Drake equation (redirected from Sagan equation)

Drake equation

 or Green Bank equation

Equation claimed to yield the number of technically advanced civilizations capable of interstellar communication in the Milky Way Galaxy as a function of several factors conducive to evolution of intelligent life with technological capabilities. It was largely developed by Frank D. Drake (b. 1930) in 1961 at a SETI conference in Green Bank, W.Va. Of all the stars that form in the Galaxy, only some will give rise to life-supporting planets, and of those planets, only some will generate life capable of high technology and yet able to avoid technological destruction. Because the numbers for each factor are poorly known, the results generated vary from zero to millions.

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Drake equation [′drāk i‚kwā·zhən]

(astronomy)

An equation which gives the number of advanced technological civilizations curently active in the Galaxy as the product of the rate at which new stars are born in the Galaxy, the probability (actually a product of probabilities) that any one of these stars will possess the necessary conditions for life to originate and to slowly evolve to a technological civilization, and the average longevity of such civilizations.