+The Doppler effect describes the perceived change in [Frequency](/wiki/frequency) or wavelength of a [Wave](/wiki/wave) for an observer in relative motion to its source. It paints a picture of movement, from the shifting pitch of a passing siren to the cosmic dance of stars revealed by their light.
+## See also
+- [Sound](/wiki/sound)
+- [Light](/wiki/light)
+- [Redshift](/wiki/redshift)
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