Pound–Rebka experiment
E817767
The Pound–Rebka experiment was a landmark 1959 physics test that measured the gravitational redshift of gamma rays in Earth’s gravitational field, providing one of the first precise terrestrial confirmations of general relativity.
All labels observed (1)
| Label | Occurrences |
|---|---|
| Pound–Rebka experiment canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T9743348 — resolving that mention is where its identity was fixed. The disambiguator weighed these candidate entities and picked the highlighted one (or “None”, minting a new entity). This is how homonymy is resolved: the same surface form can point to different entities.
NED1
Entity disambiguation (via context triple)
gpt-5-mini-2025-08-07
Target entity: Pound–Rebka experiment Context triple: [Einstein’s 1911 gravitational redshift work, relatedTo, Pound–Rebka experiment]
-
A.
Ives–Stilwell experiment
The Ives–Stilwell experiment is a classic test of special relativity that measured the relativistic Doppler effect to confirm time dilation for fast-moving ions.
-
B.
Hafele–Keating experiment
The Hafele–Keating experiment was a 1971 test of Einstein’s theory of relativity in which atomic clocks were flown around the world on commercial airliners and compared with stationary clocks to measure time dilation effects.
-
C.
Kennedy–Thorndike experiment
The Kennedy–Thorndike experiment is a classic test of special relativity that examined the constancy of the speed of light using an interferometer with unequal arm lengths and varying laboratory velocity.
-
D.
Foucault experiment
The Foucault experiment is a 19th-century optical test devised by Léon Foucault to measure the speed of light with high precision using a rotating mirror apparatus.
-
E.
Eötvös experiment
The Eötvös experiment is a classic physics test of the equivalence principle that measures whether different materials fall with the same acceleration in a gravitational field.
- F. None of above. chosen
- G. Unsure - the case is ambiguous/there is not enough information to decide.
NED2
Entity disambiguation (via description)
gpt-5-mini-2025-08-07
Target entity: Pound–Rebka experiment Target entity description: The Pound–Rebka experiment was a landmark 1959 physics test that measured the gravitational redshift of gamma rays in Earth’s gravitational field, providing one of the first precise terrestrial confirmations of general relativity.
-
A.
Ives–Stilwell experiment
The Ives–Stilwell experiment is a classic test of special relativity that measured the relativistic Doppler effect to confirm time dilation for fast-moving ions.
-
B.
Hafele–Keating experiment
The Hafele–Keating experiment was a 1971 test of Einstein’s theory of relativity in which atomic clocks were flown around the world on commercial airliners and compared with stationary clocks to measure time dilation effects.
-
C.
Kennedy–Thorndike experiment
The Kennedy–Thorndike experiment is a classic test of special relativity that examined the constancy of the speed of light using an interferometer with unequal arm lengths and varying laboratory velocity.
-
D.
Foucault experiment
The Foucault experiment is a 19th-century optical test devised by Léon Foucault to measure the speed of light with high precision using a rotating mirror apparatus.
-
E.
Eötvös experiment
The Eötvös experiment is a classic physics test of the equivalence principle that measures whether different materials fall with the same acceleration in a gravitational field.
- F. None of above. chosen
Statements (47)
| Predicate | Object |
|---|---|
| instanceOf |
gravitational redshift measurement
ⓘ
physics experiment ⓘ test of general relativity ⓘ |
| alsoKnownAs | Pound–Rebka–Snider experiment NERFINISHED ⓘ |
| city | Cambridge, Massachusetts ⓘ |
| confirmationType | terrestrial test ⓘ |
| confirmedPredictionOf | Einstein’s general theory of relativity ⓘ |
| country |
United States of America
ⓘ
surface form:
United States
|
| detectorPosition | top of tower ⓘ |
| field |
experimental gravitation
ⓘ
nuclear physics ⓘ relativistic physics ⓘ |
| followedBy | Pound–Snider experiment NERFINISHED ⓘ |
| gravitationalField | Earth’s gravitational field ⓘ |
| historicalPeriod | mid-20th century physics ⓘ |
| involves |
frequency shift proportional to gh/c²
ⓘ
gravitational potential difference ⓘ |
| location |
Harvard University
NERFINISHED
ⓘ
Jefferson Physical Laboratory NERFINISHED ⓘ |
| measured |
frequency shift of gamma rays
ⓘ
gravitational redshift ⓘ |
| namedAfter |
Glen A. Rebka Jr.
NERFINISHED
ⓘ
Robert V. Pound NERFINISHED ⓘ |
| precision | high precision ⓘ |
| publicationYear | 1960 ⓘ |
| publishedIn | Physical Review Letters NERFINISHED ⓘ |
| relatedConcept |
Mössbauer spectroscopy
NERFINISHED
ⓘ
equivalence principle NERFINISHED ⓘ gravitational time dilation ⓘ |
| result |
measured redshift agreed with general relativity within experimental error
ⓘ
observed gravitational redshift consistent with theory ⓘ |
| significance |
early experimental support for the equivalence principle
ⓘ
first precise terrestrial confirmation of gravitational redshift ⓘ |
| sourcePosition | bottom of tower ⓘ |
| status | landmark experiment in tests of general relativity ⓘ |
| testedTheory | general relativity NERFINISHED ⓘ |
| usedApparatus |
gamma-ray absorber
ⓘ
gamma-ray source ⓘ velocity transducer ⓘ |
| usedEffect | Mössbauer effect NERFINISHED ⓘ |
| usedIsotope | iron-57 NERFINISHED ⓘ |
| usedRadiation | gamma rays ⓘ |
| usedTechnique |
Doppler shift compensation
ⓘ
resonant absorption of gamma rays ⓘ |
| usedTransitionEnergy | 14.4 keV ⓘ |
| verticalSeparation | about 22.5 meters ⓘ |
| year | 1959 ⓘ |
How these facts were elicited
The pipeline generated the facts above by prompting gpt-5.1 with this entity's name + description and the instruction below.
Instruction
You are a knowledge base construction expert. Given a subject entity and a description of it, return factual statements that you know for the subject as a JSON list of dictionaries(triples), where keys must be "subject", "predicate" and "object". The number of facts may be very high, between 25 to 50 or more, for very popular subjects. For less popular subjects, the number of facts can be very low, like 5 or 10. # Requirements - If you don't know the subject at all, return an empty list. - If the subject is not a named entity, return an empty list. - Include at least one triple where predicate is "instanceOf". - Do not get too wordy. - Separate several objects into multiple triples with one object.
Input
Subject: Pound–Rebka experiment Description of subject: The Pound–Rebka experiment was a landmark 1959 physics test that measured the gravitational redshift of gamma rays in Earth’s gravitational field, providing one of the first precise terrestrial confirmations of general relativity.
Referenced by (1)
Full triples — surface form annotated when it differs from this entity's canonical label.