During 1964, Nikolai Kardashev proposed a threefold categorization of extraterrestrial cilivizations in terms of the power levels that could utilise in his article “Transmission of Information by Extraterrestrial Civilizations”.
During 1964, Nikolai Kardashev proposed a threefold categorization of extraterrestrial cilivizations in terms of the power levels that could utilise in his article “Transmission of Information by Extraterrestrial Civilizations”.
On 21 February 1964, the journal Science publishes an article entitled “The nonprevalence of humanoids” by George Gaylord Simpson.