Our search for technosignatures – clear signs of advanced civilizations beyond Earth – takes many forms. Many are driven by the famous Drake equation, which attempts to estimate how many technological civilizations there are in the Milky Way. However, there's a big fat question mark at the end of that equation in the form of a variable intended to account for the "longevity" of a civilization. And to be clear, that doesn't mean how long the civilization itself survives. It simply means how long