Scientists compare the distances to galaxies containing supernovae with the galaxies' recession speeds estimated from red-shift. The table shows results for three galaxies.
| Distance from Earth (billion light-years) | Expected recession speed (km/s) | Recession speed estimated from red-shift (km/s) |
|---|---|---|
| 1.0 | 20 000 | 21 000 |
| 2.0 | 40 000 | 44 000 |
| 3.0 | 60 000 | 69 000 |
Describe two patterns in the results.
Explain what the results suggest about the expansion of the universe and what remains uncertain.
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.