Phenomenological Model of Galactic Dynamics

Emergent Gravity from a Two-Postulate Framework Two postulates. Zero free parameters. Flat rotation curves, the baryonic Tully-Fisher relation, and halo properties all follow. P1: a₀ = cH₀/2π from T_Unruh = T_Hubble — the acceleration scale derived from horizon thermodynamics, not fitted to galaxies. P2: a_eff = a_N + √(a₀·a_N)·f(τ) — the modified dynamical law with transition function derived from information geometry. Primary test: KK246 in the Tully Void. 43.7 km/s predicted, ~42 km/s observed. Zero external field contamination. Primary prediction: v_TF(z)/v_TF(0) = (H(z)/H₀)^{1/4} — testable with JWST now.