What implication arises if preliminary estimates suggest rocky planets in the HZ around Sun-like stars are quite common?
The scientific focus shifts from *Can* these planets exist? to *Why* haven't we confirmed life on any of them yet?
If missions like Kepler suggest that the formation of rocky worlds within the liquid water zone around stable, Sun-like stars is frequent—potentially numbering in the billions within the Milky Way—it implies that the environment necessary for life to start is not rare. This statistical abundance shifts the scientific puzzle: the challenge moves away from finding suitable environments (the 'Can they exist?' question) toward understanding the step that prevents colonization by life. This suggests that either the initial emergence of life itself (abiogenesis) is an exceedingly rare event, or that the biosignatures produced by extant life are too subtle for current detection technologies to confirm.
