An automated observatory collects two sets of measurements. The laboratory wavelength of a particular absorption line is 486 nm486\ \mathrm{nm}486 nm.
| Data set | Measurements |
|---|---|
| A | In the spectra of 80 distant galaxies, the wavelength of this absorption line is between 504 nm504\ \mathrm{nm}504 nm and 526 nm526\ \mathrm{nm}526 nm. |
| B | A weak microwave signal is detected in 120 directions spread evenly across the whole sky, including regions containing no visible stars or galaxies. The signal corresponds to temperatures between 2.724 K and 2.726 K. |
Explain why the two data sets support the Big Bang theory more strongly than the Steady State theory.
94 exam-style questions on Edexcel GCSE Physics 7.2 The Universe and red-shift, covering 7.2.1 Big Bang and Steady State theories, 7.2.2 Evidence for the Big Bang, 7.2.3 The Doppler effect and red-shift, 7.2.4 Red-shift as evidence for an expanding Universe, and 7.2.5 The CMB and the accepted model. Each one has a worked solution and a mark scheme showing where the marks go.