If you’re looking for a new tactic for SETI, the search for extraterrestrial intelligence, Avi Loeb (Harvard-Smithsonian Center for Astrophysics) and Princeton’s Edwin Turner may be able to supply it. The duo are studying how we might find other civilizations by spotting the lights of their cities. It’s an exotic concept and Loeb understates when he says looking for alien cities would be a long shot, but Centauri Dreams is all in favor of adding to our SETI toolkit, which thus far has been filled with the implements of radio, optical and, to a small extent, infrared methods.
mk: This seems a worthwhile idea, but I don't think the logic holds. Light lost to space is a waste of energy. For that reason, I'd think that advanced civilizations might have lighting technologies that don't spill much into space.Also it's likely that advanced civilizations don't need artificial light, or much of it. I don't think it will be more than 200 years before the dominant lifeforms on earth aren't biological. IMO non-biological beings will have far less interest in the physical environment. That is, outside of energy production, their universe will probably be more internally-focused.
So, if you consider a 300-year window that we will be lighting up the earth at night, chances are that we won't catch anyone in that slice of history.