hubble constant: meaning, definition, pronunciation and examples
C2Technical / Academic
Quick answer
What does “hubble constant” mean?
The rate of expansion of the universe, expressed in kilometres per second per megaparsec.
Audio
Pronunciation
Definition
Meaning and Definition
The rate of expansion of the universe, expressed in kilometres per second per megaparsec.
A fundamental cosmological parameter used to calculate the age and size of the universe, as well as the distances to faraway galaxies, based on the observation that galaxies are receding from us at speeds proportional to their distance.
Dialectal Variation
British vs American Usage
Differences
No significant lexical or orthographic differences.
Connotations
Identical technical and scientific connotations in both varieties.
Frequency
Exclusively used in scientific discourse with equal frequency in both UK and US contexts.
Grammar
How to Use “hubble constant” in a Sentence
The Hubble constant is estimated at...Astronomers have measured a Hubble constant of...A discrepancy in the value of the Hubble constant suggests...Vocabulary
Collocations
Examples
Examples of “hubble constant” in a Sentence
adjective
British English
- Hubble-constant measurement
- Hubble-constant value
American English
- Hubble constant measurement
- Hubble constant value
Usage
Meaning in Context
Business
Never used.
Academic
Used extensively in cosmology, astrophysics, and physics papers and lectures to discuss the universe's expansion.
Everyday
Virtually never used in everyday conversation.
Technical
Core term in astronomy and cosmology for describing cosmic expansion and calculating distances and the age of the universe.
Vocabulary
Synonyms of “hubble constant”
Strong
Neutral
Weak
Vocabulary
Antonyms of “hubble constant”
Watch out
Common Mistakes When Using “hubble constant”
- Using lower case ('hubble constant').
- Referring to it as the 'Hubble's constant'.
- Confusing it with the Hubble Space Telescope.
- Mispronouncing 'Hubble' to rhyme with 'bubble' (it is /ˈhʌb.l̩/).
FAQ
Frequently Asked Questions
It is a constant in space at a given cosmic time, but its value is thought to have changed over the history of the universe. The current measured value is referred to as H₀.
The constant is named after Edwin Hubble, whose observations in the 1920s established that galaxies are receding, implying an expanding universe. The constant itself was later formulated from his work.
It is typically measured in kilometres per second per megaparsec (km/s/Mpc), which describes how much faster a galaxy recedes for every additional megaparsec of distance from us.
Different methods (like using nearby supernovae versus the cosmic microwave background) yield slightly different values for H₀. This discrepancy, known as the 'Hubble tension', suggests potential new physics or unaccounted-for systematic errors.
The rate of expansion of the universe, expressed in kilometres per second per megaparsec.
Hubble constant is usually technical / academic in register.
Hubble constant: in British English it is pronounced /ˌhʌb.l̩ ˈkɒn.stənt/, and in American English it is pronounced /ˌhʌb.l̩ ˈkɑːn.stənt/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “N/A”
Learning
Memory Aids
Mnemonic
Imagine the universe as a balloon being inflated (Hubble). The constant (fixed number) tells you how fast the ink dots (galaxies) on the balloon move apart for every centimetre of rubber (megaparsec).
Conceptual Metaphor
THE UNIVERSE IS AN EXPANDING FABRIC/SPONGE (where the Hubble constant is the rate of stretching).
Practice
Quiz
What does the Hubble constant measure?