Drake equation

The Drake equation (also known as the Green Bank equation or the Sagan equation) is a famous result in the speculative fields of xenobiology, astrosociobiology and the search for extraterrestrial intelligence.

Related Topics:
Xenobiology - Astrosociobiology - Search for extraterrestrial intelligence

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This equation was devised by Dr. Frank Drake in the 1960s in an attempt to estimate the number of extraterrestrial civilizations in our galaxy with which we might come in contact. The main purpose of the equation is to allow scientists to quantify the uncertainty of the factors which determine the number of extraterrestrial civilizations.

Related Topics:
Frank Drake - 1960s - Extraterrestrial

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The Drake equation is closely related to the Fermi paradox. It was cited by Gene Roddenberry as supporting the multiplicity of starfaring civilizations shown in Star Trek, the television show he created.

Related Topics:
Fermi paradox - Gene Roddenberry - Star Trek

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The Drake equation states that:

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:N = R^{*} ~ imes ~ f_{p} ~ imes ~ n_{e} ~ imes ~ f_{l} ~ imes ~ f_{i} ~ imes ~ f_{c} ~ imes ~ L

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where:

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:N is the number of extraterrestrial civilizations in our galaxy with which we might expect to be able to communicate

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and

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:R* is the rate of star formation in our galaxy

Related Topics:
Star - Our galaxy

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:fp is the fraction of those stars which have planets

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:ne is average number of planets which can potentially support life per star that has planets

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:fl is the fraction of the above which actually go on to develop life

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:fi is the fraction of the above which actually go on to develop intelligent life

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:fc is the fraction of the above which are willing and able to communicate

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:L is the expected lifetime of such a civilization

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