Cosmology at the End of Time

If the recent acceleration phase of the expanding Universe is driven by a cosmological constant the Universe is future-eternal with a few far reaching ramifications and disturbing consequences. We demonstrate with a non-ΛCDM cosmological model, that is nearly identical to the standard cosmological model insofar observations of our past are concerned—but otherwise has an effective cosmic time cutoff—that under certain plausible assumptions observers will virtually always find themselves at or near the end of time (EOT) terminal point, where H0η0 = π, and H0 and η0 are the present day expansion rate and the conformal time, respectively. Assuming a locally flat ΛCDM model for concreteness (but with a global terminal point which is with an overwhelming probability the present time) such observers will invariably infer that the energy densities associated with the cosmological constant, Λ, and non-relativistic (NR) matter constitute 67.5% and 32.5%, respectively, of the cosmic energy budget at present, which lie well within the 2σ confidence level of the concordance 68.5% and 31.5% values. This addresses the Cosmic Coincidence Problem associated with Λ. Future high-precision cosmological probes will be able to break the observational degeneracy between the proposed model and flat ΛCDM. A few additional implications of the proposed model are discussed as well.