Resolution of Hubble Cosmic Age Tension in Thermodynamic Relativistic Gravity - Classical General Relativity (TRG-CGR) Framework

The determination of the cosmic age in standard ΛCDM cosmology is tightly coupled to the
present-day Hubble constant, leading to a persistent tension between early-universe measurements
inferred from the cosmic microwave background and late-time local determinations of the expansion
rate. In this work, we introduce a split-epoch evaluation of cosmic time within the Thermodynamic
Relativistic Gravity–Classical General Relativity (TRG-CGR) framework, in which the cosmic age
is expressed as the sum of distinct early- and late-universe contributions governed by different
effective expansion rates.
We show that the dominant contribution to the cosmic age arises from the early universe, where
the expansion rate is lower and the Hubble radius is large, while the late universe–despite exhibiting
a higher locally measured Hubble constant–contributes only a small additional proper time. Using
standard cosmological density fractions for comparison and assuming a spatially flat background
geometry, we perform a step-by-step numerical evaluation of the cosmic age with a transition
redshift zt ≃ 0.01. The resulting total age remains consistent with cosmic microwave background
constraints while simultaneously accommodating higher local measurements of H0.
This split-epoch approach demonstrates that the Hubble tension and the associated age tension
are not fundamentally observational conflicts but arise from the assumption of a single global
expansion history. The TRG-CGR framework naturally decouples late-time expansion from the
accumulated cosmic age, providing a physically consistent resolution without invoking additional
dark sector components or modifications to early-universe physics.