An astrophysicist studying high-redshift active galactic nuclei (AGN) observes that the characteristic Lyman-alpha emission line is systematically shifted toward longer wavelengths, with greater shifts observed for more distant sources.
Explain how this spectral shift provides key evidence for the Big Bang theory.
53 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.