Galactic-Scale Valve Modulation: Localised Curvature Feedback in an Expanding Universe – Addendum to "The Universal Valve Hypothesis" (v1.5F)

Abstract This addendum extends The Universal Valve Hypothesis (v1.5F) from a cosmological to a galactic scale. It refines the proposed curvature regulation model by introducing the concept of galactic scale valve modulation, in which black holes function as distributed accretive and emissive curvature valves. The document formalises the Valve Phase Boundary (VPB) as a dynamic equilibrium surface that separates gravitationally bound regions from those that reconnect with cosmic expansion. The model remains within General Relativity, introduces no new particles or negative masses, and outlines observational tests involving weak lensing under-convergence, metallicity correlations, local variation in the Hubble flow, and emissivity in cosmic voids. Description This document is an official addendum to The Universal Valve Hypothesis (v1.5F). It develops the hypothesis from a systems level cosmic framework to a galactic scale formulation, clarifying how the combined behaviour of black holes may influence the onset of expansion at different structural levels of the Universe. Three valve layers are defined: micro (individual black holes), meso (galaxies), and macro (clusters and filaments). Each contributes to curvature feedback balance within its domain. The work proposes that part of the observed dark energy effect may arise statistically from emissive curvature bias in low density regions, complementing rather than replacing the standard ΛCDM model. Falsifiability criteria are provided, allowing the model to be tested through weak lensing studies, metallicity linked expansive candidates, environmental variation in the Hubble rate, and numerical work within General Relativity. The addendum remains compatible with current observational cosmology and encourages focused research to assess potential curvature feedback signatures at galactic scales. Version v1.6H (Final Draft) License CC BY 4.0 Relation to previous work This addendum supplements The Universal Valve Hypothesis (v1.5F). It should be read together with the original paper. It does not replace the original work, but extends its theoretical scope and observational relevance. Contact: [email protected]