martes, 23 de junio de 2020

A Solution to the Fermi Paradox - Beatriz Gato Rivera

12.1
A Solution to the Fermi Paradox: the Subanthropic Principle and the Undetectability Conjecture.
Encyclopaedia Galactica.


(Sound effects and audio editing: Bert Schellekens)






The Fermi Paradox.

In the summer of 1950, at Los Alamos, nuclear physicists Enrico Fermi, Edward Teller and other colleagues brought up the subject of unidentified flying objects (UFO’s) while conversing over lunch. This topic was very popular at that time. After a while, when they had changed subjects Fermi suddenly asked: Where is everybody? Performing fast mental computations, Fermi had reached the conclusion that alien civilizations should have been visiting Earth for many thousands or millions of years. Therefore, why we do not see aliens around? This is the Fermi Paradox.

As it turns out, in our galaxy there are thousands of millions of stars much older than the Sun, many of them thousands of millions of years older (in the ‘habitable zone’ of the galaxy they are on average one thousand million years older). Therefore, many civilizations must have arisen in our galaxy much before ours and a fraction of them must have expanded through vast regions or even through the whole galaxy.

Some other arguments pointing in the same direction include estimates about the lifetime of the second generation stars, inside of which the chemical elements of organic matter are made, and also include estimates of the total time necessary for a technological civilization to colonize, or explore, the whole galaxy. Regarding the second generation stars, they are formed only two million years after the supermassive first generation stars (these burn out exploding as supernovae in one million years only and it takes another million years for the debris to form new stars). Therefore, the appearance of organic matter in our galaxy could have happened several thousands of millions of years before the Sun came into existence. As to the total time necessary to colonize, or explore, the whole galaxy by a technological civilization, conservative computations of diffusion modeling give estimates from 5 to 50 million years, which is a cosmologically short timescale. Besides these considerations, the fact that life on Earth started very early supports the views, held by many scientists, that life should be abundant in the Universe.

Many solutions have been proposed to the Fermi Paradox, that we can classify as expansionist and non-expansionist. The expansionist solutions are based on the assumption that, generically, technological civilizations do expand through large regions of their galaxy. The non-expansionist solutions, by contrast, are based on the assumption that technological civilizations do not expand beyond a small neighborhood of their galaxy. Among these solutions, the most popular ones argue that interstellar travel is impossible, regardless of the scientific and technological level reached by a civilization, or that advanced civilizations have no interest in expanding across large regions of their galaxy, or even that technological civilizations annihilate themselves, or disappear due to natural disasters, before they can spread throughout their galaxy.

In turn, the most popular expansionist solutions to the Fermi Paradox present two irreconcilable positions. On the one hand, there are those who advocate that it is highly unlikely that intelligent life will emerge in the Universe and that we are practically alone in our Galaxy. Otherwise, some alien civilizations would necessarily have visited us. At the antipodes of the former, on the other hand, are those who maintain that advanced civilizations abound in the Universe, that they visit the Earth in the present, for different reasons, and have also visited it in the past. In this regard, it should be noted that some scientists and some members of the military and pilots, of various countries, as well as many authors of popular books, have been proposing for decades that some UFOs could be extraterrestrial space craft, and some of the 'gods of the heavens', which proliferate in many ancient traditions, may have been alien astronauts. There are several reasons why such civilizations would not openly contact ours. For example, advanced civilizations might have ethical codes that prevent them from interfering with primitive civilizations, as suggested by Carl Sagan in his work COSMOS. And it could also happen that we are ignored for lack of interest, due to our very primitive level, among other possibilities.


The Subanthropic Principle and the Undetectability Conjecture.

In the summer of 2003, I made a proposal to solve the Fermi Paradox [1,2], after a simple reflection on the relations between the different civilizations put into contact in the process of expansion. Here it is crucial to differentiate between aggressive and non-aggressive advanced civilizations. Aggressive advanced civilizations would exploit and harm less advanced ones as much as it would be convenient for them, and even annihilate them in order to take over their planet. The non-aggressive advanced civilizations, on the other hand, would try to integrate the less advanced ones, pulling them to their own level, as long as the evolutionary leap between the two were not too pronounced.

In some cases, however, such advanced civilizations would find planets inhabited by primitive civilizations with an enormous gap (technological, scientific and genetic) between them. In particular, as far as brain capabilities are concerned, the differences between advanced individuals and primitive individuals could be pathetic. In these circumstances, what would be expected is that the advanced individuals would behave in an 'ecological' way towards the primitive ones, interfering as little as possible and very discreetly with their social and cultural evolution, taking into account that the open contact would destroy that civilization. With this perception it becomes less difficult to accept the possibility that the Solar System could have been explored or colonized many thousands, or even millions, of years ago by at least one non-aggressive advanced civilization that had treated, and may still treat, our planet as a nature reserve and us as a protected species.

My solution to the Fermi Paradox results from this scenario and consists of two hypotheses. The first one is The Subanthropic Principle: We are not typical among intelligent observers of the Universe. Typical civilizations in typical galaxies would be hundreds of thousands, or millions, of years more evolved than our Earth civilization.

The second hypothesis is The Undetectability Conjecture: All sufficiently advanced civilizations camouflage their planets for security reasons, due to the existence of aggressive advanced civilizations, so that no sign of civilization (or life) can be detected by external observers, who would only obtain distorted data for the purpose of deterrence. This hypothesis would explain why we would not detect any signal of intelligence coming from outer space, even if the Solar System were part of an extensive hypercivilization.

In addition, this solution implies that: At present, most probably, all typical galaxies in the Universe are already colonized (or large regions of them) by advanced civilizations. In the vast territory of these hypercivilizations, a small proportion of their individuals belong to primitive subcivilizations

Advanced civilizations would have subterranean and submarine bases on the primitive planets in their territory, for military and scientific reasons. Actually, the fact that our civilization has never been attacked by aggressive aliens, as far as we know, could be an indication that we are immersed in an advanced civilization that protects our planet as part of its territory. Curiously, in one of the videos of Stephen Hawking's Universe, the author comments: "Several of my colleagues think that we may be visited by aliens aboard some UFOs. I don't believe it because if aliens arrived here the interaction with us would be much more unpleasant, ....”. Therefore, Hawking did not contemplate the possibility of benevolent extraterrestrial civilizations, which would not attack us and might even prevent other extraterrestrial civilizations from doing so.

The Undetectability Conjecture predicts a very low probability of success for the SETI project searching for extraterrestrial intelligence. The reason is that their antennas could only detect primitive civilizations capable of producing electromagnetic emissions. But after reaching that level, any civilization would take only a few hundred years to learn to hide from outside observers, becoming undetectable! As a result, the period of detectability of an average civilization could be very short and the probability that a primitive civilization, like ours, would detect another one would be negligible. For example, it could have happened that planet Earth received the last radio or TV programs from another planet 200,000 years ago and for a period of about 500 years. This effect should be added as another factor in the Drake equation.

By contrast, this solution to the Fermi Paradox is obviously compatible with some UFOs being alien spacecraft (either extraterrestrial, or intraterrestrial from underground colonies), and is also compatible with the 'gods descending from the heavens' corresponding to various teams of scientists and technicians assisted by military personnel. These teams would have been sent to help develop the terrestrial civilization.

This solution is also compatible with the possibility of contacts between individuals from advanced civilizations and some individuals from primitive civilizations. As a matter of fact, in the article of 2003 [1], I identified three main causes or reasons that could motivate such contacts: scientific objectives in general, entertainment and/or affection, and criminal purposes of all kinds (including abductions and kidnappings).



The Soviet probe Phobos 2 sent 38 photographs of the surface of Mars, some showing strange shadows. On 25 March 1989, pointing to the satellite Phobos, the probe took a last snapshot (left), in which the satellite can be seen together with a very elongated cylindrical object, whose shape coincided with one of the shadows. Marina Popovich, a colonel in the Soviet Air Force, showed this photograph at a press conference (right) at the USSR consulate in San Francisco in 1991. (Associated Press - The New York Times)


To conclude, I suspect that the main characteristic of the scenario I propose; that is, the existence of primitive subcivilizations immersed in great hypercivilizations, is most likely true today, or will be in the future, in most galaxies.

The answer to the question whether our civilization is indeed such a subcivilization, ignorant of the existence of the great hypercivilization, will come perhaps through advanced technology that will allow us to rule out such a possibility.  But it could also come from the decision of our hosts, if they exist, to show us their faces openly, which could happen much sooner.

 



References:
[1] B. Gato-Rivera, (2003), arxiv: physics/0308078 (English and Spanish).
[2] B. Gato-Rivera, (2005), arxiv: physics/0512062 (English and Spanish).


Beatriz Gato Rivera.
Scientific Researcher. 
Instituto de Física Fundamental, CSIC, Madrid.


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