Kardashev scale
The Kardashev scale ranks civilizations by the power they control: Type I about Earth's own, Type II a star's, Type III a galaxy's. By Kardashev's own threshold, humanity is past Type I.
Kardashev's scale sorts civilizations by the power they control, and so by how easily astronomers might detect them. Type I sat close to Earth's own consumption when he defined it; Type II harnesses a star's entire output, Type III a galaxy's. In 2018 humanity used nearly five times that first threshold. Yet on a sliding version built from Carl Sagan's method, the same use scores only 0.728, and one study puts Type I in 2371.
Sources
- Centauri Dreams, “What Kardashev Really Said” (2014)
- Wright et al., “The Ĝ Infrared Search for Extraterrestrial Civilizations with Large Energy Supplies. II”, ApJ 2014
- Jiang et al., “Avoiding the Great Filter”, Galaxies 2022
- Centauri Dreams, “Toward Kardashev Type I” (2022)
- Ćirković, “Kardashev's Classification at 50+”, Serbian Astronomical Journal 2015
wormhole
Yes, by its heat. Energy a civilization collects or generates has to be shed again to stay in balance, and the natural way out is mid-infrared light. Dyson spheres, built to capture a star's output, could therefore show up as an infrared glow in sky surveys that have already been made and published.
wormhole
Yes. A civilization spread across a galaxy would make it shine unusually brightly in the mid-infrared, and one survey looked for exactly that. No galaxy in its sample hosted anyone turning more than 85 percent of its starlight into infrared. Fifty, Arp 220 among them, were bright enough to allow more than half, and those were most likely galaxies, or pairs of them, forming stars at a high rate.
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