Mach to Speed Of Light (Ma to c)
1 Mach equals 0.000001135098602 speed of light (rounded).
How to convert Mach to speed of light
To convert Mach to speed of light, multiply the number of Mach by 0.000001135098602. The factor is rounded to 10 significant digits. To go the other way, multiply speed of light by 880,980.7343 (rounded).
speed of light = Mach × 0.000001135098602
Example: 10 Mach = 0.00001135098602 speed of light.
Approximate value. Standards for the Mach varied by place and period, so this converter uses the most commonly cited value. Treat results as estimates, not exact figures.
About these units
Mach (Ma)
The speed of sound at sea level in standard conditions (15 °C): about 340.294 m/s or 1,225 km/h. The speed of sound varies with temperature and altitude.
Ernst Mach, the Austrian physicist and philosopher born in Moravia in 1838, never defined a unit of speed, yet the ratio carries his name. In 1887 he and Peter Salcher presented a paper on photographing processes in air caused by projectiles, including a shadowgraph of the bow shock around a supersonic bullet fired from a Werndl carbine. The ratio of flow speed to the local speed of sound was later named for him.
Mach is therefore a dimensionless number, not a fixed speed, and because the speed of sound depends on temperature, so does Mach 1. It is about 340 m/s (1,225 km/h) in dry air at 15 °C at sea level, 343 m/s at 20 °C, and about 295 m/s above 11 kilometers where the air is cold. Flight is called subsonic below 0.8, transonic from 0.8 to 1.2, supersonic from 1.2 to 5 and hypersonic from 5 to 10. On 14 October 1947 Chuck Yeager flew the Bell X-1 to Mach 1.06, reported as 361 m/s.
1 Mach = 340.294 meters per second (approximately).
Sources: Wikipedia: Mach number; Wikipedia: Ernst Mach; Wikipedia: Speed of sound
Speed Of Light (c)
Exactly 299,792,458 m/s, the speed of light in a vacuum and the fundamental constant that defines the meter.
Light was once thought to arrive instantly. In 1676 Ole Rømer timed eclipses of Jupiter's moon Io and concluded that light takes about 22 minutes to cross Earth's orbit. In 1729 James Bradley used the aberration of starlight to estimate about 8 minutes 12 seconds from Sun to Earth. Later experimenters used a toothed wheel (Fizeau), a rotating mirror (Foucault), and in 1930 to 1935 Michelson, Pease and Pearson used a mile-long vacuum chamber. The letter c is itself uncertain: it may stand for constant or the Latin celeritas, swiftness, and Einstein switched to it in 1907.
Since 1983 the speed of light has been fixed at exactly 299,792,458 m/s, and the meter is defined as the distance light travels in a vacuum in 1/299,792,458 of a second. Measurement therefore became a matter of defining the constant, not of improving experiments. For scale, light takes about 1.3 seconds to travel from the Earth to the Moon, about 8.3 minutes from the Sun, and roughly one nanosecond to go a foot. James Clerk Maxwell showed in 1865 that light is an electromagnetic wave.
1 speed of light = 299,792,458 meters per second (exactly).
Sources: Wikipedia: Speed of light; NIST: the meter and the SI redefinition
Related conversions
- Speed of light to Mach (reverse)
- Mach to meters per second
- Mach to kilometers per hour
- Mach to miles per hour
- Mach to knots
- Mach to feet per second
- Meters per second to speed of light
- Kilometers per hour to speed of light
- Miles per hour to speed of light
- Knots to speed of light
- Feet per second to speed of light
See all speed units.