1. The problem statement, all variables and given/known data a gas that absorbs light of wavelength 200 nm in the laboratory. Suppose there is a cold cloud of the same gas between you and a hot source of continuum (blackbody) radiation, and the cloud is moving away from Earth. You will see a spectrum with 2. Relevant equations 3. The attempt at a solution absorption line at a wavelength longer then 200nm. since the cold cloud is moving away so would have a red shift right?