# Red-shift observations of distant galaxies provide evidence about the universe. Describe what red-shift is and explain what red-shift observations of distant galaxies tell us about the universe.

> WJEC GCSE Physics (Wales) — 2.6 Particle physics and using physics to investigate the universe · Describe and Explain · 4 marks

## Mark scheme (4 marks)

1. Red-shift is when light from a galaxy is shifted towards longer wavelengths / the red end of the spectrum
2. Red-shift occurs because the galaxy is moving away from us / the Earth
3. More distant galaxies show greater red-shift, meaning they are moving away faster
4. This shows the universe is expanding

## Key terms

- [red-shift](https://www.gradenine.co.uk/glossary/red-shift)
- [universe](https://www.gradenine.co.uk/glossary/universe)

## Related

- [Revision notes for WJEC GCSE Physics (Wales)](https://www.gradenine.co.uk/learn)
- [How to answer "Describe and Explain" questions](https://www.gradenine.co.uk/tools/command-word-cheatsheet)
- [Practice this with AI marking (free)](https://www.gradenine.co.uk/start)

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Source: [GradeNine](https://www.gradenine.co.uk/q/red-shift-observations-of-distant-galaxies-provide-4c345202) · Published by Druglandscape Ltd.