A space telescope known as WISE compiled a catalog of more than 750 million objects — young stars, brown dwarfs, asteroids and comets, dusty galaxies, and many more. But it didn’t find any super-civilizations that are soaking up the energy of all the stars in their home galaxy. The craft wasn’t actually looking for such civilizations. But astronomers at Penn State realized that it might have seen evidence of them nonetheless. Decades ago, scientists had suggested that a super-civilization might use massive structures to gather the energy of all of a galaxy’s stars. Some of that energy would heat up the light-gathering structures, causing them to glow at infrared wavelengths — the type of energy that WISE was studying. So the astronomers looked through the WISE catalog, and identified 563 targets of interest. When they took a closer look at those objects, though, they found that not one looked like a civilization that was using the energy of all of its galaxy’s stars. They did find 50 o
