Source: https://guthlabs.ai/docs/instruments/relativistic-doppler-effect-calculator/
instrument / verified-clean
# Relativistic Doppler Effect Calculator
The current ledger marks this instrument verified clean within the source-bound verification corpus.
Status: **VERIFIED_CLEAN**Lifecycle: **verified-clean**
## Inspectable records
[01**Overview**Purpose and lifecycle]()[02**Mechanism**Method and assumptions]()[03**Implementation**Binding and validation]()[04**Qualification**Evidence and errata]()
## Ledger state
The current ledger marks this instrument verified clean within the source-bound verification corpus.
**Area**: Physics — Kinematics/Projectiles/Orbits, Forces/Energy/Momentum, Rotational Dynamics, Gravitation, Oscillations/Waves, Optics, E&M Fields, Relativity, Quantum, Statistical Thermo
**Tranche**: tranche-5
**Evidence ID**: t5-085
**Ledger rows**: 1
No ledger note is attached.
## Review findings
The supplied receding formula is standard and correct, and the honest-label warning about radial-only motion is appropriate. Implementation needs explicit wavelength, redshift, direction, beta-domain, and unit conventions before it can receive an unqualified PASS.
### Formula and scope findings
- The stated frequency formula is correct for radial recession when beta=v/c is positive and 0<=beta<1: f_obs=f_src*sqrt((1-beta)/(1+beta)).
- The specification does not state the formula for wavelength; under vacuum propagation it should be lambda_obs=lambda_src*sqrt((1+beta)/(1-beta))=c/f_obs.
- The specification does not define redshift z; the standard definition must be stated explicitly as z=(f_src/f_obs)-1=(lambda_obs/lambda_src)-1.
- The input includes direction, but the behavior for an approaching source is unspecified. The standard approaching formula is f_obs=f_src*sqrt((1+beta)/(1-beta)), or equivalently use signed beta with beta<0 for approach.
- The valid domain and sign convention for beta are missing: |beta|<1, with positive beta explicitly defined as recession under the supplied formula.
### Unit assumptions
- Frequencies are in hertz (s^-1), wavelengths are in meters unless a display unit is explicitly applied, and velocity fraction beta is dimensionless.
- The speed of light is c=299792458 m/s in vacuum.
- The source emits light in vacuum, so c=f*lambda applies.
- The redshift convention is z=(f_src/f_obs)-1; positive z means redshift and negative z means blueshift.
- For the receding formula, beta is positive; for the approaching test vector, the reciprocal Doppler factor is assumed.
## Boundary hardening
**BREAK_CLAIMED** · SELF_FLAGGED
The formula encounters a division-by-zero singularity at beta = -1 and should reject that input. The negative-beta plus explicit-direction case also exposes an unresolved signed-beta versus direction-field convention ambiguity.
## Errata and corrections
No applied erratum is attached to this unique-name record.
## Inspectable example
4 review vectors are recorded. One source-bound sample is shown below.
````
{
"inputs": {
"source_frequency_hz": 600000000000000,
"beta": 0.6,
"direction": "receding",
"c_m_per_s": 299792458
},
"expected_outputs": {
"observed_frequency_hz": 300000000000000,
"observed_wavelength_m": 9.993081933333334e-7,
"redshift_z": 1
},
"working": "Doppler factor=sqrt((1-0.6)/(1+0.6))=sqrt(0.4/1.6)=sqrt(0.25)=0.5. f_obs=600000000000000*0.5=300000000000000 Hz. lambda_obs=c/f_obs=299792458/300000000000000=9.993081933333333e-7 m. z=f_src/f_obs-1=600000000000000/300000000000000-1=2-1=1."
}
````
## Related workflows
No source-defined multi-instrument workflow membership is recorded.
## Sources and evidence
These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.
- `VERIFIED_LEDGER.json · VERIFIED_CLEAN`
- `evidence-tranche5/tranche5-results.json`
- `BOUNDARY_HAZARD_CATALOG.json`