Dopplers
Dopplers refer to the Doppler effects, the changes in frequency or wavelength of waves caused by the relative motion of a source and an observer. The phenomenon is named after Austrian physicist Christian Doppler, who proposed it in 1842. It applies to all waves, including sound and light, though the interpretation differs for electromagnetic radiation due to relativity.
In acoustics, the observed frequency increases when the source or observer moves toward the other, and decreases
In optics, the Doppler effect is relativistic. For light, frequency shifts depend on the relative speed with
Applications are wide: Dopplers underpin radar and Doppler weather radar, enable measurements of wind, velocity, or