Carl Sagan

Carl Sagan was an American astronomer, planetary scientist, cosmologist, astrophysicist, astrobiologist, author, and science communicator. His best known scientific contribution is research on extraterrestrial life, including experimental demonstration of the production of amino acids from basic chemicals by radiation. Sagan assembled the first physical messages sent into space: the Pioneer plaque and the Voyager Golden Record, universal messages that could potentially be understood by any extraterrestrial intelligence that might find them.

Sagan advocated scientific skeptical inquiry and the scientific method, pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence (SETI).

He suggested a change to Kardashev's original scale by interpolating and extrapolating the values given for types I (1016 W), II (1026 W) and III (1036 W), which would produce the formula K=(logP-6)/10 where K is a civilization's Kardashev rating and P is the power it uses, in watts. Humanity's civilization type as of 1973 was about 0.7, using an average power consumption of 10 terawatts (TW) as the value. In 2018, the total world average power consumption was 18.40 TW, making us 0.73 on Sagan's interpolated Kardashev scale. The calculation is (log 18 400 000 000 000 - 6) / 10.