With the 200 billion stars and 100 billion planets that lie in the Milky Way, it wouldn't be unrealistic to think that there are other forms of life in our galaxy. There might even be a few intelligent extraterrestrial civilizations far more advanced than us. In fact, the Drake equation was created to determine the number of alien civilizations in the galaxy based on the potential number of habitable stars and planets. So, after calculation, it would appear that at least 20 intelligent civilizations may well live in our neighborhood.
What is quite astonishing is that until today, we have not yet succeeded in detecting a single one of these civilizations. A name has been given to this rather contradictory situation, the Fermi Paradox.
This paradox has led a large number of researchers to form theories on the reasons behind the absence of extraterrestrial contact.
Among the hypotheses offered are those that say that the birth of life in itself is very rare, others that most civilizations subsist for a short time before destroying themselves. Another rather peculiar hypothesis states that aliens remain undetectable because they choose to be, and that there is a rather dark reason behind this silence. This theory is called "The Dark Forest Solution" or the theory of the dark forest.
This theory is based on the story told in the science fiction novel titled "The Dark Forest" written by Liu Cixin.
The Basics of Dark Forest Theory
The reasoning behind this theory is well explained in Liu Cixin's novel. The book is mostly about the best way in which one should interact with potentially hostile alien life forms. So, according to the book, all life forms desire to stay alive; there is no way of knowing if other civilizations will want to destroy you if they have the chance; and finally, the safest option for all species is to annihilate other life forms before they have a chance to do the same.
Based on this way of thinking, any contact with another civilization is dangerous since sending a message would be a way of revealing one's position. Everyone thus tries to remain in complete radio silence.
The novel explains the reason behind this paranoia by comparing the Universe to a dark forest. In this forest, each civilization is a hunter who moves between the trees making as little noise as possible.
He must be very careful since other hunters do exactly the same and whoever is discovered will be immediately eliminated to avoid any risk.
Also read: What if the Milky Way housed the ruins of ancient extraterrestrial civilizations?
Is this theory possible?
What about this theory in reality? Apparently, it has the advantage of affecting only one of the variables of the Drake equation, and especially the one which is the source of much speculation. Also, with this theory, one does not have to make assumptions about how all extraterrestrial civilizations behave since it only takes one advanced race to do so to cause the observed situation.
This theory could thus explain why we have not yet detected radio signals in the last hundred years when we have been able to do so. Perhaps other civilizations are so afraid of being spotted that they choose not to emit any signals that can reveal their existence.
On the other hand, we have sent our radio signals into space, either on purpose or by accident, for the past hundred years. Any extraterrestrial civilization within a radius of 100 light years from Earth could thus currently receive a barrage of radio signals from our planet.
Read also: We discovered a strange extraterrestrial radio signal from an exoplanet
If this theory is correct, then it could be that humanity has put itself in danger with all the signals emitted so far. But in the end, this is only a theory and only time will tell which of all the assumptions made about aliens is indeed the correct one.