# Explain how observations of red-shift in light from distant galaxies support the Big Bang theory.

> AQA GCSE Physics (8463) — 4.8.2 Red-shift (Phys only) · Explain · 4 marks

## Mark scheme (4 marks)

1. Red-shift is an increase in the observed wavelength (/ decrease in frequency) of light from a galaxy
2. Red-shift indicates that galaxies are moving away from us / the Earth
3. The more distant the galaxy, the greater the red-shift / the faster it is moving away
4. This shows the universe is expanding, which is consistent with / supports the idea that it began from a single point (the Big Bang)

## Key terms

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

## Related

- [Revision notes for AQA GCSE Physics (8463)](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-in-37b73747) · Published by Druglandscape Ltd.