Two research groups working independently obtain the same red-shift result for one galaxy.
Why does this make the result more useful as scientific evidence?
It shows the galaxy must be further away than expected
It shows the measurement can be repeated by others
It shows that only two groups need to make the check
It shows the theory behind the measurement is proved
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.