The Fermi paradox: if aliens exist, why haven’t they visited us?

The Fermi paradox invites us to think about whether extraterrestrial civilizations exist.

When human beings look up at the sky, they can only wonder. The universe is everything: a place where we live, nothingness, immensity, the incomprehensible and life.

The Milky Way, the galaxy where the solar system is located (and in turn the Earth) has a mass of 10 to 12 suns, with billions of stars similar to the Sun itself that gives us life. If this seems inconceivable to you, imagine if we take into account that it is estimated that there are two trillion galaxies in the entire universe.

As anthropocentric as human thinking may be, (almost) everyone agrees that the probability that we are the only living and thinking form in the universe is very low.The term "matter" encompasses the totality of all forms of matter, energy, space-time (what you see and conceive and what you don't). In the face of such a vast and incomprehensible whole, statistically there must be some other living entity, right?

We are not even talking about extraterrestrials with human forms, but an acellular microscopic entity, a concept, an ethereal "something" that can be classified as an open but self-regulating system (as the cell is), although we are not able to understand it. Based on these philosophical and Biological premises, we expose you everything you should know about Fermi's paradoxThe Fermi paradox, since not all thinkers think the same regarding the existence of intelligent life beyond the Earth.

What is the Fermi paradox?

The premise of this paradox is very simple: if intelligent life existed beyond our planet, we would have already observed evidence of it throughout our evolutionary history..

Based on scale and probability alone, there is no doubt that intelligent species or entities should exist outside of Earth, but the fact that interaction with external biological entities has been nil tells us otherwise. Any sign: a fragment of a construction, parts of a space vehicle, a communicative signal, footprints, organic matter, or biological clues would have been enough to demolish Fermi's paradox.

Curiously, as studies well versed in the subject indicate, the Fermi paradox was neither coined by the physicist Enrico Fermi (creator of the first nuclear reactor) nor is it a paradox in itself. Fermi went on to postulate questions such as "Where is everybody?", but the first ideation of this thought came from Michael Hart, who postulated that interstellar travel and the colonization of planets would have been inevitable at this point if intelligent life forms truly existed.. In other words: "They are not here, and therefore, they do not exist".

This is a very clear apparent contradiction. Here are a number of facts that put the thought into perspective:

• There are billions of Sun-like stars in the Milky Way. Theoretically, by statistics and scale there should be life on some of them.
• Many of these stars (and hence their planets) are much older than the Sun. If we conceive of Earth as a type planet, many others should have developed intelligent life long ago.
• Because of the age of many of these bodies, the intelligent life inhabiting them would have had more than enough time to develop interstellar travel.
• Despite the slowness of the study of Earth's interstellar travel, it is estimated that the entire Milky Way could be traversed in a few million years.
• Because many stars are billions of years old, by statistics, the Earth should have already been visited.
• Despite these postulations, our planet has not had any contact with extraterrestrial life. Nor is there evidence of colonization on other observed planets.

Things get even more interesting if we know that, even if 99% of intelligent civilizations had self-annihilated, the absence of interaction with humans or the rest of the planets remains unexplained.. The idea, again, is clear: they are not here, and therefore do not exist.

The Drake equation

The Drake equation, postulated by the American astronomer who gives it its name, tries to estimate the number of civilizations present in our galaxy by mathematical processes.. The equation is as follows:

Put simply, this operation takes into account the rate of star formation, the number of stars that have planets orbiting around them, the fraction of planets that could have developed life, the fraction of planets that could have developed intelligent life, the percentage of these "communities" capable of emitting detectable signals in space, and the time interval during which these signals could have been emitted.

With all these parameters in mind, Drake postulates that there should be 10 detectable civilizations in the Milky Way galaxy.which, we recall, has a calculated mass of 10 to 12 suns. However, other professionals are not so "generous", since other estimates using the same formula calculate 0.000000067 or less, depending on the parameters used.

Against the Drake equation, it can be argued that this formula does not take into account that fraction of planets with chemical elements conducive to life, such as water or carbon, as well as the presence of a stable and durable ecosphere over time. While it is true that all these parameters only apply to the life present on our planet, we have no others, since this is the only concept of existence that we can imagine.

Scientific explanations to Fermi's paradox.

The Fermi paradox is based on the Drake equation to defend the non-existence of intelligent life in the universe. If mathematically there are a total of 10 civilizations emitting signals in the Milky Way, it is clear that we should have detected them. All this is further cemented if we keep in mind that the Earth is a typical planet (principle of mediocrity). If life has arisen in a place where the initial characteristics were not far from the average, then it may have arisen in thousands of others..

The biggest conceptual hole in all these postulations is that the Drake equation uses point estimates, or in other words, the use of collected data to give the most reliable guess at a complete value. These estimates assume that we have absolute knowledge of parameters that are impossible to understand on a large scale, such as the probability of the appearance of life or the potential number of intelligent societies.

Let's face it: even in the scientific community itself it is difficult to estimate what intelligence as such is.Imagine what a puzzle it must be to apply such an ethereal concept to a living entity that may not even be governed by the same parameters as we are. When we take realistic uncertainty into account, replacing point estimates with probability distributions that reflect current scientific knowledge, the observed picture is much different.

The brilliant scientific publication Dissolving the Fermi Paradox (published in 2018 on the Researchgate portal) does just this, and presents us with data that directly clashes with the Fermi paradox. Taking into account actual scientific knowledge, it can be calculated that the probability that we are alone in the Milky Way Galaxy ranges from 53 to 99.6%. We go further, as the probability that we are alone in the entire universe is placed at 39-85%.

Summary

While the Fermi paradox and the Drake equation are of great scientific and philosophical interest, we can only acknowledge that the parameters that give rise to life, the concept of intelligence or even the record of universal communication methods are out of our hands. Perhaps intelligent life has been trying to communicate with us for centuries, but its methods may be imperceptible to us. their methods may be imperceptible to human cognition or the machinery developed by our species..

It may also be that our planet is not as typical as we think, or that the conditions necessary for the appearance of life are so extremely rare that they have not really been replicated on other planets. At this point, we can only look to the sky and, as we have always done, continue to advance in search of knowledge and hope that someday the answers will come.