Hubble's law

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Thân thiện
Definition

Proper noun: - Hubble's Law: A fundamental principle in observational cosmology stating that the velocity at which a distant galaxy is receding from an observer is directly proportional to its distance from that observer. This relationship is evidence for the expansion of the universe.

Usage
  • Hubble's Law is used as a singular, uncountable noun phrase to describe this specific scientific principle.
    • The discovery of Hubble's Law provided the first observational evidence for an expanding universe.
    • According to Hubble's Law, a galaxy twice as far away is moving away twice as fast.
Advanced Usage
  • The Hubble Constant (H₀): The constant of proportionality in Hubble's Law. Its value represents the rate of expansion of the universe (measured in kilometers per second per megaparsec).
    • Determining an accurate value for the Hubble Constant is a major goal of modern cosmology.
Variants and Related Words
  • Hubble flow: The smooth, overall expansion of the universe described by Hubble's Law.
  • Hubble parameter: A more general term for the Hubble Constant, acknowledging that the expansion rate can change over cosmic time.
Synonyms
  • Hubble–Lemaître law: An alternative name acknowledging the contributions of both Edwin Hubble and Georges Lemaître.
Noun
  1. (astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer

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