Are We Missing Alien Lighthouses?

Searching for extraterrestrial intelligence has so far meant primarily focusing on one particular type of signal - and that signal has normally been based on what our own current cutting edge technology is. But what if that’s the wrong way to look for signs of an alien intelligence? What if a resource-conscious civilization decided it was too complicated to send femto-second lasers in high energy bursts out across the universe. A new paper, available in pre-print on arXiv, from researchers