The Spacetime Flow Hypothesis (SFH) models gravity and cosmology as consequences of a dynamical flow of proper time, described by a Lorentz-invariant four-vector field and an associated scalar resistance field. In this framework, redshift, gravitational effects, and cosmic evolution arise from causal delay in time flow rather than from spacetime curvature or metric expansion. We apply SFH’s first-principles flow equations to Type Ia supernova time dilation and luminosity distance. Using a physically derived flow-decay law fixed independently of supernova data, we compute the redshift dependence of the luminosity–distance relation and compare it to the Pantheon+ SH0ES sample (N = 1701). Absolute distance normalization is treated as a standard nuisance parameter, directly analogous to the supernova absolute magnitude in ΛCDM analyses. The resulting fit yields χ² = 1587.12 for 1700 degrees of freedom (χ²/dof = 0.934), with a mean residual of 0.01 mag, demonstrating ΛCDM-level agreement in the redshift-dependent shape of the distance and time-dilation behavior without invoking dark energy, spacetime curvature, or model-specific fitted cosmological parameters. Derivation of the absolute normalization from flow dynamics is identified as a Phase-II objective. Foundational Theory Spacetime Flow Hypothesis — Core Field-Theoretic Framework. DOI : https://doi.org/10.5281/zenodo.18140096Defines the flow-field, scalar resistance α(x), drift law, energy conservation, and Lagrangian. Empirical Validation Gravitational Wave Orbital Decay — Binary pulsars (leading-order agreement with GR from first principles). DOI: https://doi.org/10.5281/zenodo.18214948 Galaxy Rotation Curves — 20/20 fits without dark matter. DOI: https://doi.org/10.5281/zenodo.18136466 Gravitational Lensing Time Delays — 10 strong-lens delays from baryons only. DOI : https://doi.org/10.5281/zenodo.18136510 Predictive Frontier (New V2) Fast-Flow Bubble — Local void explains Hubble tension (11σ match to Pantheon+ residuals). DOI : https://doi.org/10.5281/zenodo.18136251 (New V2) ISW Effect — The Integrated Sachs–Wolfe Effect without Dark Energy: A Causal Gradient Prediction. DOI : https://doi.org/10.5281/zenodo.18136185 (New) Filament Rotation — Cosmic filaments rotate only when ∇α is asymmetric; DOI : https://doi.org/10.5281/zenodo.18141156 Together with prior empirical validations of SFH across binary pulsars, supernova time dilation, galaxy rotation curves, gravitational lensing delays, and large-scale ISW correlations, filament-rotation result supports a unified, causal interpretation of gravity based on gradients in the flow of proper time. Version 2 (December 2025). This revision improves presentation and technical consistency relative to Version 1. Clarifications were made to the analytic derivation, figure placement was corrected, and the bibliography was cleaned and consolidated. No changes were made to the underlying model or quantitative results. Correspondence: Daniel Beaupré — GitHub: https://github.com/dbeaup01
Daniel Beaupré (Sun,) studied this question.