If we look at the sky we will see, in the best of cases, a couple of thousand stars. It is the most we can see from here. But in our galaxy alone, there are several hundred billion. And there are even more galaxies, even, than stars in the Milky Way. And all this space, is it empty?
It becomes very difficult to think that we are alone meanwhile astro. However, if not, why haven’t we detected even the slightest sign of our cosmic neighbors? The explanations could be several.
Where is everybody?
Enrico Fermi, in his flawless suit under an equally elegant robe, smiles thoughtfully. “So where are they?” He asks thoughtfully. His companions, equally dressed but seated at the table, look at him under their own robes. No one throws an answer at him. We have probably all asked ourselves the question at one time or another: If the universe is so big, where is everyone?
In such an immense expanse, with billions of stars similar to our own, there would have to be other extraterrestrial civilizations at least as intelligent as ours. But, to date, we have not detected a trace. Moreover, in the last systematic scan carried out in 2015, we found that the number of existing civilizations out there, in the analyzed systems, is zero. This is the beginning of the Fermi paradox.
This can be summarized as follows: “The common belief that the universe has numerous technologically advanced civilizations, combined with our observations that suggest the opposite, is paradoxical in suggesting that our knowledge or observations are flawed or incomplete.”
They say that for Fermi, the unfinished answer to the paradox was an unflattering answer. It must be remembered that Fermi was one of the protagonists in the development of nuclear weapons and believed that humanity was flirting with its self-destruction. Did the physicist, in the paradox, see a reflection of our future? In any case, the doubt remains.
We shouldn’t be alone, should we?
The most famous Drake’s formula, is an equation that tries to calculate the number of possible intelligent civilizations in our galaxy. The calculations take into account figures such as the rate of formation of stars suitable for life, the number of planets in the habitable zone and factors such as “the appearance of life” or “the appearance of intelligent life”.
This formula was developed in 1960 by Frank Drake, president of the SETI institute, and although in reality it’s just a speculative gameBecause we can’t solve some of the variables, it’s the first theoretical approximation we have to calculate how many neighbors are out there.
When the first calculations to test the estimate were made in 1961, the data returned a total of ten detectable civilizations per year. Definitely an overly optimistic figure. With some adjustments and better variables, obtained over the years, this figure it has gone from 10 to 0.00000007, 0.00000002 and 0.000000008 detectable civilizations per year, figures much more in line with our reality.
In any case, It is still very strange that we have not seen anything or anyone. If it really were a technified civilization and more advanced than ours, we should be able, at a minimum, to detect some signal (especially in the infrared, for example, due to the heat that would escape from its devices, or through some kind of voluntary message. ). But this is not the case, and we do not know why. Although we can imagine why.
The cusp of a civilization and the Kardashov scale
In 1964, Nikolai Kardashev proposed a somewhat general classification of civilizations. A Type I civilization would be able to harness all the energy of its home planet. We would be, for example, a type 0.7 civilization (according to calculated by Carl Sagan in 1973). A type II civilization would be able to harness all the energy coming from its native star. Type III would harness all the energy in the galaxy, fully. This would be the maximum to which you can aspire.
If there were in our galaxy some type II or III civilization, we would almost certainly know. At least the type III ones. The type II, although more difficult, especially if it is on the other side of the galaxy, for example, could not go unnoticed forever.
Our probes should have detected its incredible technology long ago. In fact, by Drake’s calculations, various type II civilizations should exist in our galaxy. Therefore, the first explanation is that there are not so advanced. Hopefully some kind of intelligent civilization does exist, but if it is located very far away in the Milky Way itself, it is easy to understand that we cannot contact them. But what if one of them had appeared at “home”? Why haven’t we contacted anyone?
Reason number 1: the Great Filter
One possible answer is a hypothesis called the Great Filter. This was proposed in 1996 by Robin Hanson, an economist who saw the existence of an evolutionary event that prevents the systematic advance envisioned in our formulas. Imagine our evolution, including biological, cultural and technological, as a continuous line where certain milestones occur.
Progress You should be stuck in one of the steps necessary to become a Type II or III civilization. We are currently in a step before space colonization. Let’s hope and suppose there are galactic neighbors out there. Are they in the same situation? From behind maybe? It is fair to think that they are not far ahead, or we would have seen them. Where does the Great Filter work?
We haven’t been through it yet
One highly likely hypothesis is that the Great Filter is in front of us, at some point ahead of space exploration. This would explain why there is no type of colonization detected in our galaxy, but it suggests that there are other possible neighbors, waiting.
Still, it’s bad news because it would imply a good chance that we will never reach more. The filter, in this case, could be an irreparable depletion of resources, a war that would end civilization as we know it, a disease … In any case, it would be an evolutionary impediment present in an advanced civilization, but not so much as to colonize the stars.
We are special
Another possibility is that we are “the chosen ones”, the only living beings around us capable of overcoming that Great Filter. That would mean that we are on our way to becoming the first intergalactic inhabitants of the Milky Way. In such a case, the Great Filter would be behind our present moment. Perhaps that is the appearance of life, or the evolution of intelligent and technified life. We do not know.
The fact is that if we found, for example, the remains of extraterrestrial life in the form of microorganisms, we would probably be faced with the indication that this Great Filter is at a moment between our moment and the appearance of the organisms. This would be a sign that it is quite easy for us to be alone.
Reason number 2: Type I and II civilizations are very, very far away
Let’s imagine that there are titanic civilizations, much larger than Asimov himself could imagine in “Foundation”. Why haven’t we seen anything about them? Because they are elsewhere. Another place in time and space, needless to say. The universe is gigantic. The Milky Way is brutally big and old.
Let’s imagine that yes, there was an intelligent civilization that visited our Earth billions of years ago. It would be impossible to know. This hypothesis is the preferred one of the defenders of anachronisms and UFOs. But realistically, it’s like they never visited us.
On the other hand, if the civilization were type II, taking advantage of entire systems, but were at the other end of the galaxy … it would be very difficult for us to see her, considering that our ability to receive signals is limited to just 100 light years from here. The same we could think of a type III civilization that was found in a galaxy other than ours. How were we to find out?
Reason number 3: we are the first
A hopeful possibility explains that we are among the first to advance so far as to conquer space. In such a case, it is only a matter of time before someone finds our signals or we find theirs.
Maybe we are living in a time of cosmological settlement that allows the emergence of new civilizations. The previous billions of years may have only served to shape the universe. Now is the time to evolve. Maybe.
Reason number 4: We are surrounded by signals, but we are space hicks
It could be, and it is not unreasonable, that our environment is full of signals that indicate intelligent extraterrestrial life but that we cannot see them. Maybe our technology is not advanced enough or we may not be looking at the right signals.
This too It would be related to the fact that no one had noticed our presenceIn the same way that we do not look at the mites that live on our plants or the ants that swarm our kitchen. And it’s not that it’s an intended comparison.
Reason number 5: The truth is out there and it’s not good at all
What if all the UFO conspirators were right? It is not that we have been visited by an alien race that wants to remain anonymous. This is highly unlikely, if not impossible, considering how social we are and how difficult it is to maintain such an interaction.
But, What if there was a civilization out there taking care that no other exceeded a certain level of technology? Or was she a super predator hunting other civilizations? It may also be that there is a superculture observing us, as if we were animals in a zoo, from its own solar system. In any case, these are the least likely hypotheses of all.
Reason number 7: Bonus, everything is a lie
There is one last hypothesis to be thrown into the air: that everything we believe to be reality is not true. What if the universe was a hologram? What if we are actually in a super advanced virtual simulation? What if we are really just scientific proof (if that word makes sense) of a gigantic “ultracivilization” whose dimensions resemble what we usually call God?
This idea has been wonderfully explored by Asimov in several of his short stories. And the result is disturbing. In such cases we can do little. Although our reality is a total lie, it’s the only reality we have, and according to some Oxford experts we are an exception, a very rare exception, so for now we will have to settle for it.