Hubble constant H₀
E437255
The Hubble constant H₀ is the cosmological parameter that quantifies the present-day rate at which the universe is expanding, relating galaxies’ recession velocities to their distances.
All labels observed (3)
| Label | Occurrences |
|---|---|
| Hubble constant | 5 |
| Hubble constant H0 | 1 |
| Hubble constant H₀ canonical | 1 |
How this entity was disambiguated
This entity first appeared as the object of triple T4384255 — 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: Hubble constant H₀ Context triple: [Lemaître–Hubble law, hasParameter, Hubble constant H₀]
-
A.
Lemaître–Hubble law
The Lemaître–Hubble law is the fundamental cosmological relation that expresses the proportionality between a galaxy’s recessional velocity and its distance, providing the first observational evidence for the expansion of the universe.
-
B.
Lambda-CDM model
The Lambda-CDM model is the standard cosmological framework describing a universe dominated by dark energy (Λ) and cold dark matter (CDM), successfully explaining the large-scale structure, expansion history, and cosmic microwave background observations.
-
C.
The Expanding Universe
"The Expanding Universe" is a chapter in Stephen Hawking’s popular science book *A Brief History of Time* that explains how observations and cosmological theory reveal that the universe is growing larger over time.
-
D.
steady-state cosmology
Steady-state cosmology is a now largely discredited cosmological model proposing an eternal, unchanging universe in which new matter is continuously created to maintain constant density despite expansion.
-
E.
The Big Bang
The Big Bang is the climactic Series 5 finale of the British science-fiction television show Doctor Who, featuring the Eleventh Doctor in a time-bending resolution to the season’s overarching storyline.
- 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: Hubble constant H₀ Target entity description: The Hubble constant H₀ is the cosmological parameter that quantifies the present-day rate at which the universe is expanding, relating galaxies’ recession velocities to their distances.
-
A.
Lemaître–Hubble law
The Lemaître–Hubble law is the fundamental cosmological relation that expresses the proportionality between a galaxy’s recessional velocity and its distance, providing the first observational evidence for the expansion of the universe.
-
B.
Lambda-CDM model
The Lambda-CDM model is the standard cosmological framework describing a universe dominated by dark energy (Λ) and cold dark matter (CDM), successfully explaining the large-scale structure, expansion history, and cosmic microwave background observations.
-
C.
The Expanding Universe
"The Expanding Universe" is a chapter in Stephen Hawking’s popular science book *A Brief History of Time* that explains how observations and cosmological theory reveal that the universe is growing larger over time.
-
D.
steady-state cosmology
Steady-state cosmology is a now largely discredited cosmological model proposing an eternal, unchanging universe in which new matter is continuously created to maintain constant density despite expansion.
-
E.
The Big Bang
The Big Bang is the climactic Series 5 finale of the British science-fiction television show Doctor Who, featuring the Eleventh Doctor in a time-bending resolution to the season’s overarching storyline.
- F. None of above. chosen
Statements (48)
| Predicate | Object |
|---|---|
| instanceOf |
astrophysical quantity
ⓘ
cosmological parameter ⓘ physical constant ⓘ |
| appearsInEquation | v = H₀ d ⓘ |
| canBeWrittenAs | H₀ = (1/a)(da/dt)|₀ ⓘ |
| dependsOn | cosmological model assumptions ⓘ |
| describes | present-day expansion rate of the universe ⓘ |
| earlyEstimateWas | about 500 km s⁻¹ Mpc⁻¹ ⓘ |
| hasApproximateValue | 70 km s⁻¹ Mpc⁻¹ ⓘ |
| hasAssociatedTension | Hubble tension ⓘ |
| hasDifferentEstimatesFrom |
early-universe probes
ⓘ
late-universe probes ⓘ |
| hasDimension | inverse time ⓘ |
| hasSymbol | H₀ ⓘ |
| hasTypicalUnit |
kilometers per second per megaparsec
ⓘ
km s⁻¹ Mpc⁻¹ ⓘ |
| helpsDetermine |
Hubble radius
ⓘ
Hubble time ⓘ |
| isCentralTo |
Hubble–Lemaître law
ⓘ
linked to:
Lemaître–Hubble law
age of the universe estimates ⓘ cosmological distance scale calibration ⓘ |
| isConstrainedBy |
BAO measurements
ⓘ
DES collaboration ⓘ H0LiCOW collaboration ⓘ Planck satellite observations ⓘ
linked to:
Planck spacecraft
SH0ES project ⓘ WMAP observations ⓘ |
| isDefinedAt | redshift z = 0 ⓘ |
| isInferredFrom |
baryon acoustic oscillations
ⓘ
cosmic microwave background anisotropies ⓘ large-scale structure surveys ⓘ |
| isKeyObservableFor | precision cosmology ⓘ |
| isMeasuredBy |
Cepheid variable observations
ⓘ
Type Ia supernova observations ⓘ distance ladder methods ⓘ gravitational lens time delays ⓘ surface brightness fluctuations ⓘ |
| isParameterOf |
Friedmann–Lemaître–Robertson–Walker cosmology
ⓘ
linked to:
FLRW cosmological models
ΛCDM model ⓘ
linked to:
Lambda-CDM model
|
| isRelatedTo |
critical density of the universe
ⓘ
scale factor time derivative ⓘ |
| isSometimesExpressedAs | h = H₀ / (100 km s⁻¹ Mpc⁻¹) ⓘ |
| isTimeDependent | true ⓘ |
| isUsedTo | convert redshift to distance in nearby universe ⓘ |
| namedAfter | Edwin Hubble ⓘ |
| refersToEpoch | present cosmological time ⓘ |
| relates | recession velocity of galaxies to their distance ⓘ |
| wasFirstEstimatedBy | Edwin Hubble ⓘ |
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: Hubble constant H₀ Description of subject: The Hubble constant H₀ is the cosmological parameter that quantifies the present-day rate at which the universe is expanding, relating galaxies’ recession velocities to their distances.
Referenced by (7)
Full triples — surface form annotated when it differs from this entity's canonical label.
linked to: Hubble constant H₀
A Relation between Distance and Radial Velocity among Extra-Galactic Nebulae
→
relatesTo
→
Hubble constant
ⓘ
linked to: Hubble constant H₀
subject linked to:
Physical Cosmology
linked to: Hubble constant H₀
linked to: Hubble constant H₀
linked to: Hubble constant H₀
linked to: Hubble constant H₀