"Dark Forest" is a concept from the science fiction novel "The Dark Forest" by Liu Cixin, which is the second book in the Remembrance of Earth's Past trilogy. The theory suggests that the universe is like a dark forest where every civilization is a silent hunter. To survive, civilizations must remain hidden, as revealing their presence could attract dangerous attention from others. In this metaphorical forest, any signal sent into space could be interpreted as a threat, leading to preemptive strikes by more advanced civilizations. This idea explores themes of communication, survival, and the potential dangers of contact with extraterrestrial life.