From here to eternity, the far future of the universe

A review of what established physics predicts for the universe after the present epoch: the end of star formation, the cooling of stellar remnants, the possible decay of protons, the evaporation of black holes by Hawking radiation, and the approach to a cold, nearly empty de Sitter state. Each statement is marked as measured, calculated with known physics, or speculative. A timeline gives every step with its source; four computed figures show the eras on a logarithmic time axis, the accelerating expansion and the cosmic event horizon (Planck 2018 parameters), proton-lifetime bounds from Super-Kamiokande against a grand-unified estimate, and black-hole evaporation time against mass. A section on time itself discusses the thermodynamic arrow of time and its disappearance in the heat death, the entropy cost of keeping time with clocks, whether time can end (de Sitter, Big Rip, Big Crunch), and the problem of time in quantum gravity; two further computed figures show three possible ends of cosmic time from the Friedmann equations and the entropy budget of the observable universe against the de Sitter maximum. Open questions (vacuum decay, evolving dark energy after DESI, Boltzmann brains, cyclic cosmologies, and Dyson's question whether life can last forever) are treated separately and labelled as such. 78 references, nearly all peer-reviewed with DOIs checked against Crossref. This is a review of published work and reports no new results. The text was drafted by Anthropic's Claude, an AI system, under the author's direction. A living version is kept on ScholarlyWiki as "Physics:Quantum From here to eternity, the far future of the universe".