[cgriswald]

We may not be able to understand the ten-lane superhighway, but we can certainly distinguish it from natural phenonemon.

Radio SETI is the most popular, but searches have been done in a wide variety of ways. For instance, A search for a complete Dyson swarm can be done by looking for "stars" which only emit radiation in the far infrared. Partial Dyson swarms can be detected by comparing the mag of a star at two different wavelengths. Megastructures are potentially detectable via the tranit method. And searches have been done to look for signs of galactic engineering.

I'm still willing to entertain the idea that Kaku is correct, but it mostly just seems like wishful thinking to me.

The evidence thus far suggests that even if life is everywhere in the universe, technological life may not be.