A team of astronomers led by Leiden University researcher Hongying Chen is actively searching the skies for advanced alien life forms, a report by Inverse explains.
They are looking for infrared signals that they believe could be the exhaust emissions of hypothetical Dyson spheres — massive megastructures that harness the energy of the surrounding universe. Their new paper focuses on two distant galaxies whose infrared emissions have so far eluded easy explanation.
Searching for hyper-intelligent alien life
Is there life somewhere out there? The Fermi Paradox posits that it is extremely likely, given the fact that there are billions of stars in the Milky Way alone, many of which have orbiting planets in habitable zones. And yet, we have detected no signs of intelligent alien life. New discoveries — such as the recent finding that Mars was always too small to retain surface waters — are constantly changing our understanding of the likelihood that we will one day discover intelligent life in the far reaches of space.
Chen and his team believe that, if life is out there, the most likely way to find it is to search for the footprint of the most advanced civilizations. Specifically, they are searching for Kardashev Type III civilization (K3) lifeforms. The Kardashev scale was proposed by Soviet astronomer Nikolai Kardashev in 1964 as a means to measure a hypothetical civilization's level of technological advancement based on the amount of energy it is able to harness from the surrounding universe.
K3 lifeforms sit at the top of the scale as the most advanced type of alien civilization. According to the scale, they would be able to harness the power of black holes, stars, and quasars for their energy needs using technologies similar to the hypothetical Dyson sphere — a massive structure that could surround a celestial object such as a star without collapsing. Humans, it is worth noting, are not even considered Type 1 yet, as that would require us efficiently harnessing the power of the Sun. Chen and his team scanned part of the Northern Sky to search for galaxies that may be home to K3 alien lifeforms. Out of the 21 galaxies they analyzed, two have stood out so far. They detail their findings in a paper published in the Monthly Notices of the Royal Astronomical Society.
Narrowing down an endlessly wide investigation
The team behind the new study believes they can detect a Type III civilization by searching the skies for mid-infrared emissions. These, they say, could be telltale signs for the emissions of Dyson Spheres from advanced alien races — in their paper, Chen's team says that K3 civilizations are likely to "generate strong excess emission in the mid-infrared (MIR) that is associated with the waste heat they generate." The researchers looked at the emissions of 21 galaxies with high mid-infrared emissions and found that four of these had mid-infrared emissions enhanced by a factor of 10. One of these was an active galactic nuclei, while another was a star-forming galaxy, meaning they are natural sources for mid-infrared emissions. However, the other two galaxies, called ILT J134649.72+542621.7 and ILT J145757.90+565323.8, cannot be so easily explained, and the researchers say they "warrant further investigation."
Next, the researchers aim to figure out the exact source of those infrared emissions. "We can look at their emissions in other wavelengths such as X-ray, optical, and see if their spectral energy distribution is active galactic nuclei-like or star-forming-galaxy-like," Chen told Inverse in an interview. "We can also have high-resolution radio observations on them to look at their morphology." They also plan to scan other parts of the skies to search for potential signs of hyper-advanced alien life.