  The Kepler mission has shown that a significant fraction of all stars may
have an Earth-size habitable planet. A dramatic support was the recent
detection of Proxima Centauri b. Using a Drake-equation like formalism I derive
an equation for the abundance of biotic planets as a function of the relatively
modest uncertainty in the astronomical data and of the (yet unknown)
probability for the evolution of biotic life, Fb. I suggest that Fb may be
estimated by future spectral observations of exoplanet biomarkers. It follows
that if Fb is not very small, then a biotic planet may be expected within about
10 light years from Earth. Extending this analyses to advanced life, I derive
expressions for the distance to putative civilizations in terms of two
additional Drake parameters - the probability for evolution of a civilization,
Fc, and its average longevity. Assuming "optimistic" values for the Drake
parameters, (Fb~Fc~1), and a broadcasting duration of a few thousand years, the
likely distance to the nearest civilizations detectable by SETI is of the order
of a few thousand light years. Finally I calculate the distance and probability
of detecting intelligent signals with present and future radio telescopes such
as Arecibo and SKA and how it could constrain the Drake parameters.
