Observable detail · SOLAR
Nordtvedt η
equivalence-principle parameter
| Prediction | η = 4β − γ − 3 ≈ +2.0 × 10⁻⁵ |
|---|---|
| Measured | |η| < 4.4 × 10⁻⁴ (LLR) |
| Residual | 1σ consistent |
| Status | hit |
| Source paper | DCT-PPN-01 |
Mechanism
η = 4β − γ − 3 from Nordtvedt 1968. With γ − 1 = −1.998 × 10⁻⁵ and β − 1 = 5 × 10⁻¹¹, η = +2.0 × 10⁻⁵. Current LLR bound consistent; LUNAR (~2035) projects σ_η = 10⁻⁶, giving 20σ decisive test.
Derivation
η = 4β − γ − 3 from Nordtvedt 1968. With γ − 1 = −1.998 × 10⁻⁵ and β − 1 = 5 × 10⁻¹¹, η = +2.0 × 10⁻⁵. Current LLR bound consistent; LUNAR (~2035) projects σ_η = 10⁻⁶, giving 20σ decisive test.
The closed-form prediction is
$$ \text{predicted} = η = 4β − γ − 3 ≈ +2.0 × 10⁻⁵ $$against the measurement |η| < 4.4 × 10⁻⁴ (LLR), giving residual 1σ consistent.
Python verification
The verification script for this observable is gravity_tests.py. Run it with python3 gravity_tests.py to reproduce the canonical DCT result against the public-archive measurement source listed above (Williams et al. 2009 LLR; LUNAR mission concept.).
Methodology
| Domain | Solar-system / strong-gravity (GR) |
|---|---|
| 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: llr-g-dot · beta-ppn · microscope-ep.
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-PPN-01) is the canonical source of the derivation chain.
References
- Williams et al. 2009
- Source paper: DCT-PPN-01
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