As of this moment, we know of one galaxy that contains intelligent life … OK, life. That life is us and we’ve been looking for life on other planets ever since we realized there were other planets and stars in the Milky Way. We haven’t found it yet, but two researchers have gone beyond the Milky Way to look for galaxies that might be home to hyper-advanced life forms – aliens that can harness the energy of an entire galaxy. Believe it or not, they’ve identified two of them. Should we be excited … or worried?
“Kardashev Type III civilisations have by definition energy requirements that are likely to generate strong excess emission in the mid-infrared (MIR) that is associated with the waste heat they generate.”
In a paper published in the journal Monthly Notices of the Royal Astronomical Society, astronomer Hongying Chen from Leiden University describes how he and his team went looking for Kardashev Type III (K3) civilizations. The Kardashev scale was developed in 1964 by Soviet astronomer Nikolai Kardashev as a method to judge the intelligence of an alien civilization by how much energy it uses. We piddly humans are but a fraction of Type I, which is a civilization that can use and store all of a planet’s energy. Type II can use and control the energy of a star, while Type III is master of all of the energy in its galaxy. The only way we humans can even conceive of doing this is with a Dyson sphere – those hypothetical megastructures built around a star or a black hole to harvest their energy. If you follow the philosophy that if we can conceive of something then it must exist somewhere, you’ll understand why Chen and his team went looking for the estimated energy signature of a hyper-hypothetical galactic Dyson sphere – an emission in the mid-infrared range (MIR).
“For those civilisations that capture starlight via Dyson sphere like constructions, the Optical to MIR flux ratio of the host galaxies is also expected to be unusually low.”
Chen and study co-author Michael Garrett looked at results from the LOFAR Two-meter Sky Survey (LoTSS) which is creating a radio map of the entire northern sky. According to an understandable explanation by Inverse, they found four galaxies with mid-infrared emissions in the range they were looking for. (Photos here.) Two had natural explanations for them -- one was an active galactic nuclei and the other was a star-forming galaxy. The other two galaxies, called ILT J134649.72+542621.7 and ILT J145757.90+565323.8, could not be explained. Are those the ones with galactic Dyson spheres run by hyper-advanced civilizations?
“These sources deserve further study and investigation.”
Chen and Garrett aren’t ready to make that kind of commitment, but they didn’t rule it out either.
“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. We can also have high-resolution radio observations on them to look at their morphology.”
That’s not the same as sending a digital signal asking if they’re Type III aliens, but that’s the best we not-even-Type-I humans can do for now. Fortunately, these powerful aliens are in other galaxies. Then again, if they can build a galactic Dyson sphere, who’s to say they can’t develop faster-than-light, wormhole jumping transportation and be here tomorrow?
In the meantime, we should be cramming for out Type I qualification test.