Our Milky Way galaxy has around 200 billion stars and at least 100 billion planets. Drake’s equation, which takes these and other factors into consideration, such as the probability of life on Earth and the probability of intelligent life, predicts that our galaxy has roughly 20 sophisticated civilizations.
Despite our efforts to send them communications and the advancement of our astronomical knowledge, we have yet to find any signs (at least officially recognized) of these civilizations.
The Fermi paradox poses the same question, marveling at the lack of apparent signs of extraterrestrial civilizations’ activities, which should have settled throughout the whole Universe during billions of years of evolution.
Many explanations have been proposed to explain this. Some argue that life is a highly uncommon occurrence in general, and that life on Earth arose only as a result of an extraordinarily unusual set of conditions. Others argue that man’s evolution as an intellectual creature is an exception and that it is unlikely to occur elsewhere, even if all other prerequisites for plants and animals are met.
Then there’s the Dark Forest idea, which was conceived in Chinese writer Liu Cixin’s science fiction novel “Dark Forest.”
The plot of the story, which is the second in the trilogy, is on how to deal with possibly hostile extraterrestrial species.
The novel makes the following points:
1) Life, especially evolved life, is concerned with surviving.
2) It is difficult to predict whether or not other living forms would be able to eliminate you if given the opportunity.
3) In the absence of certain survival guarantees, the safest choice for any living species is to eliminate potentially harmful life forms before they can do the same to them.
Each space civilization aspires to grow indefinitely, but because each galaxy’s resources are finite, all civilizations capable of interstellar travel become competitors for the same resources.
As a result, each civilisation A cannot be certain that, if it learns of the presence of another adequately evolved civilization B, it will not become its adversary. It can’t even rely on civilization B’s technological gap because science and technology are progressing at an exponential rate and can overtake civilization A’s.
As a result, every civilisation with technology capable of destroying other civilizations will kill all civilizations it knows about in order to avoid being a victim of such an assault.
This solves the Fermi paradox: highly sophisticated civilizations simply try not to reveal their presence because doing so would almost certainly result in an assault.
One of the key characters in Liu Cixin’s novel, Luo Ji, refers to this as the Dark Forest Theory, equating it to a forest full of concealing hunters destroying any beast that betrays itself.
To avoid betraying themselves, the advanced space civilization will maintain tight radio silence and, most likely, their spacecraft will not scour the galaxy for resources or anything else.
They can also use any available means to conceal evidence of their planet’s existence. This idea is so reasonable and realistic that it has sparked substantial debate among scientists since the publication of Liu Cixin’s novel. And the hypothesis worried them because they knew what we’d done.
We’ve been sending radio signals into space for over a century, signaling the presence of intelligent life on our planet, and all prospective extraterrestrial civilizations within a 100 light-year radius have undoubtedly heard these messages. They are aware of our existence.
Stephen Hawking, the late theoretical physicist, and cosmologist was once concerned about this and opposed releasing any information about humans into space.
If we haven’t been attacked yet, it’s simply because the civilizations that have known about us are also terrified of us, unaware of our true degree of technological advancement, and don’t want to reveal themselves and sentence themselves to annihilation. But what if our transmissions are intercepted by the ruthless conquerors?