The Cosmic Coincidence as a Temporal Selection Effect Produced by the Age Distribution of Terrestrial Planets in the Universe

The energy densities of matter and the vacuum are currently observed to be ofthe same order of magnitude: $(\Omega_{m 0} \approx 0.3) \sim (\Omega_{\Lambda0} \approx 0.7)$. The cosmological window of time during which this occurs isrelatively narrow. Thus, we are presented with the cosmological coincidenceproblem: Why, just now, do these energy densities happen to be of the sameorder? Here we show that this apparent coincidence can be explained as atemporal selection effect produced by the age distribution of terrestrialplanets in the Universe. We find a large ($\sim 68 %$) probability thatobservations made from terrestrial planets will result in finding $\Omega_m$ atleast as close to $\Omega_{\Lambda}$ as we observe today. Hence, we, and anyobservers in the Universe who have evolved on terrestrial planets, should notbe surprised to find $\Omega_m \sim \Omega_{\Lambda}$. This result isrelatively robust if the time it takes an observer to evolve on a terrestrialplanet is less than $\sim 10$ Gyr.Comment: Submitted to Ap