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Astronomy & Space vocabulary · Cosmology

Redshift

Meaning in astronomy & space, with examples

/ˈredʃɪft/nounCommon term

In astronomy & space, redshift means: The stretching of light from an object that is moving away from us or whose light crosses expanding space, so that its spectral lines shift to longer, redder wavelengths.

In Turkish: kırmızıya kayma

How it is used

A key measurement in cosmology, written as z. Astronomers measure a galaxy's redshift to find how far away it is; 'high-redshift galaxies' are very distant and seen as they were long ago. The opposite is 'blueshift'.

Example sentences

  1. In the 1920s astronomers found that a galaxy's redshift grows with its distance.

  2. The galaxy has a redshift above 10, so we see it as it was a few hundred million years after the Big Bang.

Common collocations

  • high redshift
  • measure the redshift
  • cosmological redshift
  • redshift survey
  • spectroscopyThe study of light by splitting it into its colours, or spectrum. The dark and bright lines in a spectrum reveal an object's chemical make-up, temperature and motion.
  • Big BangThe scientific model in which the universe began about 13.8 billion years ago in an extremely hot, dense state and has been expanding and cooling ever since.
  • dark energyThe unknown cause of the accelerating expansion of the universe. It makes up about two thirds of the total energy content of the universe.
  • galaxyAn enormous system of stars, gas, dust and dark matter held together by gravity. A large galaxy can contain hundreds of billions of stars.
  • universeAll of space and time and everything in it: matter, energy, planets, stars and galaxies. Its observable part is about 93 billion light-years across.

More terms: Cosmology

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