Where Are All the Aliens? The Universe's Greatest Mystery The cosmos contains billions of habitable planets, yet we hear nothing. Are advanced civilizations hiding, extinct, or simply not there? The eerie silence defies logic.if life is common, why no signals, megastructures, or visitors? Perhaps intelligence is rare, or doomed to self-destruct. Maybe we’re in a galactic zoo, or the first to awaken. Or worse: a Great Filter awaits, threatening our future. The answer could reveal human