The Drake Equation

The Drake Equation's premise is to calculate the possibility of extraterrestrials in our galaxy (the Milky Way). Founded by our dear Dr. Donald Drake he uses the following formula to derive the probabilities. It cannot be exact, however, to us as humans it may be the best or one of the best plausible derivatives   we can come up with (when speaking of potential civilized extraterrestrials),

                                             (source link represented by clicking picture)

N = Civilizations within our galaxy that we may be able to communicate with

 

R* = Star formations rate

 

f_p = The fraction of R*'s stars that have planets.

 

n_e = Average number of planets that could support life according to each star that has planets.

 

f_l = Fraction of the above that has the possibility to support life.

 

f_i = Fraction of the above that can create intelligent life 

 

f_c = Fraction of the above that are technically advanced enough for us to find evidence of them in space. (radio waves etc......) 

 

L = Length of time to detect the above technology from the planet.

400 billion x  1/4 x 2 x 1/2 x 1/10 x 1/10 x 1/ 100 million = about 10 civilizations we can communicate with.

(The math above represents that civilizations with technology are only lasting a few decades. Below is another representation if civilized worlds where to be able to prosper millions of years.) 400 billion x 1/4 x 2 x 1/2 x 1/10 x 1/10 x 1/ 100 = about a million civilizations we can communicate with.