Drake equation

The Drake equation was devised in an attempt to estimate the number of extraterrestrial alien species that could communicate with Humans. The first and more mathematical variation stated:
 * $$N = R^{*} ~ \times ~ f_{p} ~ \times ~ n_{e} ~ \times ~ f_{l} ~ \times ~ f_{i} ~ \times ~ f_{c} ~ \times ~ L$$


 * where:


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


 * and


 * R* is the rate of star formation in our galaxy
 * fp is the fraction of those stars which have planets
 * ne is average number of planets which can potentially support life per star that has planets
 * fl is the fraction of the above which actually go on to develop life
 * fi is the fraction of the above which actually go on to develop intelligent life
 * fc is the fraction of the above which are willing and able to communicate
 * L is the expected lifetime of such a civilization

The second variation stated:
 * $$F f ^ 2 (M g E) - C ^ 1 Ri^1 ~ \times ~ M = L / So$$

In 1996, Rain Robinson had a poster of the two variations of the equation. 

External link


Équation de Drake