Scientists find no obvious signs of life in 100,000 galaxies

A new study has found no obvious signs of highly advanced extraterrestrial life in 100,000 galaxies, but about 50 of those galaxies have shown suspicious infrared activity which may indicate presence of alien life, scientists say.
The research used observations from NASA's Wide-field Infrared Survey Explorer (WISE) orbiting observatory.
"The idea behind our research is that, if an entire galaxy had been colonised by an advanced spacefaring civilisation, the energy produced by that civilisation's technologies would be detectable in mid-infrared wavelengths - exactly the radiation that the WISE satellite was designed to detect for other astronomical purposes," said Jason T Wright at Penn State University.

"Whether an advanced spacefaring civilisation uses the large amounts of energy from its galaxy's stars to power computers, space flight, communication, or something we can't yet imagine, fundamental thermodynamics tells us that this energy must be radiated away as heat in the mid-infrared wavelengths," said Wright, an assistant professor of astronomy and astrophysics at the Center for Exoplanets and Habitable Worlds.
Roger Griffith, the lead author of the paper at Penn State, scoured almost the entire catalogue of the WISE satellite's detections - nearly 100 million entries - for objects consistent with galaxies emitting too much mid-infrared radiation.
He then individually examined and categorised around 100,000 of the most promising galaxy images.

"We found about 50 galaxies that have unusually high levels of mid-infrared radiation," Griffith said.

"Our follow-up studies of those galaxies may reveal if the origin of their radiation results from natural astronomical processes, or if it could indicate the presence of a highly advanced civilisation," he said.
"Our results mean that, out of the 100,000 galaxies that WISE could see in sufficient detail, none of them is widely populated by an alien civilisation using most of the starlight in its galaxy for its own purposes," Wright said.
"That's interesting because these galaxies are billions of years old, which should have been plenty of time for them to have been filled with alien civilisations, if they exist. Either they don't exist, or they don't yet use enough energy for us to recognise them," Wright said.

The researchers also discovered within our own Milky Way galaxy a bright nebula around the nearby star 48 Librae, and a cluster of objects easily detected by WISE in a patch of sky that appears totally black when viewed with telescopes that detect only visible light.
"This cluster is probably a group of very young stars forming inside a previously undiscovered molecular cloud, and the 48 Librae nebula apparently is due to a huge cloud of dust around the star, but both deserve much more careful study," said Matthew Povich, an assistant professor of astronomy at Cal Poly Pomona, and a co-investigator on the project.