Saturn’s Titan: A Strict Test for Life’s Cosmic Ubiquity.
The first four terms of the Drake equation beingFrom the point of view of “astrobiological Copernicanism”—
whether life itself is a common cosmic phenomenon—it is enough to consider a
“truncated Drake equation” of the first four terms only, multiplied by the duration of time
over which a planet remains habitable. This is the number of life-bearing planets in the
1. Rate of star formation
2. Fraction of stars with planets
3. Average number of habitable worlds per planetary system
4. Fraction of habitable planets where life actually forms [or gets transferred to]
What this means... the number of habitable worlds is a factor in the equation for how much life there is in the galaxy. It is not the only factor.