Drake equation
Description
is a probabilistic argument used to estimate the number of active, communicative extraterrestrial civilizations in the Milky Way galaxy
Related formulasVariables
N | the number of civilizations in our galaxy with which communication might be possible (i.e. which are on our current past light cone) (dimensionless) |
R | the average number of star formation per year in our galaxy (year-1) |
fp | the fraction of those stars that have planets (dimensionless) |
ne | the average number of planets that can potentially support life per star that has planets (dimensionless) |
fl | the fraction of planets that could support life that actually develop life at some point (dimensionless) |
fi | the fraction of planets with life that actually go on to develop intelligent life (civilizations) (dimensionless) |
fc | the fraction of civilizations that develop a technology that releases detectable signs of their existence into space (dimensionless) |
L | the length of time for which such civilizations release detectable signals into space (year) |