Bright idea
In the search for extraterrestrial intelligence, astronomers have hunted for radio signals and ultra-short laser pulses. In a new paper, Avi Loeb of the Harvard-Smithsonian Center for Astrophysics (CfA) and Edwin Turner of Princeton University suggest a new technique for finding aliens: Look for their city lights. “Looking for alien cities would be a long shot, but wouldn’t require extra resources. And if we succeed, it would change our perception of our place in the universe,” said Loeb. As with other methods in the search for alien life, these rely on the assumption that aliens would use Earth-like technologies. This is reasonable because any intelligent life that evolved in the light from its nearest star is likely to have artificial illumination that switches on during the hours of darkness. How easy would it be to spot a city on a distant planet? Clearly, this light would have to be distinguished from the...