Time Curvature in FLRW Cosmology: Supernova and Hubble Constraints

This paper explores a geometric reinterpretation of late-time cosmic expansion within the standard FLRW cosmological framework by introducing a simple nonlinear mapping between observer time and cosmic evolution time. Using the publicly released Pantheon+SH0ES dataset of 1700 Type Ia supernovae, we constrain a single time-curvature parameter through weighted least squares and chi-squared minimization. The supernova-only fit identifies a preferred value of the deformation parameter, and a joint alignment yields a present-day Hubble constant of 73.0 km/s/Mpc consistent with late-universe measurements. A full set of robustness diagnostics confirms that the agreement is stable across the redshift range and not driven by localized subsets of the data. The results show that a minimal geometric deformation of time can reproduce late-time expansion observations within the supernova domain without introducing an explicit dark energy component.