I love you, wikipedia!
where:
- N = the number of civilizations in our galaxy with which communication might be possible;
and
- R * = the average rate of star formation per year in our galaxy
- f p = the fraction of those stars that have planets
- n e = the average number of planets that can potentially support life per star that has planets
- f l = the fraction of the above that actually go on to develop life at some point
- f i = the fraction of the above that actually go on to develop intelligent life
- f c = the fraction of civilizations that develop a technology that releases detectable signs of their existence into space
- L = the length of time for which such civilizations release detectable signals into space [ 5 ]