Christian Andreas Doppler was an Austrian mathematician and physicist. He is celebrated for his principle — known as the Doppler effect — 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.... More • http://en.wikipedia. ... an_Doppler View • Books • Images • Videos • Search Related • Mathematicians • Scientists • Astronomy • Austria • Industrial Revolution • Mathematics • November 29 • Physicists • Physics • Sagittarius • Waves