# When astronomers observe light from distant galaxies, they notice that the light appears redder than expected. This observation is known as redshift. Explain what redshift tells us about the motion of distant galaxies and what this suggests about the origin of the universe.

> Eduqas GCSE Physics — 2.1 Light, lenses and the universe · Explain · 4 marks

## Mark scheme (4 marks)

1. Redshift means the wavelength of light from distant galaxies is longer / shifted towards the red end of the spectrum
2. Redshift indicates that distant galaxies are moving away from us
3. The further away the galaxy, the greater the redshift / faster it is moving away
4. This suggests the universe began from a single point in a very hot, dense state / the Big Bang

## Key terms

- [redshift](https://www.gradenine.co.uk/glossary/redshift)
- [galaxies](https://www.gradenine.co.uk/glossary/galaxies)
- [universe](https://www.gradenine.co.uk/glossary/universe)

## Related

- [Revision notes for Eduqas GCSE Physics](https://www.gradenine.co.uk/learn)
- [How to answer "Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
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Source: [GradeNine](https://www.gradenine.co.uk/q/when-astronomers-observe-light-from-distant-bb09f6fe) · Published by Druglandscape Ltd.