The researchers, led by Penn State University assistant professor of astronomy and astrophysics Jason T. Wright, studied data from NASA’s Wide-Field Infrared Survey Explorer (WISE) space telescope in search of unexpectedly high levels of mid-infrared radiation.
Out of 100,000 galaxies imaged, only 50 of them had levels that appeared to be too high. Further investigation, however, found no obvious signs of activity that could be attributed to advanced civilizations, they wrote in The Astrophysical Journal Supplement Series.
No signs of intelligent life anywhere
The idea behind the research, Wright explained, “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.”
Wright, who conceived of and initiated the research, and his colleagues, based their work on a hypothesis proposed in the 1960s. This claimed that advanced extraterrestrial civilizations could be located by tracking their mid-infrared emissions. However, before WISE, there was no way to make the sensitive measurements of this radiation required to do so.
Roger Griffith, a postgraduate researcher at Penn State and the lead author of the paper, reviewed nearly the entire catalog of the satellite’s detections for objects consistent with galaxies that were emitting too much mid-infrared radiation. Griffith selected 100,000 promising candidates, and of those, 50 had unusually high levels of mid-infrared radiation, but no obvious signs of aliens.
Don’t give up hope just yet, however
Wright explained that follow-up studies of those galaxies could reveal if that radiation is the result of natural astronomical processes or some other cause, adding that the non-detection of any obvious alien-inhabited galaxies is in and of itself an interesting finding.
“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,” he 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 civilizations, if they exist. Either they don’t exist, or they don’t yet use enough energy for us to recognize them.”
While some may be disappointed by the apparent absence of advanced alien civilizations in the universe, CNET points out that there could still be primitive settlements out there that don’t have the ability to generate mid-infrared emissions, and that 100,000 galaxies is a rather small sample size in a universe that is home to at least 100 billion known galaxies.
“As we look more carefully at the light from these galaxies,” Wright said, “we should be able to push our sensitivity to alien technology down to much lower levels, and to better distinguish heat resulting from natural astronomical sources from heat produced by advanced technologies. This pilot study is just the beginning.”
via Search of 100,000 galaxies found no alien life – Space News – redOrbit.
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