The wavelength of an absorption line measured in a laboratory is 500.0 nm.
A science writer compares this wavelength with measurements of the same absorption line from three galaxies.
| Galaxy | Distance from Earth in million light-years | Observed wavelength in nm |
|---|---|---|
| L | 140 | 505.0 |
| M | 420 | 515.0 |
| N | 700 | 525.0 |
The science writer concludes:
"The measurements are evidence that space is expanding. Running this expansion backwards means that the universe began as a large, cold region."
Evaluate the science writer's conclusion.
Use the data and ideas about the expanding universe.
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.