Submission + - City lights could reveal alien civilizations (extremetech.com) 1
MrSeb writes: "New research conducted by Abraham Loeb from Harvard University and Edwin Turner from Princeton University shows that electric, artificial lights on remote planets could be detected using next-generation ground and space telescopes. The basic approach is simple: planets that are exclusively illuminated by a local sun will have one "light signature," while a planet with artificial lights will have another. Loeb and Turner say that this technique, with our current telescopes, would be able to pick out a major terrestrial city on the edge of the Solar System, in the Kuiper belt (50 AU) — but future telescopes, or the telescopes belonging to advanced, alien races, could see farther. More interesting than the how is the why. Why are Loeb and Turner interested in weak, visible-light spectra rather than the megawatts of easily-detectable radio waves that are pumped into space every second? Because the amount of radio waves being produced by humanity — mostly thanks to fiber optic networks — is on the decline. In turn, this infers that other, advanced civilizations might have moved beyond radio communications too. In this case, radio astronomy won't help us (or alien civilizations) the search for extraterrestrial intelligence (SETI) — but looking for artificial light would."