The Drake equation is: � = � ∗ ⋅ � p ⋅ � e ⋅ � l ⋅ � i ⋅ � c ⋅ � {\displaystyle N=R_{*}\cdot f_{\mathrm {p} }\cdot n_{\mathrm {e} }\cdot f_{\mathrm {l} }\cdot f_{\mathrm {i} }\cdot f_{\mathrm {c} }\cdot L} where N = the number of civilizations in the Milky Way galaxy with which communication might be possible (i.e. which are on the current past light cone); and R∗ = the average rate of star formation in our Galaxy fp = the fraction of those stars that have planets ne = the average number of planets that can potentially support life per star that has planets fl = the fraction of planets that could support life that actually develop life at some point fi = the fraction of planets with life that actually go on to develop intelligent life (civilizations) fc = 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][6]