"Austrian mathematician and physicist" . . . . "Doppler, Christian"@en . . . "1803-11-29Z"^^ . . "Christian Andreas Doppler (/\u02C8d\u0252pl\u0259r/; 29 November 1803 \u2013 17 March 1853) was an Austrian mathematician and physicist. He is celebrated for his principle \u2014 known as the Doppler effect \u2014 that the observed frequency of a wave depends on the relative speed of the source and the observer. He used this concept to explain the color of binary stars."@en . . "Christian Doppler"@en . "1853Z"^^ . "1853-03-17Z"^^ . "1803Z"^^ .