Brian C. Lacki, a theoretical astrophysicist working with the Breakthrough Listen Initiative, recently took a big step forward in our search for ETI. His innovative research is advancing the frontiers of knowledge in this burgeoning field. In a new paper, Lacki applies the Kardashev scale as a yardstick to determine the scale of energy use from an advancing civilization. He uses this approach to determine the likelihood of advanced civilizations existing across the universe. His results imply that if the universe is teeming with civilization spanning the galaxy, it is extremely uncommon.
The Kardashev scale, introduced by Russian astrophysicist Nikolai Kardashev in 1964, ranks civilizations according to their energy consumption. A Type I civilization harnesses energy at the scale of a whole planet. In comparison, a Type II civilization makes use of the vast energy output of their star. The most advanced, Type III civilizations, are speculated to harness the energy of a full galaxy. In both public and academic circles, Lacki’s research has provided important perspective on the prospects of finding such civilizations, assuming their radio emissions can be found.
Understanding the Kardashev Scale
The Kardashev scale is a method of measuring a civilization’s level of technological advancement based on the amount of energy they are able to use. A Type I civilization, for instance, would be capable of using all the energy that can be found and harnessed on its native planet. This means tapping into geothermal, solar, wind, and other renewable energies to power its mega-tech boost.
Type II civilizations expand on this idea even further by harnessing the complete energy emission of their home sun. These civilizations would build enormous structures, such as Dyson spheres, to collect and utilize stellar energy for their activities. Synthetic signatures These technologically sophisticated societies would likely emit signals that could be detected across tens of thousands of light years.
Finally, Type III civilizations are those that are able to control energy at the scale of the entire galaxy. This would be very much like harnessing the energy radiated by billions of stars. As for Lacki, he thinks we can find proof of these civilizations by studying unusual radio emissions. This would provide priceless clues about the nature of intelligent life outside of our planet.
Rarity of Type III Civilizations
Lacki’s research suggests the chances of picking up radio signals from mature Kardashev Type III civilizations is extremely slim. His models predict that less than one in 10^17 stars are able to host such advanced societies. Furthermore, the analysis reveals that only about one in a million large galaxies may harbor a Type III civilization capable of broadcasting radio signals.
This stark statistical reality underlines just how difficult the research enterprise is stacked against those researchers racing to find evidence of extraterrestrial life. Maybe those civilizations do exist, but their rarity makes them difficult to detect. We just don’t come across them frequently enough to identify them with such expediency. As Lacki’s work shows, it’s critical to refine the methodologies we use in searching for technosignatures from these advanced societies.
Technosignature Searches and Future Research
After all, the search for signs of extraterrestrial intelligence (ETI) goes well beyond just searching for radio signals. Researchers are hoping to discover dozens of different technosignatures that would point to the existence of advanced civilizations elsewhere in our galaxy. These exclusions outright, or limit their impact, such as sources of excess infrared radiation – which could come from heat given off by megastructures such as Dyson shells.
Lacki’s research contributes to this multifaceted approach by evaluating individual radio broadcasts that might stand out against the cosmic background noise. Lacki takes apart data recorded at partner observatories as a part of the Breakthrough Listen Initiative. His results provide key lessons on how scientists can better focus their searches.
His paper is the third in a series spotlighting new discoveries from these initiatives. As observational technology grows, researchers race to be the first to collect a new set of data. Their goal is to refine their ideas about how and where to look for evidence of complex extraterrestrial life.