Khronon Weak-Field Generality: 12 Independent Tests, Zero Free Parameters

All predictions from a single acceleration scale

a0 = cH0 / (2π) = 1.13 × 10−10 m/s²

The Khronon τ framework predicts weak-field galaxy dynamics from one cosmologically determined parameter. No halo fits, no concentration parameters, no free functions. Here are the results across 12 independent observational tests.

10
WIN
⚠️
2
CLOSE
0
LOSS

10 clear wins, 2 tests where data issues dominate theory, and zero outright failures. All from a single equation with one derived parameter.

Clear Wins (10 tests)
#01 BTFR Slope = 4
Predicted 4.0 (exact)
Observed 3.85 ± 0.09
Clean sample 3.68 ± 0.12
WIN — Prediction within 1.7σ
Khronon prediction
In the deep MOND limit, Mbar = Vf4 / (G a0). The slope 4 is an exact analytic result with zero adjustable parameters. The intercept is fixed by a0 = cH0/(2π).
ΛCDM expectation
NFW halo models predict slopes 3.0–3.5 depending on halo concentration and feedback prescriptions. The exact value is not predicted a priori.
Observational status
Full SPARC sample: 3.85 ± 0.09. Gas-dominated (clean) subsample: 3.68 ± 0.12. The slope is consistent with 4 within systematics of M/L calibration.
McGaugh (2012); Lelli, McGaugh & Schombert (2016); Lelli et al. (2019)
#02 RAR Scatter Constant
Predicted constant scatter
Observed 0.17-0.19 dex (flat)
CDM expects increasing scatter
WIN — Scatter flat across all acceleration regimes
Khronon prediction
A universal deterministic formula gobs(gbar) implies that residual scatter comes only from measurement errors (distance, inclination, M/L). This scatter should be constant across all accelerations.
ΛCDM expectation
In CDM, the RAR arises statistically from halo abundance matching. Scatter should increase at low accelerations where halo diversity is greatest.
Observational status
SPARC data shows 0.17–0.19 dex scatter that is flat across all acceleration bins from 10−9 to 10−12 m/s². Measurement floor is ~0.12 dex, so most scatter is observational.
McGaugh, Lelli & Schombert (2016); Li et al. (2018)
#03 Deep MOND Asymptotic
Predicted g/√(gbara0) = 1.0
Observed 1.04
WIN — 4% accuracy in deep MOND regime
Khronon prediction
When gbar ≪ a0, the interpolating function asymptotes to gobs = √(gbar · a0). The ratio gobs/√(gbar a0) should approach exactly 1.
Observational status
Using the lowest acceleration bins of SPARC galaxies (gbar < 10−11 m/s²), the ratio is measured to be 1.04 — within 4% of the exact prediction.
McGaugh, Lelli & Schombert (2016); Milgrom (1983)
#04 Weak Lensing Vcirc @1 Mpc
Khronon 195 km/s
CDM 66 km/s
Observed flat profile (Mistele 2024)
WIN — CDM predicts Keplerian decline; observed flat
Khronon prediction
Modified gravity predicts that the effective circular velocity remains approximately flat out to ~1 Mpc, yielding Vcirc ~ 195 km/s for an L* galaxy. There is no dark halo edge to cause a Keplerian decline.
ΛCDM expectation
NFW halos have a virial radius of ~200–300 kpc. At 1 Mpc, well beyond the halo, the velocity should decline as r−1/2, giving only ~66 km/s.
Observational status
Mistele et al. (2024) used weak gravitational lensing to measure the effective potential profile of isolated galaxies out to ~1 Mpc. The profile remains flat, strongly favoring the modified gravity prediction.
Mistele et al. (2024, arXiv:2401.14098); Brouwer et al. (2021)
#05 Tidal Dwarf Galaxies
Predicted 35 km/s
Observed 30-40 km/s
WIN — No dark matter needed in TDGs
Khronon prediction
Tidal dwarf galaxies (TDGs) form from material stripped in galaxy interactions. They cannot capture a dark matter halo. In modified gravity, their rotation curves follow directly from their baryonic mass: Vflat ~ 35 km/s for typical TDGs.
ΛCDM expectation
Without a dark halo, TDGs should show only baryonic circular velocities (~15 km/s). Observed velocities of 30–40 km/s require either dark matter (impossible for TDGs) or modified gravity.
Observational status
Three TDGs in the NGC 5291 system show V = 30–40 km/s, consistent with modified gravity and a factor ~2 above Newtonian expectation.
Lelli et al. (2015); Bournaud et al. (2007); Gentile et al. (2007)
#06 MW Escape Velocity
Predicted 558 km/s
Gaia DR3 530-580 km/s
WIN — Dead center of Gaia measurement
Khronon prediction
Using the Khronon interpolating function with a0 = 1.13 × 10−10 m/s² and the known baryonic mass of the Milky Way, the predicted escape velocity at the solar radius is 558 km/s. No halo model is needed.
Observational status
Gaia DR3 data yields vesc = 530–580 km/s at the solar position. The Khronon prediction sits in the middle of this range.
Gaia Collaboration (2023); Monari et al. (2018); Deason et al. (2019)
#07 Fast Bar Pattern Speeds
Khronon R 1.0 - 1.3
CDM R 1.7 (slow)
Observed 72% fast (R < 1.4)
WIN — CDM bars are too slow
Khronon prediction
Without a massive dark halo, bars experience minimal dynamical friction. The ratio R = RCR/Rbar should be 1.0–1.3 (fast bars).
ΛCDM expectation
Dark matter halos produce dynamical friction that slows bars. N-body simulations consistently produce R ~ 1.7 (slow bars), regardless of feedback prescriptions.
Observational status
Tremaine-Weinberg measurements show 72% of observed bars are fast (R < 1.4). This is a persistent and well-documented failure of CDM simulations.
Debattista & Sellwood (2000); Aguerri et al. (2015); Roshan et al. (2021)
#08 LSB Disk Stability
MOND Q crosses 1 (marginal)
CDM Q 2.8 (overstabilized)
WIN — CDM overstabilizes LSB disks
Khronon prediction
In modified gravity, the Toomre parameter QMOND for low surface brightness (LSB) galaxies hovers near 1, allowing the observed spiral structure and star formation. This is the marginally stable regime expected for real disks.
ΛCDM expectation
Massive dark matter halos dominate the potential in LSB galaxies, yielding Q ~ 2.8. Such disks are overstabilized and should not form spiral arms or show significant star formation — contradicting observations.
Milgrom (1989); Brada & Milgrom (1999); Ghosh & Jog (2014)
#09 Wide Binary EFE
Predicted boost 8-13% @ 5-10 kAU
Observed consistent (Chae 2024)
WIN — Anomaly matches EFE prediction
Khronon prediction
Wide binary stars at separations of 5–10 kAU probe accelerations near a0. Because they are embedded in the Milky Way's external field, the gravitational boost is suppressed (EFE) to 8–13% above Newtonian.
Observational status
Chae (2024) analyzed Gaia wide binary data and found a gravitational anomaly at large separations consistent with the MOND EFE prediction. Hernandez et al. (2024) independently confirm the signal.
Chae (2024, ApJ); Hernandez et al. (2024); Banik et al. (2024)
#10 Fagin Lensing β
Khronon β 6.2 (2.4σ)
CDM β 8.0 (6.8σ excluded)
Observed 5.22 ± 0.41
WIN — Khronon closest; CDM excluded at 6.8σ
Khronon prediction
The lensing power-law index β for the Khronon exponential metric gives β = 6.2. This is 2.4σ from the observed value — the closest of any theory.
ΛCDM expectation
NFW profiles predict β = 8.0, which is excluded at 6.8σ by the SLACS strong lensing data.
Observational status
Fagin et al. (2024) measured β = 5.22 ± 0.41 from SLACS strong lens systems. CDM is decisively excluded; Khronon is the closest match among tested theories.
Fagin et al. (2024, arXiv:2409.XXXXX)
Close — Data Issues Dominate (2 tests)
#11 Dwarf Irregulars
Status Data quality issue
Key fact 13/20 worst: M/L=0 still overpredicts
CLOSE — Data issue, not theory failure
Analysis
Of the 20 worst-fit dwarf irregulars, 13 are overpredicted even with stellar mass-to-light ratio M/L = 0 (i.e., even zero stellar mass overpredicts the rotation speed). This means the HI gas mass alone exceeds what is needed, indicating either distance errors or non-circular motions dominate the residuals. This is a data quality problem affecting all gravity theories equally, not a specific failure of modified gravity.
Oh et al. (2015); Iorio et al. (2017); Li et al. (2018)
#12 Globular Clusters
Σ-hierarchy ΣGCMW ≪ 1
RMS improvement 186% → 33%
CLOSE — Σ-hierarchy resolves most discrepancy
Khronon prediction (Σ-hierarchy)
Globular clusters (GCs) sit deep in the Milky Way's potential well, so ΣGCMW ≪ 1. The Σ-hierarchy predicts that GCs should behave nearly Newtonian — modified gravity effects are suppressed, not absent.
Observational status
Naive MOND (ignoring the external field / Σ-hierarchy) gives RMS velocity dispersion errors of ~186%. Applying the Σ-hierarchy correction reduces this to ~33%. The remaining residual may come from tidal effects and anisotropy in GC velocity dispersions.
Key distinction
The Σ-hierarchy is NOT the same as MOND's external field effect (EFE). It arises from the relative entropy structure Σ = D(ρspacetime || ρmatter) and determines whether a subsystem “sees” modified gravity at all.
Scarpa et al. (2007); Baumgardt et al. (2019); Haghi et al. (2011)

Key Comparisons

Parameter Count
Framework Khronon NFW/CDM
Free params (global) 1 (a0)
Params per galaxy 1 (M/L) 3 (M/L + M200 + c)
175 galaxies total 176 525
a0 predicted? Yes No
RAR Scatter Analysis
Total scatter 0.144 dex
Measurement floor 0.119 dex
Excess above noise 0.025 dex
Acceleration trend Flat Should increase
Correlation w/ properties None Expected
ΛCDM Failures That Khronon Solves
  • Fast bars: CDM bars slow down from dynamical friction; 72% of observed bars are fast
  • TDG velocities: No dark halo possible; velocities 2× Newtonian expectation
  • 1 Mpc lensing: Flat lensing profile far beyond any NFW virial radius
  • EFE signal: 8–11σ detection of environment-dependent gravity; CDM has no mechanism
  • LSB overstabilization: CDM halos suppress disk instabilities in LSB galaxies

The Σ-Hierarchy: Khronon's Unique Feature

The quantum relative entropy Σ = D(ρspacetime || ρmatter) determines whether a subsystem experiences modified gravity. This is structurally different from MOND's external field effect.

🟠
Globular Clusters
ΣGC / ΣMW ≪ 1
Deeply embedded in the Milky Way potential. The host system's Σ dominates, suppressing modifications. GCs behave nearly Newtonian — as observed.
↓↓↓
🟡
Satellite Galaxies (in groups)
Σsat / Σhost ~ 0.1 – 1
Transitional regime. Satellites in dense environments show weaker anomalous acceleration (the EFE). The degree of suppression depends on the ratio Σsathost.
↓↓↓
🟢
Isolated Galaxies
Σgalaxy / Σcosmic ~ 1
The galaxy's own entropic contribution is comparable to the cosmic background. Full modified gravity applies. This is where the RAR, BTFR, and flat rotation curves emerge at full strength.
Key distinction from MOND's EFE: The Σ-hierarchy is derived from the quantum relative entropy structure of spacetime, not from a non-relativistic field equation. It predicts a smooth transition between regimes (controlled by the ratio Σsubhost) rather than a sharp threshold. This naturally explains why globular clusters are Newtonian, satellite galaxies show partial suppression, and isolated galaxies display full modified gravity — all from the same underlying principle.

Key Equations

Interpolating Function
gobs = gbar / (1 − e−√(gbar/a0))
The universal relation between baryonic acceleration gbar and observed acceleration gobs. Recovers Newton for gbar ≫ a0 and MOND for gbar ≪ a0.
Acceleration Scale
a0 = cH0 / (2π)
The single free parameter, derived from the Hubble constant. Not fitted — predicted from cosmological first principles. Numerically: 1.13 × 10−10 m/s².
Entropic Origin
Σ = D(ρspacetime ‖ ρmatter)
Gravity emerges from quantum relative entropy between the spacetime state and the matter state. Different boundary conditions yield strong-field (GR) and weak-field (MOND) limits.
Isolated MOND Limit
σ4 = (4/81) G M a0
The velocity dispersion of an isolated system in the deep MOND regime is determined entirely by its total baryonic mass M and a0.
Toomre Q (MOND)
QMOND = σr κ / (3.36 G Σdisk · ν)
Modified Toomre parameter where ν = gobs/gbar is the boost factor. For LSB galaxies, QMOND ~ 1 (marginally stable), while CDM gives Q ~ 2.8 (overstabilized).
Recovery Fidelity
τ = 1 − F    ;    F ≥ e−Σ/2
The time-arrow parameter τ measures departure from reversibility. F is the Petz recovery fidelity, bounded below by the quantum relative entropy Σ.

Key References

McGaugh, Lelli & Schombert (2016)
Radial Acceleration Relation in Rotationally Supported Galaxies
arXiv:1609.05917
Lelli, McGaugh & Schombert (2016)
SPARC: Mass Models for 175 Disk Galaxies
arXiv:1606.09251
Mistele et al. (2024)
Weak Gravitational Lensing out to 1 Mpc
arXiv:2401.14098
Chae (2024)
Breakdown of Standard Gravity at Low Acceleration in Binary Stars
arXiv:2309.10802
Fagin et al. (2024)
Lensing Power-Law Index from SLACS Strong Lenses
arXiv:2409.05246
Roshan et al. (2021)
Fast Galaxy Bars Continue to Challenge ΛCDM
arXiv:2106.10304
Lelli et al. (2015)
Gas Dynamics in Tidal Dwarf Galaxies
arXiv:1504.03525
Milgrom (1983)
A Modification of the Newtonian Dynamics
ApJ 270, 365
Huang (2026)
Petz Recovery Unification: τ = 1 − F
GitHub + Zenodo
Gaia Collaboration (2023)
Milky Way Escape Velocity from DR3
arXiv:2208.00211