Physics A-Level
Hubble's law
What Hubble's law means in Physics A-Level, as defined for AQA, OCR.
Definitions of Hubble's law
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Reference: OCR
The recessional speed v of a galaxy is approximately proportional to its distance d from the observer: v ≈ H₀ d.
The recession speed v of a distant galaxy is proportional to its distance d from Earth, written as v = Hd.
Distance is estimated from v = H₀d, so d = v / H₀, using an accepted value of the Hubble constant.
Topics that use Hubble's law
- Hubble's law (A-level only) (AQA A-Level)
- Quasars (A-level only) (AQA A-Level)
- Cosmology (OCR A-Level)
Related terms
- Cosmological redshift
- Age of the universe
- Big Bang nucleosynthesis
- red shift
- Accretion discs and black hole mass
- Active galactic nuclei
- Astronomical distance units
- Baseline
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