An orbiting detector measures weak background radiation from three widely separated regions of the sky. Signals from individual stars and galaxies are removed from the measurements.
| Region of sky | Wavelength of strongest signal / mm | Intensity compared with region Q |
|---|---|---|
| P | 1.08 | 1.01 |
| Q | 1.10 | 1.00 |
| R | 1.09 | 0.99 |
Explain why these measurements are consistent with cosmic microwave background radiation and how the Big Bang theory accounts for the measured wavelengths.
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.