(estimate of advanced life in the Milky Way)
The Drake equation is a well-known example of a
model to estimate the number of detectable extraterrestrial
advanced civilizations in the galaxy,
a number of interest in
the field of SETI (search for extraterrestrial intelligence).
It was formulated by astronomer Frank Drake in 1961.
N = R* × fp × ne × fl × fi × fc × L
- N - the number.
- R* - average rate of star formation in the galaxy.
- fp - average fraction of those stars with planets.
- ne - average number of life-supportable planets in such systems, i.e., in the habitable zone and so forth.
- fl - fraction of those that actively develop life.
- fi - fraction of those that develop intelligent life.
- fc - fraction of those that develop technology that can release detectable signals.
- L - length of time for which such systems release detectable signals.