# Explain how observations of red shift in light from distant galaxies provide evidence for the Big Bang theory.

> Eduqas GCSE Physics — 10.2 Red shift and the Big Bang · Explain · 4 marks

> Astronomers observe that light from almost all distant galaxies is shifted towards the red end of the spectrum. The further away a galaxy is, the greater the red shift observed.

## Mark scheme (4 marks)

1. Red shift indicates that galaxies are moving away from us / the universe is expanding
2. Greater red shift from more distant galaxies shows they are moving away faster
3. This expansion implies that all matter was originally in one place / at one point
4. The Big Bang was the event at the start of the universe / the start of space and time

## Key terms

- [red shift](https://www.gradenine.co.uk/glossary/red-shift)
- [Big Bang](https://www.gradenine.co.uk/glossary/big-bang)

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- [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/explain-how-observations-of-red-shift-22c690cb) · Published by Druglandscape Ltd.