A team from Penn State University analyzed data from NASA’s Wide-field Infrared Survey Explorer (WISE) satellite to look for signs of infrared radiation that would potentially be generated by alien life in a star-voyaging civilization.
Search for mid-infrared wavelengths
“The idea behind our research is that, if an entire galaxy had been colonized by an advanced spacefaring civilization, the energy produced by that civilization’s technologies would be detectable in mid-infrared wavelengths – exactly the radiation that the WISE satellite was designed to detect for other astronomical purposes,”says Jason T. Wright, an astronomer and astrophysicist at Penn State’s Center for Exoplanets and Habitable Worlds.
Interest in mid-infrared emissions first came up 50 years ago after physicist Freeman Dyson claimed that they might provide significant evidence of extraterrestrial life in an advanced alien civilization. It was previously impossible to measure such radiation until space telescopes such as WISE were developed.
The research team analyzed over 100 million WISE observations for evidence of galaxies that were emitting higher levels of infrared radiation than could be accounted for by natural processes. From this sample around 100,000 promising galaxies were identified, a much wider scope than during previous research, which involved only around 100 galaxies with potential for hosting alien life.
Advanced forms of extraterrestrial life could be out there
The latest WISE survey highlighted 50 galaxies with unusual radiation patterns, but it is unsure whether they are natural anomalies or evidence of advanced alien life.
“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 civilization using most of the starlight in its galaxy for its own purposes,” says Wright.
The galaxies have existed for billions of years, sufficient time for advanced alien civilizations to have developed, if they exist at all.
“Either they don’t exist, or they don’t yet use enough energy for us to recognize them,” Wright says. Despite drawing a blank this time, researchers believe that their theory is solid enough to merit further investigation.
“Whether an advanced spacefaring civilization 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,” Wright says.