The Kardashev scale is a method of measuring a civilization’s level of technological advancement based on the amount of energy it is able to use. The measure was proposed by Soviet astronomer Nikolai Kardashev in 1964.
The scale has three designated categories.
- A Type I civilization, also called a planetary civilization—can use and store all of the energy available on its planet.
- A Type II civilization, also called a stellar civilization—can use and control energy at the scale of its planetary system.
- A Type III civilization, also called a galactic civilization—can control energy at the scale of its entire host galaxy.
Technological level of a civilization that is “close to the level presently attained on Earth, with energy consumption at 4×1012 watts. Currently, the civilization of Type I is usually defined as one that can harness all the energy that falls on a planet from its parent star (for Earth–Sun system, this value is close to 1.74×1017 watts), which is about four orders of magnitude higher than the amount presently attained on Earth, with energy consumption at ≈2×1013 watts.
The astronomer Guillermo A. Lemarchand stated this as a level near contemporary terrestrial civilization with an energy capability equivalent to the solar insolation on Earth, between 1016 and 1017 watts.
A civilization capable of harnessing the energy radiated by its own star—for example, the stage of successful construction of a Dyson sphere or Matrioshka brain —with energy consumption at ≈4×1026 watts. Lemarchand stated this as a civilization capable of using and channeling the entire radiation output of its star. The energy use would then be comparable to the luminosity of the Sun, about 4×1026 watts.
A civilization in possession of energy at the scale of its own galaxy, with energy consumption at ≈4×1044 erg/sec (1037 watts). Lemarchand stated this as a civilization with access to the power comparable to the luminosity of the entire Milky Way galaxy, about 4×1037 watts.
There are also 2 extended categories.
- A Type IV civilization, also called a universal civilization, can control energy at the scale of its entire host universe.
- A Type Ω or Type V civilization, also called a multi-universal civilization, can control energy at the scale of multiple universes, and may be able to create universes.
At the current time, humanity has not yet reached Type 1 civilization status. Physicist and futurist Michio Kaku suggested that, if humans increase their energy consumption at an average rate of 3 percent each year, they may attain Type I status in 100–200 years, Type II status in a few thousand years, and Type III status in 100,000 to a million years.
In 2015, a study of galactic mid-infrared emissions came to the conclusion that “Kardashev Type-III civilizations are either very rare or do not exist in the local Universe”.
In 2016, Paul Gilster, author of the Centauri Dreams website, described a signal apparently from the star HD 164595 as requiring the power of a Type I or Type II civilization, if produced by extraterrestrial lifeforms. However, in August 2016 it was discovered that the signal’s origin was most likely a military satellite orbiting the Earth.