>[!abstract] >The concept of quiet and loud aliens is used in the modeling of hypotheses for the prevalence of extraterrestrial intelligence, particularly in the context of the [[Fermi Paradox]]. Hypothetical "loud" aliens expand their sphere of influence rapidly in a highly detectable way; hypothetical "quiet" aliens are hard or impossible to detect. A special type of loud alien civilizations are "grabby aliens" who also inhibit the development of other technological civilizations in their sphere of influence (Wikipedia, 2024). >[!related] >- **North** (upstream): [[Fermi paradox (the broader question: if intelligent life is common, why don’t we see evidence of it?)]] >- **West** (similar): [[Dark forest hypothesis]] (the idea that civilizations stay quiet to avoid detection and destruction) >- **East** (different): [[Loud aliens]] (civilizations broadcasting or altering their environment in obvious ways, e.g., Dyson spheres, technosignatures) >- **South** (downstream): [[SETI strategies]] (searching for radio signals, megastructures, or other traces depending on whether we expect quiet or loud civilizations)