How far are Extraterrestrial Life and Intelligence after Kepler ?

TL;DR

This paper uses a Drake-equation-like model to estimate the abundance and detectability of extraterrestrial life and civilizations based on recent exoplanet discoveries and future spectral observations.

Contribution

It introduces a formalism linking astronomical data and biological probabilities to estimate the distance to extraterrestrial life and civilizations.

Findings

Potential biotic planets within 10 light years if Fb is high

Estimated nearest civilizations detectable within a few thousand light years

Detection probabilities depend on Drake parameters and telescope capabilities

Abstract

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.