TY - CHAP M1 - Book, Section TI - Chapter 4. Quantitative Echocardiography A1 - Mahmood, Feroze A1 - Matyal, Robina A2 - Mathew, Joseph P. A2 - Swaminathan, Madhav A2 - Ayoub, Chakib M. PY - 2010 T2 - Clinical Manual and Review of Transesophageal Echocardiography, 2e AB - Christian Doppler, in his 1842 paper titled, “On the Coloured Light of the Binary Stars and Some Other Stars of the Heavens,” was the first to note that stars moving towards the earth emitted blue light while stars moving away from earth radiated red light. Thus, he postulated that the observed frequency of a wave depends on the relative speed of the source and the observer. Although Doppler himself never extended the principle to other natural phenomena, the common observation that the pitch of sound is different for a locomotive approaching the listener than one moving away led to a more widespread application of Doppler's initial observation. SN - PB - The McGraw-Hill Companies CY - New York, NY Y2 - 2024/03/28 UR - accessanesthesiology.mhmedical.com/content.aspx?aid=6915504 ER -