Cosmic distance ladder

Cepheid + SN Ia distance ladder — DCT predicts the late-time value exactly.

Prediction	\(H_0 = 73.019\) km/s/Mpc (Jordan frame, all late-time methods)
Measured	SH0ES Cepheid + SN Ia: \(H_0 = 73.04 \pm 1.04\)
Residual	0.0σ
Status	Tied
Source paper	DCT-COS-01

Mechanism

DCT predicts \(H_{\rm phys} = H_E/\sqrt{P_0} = 73.019\) km/s/Mpc in the Jordan/physical frame with \(P_0 = 0.851\) and \(H_E = 67.36\) km/s/Mpc the Einstein-frame Planck value. Methods that measure the late-time Hubble flow — Cepheid ladders, megamasers, TRGB, SBF, strong-lens time delays — are all calibrated against the same Jordan-frame distance scale and recover the DCT-predicted value rather than the Planck-inferred 67.36 km/s/Mpc.

Derivation

Conformal-frame transformation: \(g_{\mu\nu}^{\rm Jordan} = P^{-1} g_{\mu\nu}^{\rm Einstein}\). Locally measured Hubble rate \(H_{\rm phys} = H_E/\sqrt{P_0}\) with \(P_0 = 0.851\) and \(H_E = 67.36\) (Planck CMB inferred Einstein-frame value) gives \(H_{\rm phys} = 67.36/\sqrt{0.851} = 73.019\) km/s/Mpc. All late-time Hubble probes recover the same Jordan-frame value.

Python verification

The verification script for this observable is cosmology_tests.py. Run it with python3 cosmology_tests.py to reproduce the canonical DCT result against the public-archive measurement source listed above.

Methodology

Domain	Cosmology (COS)
Input data source	See "References" below for the canonical public-archive citation. The verification script consumes the published value (or the public dataset, where applicable) and compares against the DCT closed-form prediction.
Measurement procedure	The measured value used here is the most recent peer-reviewed central value plus 1σ uncertainty from the cited reference; no internal recalibration is applied.
Acceptance threshold	HIT: residual within 1σ of measurement. SOFT: directional agreement, residual within bracketing range. OPEN: untested or unresolved.
Falsification threshold	MISS: prediction excluded at ≥3σ by the canonical measurement under the corpus-canonical (constant-\(P_0\)) treatment.
Current status	See the verdict pill in the prediction table above.

Cross-references

Related observables in the same domain: sh0es-h0 · trgb-h0 · sbf-h0 · megamaser-h0.

Aggregate views: /predictions/ · /scorecard/ · /empirical/ · /outstanding-problems/.

Audit notes

Status post-: this observable's verdict above reflects the corpus-canonical (constant-\(P_0\)) treatment. Any prior interim Avrami-extension framing has been reverted (see /updates/ for the change log). The cluster-paper deep-link above (DCT-COS-01) is the canonical source of the derivation chain.

References

Riess et al. 2022 (SH0ES)
Source paper: DCT-COS-01

Back to all observables or the predictions table.