Are we missing alien lighthouses?

Searching for extraterrestrial intelligence has so far primarily meant focusing on one particular type of signal—and that signal has normally been based on our own current cutting-edge technology.

But what if that's the wrong way to look for signs of alien intelligence?

What if a resource-conscious civilization decided it was too complicated to send femtosecond lasers in high-energy bursts across the universe?

A new paper, available as a preprint on arXiv, from researchers Dániel Apai, Chia-Lung Lin and Kevin Wagner suggests that might actually be what happens and that we should start looking for long-duration pulsing interstellar beacons. ...