The Big Bang Theory concludes that the Universe expanded from a single dense point approximately 13.6 billion years ago and is still rapidly expanding now. In 1929 the astronomer Edwin Hubble used evidence of light spectra to indicate the motion of distant galaxies. Below, Figure 1 represents emission spectra of two distant galaxies and a stationary laboratory reference for comparison. Figure 2 is Hubble's original analysis of data on galaxy velocity and distance from Earth. Question: In the space provided, please describe the following: 1. What does a shifted emission spectra tell us about the object? 2. How does the red-shift of the emission spectra of distant galaxies support the Big Bang Theory?