See if you can solve this one
N = N* fp ne fl fi fc fL
My "sig" would give you a cule.
N* = the number of stars in the Milky Way galaxy:
fp = fraction of stars with planets around them:
ne = number of planets per star ecologically able to sustain life:
fl = fraction of those planets where life actually evolves:
fi = the fraction of fl that evolves intelligent life:
fc = the fraction of fi that communicates:
fL = the fraction of the planet's life during which the communicating civilizations survives:
P.S. Sorry I couldn't help it, had to pose this one, It will blow your mind!