Jan 26, 2020, 7:53 AM
This list appears to omit what is possibly the most important criteria:
“Fraction of those planets with a molten iron core, and a moon large enough to keep it molten, so that an electromagnetic shield can protect the atmosphere.”
Rate of star formation, R” = 1 solar masses
Fraction of stars with planets, fp = 1
Number of habitable planets per star, ne = 4
Fraction of those planets that develop life, fl = 0.25
Fraction of the above that develop intelligent life, fi = 1
Fraction of planets with intelligent life that send signals into
space, to = 1
Lifetime of a civilisation that sends signals into space, L = 100