Trail runs cold on alien hotspots, for now

A search of 100,000 galaxies for signs of highly advanced extraterrestrial life, carried out by researchers in the US, has found no evidence that they harbour advanced civilizations. Scouring through observations from NASA's WISE orbiting observatory, the researchers looked for unusually high amounts of mid-infrared radiation, which could mark out a colonized galaxy. The research is a significant expansion of previous work, which only studied about 100 galaxies. Although the team has not found any obvious signs of advanced life just yet, it has come across some puzzling new sources of mid-infrared radiation that need further study.