The hunt for alien life goes on. A team of scientists used NASA’s WISE (Wide-field Infrared Survey Explorer) orbiting observatory to look for advanced civilizations. Out of 100,000 galaxies, they found no obvious indications of life.
Jason T. Wright, an assistant professor of astronomy and astrophysics at the Center for Exoplanets and Habitable Worlds at Penn State University, explains what they were looking for.
“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,” Wright said.
According to Wright, energy used by an advanced civilization must be radiated away as heat in the mid-infrared wavelengths. It’s fundamental thermodynamics.
Here’s an example of the type of image Wright and his team were looking at.
This is how the Great Galaxy in Andromeda looks through NASA’s WISE space telescope.
The orange rings around the blue center? That’s heat from stars forming. The team of scientists were looking for any unusual amounts of mid-infrared emission.
The idea of using mid-infrared emissions to spot advanced alien civilizations isn’t a new one. Theoretical physicist Freeman Dyson first proposed the idea in the 1960s. But, telescopes were not advanced enough back then to look for the waste heat. Today is different with space telescopes like WISE able to see the cosmos like never before.
There is a bit of hope out of the 100,000 galaxies observed. About 50 of them had unusually high levels of mid-infrared radiation according to Roger Griffith, lead author of the paper.
“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 civilization,” said Griffith.
According to Wright, each of the galaxies observed has been around for billions of years. Plenty of time for an advanced civilization to form. “ Either they don’t exist, or they don’t yet use enough energy for us to recognize them,” Wright said.
NASA’s WISE telescope isn’t the only telescope used for observing objects through infrared. NASA’s Spitzer Space Telescope and Herschel Space Observatory also peer into the cosmos through infrared.
WISE stands out by surveying the entire sky.
It’s not just galaxies on WISE’s radar. It has also spotted near-Earth objects such as asteroids and comets.
Image credits: NASA. Top image is the entire sky mapped by WISE