The Kardashev scale
This page delivers no verdict; it presents claims and evidence with their sources. No theory in science is absolute. Method
For everyone
The Soviet astronomer Kardashev classified civilisations by the energy they use: Type I uses the energy of a planet, Type II that of a star, Type III that of a galaxy. By the formula Carl Sagan proposed for intermediate values, humanity stands at about 0.73 on 2025 energy data.
For specialists
Sagan's interpolation is K = (log₁₀ P − 6)/10 with P in watts, so Type I corresponds to 10¹⁶ W, Type II to 10²⁶ W and Type III to 10³⁶ W. World total primary energy supply in 2025 was about 600 EJ, an average power of about 1.9 × 10¹³ W, which gives K ≈ 0.728. The scale is criticised for leaving out measures such as information, efficiency or sustainability.
Claims
Evidence
Supporting
World primary energy supply was about 600 EJ in 2025, equivalent to 1.9 × 10¹³ W.[3]
Challenging
—
Positions
- Kardashev (1964)
- Energy use is a suitable measure for classifying civilisations that might be detected from space.[1]
Connections
Sources
- Article (1964). Transmission of information by extraterrestrial civilizations. Soviet Astronomy 8, 217–221
- Book (1973). The Cosmic Connection: An Extraterrestrial Perspective. Doubleday, New York
- Report (2026). Statistical Review of World Energy 2026energyinst.orgarchive
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Cite this page
Athena contributors. (2026). The Kardashev scale. Athena: The tree of human knowledge. Retrieved November 1, 2026, from https://latifkedi.github.io/athena/en/d/kardasev/
@misc{athena_kardasev,
title = {The Kardashev scale},
author = {{Athena contributors}},
year = {2026},
howpublished = {\url{https://latifkedi.github.io/athena/en/d/kardasev/}},
note = {Athena: The tree of human knowledge. Accessed: 2026-11-01}
}Added: September 27, 2026 · Last changed: September 27, 2026 · Page history