hubble's constant: meaning, definition, pronunciation and examples
C2Scientific/Technical/Academic
Quick answer
What does “hubble's constant” mean?
The constant in Hubble's law that describes the rate of expansion of the universe, relating the recessional velocity of a galaxy to its distance from Earth.
Audio
Pronunciation
Definition
Meaning and Definition
The constant in Hubble's law that describes the rate of expansion of the universe, relating the recessional velocity of a galaxy to its distance from Earth.
In modern cosmology, it is a key parameter (denoted H₀) for calculating the age and size of the observable universe, representing the expansion rate in kilometres per second per megaparsec (km/s/Mpc).
Dialectal Variation
British vs American Usage
Differences
No significant differences in usage. Spelling follows standard UK/US conventions in surrounding text (e.g., 'metre' vs. 'meter'), but the constant's name is identical.
Connotations
Identical scientific connotations.
Frequency
Used with equal frequency in astrophysics and cosmology contexts in both varieties.
Grammar
How to Use “hubble's constant” in a Sentence
The [instrument/study] measured Hubble's constant at [value].Hubble's constant, which is [value], indicates...A value for Hubble's constant was obtained.They derived Hubble's constant from [data].Vocabulary
Collocations
Examples
Examples of “hubble's constant” in a Sentence
adjective
British English
- Hubble's-constant measurement
- Hubble's-constant value
American English
- Hubble's-constant measurement
- Hubble's-constant value
Usage
Meaning in Context
Business
Virtually never used.
Academic
Core term in astronomy, cosmology, and astrophysics research papers and textbooks.
Everyday
Extremely rare, only in popular science discussions about the universe.
Technical
Essential parameter in cosmological models, distance ladder calculations, and telescope data analysis.
Vocabulary
Synonyms of “hubble's constant”
Strong
Neutral
Weak
Vocabulary
Antonyms of “hubble's constant”
Watch out
Common Mistakes When Using “hubble's constant”
- Writing 'Hubble constant' without the possessive 's' (though occasionally accepted, 'Hubble's constant' is standard).
- Confusing it with the Hubble Space Telescope.
- Using incorrect units (e.g., just km/s instead of km/s/Mpc).
- Pronouncing 'Hubble' as 'hobble' or 'hubb-el'.
FAQ
Frequently Asked Questions
Kilometres per second per megaparsec (km/s/Mpc). It represents speed (km/s) per unit of distance (Mpc).
The American astronomer Edwin Hubble, who provided early observational evidence for the expansion of the universe in the 1920s.
It refers to the persistent discrepancy between measurements of Hubble's constant from the early universe (like the Cosmic Microwave Background) and measurements from the local, modern universe.
No, it is believed to change over the lifetime of the universe. 'Hubble's constant' technically refers to its present-day value (H₀). Over cosmic time, it is called the Hubble parameter.
The constant in Hubble's law that describes the rate of expansion of the universe, relating the recessional velocity of a galaxy to its distance from Earth.
Hubble's constant is usually scientific/technical/academic in register.
Hubble's constant: in British English it is pronounced /ˌhʌb.l̩z ˈkɒn.stən.tl̩/, and in American English it is pronounced /ˌhʌb.l̩z ˈkɑːn.stən.tl̩/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Imagine the universe as a raisin cake baking in an oven. Hubble's Constant (H) is how fast the space (the dough) between the raisins (galaxies) is expanding every second for every megaparsec of distance.
Conceptual Metaphor
The universe's speedometer (measuring the rate of expansion of space itself).
Practice
Quiz
What does Hubble's constant (H₀) directly relate?