BRAINCAKEHubble's Law
In the 1920s Edwin Hubble measured the red shifts of galaxies and estimated their distances. He found that the further away a galaxy is, the faster it is moving away from us.
Hubble's law: the recession speed v of a galaxy is directly proportional to its distance d from us:
v = H0d
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Key terms in this lesson
- cosmological principle
- The principle that, on a large enough scale, the universe is homogeneous and isotropic, and the same laws of physics apply everywhere.
More in Astrophysics and Cosmology
- The Astronomical Unit, Light Year and Parsec
- Stellar Parallax
- The Cosmological Principle
- The Doppler Effect and Red Shift
- The Big Bang Theory
- Cosmic Microwave Background Radiation
- The Age of the Universe
- Evolution of the Universe
All 24 lessons in Astrophysics and Cosmology · All OCR A-level Physics topics