The gravitational Olbers’ paradox and the entropic accelerating universe

The accelerating expansion of the Universe is reframed as the resolution to a gravitational analogue of Olbers’ Paradox. Because gravitational influence propagates at the speed of light—confirmed by the binary neutron star merger GW170817—each observer is surrounded by a cosmological event horizon beyond which matter exerts no gravitational pull. The horizon is a thermodynamic object: it possesses a temperature proportional to the Hubble parameter and an entropy proportional to its area. As the universe expands, the horizon grows and its entropy S H ∝ R H 2 increases geometrically—present in any expanding spacetime regardless of matter content. The second law of thermodynamics drives the universe toward states of larger horizon radius. The resulting entropic pressure, P = − 2 3 ρ crit c 2 , yields an effective equation of state ω eff = − 2 / 3 , providing accelerating expansion with no vacuum energy contribution and dissolving the cosmological constant problem without fine-tuning. The contribution of this work is to identify this result as the resolution of the gravitational Olbers’ paradox, supplying the physical justification for horizon thermodynamics that earlier entropic-force treatments acknowledged was lacking. The predicted dynamical dark energy, with ω ≠ − 1 evolving with redshift, is consistent with the 4.2 σ deviation from ΛCDM reported by the DESI Year 3 (DR2) survey.