Experimental evidence supports the Doppler shift of light, demonstrating that light from fast-moving objects exhibits higher frequencies when approaching and lower frequencies when receding. Police radar guns utilize this principle by measuring frequency differences in radio waves, which are a form of light. Simple experiments, like spinning a buzzer, illustrate acoustic Doppler effects, while optical measurements require more sophisticated equipment but are feasible in undergraduate labs. The shift in light frequency is measurable even at relatively low speeds, with significant effects observed in distant galaxies, which can be red-shifted into the infrared spectrum. The sun's rotation provides a practical example, with measurable frequency shifts detectable in its spectrum.
