Implications of Directed Energy for SETI

We compute the detectability of directed energy sources from distant civilizations that may exist. Recent advances in our own directed energy abilities allow us to foresee our own capability that will radically change our ability to broadcast our presence and hence allow us to ponder the reverse case of detection. In the next few decades we will evolve to the point where we will be able to produce the brightest SED (spectral energy distribution) in the known universe. We show that systems of this type have the ability to be detected at vast distances and indeed can be detected across the entire horizon. This profoundly changes the possibilities for searches for extra-terrestrial technology advanced civilizations. Even modest searches are extremely effective at detecting or limiting many civilization classes. For example, even a single civilization anywhere in our galaxy that is of comparable technological advancement to our own can be detected with near unity probability with a small cluster of 0.1 m telescopes on Earth while a 1 m class telescope has the ability to detect even a single civilization anywhere in the Andromeda galaxy. We compare ground based surveys with aperture sizes from 1mm (smaller than a cell phone optic) to 1 m (modest telescope) and compute blind transmission and blind reception probabilities. We propose a search strategy, using small Earth based telescopes, that will observe more than 1012 stellar and planetary systems with possible extensions to more than 1020 systems allowing us to test the hypothesis that other similarly or more advanced civilization with this same capability, and are broadcasting, exist. We show that such searches have unity probability of detecting even a single comparably advanced civilization anywhere in our galaxy within a relatively short search time (few years) IF that civilization adopts a simple beacon strategy we call “intelligent targeting”, IF that civilization is beaconing at a wavelength we can detect and IF that civilization left the beacon on long enough for the light to reach us now. In this blind beacon and blind search strategy the civilization does not need to know where we are nor do we need to know where they are. This same basic strategy can be extended to extragalactic distances. Portions of this paper come from our recent paper entitled “The Search for Directed Intelligence”.