The COSETI Observatory
R* = Rate of star formation.
s = Fraction with good suns.
p = Fraction with planets.
The subscript “o” accounts for the matching of electromagnetic transmitting and receiving technologies.
i = Fraction with intelligence.
c = Fraction wishing to communicate.
o = Fraction using optical means.
L = Lifetime of civilization.
If all ETIs use laser technology to transmit and we use microwave technology to receive, the number of detectable civilizations falls to zero!
The Modified Drake Equation