Brief Detectability Windows

Civilizations may produce technosignatures only during short, fragile periods when their energy use or communication methods are both high and externally visible. After a rapid shift (collapse, deliberate darkening, or technological stealth) that window closes and the civilization becomes effectively invisible to distant observers. — If detectability is transient, silence is ambiguous: it could mean we are alone, or that most civilizations pass through brief, easily missed stages—shaping SETI strategy, existential‑risk priorities, and funding for technosignature searches.