The Doppler effect ( or Doppler shift ), named after the Austrian physicist Christian Doppler, who proposed it in 1842 in Prague, is the change in frequency of a wave ( or other periodic event ) for an observer moving relative to its source.

The Doppler effect ( or Doppler shift ), named after Austrian physicist Christian Doppler who proposed it in 1842, is the difference between the observed frequency and the emitted frequency of a wave for an observer moving relative to the source of the waves.

0.005 seconds.