hubble law
Học thuậtThân thiện
The Hubble law describes the relationship between a galaxy's distance and its redshift.
Definition
- Noun:
- Hubble's Law: In astronomy, the principle stating that the velocity at which a distant galaxy is receding from an observer is directly proportional to its distance from that observer. This observed relationship is a key piece of evidence for the expansion of the universe.
Usage
- The term "Hubble law" is used primarily in cosmological and astronomical contexts to describe the relationship between redshift and distance.
- It is often stated with the formula: v = H₀ × d, where is the recession velocity, is the proper distance, and is the Hubble constant.
Examples
- Noun:
- The discovery of the Hubble law provided the first observational foundation for the Big Bang theory.
- Astronomers use the Hubble law to estimate the distances to faraway galaxies by measuring their redshifts.
Advanced Usage
- "Hubble flow": The motion of galaxies resulting from the expansion of the universe, as described by the Hubble law.
- Galaxies embedded in the Hubble flow are receding from each other.
- "Hubble constant (H₀)": The constant of proportionality in the Hubble law, representing the rate of expansion of the universe.
- Precisely measuring the Hubble constant is a major goal of modern cosmology.
Variants and Related Words
- Hubble's law: The most common variant, often used interchangeably with "Hubble law."
- Hubble-Lemaître law: An alternative name acknowledging the contributions of astronomer Georges Lemaître.
Synonyms
- Law of redshift: A descriptive synonym emphasizing the observed phenomenon.
- Cosmic expansion law: A broader term referencing the underlying cause of the relationship.
Related Phrases
- To obey the Hubble law: Describes galaxies whose motion conforms to the predicted relationship.
- Most galaxies on large scales obey the Hubble law.
The Hubble law describes the relationship between a galaxy's distance and its redshift.
Noun
- (astronomy) the generalization that the speed of recession of distant galaxies (the red shift) is proportional to their distance from the observer