The galactic acceleration scale a₀ ≈ 1. 2 × 10⁻¹⁰ m s⁻² numerically satisfies a₀ ≈ cH₀/2π to within ~10%, a coincidence noted since Milgrom (1983) and still unexplained. Milgrom has long drawn the consequence: if the link is to the expansion rate rather than to Λ alone, a₀ is not constant but decreases with cosmic time, and in the deep-MOND regime rotation velocities scale as a₀^ (1/4). For a ΛCDM expansion history this fixes a specific curve, a₀ (z) ∝ H (z), rising by 76% at z = 1 and by a factor 3 at z = 2. Until recently that curve was untested at the required precision. It is no longer. Ciocan et al. (2026) have measured the radial-acceleration-relation bend scale for 79 star-forming galaxies over 0. 33 < z < 1. 44 and find a₀ increasing with redshift at high significance. This note confronts the hypothesis with that measurement, and separates two questions that must not be conflated: whether a₀ (z) follows the shape of H (z), and whether its normalisation is c/2π. The measured evolution disfavours a constant a₀ under the published modelling and calibration, and a uniform baryonic-mass recalibration cannot by itself account for the reported redshift trend; both non-evolving interpretations are therefore disfavoured under those assumptions. The tracks-H shape is not visibly ruled out by the binned estimates, but it has not been decisively tested against them, and the note states what such a test requires. The strict normalisation A = cH₀/2π is disfavoured under the published calibration, which implies H₀ ≈ 95 km s⁻¹ Mpc⁻¹; it is not excluded, since on deep-MOND scaling a uniform baryonic-mass offset of roughly 0. 13 dex — smaller than the molecular-gas systematic alone — would restore it. No mechanism is proposed, and no part of the scaling is new: the hypothesis, its adiabatic justification and the a₀^ (1/4) response are Milgrom's. What this note contributes is the confrontation itself — the separation of the two claims, the amplitude they jointly require, and an argument for why the two verdicts have different robustness against the calibration that dominates the measurement.
David Rømer Voigt (Sat,) studied this question.