Because of the Doppler Effect, visible light waves observed on Earth emitted from a star that is approaching us will appear to astronomers to be... Question 16 options: traveling at a faster speed, but have the same frequency and wavelength. compressed to higher frequency and blue-shifted on the spectral scale. stretched to lower frequency and blue-shifted on the spectral scale. stretched to a lower frequency and red-shifted on the spectral scale. compressed to a higher frequency and red-shifted on the spectral scale