According to the materials of the article published in the electronic library Arxiv.org, the reason that humanity has not yet become acquainted with an intelligent extraterrestrial civilization lies in the ability of aliens to hide well from the population of the Earth their active communication with each other and, accordingly, signs of their own existence. Although in the Universe around us, some kind of 'cliques' probably exist.
Half a century ago, American astronomer Frank Drake came up with a formula by which to calculate the number of civilizations in the galaxy that are possible for contact, thus the scientist tried to estimate our chances of detecting extraterrestrial intelligence.
In response to the high assessment of the chances of interplanetary contact, physicist Enrico Fermi, using this formula, formulated a thesis, better known as the Fermi paradox. According to him, if there are so many extraterrestrial civilizations, then why have no traces of them been found so far?
Cosmic silence
The plausibility of the popular explanation for the Fermi Paradox (called the 'Galactic Club' or 'Galactic Zoo' in academia) was tested by Scottish astronomer Duncan Forgan of the University of St Andrews. The idea was developed and then popularized by the famous Australian astrophysicist Ronald Bracewell in the mid 70s.
Its essence is this: humanity has not yet contacted extraterrestrial civilizations due to the fact that they actively hide their fact of existence from terrestrial inhabitants, communicating with each other within the framework of a kind of 'galactic club of civilizations', where the Earth is not yet worthy to enter.
Opponents of this theory are sure that aliens are not able to organize such a club because of the difficulties in communication, as well as the impossibility of keeping all extraterrestrial civilizations from accidental contact with earthlings until they contact the 'management' of the club and accept the rules of communication in it.
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This problem interested Forgan, who tried to calculate whether such a 'club of civilizations' could really maintain discipline in the 'galactic arena'. To do this, he counted the number of civilizations that have emerged in the Milky Way from the moment the galaxy appeared to the present day and determined the number of possible cultural ties between them.
Universal conspiracy theory
According to these calculations, the existence of a single 'alien club' is impossible due to the huge distances between different corners of the Galaxy. At the same time, the presence of several local coalitions of aliens, capable of effectively maintaining communication with each other, can solve the problem of the 'galactic isolation' of the Earth.
Their existence will become possible in the case of a rather rare appearance of alien civilizations in close proximity to each other, as well as provided that they will exist for over 250 thousand years. The number of such 'clicks' will depend on the duration of the gap between the births of new civilizations: the larger the gap, the more groups of aliens will exist in the Milky Way.
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Of course, all this is not an accurate confirmation of the existence of an alien intelligence. It's just that in this case, the existence of a global 'Galactic Club' is hardly possible. According to the astronomer, the existence of the 'Galactic Empire' – the hegemon – is possible only if alien civilizations live on average for millions of years, appear very quickly (every few million years), and their total number is several hundred.
According to Forgan, all this is unlikely, in contrast to the emergence of local coalitions of aliens, hiding from us independently of each other.
