Questions concerning or involving the Drake equation which estimates the probability of making contact with intelligent life in the Milky Way.

The Drake equation is a formula proposed by Frank Drake of the National Radio Astronomy Observatory (NRAO) in Green Bank, West Virginia in 1960 with the goal to estimate the probability of making contact with intelligent life in the Milky Way, by giving a product for the number $N$ of broadcasting civilizations:

$N = R \cdot f_p \cdot n_e \cdot f_l \cdot f_i \cdot f_c \cdot L$

Here,

  • $R$ is the average rate of formation of suitable stars in the Milky Way (in stars/year).
  • $f_p$ is the fraction of stars that form planets
  • $n_e$ is the average number of habitable planets per star
  • $f_l$ is the fraction of habitable planets where life emerges
  • $f_i$ is the fraction of habitable planets with life where intelligent evolves
  • $f_c$ is the fraction of planets with intelligent life capable of interstellar communication
  • $L$ is the number of years a civilization remains detectable