They key to finding aliens, according to a veteran astronomer, is to look for evidence of their manufactured artificial intelligence, or what he calls their "sentient machines." As reported by BBC News, what initially sounds counter-intuitive -- shouldn't SETI keep searching for radio technology in the skies? -- makes perfectly good sense when you think about it. Dr. Seth Shostak argues that the time lapse between civilizations developing radio broadcast technology and creating devices with artificial intelligence is so (relatively) brief that it's best to focus on the "sentient machines" and where they're more likely to hang out: near "hot, young stars" where matter and energy exist in abundance.
In other words, complex machines with artificial intelligence created by superior alien creatures very much resemble nerdy college freshmen who like to hang out near hot, young women in hopes of getting laid. Somehow, that's very reassuring ... and could also make for a pretty good movie!