Likelihood of Extraterrestrial Intelligence

30.06.2021 |

Episode #9 of the course The evolution of life in the universe by Silvano P. Colombano Ph.D.


Thinking about the possibility of the existence of extraterrestrial intelligence (ETI) is more than just interesting speculation. It also sheds a light on what our own continuing path might be, and of course, it might allow for the possibility of some ETI-facilitated technology leap, whether or not that might cause a problematic cultural and social shock.


Planetary Systems Are Ubiquitous and Often Much Older Than Our Own

The facts are simple and clear: A recent NASA project, Kepler, was finally able to demonstrate what had been assumed by scientists, and that is that planetary systems like our own accompany most or all stars we can observe. In the majority of cases these also include planets in a zone where liquid water would be possible, and thus conditions that might allow the evolution of life as we saw on Earth. What is most interesting is that planetary systems as old as 10.4 billion years (Gyr) such as Kepler-1, and 11.2 Gyr (Kepler-444). Considering that the age of our solar system is about 4.5 Gyr, Earth-like planets could exist that are 6 Gyr, older than our own.

If we consider that technological development in our civilization started only about 10K years ago and has seen the rise of scientific methodologies only in the past 500 years, we can surmise that we might have a real problem in predicting technological evolution even for the next thousand years, let alone 6 Million times that amount!


The Existence of Extra-Planetary Civilizations

There is a staggering number of possible Earth-like systems in the universe. In addition, the chemical elements and laws of physics that were responsible for the origin of life are present and apply everywhere. These facts lead to the very reasonable assumption that extraterrestrial civilizations should be very common. An attempt to quantify this assumption took the form of the famous “Drake Equation”, presented in 1961 at the first meeting of a SETI (Search for Extraterrestrial Intelligence) gathering.


The Drake Equation 

The equation simply tries to estimate the number of possible civilizations in our galaxy that might be able, or even attempt, to communicate with us via some kind of radio beacon, or might be unwittingly emitting some technological “signature”. The resulting number is based on factors such as the rate of star formation, fraction of stars that have habitable planets, fraction of habitable planets that actually develop life, fraction of habitable planets where intelligence and civilization have evolved, fraction of civilization with detectable technologies, and other factors. We can make reasonable estimates for the astrophysical factors, but the ones that are biological and cultural in nature are extremely uncertain, so the final number remains very uncertain as well, but it has been estimated from “0” to 15,600,000 with “20” as the original estimate by Frank Drake.



There are several versions of the Drake equation, incorporating other factors, such as the likelihood that civilizations will be able to survive their own technologies (as opposed to collapsing in all-out wars!), but the original one in 1961 was specifically meant to estimate the number of civilizations that might send radio beacons or whose radio signals we might be able to recognize within the radio noise of space. The SETI group proposed embarking on a project for detecting such signals. The fundamental assumption they made was that interstellar travel would be practically impossible and only communication, with its ability to “travel” at the speed of light, would be a feasible way to establish the presence of interstellar civilizations.

This assumption is not unreasonable if one considers the staggering distances and energy requirements to accomplish interstellar travel. Just as an example, let’s take the NASA mission “Deep Space 1” that took place in 1998 with an “ion drive”, the most advanced engine we have. It took 20 months of thrusting to reach 35,000 mi/hr. The same spacecraft at that speed would take 81,000 years to cover the 4.24 light-year distance to the closest star, Proxima Centauri.

NASA took on the SETI project in 1992, only to see it canceled by congress a year later, but SETI has been able to survive as an independent institute and has been conducting its search for signals to this day, unfortunately with no positive results.


Where is Everybody?

The idea that there must be several civilizations out there has not gone unchallenged. One of the main arguments against it is known as the “Fermi Paradox”, after the famous physicist Enrico Fermi who has been quoted for blurting out in 1950 to other scientists “but where is everybody?”. The argument (brought up by many before Fermi), is that if older civilizations exist that became capable of interstellar travel, they would have had enough time to traverse the entire galaxy. So where are they? Why are we not seeing evidence…

Well, perhaps we have not been looking hard enough or smartly enough, or perhaps we have built psychological or cultural barriers to our very ability to see the evidence.


Are UFOs Real?

There have been reports of “Unidentified Flying Objects” for many years. Now the name “UAP” (Unidentified Aerial Phenomena) is often used, but the essence is the same. Many or most UAP are mistaken natural phenomena or technical glitches in recording equipment. Many are probably the result of hallucinations and mental health issues. Some are hoaxes. Because of all these possibilities serious scientists have been reluctant to associate themselves with studies of these phenomena. This is very unfortunate, but perhaps it’s beginning to change.

In 2019 at a SETI meeting where some NASA scientists had been invited, I presented a short position paper where I suggested that, while certainly worth pursuing, the SETI approach of simply searching for signals or possibly other distant civilization “signatures” was too limiting in its fundamental assumption that interstellar travel is impossible. I made the point that serious consideration of UAP evidence should be a part of their research portfolio. Even if an extremely small percentage of UAP might be candidates for evidence of ETI, the benefit to cost ratio would be much higher than that of other highly technological approaches (radio-telescopes etc.). My paper received a lot of attention in the media (you can google it), attention that was not deserved, as I didn’t say anything particularly new, but the fact that I was a “NASA scientist” seemed important. I am confident that UAP studies are finally becoming mainstream science, and we’ll soon be able to answer the question of whether “we are alone” or not.


Recommended book

Are We Alone? The Possibility of Extraterrestrial Civilizations by Robert T. Rood, and James S. Trefil


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