Ernst Mach Ernst Mach Ernst Waldfried Josef Wenzel Mach (; ; 18 February 1838 – 19 February 1916) was an Austrian physicist and philosopher, noted for his contributions to physics such as study of shock waves. The ratio of one's speed to that of sound is named the Mach number in his honor. As a philosopher of science, he was a major influence on logical positivism and American pragmatism. Through his criticism of Newton's theories of space and time, he foreshadowed Einstein's theory of relativity. Ernst Waldfried Josef Wenzel Mach was born in Chrlice (), Moravia (then in the Austrian empire, now
Critical Mach number not designed to fly at or above the critical Mach number, the shock waves that form in the airflow over the wing and tailplane are sufficient to stall the wing, render the control surfaces ineffective, or lead to loss of control of the aircraft (such as Mach tuck, when shock waves in the airflow over the elevator send the aircraft into an uncontrollable dive). These problematic phenomena appearing at or above the critical Mach number became known as compressibility. Compressibility led to a number of accidents involving high-speed military and experimental aircraft in the 1930s and 1940s. Although unknown at