The best place to look for alien megastructures might be moon dust

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 it actively creates a signature that is detectable by our current technology.