Question

How do changes in light wavelengths support the most widely accepted ideas about the universe?A. Galaxies are moving away from Earth, as shown by the shift of their light toward the blue end of the spectrum.B. Galaxies are moving toward Earth, as shown by the shift of their light toward the blue end of the spectrum.C. Galaxies are moving toward Earth, as shown by the shift of their light toward the red end of the spectrum.D. Galaxies are moving away from Earth, as shown by the shift of their light toward the red end of the spectrum.

Answer 1

Take into account that the change in the wavelength of the light is due to the Doppler effect for electromagnetic waves.

If the source of the light is going away of a perceiver, the frequency of the perceived wave is lower than the original wave. It means that the perceived wavelength is larger.

Our ideas of the universe states primarly that the universe expands. All galaxies are moving away from Earth, as shown by the shift of their light toward thr red end of the spectrum. (which is the same that the detected light has a larger wavelength than the sorce)