Convert light speed (vacuum) to mach (20 Celcius dry air)
Selected category: speed.
Definition and details for light speed (vacuum):
Speed of light (c) in vacuum is equal to 299 792 458 meters/sec with a relative measurement uncertainty of 4 parts per billion. Up to 17th century humanity wasn't sure if light was transmitted instantaneously or simply very quickly. The Danish astronomer, Ole Christensen Rømer first demonstrated that light travelled at a finite speed when he studied the apparent motion of Jupiter's moon Io.
Definition and details for mach (20 Celcius dry air):
Mach (M or Ma) is a relative speed unit, used to compare an aircraft's speed with the speed of the sound in the atmosphere. It was named "Mach" to honor the Austrian physicist Ernst Mach (1838-1916). But because sound speed value depends on the density and temperature of the air, sometimes mach is calculated at 20 ºC in dry air. Conversion center, here uses these initial conditions.