Kardashev Scale

The **Kardashev scale** (Russian: Шкала Кардашева, *Shkala Kardasheva*) 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 and came to bear his name.

The scale is hypothetical, and regards energy consumption on a cosmic scale. Various extensions of the scale have since been proposed, including a wider range of power levels (types 0, IV to V) and the use of metrics other than pure power (e.g., computational growth).

Kardashev first outlined his scale in a paper presented at the 1964 Byurakan conference, a scientific meeting that reviewed the Soviet radio astronomy space listening program. This paper, entitled "Передача информации внеземными цивилизациями" (and then translated into English "Transmission of Information by Extraterrestrial Civilizations"), proposes a classification of civilizations into three types, based on the postulate of exponential progression. A type I civilization is able to access all the energy available on its planet and store it for consumption. A type II civilization can directly consume the energy of a star. Finally, a type III civilization is able to capture all the energy emitted by its galaxy. In a second article, entitled "Strategies of Searching for Extraterrestrial Intelligence" and published in 1980, Kardashev wonders about the ability of civilization, which he defines by its capacity to access energy, to maintain itself and to integrate information from its environment. Two other articles followed: "On the Inevitability and the Possible Structure of Supercivilizations" and "Cosmology and Civilizations", published respectively in 1985 and 1997; the Soviet astronomer proposes tracks to detect supercivilizations and to direct the SETI programs.

The scale defined by Kardashev has been the subject of two main re-evaluations: that of Carl Sagan, who refines the types, and that of Michio Kaku, who discards the energy postulate in favor of the knowledge economy. Other debates on the nature of the different types have allowed many authors to question Kardashev's original classification, either to complete it or to refute it. Two critical perspectives have thus emerged: one that questions Kardashev's postulates, judging them to be incomplete or inconsistent, the other that establishes alternative scales. The Kardashev scale has given rise to numerous scenarios exploring the possibility of more evolved civilizations. These scenarios question, each one in its own way, the three postulates of Kardashev defining a civilization: energy sources, technology and the transmission of interstellar messages.

The framework for the search for and detection of advanced civilizations was constructed and theorized during the conference held in 1964 in Armenia, at the Byurakan astrophysical observatory. Starting from a functional definition of civilization, based on the immutability of physical laws and using the human civilization as a model of extrapolation, the initial model of Kardashev was developed. Several scientists have conducted various searches for possible civilizations, but without conclusive results. Based on these criteria, unusual objects, now known to be either pulsars or quasars, were identified. Kardashev has described in his various publications a set of listening and observing parameters to be taken into account; however, some authors, notably Samouïl Aronovitch Kaplan and Guillermo A. Lemarchand, consider that these are insufficient and need to be completed.

## Types

### Type I

A civilization "close to the level presently attained on Earth, with energy consumption at ≈4×1019 erg/sec" (4×1012 watts). A Type I civilization is usually defined as one that can harness all the energy that reaches its home planet from its parent star (for Earth, this value is around 2×1017 watts), which is about four orders of magnitude higher than the amount presently attained on Earth, with energy consumption at ≈2×1013 watts as of 2020. The astronomer Guillermo A. Lemarchand defined Type I as a level near contemporary terrestrial civilization with an energy capability equivalent to the solar insolation on Earth, between 1016 and 1017 watts.

### Type II

A civilization capable of harnessing the energy radiated by its own large star—for example, by means of the successful completion of a Dyson sphere or Matrioshka brain—with energy consumption at ≈4×1033 erg/sec. Lemarchand defined civilizations of this type as being 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 4×1033 erg/sec (4×1026 watts).

### Type III[

A civilization in possession of energy at the scale of its own galaxy, with energy consumption at ≈4×1044 erg/sec. Lemarchand defined civilizations of this type as having access to power comparable to the luminosity of the entire Milky Way galaxy, about 4×1044 erg/sec (4×1037 watts).

## Others

**Types 0, IV, and V Kardashev rating:** The most straightforward extension of the scale would include Type 0 civilizations, who do not rank on the Kardashev scale, to even more hypothetical Type IV beings who can control or use the entire universe or Type V who control collections of universes. The power output of the visible universe is within a few orders of magnitude of 1045 W. Such a civilization approaches or surpasses the limits of speculation based on current scientific understanding and may not be possible.