Mach number a small area around the object's leading edge. (Fig.1b) Fig. 1. "Mach number in transonic airflow around an airfoil; M < 1 (a) and M > 1 (b)." When an aircraft exceeds Mach 1 (i.e. the sound barrier), a large pressure difference is created just in front of the aircraft. This abrupt pressure difference, called a shock wave, spreads backward and outward from the aircraft in a cone shape (a so-called Mach cone). It is this shock wave that causes the sonic boom heard as a fast moving aircraft travels overhead. A person inside the aircraft will not hear this.
Ernst Mach one another, by triggering edge-detection in the human visual system. More clearly than anyone before or since Mach made the distinction between what he called "physiological" (specifically visual) and "geometrical" spaces. Mach's views on mediating structures inspired B. F. Skinner's strongly inductive position, which paralleled Mach's in the field of psychology. In homage his name was given to: 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