Successor to the Drake Equation

[ignorantianescia]

This Fermi estimate is presented as the new kid on the rock:

N = N_*F_QF_HZF_OF_LF_S

N = the number of planets with detectable signs of life
N_* = the number of stars observed
F_Q = the fraction of stars that are quiet
F_HZ = the fraction of stars with rocky planets in the habitable zone
F_O = the fraction of those planets that can be observed
F_L = the fraction that have life
F_S = the fraction on which life produces a detectable signature gas

www.theguardian.com/science/across-the-universe/2013/sep/04/equation-alien-life-universe

Many of us have glanced upwards at the stars and wondered whether there is other life out there somewhere. Few, however, have then tried to write down an equation to express the probability in numbers.

Sara Seager of the Massachusetts Institute of Technology has done just that. Her equation collects together all the factors that could determine how many planets with detectable signs of life may be discovered in the coming years.

[unkleE]

The Drake Equation isn't the only one. About 15 years ago Ward and Brownlee, investigating the same questions, developed the Rare Earth Equation. I think Stuart Clark is right, the equations tell us very little beyond clarifying the assumptions of the proponent, which is of course useful.