A model gives the separation between four galaxies at an earlier stage and at a later stage.
| Pair of galaxies | Separation at earlier stage / million light-years | Separation at later stage / million light-years |
|---|---|---|
| A and B | 20 | 24 |
| A and C | 40 | 48 |
| A and D | 60 | 72 |
| B and C | 20 | 24 |
| B and D | 40 | 48 |
| C and D | 20 | 24 |
A student claims that galaxy A must be at the centre of the expansion because its separation from each of the other galaxies increases. Evaluate this claim using the data in the table.
79 exam-style questions on AQA GCSE Physics 8.2 Red-shift, covering 8.2 Red-shift. Each one has a worked solution and a mark scheme showing where the marks go.