Dark Forest Hypothesis

Despite some deluded minds that continue to claim that alien UFO's exist, there is no known reliable or reproducible evidence that aliens have ever visited or attempted to contact Earth. No transmissions and no firm evidence of intelligent extraterrestrial life have been detected or observed.

That is a problem, because cosmologists presume that the universe is filled with a very large number of planets, where the probability is that some present the conditions hospitable for life. Some of these planets must be home to intelligent life. This discrepancy between the lack of conclusive evidence of advanced extraterrestrial life and the apparently high likelihood of its existence is called the Fermi Paradox.

The Dark Forest Hypothesis is the conjecture that many alien civilizations do exist throughout the universe, but they are both silent and hostile, maintaining their undetectability for fear of being destroyed by another hostile and undetected civilization[1]. Also, according to the dark forest hypothesis, since the intentions of any newly contacted civilisation can never be known with certainty, then if one is encountered, it is best to shoot first and ask questions later, in order to avoid the potential extinction of one’s own species.

Think of a dark and forbidden forest filled with armed hunters stalking though the forest in search of prey. Any sound made by potential prey would potentially result in a kill. Viewed the other way: any sound made by the hunters might attract a top predator.

Therefore, any space-faring civilization would view any other intelligent life as an inevitable threat. They will then strife to destroy any nascent life that makes itself known. As a result, the electromagnetic radiation surveys would not find evidence of intelligent alien life.

The hypothesis derives its name from Liu Cixin's science fiction novel 'The Dark Forest' (2008), although the concept predates the novel[2].

[1] Yu: The Dark Forest Rule: One Solution to the Fermi Paradox in Journal of the British Interplanetary Society - 2015
[2] Brin: The Great Silence - the Controversy Concerning Extraterrestrial Intelligent Life in Quarterly Journal of the Royal Astronomical Society - 1983