Final answer:
Light shows the Doppler effect due to its wave nature, allowing observation of shift in frequency as the relative position between the source and observer changes, which can be used to measure radial velocities of astronomical bodies.
Step-by-step explanation:
Light can exhibit the Doppler effect because it behaves as a wave, and the Doppler effect applies to any wave when there is relative motion between the observer and the source of the wave. When a source of light is moving toward an observer, the light waves seem to pile up, resulting in a higher frequency or a shift to the blue end of the spectrum, known as a blue shift. Conversely, if the light source is moving away from the observer, the waves 'stretch out', leading to a lower frequency or a shift to the red end of the spectrum, known as a red shift.
This phenomenon can be used to calculate the radial velocity of an object, such as a star or galaxy, by using the known speed of light, the original wavelength of the emitted light, and the observed wavelength difference due to the Doppler shift. The Doppler effect has crucial implications in astrophysics, such as measuring the universe's expansion and investigating the motion of astronomical bodies.