The Fermi Paradox is an argument that is invoked when one wonders about the possibility of the existence of a technologically advanced extraterrestrial civilization in the Milky Way. It is the subject of much debate but given the current data provided by theexobiology – namely the discovery of molecules organic in the clouds molecules and the existence of very many exoplanets potentially habitable in the Milky Way -, it is difficult to imagine that this argument does not constitute an extremely serious objection to the existence of these civilizations. At the very least, they would be very rare and not very durable.
The argument, according to the more or less documented legend, dates back to the year 1950. While they were busy designing the bomb hydrogen, Enrico Fermi and Edward Teller have lunch with a few colleagues at Los Alamos. The conversation door on the possibility that UFOs – which are beginning to hit the headlines in the United States – are indeed extraterrestrial craft capable of crossing the wall of the speed of light.
Fermi estimates
Accustomed to rapid estimates of orders of magnitude in physics, Fermi would have been quick to estimate the time it would take for a growing civilization in the Galaxy, according to an exponential law, to colonize all the stars, even while moving at a tiny fraction of the speed of light. In doing so, he no doubt quickly established at that time a equation analogous to the famous drake equation of Seti program.
His conclusion seems clear, if such a civilization existed, it should be there! Since Fermi hasn’t posted anything about it, we don’t really know what he had in mind. Still, what we call today the “Fermi paradox” unquestionably takes one of its major sources from an article published in 1975 by theastrophysicist american Michael H. Hart. The basic reasonings of the Fermi paradox are exposed there as well as the various conclusions to which they lead.
A modern formulation of the Fermi paradox
In a somewhat more developed form, the argument from the Fermi paradox is generally stated today in the following way.
It would take less than 100 million years for a civilization capable of reaching a significant fraction of the speed of light (which is not unthinkable when you consider projects like Daedalus using thermonuclear explosions) has visited all the stars in the Milky Way. This supposes in particular that from each planet new exploration and colonization missions start, which would lead in a way to a chain reaction (a first planet would give two ships, which with two other planets would give four, etc.).
However, the age of the Milky Way is greater than 10 billion years, which should have allowed the appearance of numerous extraterrestrial civilizations in the Galaxy for billions of years. They would have had plenty of time to create a galactic empire of which the Earth would have been a part for a very long time, even before the birth of humanity. At a minimum, the buildings from successive empires in the Milky Way should be everywhere around us in the Solar System.
This conclusion is valid even if civilizations are content to colonize only a portion of the Milky Way, provided of course that they appear in large numbers and last long enough. We are therefore led to think that the appearance of a technologically advanced civilization is very rare or at the very least that it generally disappears before being able to embark on interstellar travel.
For decades, proponents of ET-human contact have struggled to escape the pessimistic conclusion of the so-called “Fermi Paradox” argument. They assume for example that the advanced civilizations are there but that they do not show themselves in order to avoid a culture shock. The reasoning is fallacious since the Fermi paradox assumes that the Earth should have been colonized long before the appearance of man.
We can also think that these civilizations quickly became great AI folded in on themselves in a virtual world infinitely more interesting than the real world, abandoning any desire to colonize the Milky Way.
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