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
Mach Song population segments not reached by their media partners. On certain issues, Mach Song Media mobilizes local faith and community organizations to reach deep into their constituencies. So far they have worked with over 200 such organizations on various issues and have the capacity to reach 1,000 faith and community organizations in the Vietnamese communities across the US. "Boat People SOS" has invested over 1 million dollars to develop its own network of Vietnamese-language mass media. This network includes Mach Song monthly publication, Mach Song radio programs and Mach Song television programs. If necessary, Mach Song can readily increase the circulation