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Glite Dictionary
Hubble's constant

Hubble's constant

8.1
A number that shows how fast the universe is expanding now
  • noun
  • /ˈhʌbəlz ˈkɒnstənt/
  • Specialized
translation icon : constante de Hubble
  • Most astronomers accept a value for Hubble's constant of about 50 km/s/Mpc.

Examples

  • The slope of the line, which is called Hubble's constant, is a key cosmological parameter.

    Academic text (1992)

  • Most astronomers agree that Hubble's constant is approximately 70 km/s/Mpc, indicating the universe's expansion rate.

  • Researchers are studying Hubble's constant to better understand the speed at which galaxies are receding from Earth.

  • Hubble's constant helps scientists measure how quickly the universe is expanding by relating galaxy speed to their distance.

Synonyms

Hubble constant
vsHubble's constant
  • Specialized
1 9.1

A number that shows how fast the universe is getting bigger

is defined specifically as the ratio of speed to Earth distance
Hubble parameter
vsHubble's constant
  • Specialized
9.9

A number that shows how fast galaxies move apart depending on distance

is defined as a ratio measured from Earth for the current expansion
Hubble's parameter
vsHubble's constant
  • Specialized
9.9

A number that shows how fast the universe is expanding now

is instead framed as that ratio measured from Earth now

Surface Forms

Hubble's constant singular
Hubble's constants plural

Morphology

Hubble's + constant

The construction is a possessive proper name + 'constant', so a learner who knows 'Hubble' and 'constant' can infer this is a fixed value associated with Hubble. However, the precise scientific sense (the ratio of recession speed to distance used to measure cosmic expansion) is technical and not predictable from the parts alone, so domain knowledge is required.

Etymology

Hubble's constant comes from astronomer Hubble, who saw that distant galaxies move away faster the farther they are. People used the word constant to mean a single number that measures how fast the universe is growing, so today Hubble's constant means that number — the universe's 'expansion rate'.