Doppler Shift Animation


Another in my series of wave animations. This is also in UHD (4K) and you can watch it at full size from this blog by clicking the video expand button.

Generalised animation of the increase in frequency observed in waves emitted from an approaching source (or conversely a decrease in frequency in waves emitted from a receding source). This Doppler Shift happens in sound waves (e.g. a siren of an approaching emergency vehicle or the change in pitch of a passing car engine) and in light waves (the red Doppler shift of a receding star or the blue Doppler shift of an approaching star, redshift and blueshift).

This animation uses a ball as the wave source. As the ball moves from left to right it emits wave-fronts that continue to radiate out from their position of origin. The ball moves on and creates a new point of origin for the next wavefront and so on. In this way, the waves bunch together at the front of the ball and spread out behind. Similar to a jet plane approaching the speed of sound and radiating sound waves. In the case of light waves then the higher frequency at the front yields a bluer light (blue shift), while behind the light source (e.g. a star) the light is stretched out, lengthening the frequency, creating a redshift. Licence this Doppler animation.

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