spoil it for you I am not going into the details of the script, but will describe the two things that in my opinion are central in “Contact”: The Message and The Artist’s Signature. In short, mankind received a radio-transmitted message with its SETI facilities in the US. The transmission was from a distant star called Vega. Since our planet is rotating, the message was received by many radio astronomers all across the globe. Thus global cooperation was required in order to get it in full. Then the message was decoded and it turned out that it is the blueprint for a mysterious Machine. Humanity unites in building it, thus effectively ending global conflicts. This is perhaps the main idea of the book, which I was unable to see back in the day. One needs to put this work in the context of the time when it was written and combine it with the ideas of Sagan himself. It was an era where nuclear apocalypse was still a very probable event. If there wasn’t anything to unite the rival superpowers, it would just be a question of time before another world war starts, and after it the next one would probably be fought with stones and arrows. In “Contact”, Sagan presents how a scientific discovery of this magnitude can unite humanity, thus showing the utmost importance of both SETI and scientific research in general for humanity’s progress. Read the rest of this entry »

The Drake Equation.

One of the fundamental topics in Astrobiology is the study of the distribution of Life in the Universe. The very existence of Life elsewhere is putative – we are, of course, yet to find any solid proof for that. Nevertheless with the power of mathematics, and with our ever-increasing knowledge of the world around us we are able to estimate the probability of the existence of an extraterrestrial civilization with which we would be able to communicate.

Frank Drake’s equation is a wonderful product of thought and is one of the fundamentals of SETI (Search for Extraterrestrial Intelligence). The following is an excerpt from the article on their own website (http://www.seti.org/page.aspx?pid=336)

The equation is usually written:

N = R* • fp • ne • fl • fi • fc • L

Where

N = The number of civilizations in The Milky Way Galaxy whose electromagnetic emissions are detectable.

R* =The rate of formation of stars suitable for the development of intelligent life.

fp = The fraction of those stars with planetary systems.

ne = The number of planets, per solar system, with an environment suitable for life.

fl = The fraction of suitable planets on which life actually appears.

fi = The fraction of life bearing planets on which intelligent life emerges.

fc = The fraction of civilizations that develop a technology that releases detectable signs of their existence into space.

L = The length of time such civilizations release detectable signals into space.

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