The diagram shows the emission spectra obtained from stars in two different local galaxies, Galaxy A and Galaxy B, alongside a reference spectrum from a laboratory source on Earth.
Which of the following statements is correct?
(Take the speed of light c=3.00×108 m s−1c = 3.00 \times 10^8 \text{ m s}^{-1}c=3.00×108 m s−1)
Both galaxies show a cosmological red-shift and are moving away from Earth.
Galaxy A is moving away from Earth at a speed of 6.0×106 m s−16.0 \times 10^6 \text{ m s}^{-1}6.0×106 m s−1.
Galaxy B is moving towards Earth at a speed of 1.5×107 m s−11.5 \times 10^7 \text{ m s}^{-1}1.5×107 m s−1.
Galaxy A is moving towards Earth faster than Galaxy B.