seti.org
The Fermi Paradox
Although the Fermi Paradox notes that intelligent civilizations could have colonized the Milky Way in a fraction of its age, the lack of detectable signs remains puzzling, with proposed explanations ranging from prohibitive travel costs and sociobiological limits to quiet galactic regions, zoo-like observational containment, or a choice not to reveal themselves, tempered by caution against overgeneralizing from local observations, and all of which sustain the case for continued SETI efforts to test for alien life, a point underscored by Enrico Fermi's insight that even modestly powered civilizations could spread rapidly.
