Looking for Alien Life? Seek Out Alien Tech

Back in 1950, Enrico Fermi posed the question now known as the Fermi Paradox: Given the countless galaxies, stars, and planets out there, the odds are that life exists elsewhere--so why haven't we found it? The size of the universe is only one possible answer. Maybe humans have already encountered extraterrestrial (ET) life but didn't recognize it. Maybe it doesn't want to be found. Maybe it doesn't find us interesting.