Abstract: A short biography of the great Austrian physicist Christian Doppler is presented. His famous paper 〖JP2〗“On the colored light of double stars and of some other stars in the sky” was the first to explain that a star′s〖JP〗 color depended on its motion. An account is given of the early experiments that demonstrated the Doppler effect in acoustics, astronomy and optics. The historical impact of this effect and the significance of commemorating Christian Doppler are discussed.