Ernst Mach of experimental physics concentrated on the interference, diffraction, polarization and refraction of light in different media under external influences. From there followed important explorations in the field of supersonic fluid mechanics. Mach and physicist-photographer Peter Salcher presented their paper on this subject in 1887; it correctly describes the sound effects observed during the supersonic motion of a projectile. They deduced and experimentally confirmed the existence of a shock wave of conical shape, with the projectile at the apex. The ratio of the speed of a fluid to the local speed of sound "v"/"v" is now called the Mach number. It
Alexander Mach Alexander Mach Alexander Mach (11 October 1902 in Slovenský Meder (today Palárikovo) – 15 October 1980 in Bratislava) was a Slovak nationalist politician. Mach was associated with the far right wing of Slovak nationalism and became noted for his strong support of Nazism and Germany. Mach joined the Slovak People's Party at an early age and came to prominence within that movement as an aide to Vojtech Tuka. Under Tuka's tutelage Mach served as editor of the party organs "Slovak" and "Slovenska Pravda" and was appointed to the party's political committee in 1924. He belonged to the non-clerical wing of