Mach to Light Speed
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Conversion Table

How to convert

1 mach (M) = 1.1351E-06 light speed (ls). Mach (M) is a unit of Speed used in Metric system. Light Speed (ls) is a unit of Speed used in Metric system.

Mach number

Definition of Mach

Mach, commonly denoted M or Ma, is a dimensionless quantity in fluid dynamics representing the ratio of flow velocity past a boundary to the local speed of sound. It is named after the Austrian physicist and philosopher Ernst Mach, who studied gas dynamics and shock waves. Mach number is used to classify the flow regimes based on the effects of compressibility and shock waves on the flow.

How to Convert Mach

To convert mach to other units of speed, we need to multiply by the local speed of sound in the medium, which depends on the temperature and pressure of the gas. For example, to convert mach to meters per second, we need to multiply by the speed of sound in air at sea level, which is about 340 m/s. To convert mach to kilometers per hour, we need to multiply by the speed of sound in air at sea level and by 3.6, since there are 3.6 seconds in one hour.

Here are some examples of how to convert mach to other units of length in the US Standard system and the SI system:

• To convert 1 M to meters per second (m/s), we multiply by 340: 1 M x 340 = 340 m/s
• To convert 2 M to kilometers per hour (km/h), we multiply by 340 and by 3.6: 2 M x 340 x 3.6 = 2448 km/h
• To convert 3 M to miles per hour (mph), we multiply by 340 and by 2.2369362920544, since there are 2.2369362920544 miles in one kilometer: 3 M x 340 x 2.2369362920544 = 2285.714285714 mph
• To convert 4 M to feet per second (fps), we multiply by 340 and by 3.2808398950131, since there are 3.2808398950131 feet in one meter: 4 M x 340 x 3.2808398950131 = 4465.306122449 fps
• To convert 5 M to knots (kn), we multiply by 340 and by 1.9438444924406, since there are 1.9438444924406 nautical miles in one kilometer: 5 M x 340 x 1.9438444924406 = 3316.326530612 kn
• To convert 6 M to centimeters per second (cm/s), we multiply by 340 and by 100, since there are 100 centimeters in one meter: 6 M x 340 x 100 = 204000 cm/s

Where Mach Is Used

Mach is used in various fields of science and technology where the speed and direction of movement of objects or phenomena are measured or applied in relation to the speed of sound in the medium. For example:

• In aerodynamics and aeronautics, mach is used to measure the speed and performance of aircraft, rockets, missiles, and other flying vehicles, as well as the effects of air resistance, drag, lift, and thrust on them.
• In acoustics and sound engineering, mach is used to measure the intensity and frequency of sound waves, as well as the effects of reflection, refraction, diffraction, interference, and Doppler shift on them.
• In meteorology and climatology, mach is used to measure the speed and direction of wind, storms, hurricanes, tornadoes, and other weather phenomena, as well as the effects of temperature, pressure, humidity, and density on them.

History of Mach

The concept of mach number was first introduced by Swiss engineer Jakob Ackeret in his doctoral thesis in 1929. He proposed it as a convenient way to express the ratio of flow velocity to speed of sound in gas dynamics problems. He also named it after Ernst Mach, who had conducted experiments on supersonic projectiles and shock waves in the late nineteenth century.

The term mach number was later popularized by German-American engineer Theodore von Karman, who used it extensively in his research on aerodynamics and supersonic flight in the early twentieth century. He also established the first supersonic wind tunnel at Caltech in 1939.

The first human-made object to break the sound barrier was a rocket-powered plane called Bell X-1 piloted by Chuck Yeager in October 1947. He achieved a speed of about Mach 1.06 at an altitude of 13,000 meters.
The first human to travel faster than sound was Soviet cosmonaut Yuri Gagarin, who orbited the Earth at a speed of about Mach 25 in April 1961.
The fastest manned aircraft ever flown was the North American X-15, which reached a speed of about Mach 6.7 in October 1967.

The fastest unmanned aircraft ever flown was the NASA X-43A, which reached a speed of about Mach 9.6 in November 2004.

Example Conversions of Mach to Other Units

Here are some examples of how to convert mach to other units of speed, using the conversion factors given above:

• To convert 1 M to meters per second, we multiply by 340: 1 M x 340 = 340 m/s
• To convert 2 M to kilometers per hour, we multiply by 340 and by 3.6: 2 M x 340 x 3.6 = 2448 km/h
• To convert 3 M to miles per hour, we multiply by 340 and by 2.2369362920544: 3 M x 340 x 2.2369362920544 = 2285.714285714 mph
• To convert 4 M to feet per second, we multiply by 340 and by 3.2808398950131: 4 M x 340 x 3.2808398950131 = 4465.306122449 fps
• To convert 5 M to knots, we multiply by 340 and by 1.9438444924406: 5 M x 340 x 1.9438444924406 = 3316.326530612 kn
• To convert 6 M to centimeters per second, we multiply by 340 and by 100: 6 M x 340 x 100 = 204000 cm/s
• To convert 7 M to millimeters per minute, we multiply by 340 and by 1000, since there are 1000 millimeters in one meter, and multiply by 60, since there are 60 minutes in one hour: 7 M x 340 x 1000 x 60 = 142800000 mm/min

Light Speed

Definition of Light Speed

Light speed, commonly denoted c, is a universal physical constant that is exactly equal to 299,792,458 metres per second (approximately 300,000 kilometres per second; 186,000 miles per second; 671 million miles per hour). It is the speed at which light waves propagate through vacuum, and also the upper limit for the speed at which any form of matter or energy can travel through space. Light speed is an essential parameter in the theories of relativity and electromagnetism, and has relevance beyond the context of light and electromagnetic waves.

How to Convert Light Speed

To convert light speed to other units of speed, we need to multiply or divide by the corresponding conversion factors. For example, to convert light speed to kilometers per hour, we need to multiply by 3,600, since there are 3,600 seconds in one hour. To convert light speed to miles per hour, we need to multiply by 2.2369362920544, since there are 2.2369362920544 miles in one kilometer.

Here are some examples of how to convert light speed to other units of length in the US Standard system and the SI system:

• To convert c to kilometers per hour (km/h), we multiply by 3,600: c x 3,600 = 1,079,252,848.8 km/h
• To convert c to miles per hour (mph), we multiply by 2.2369362920544: c x 2.2369362920544 = 670,616,629.384 mph
• To convert c to feet per second (fps), we multiply by 3.2808398950131, since there are 3.2808398950131 feet in one meter: c x 3.2808398950131 = 983,571,056.43 fps
• To convert c to knots (kn), we multiply by 1.9438444924406, since there are 1.9438444924406 nautical miles in one kilometer: c x 1.9438444924406 = 582,749,918.284 kn
• To convert c to meters per second (m/s), we use the exact value: c = 299,792,458 m/s
• To convert c to meters per minute (m/min), we multiply by 60, since there are 60 seconds in one minute: c x 60 = 17,987,547,480 m/min

Where Light Speed Is Used

Light speed is used in various fields of science and technology where the properties and behavior of light and electromagnetic waves are studied or applied. For example:

• In astronomy and cosmology, light speed is used to measure astronomical distances and time scales, such as light-years and parsecs. It also determines the observable size and age of the universe and the effects of gravity on light such as gravitational lensing and gravitational redshift.
• In physics and engineering, light speed is used to calculate the energy and momentum of particles and fields using the famous equation E = mc2. It also sets the limit for causality and information transfer in physical systems.
• In communication and navigation, light speed is used to determine the delay and bandwidth of signals transmitted through various media such as optical fibers or radio waves. It also affects the accuracy and precision of measurements based on time-of-flight or Doppler effect methods.

History of Light Speed

The concept of light speed has a long history that spans across different cultures and disciplines. Some of the milestones in its development are:

• In ancient times, many philosophers and scientists assumed that light traveled instantaneously or infinitely fast.
• In the late 17th century, Danish astronomer Ole Romer was the first to demonstrate that light had a finite speed by observing the apparent motion of Jupiter’s moon Io. He estimated that light took about 22 minutes to cross the diameter of Earth’s orbit.
• In the early 18th century, English astronomer James Bradley discovered the aberration of starlight caused by Earth’s motion around the Sun. He used this phenomenon to calculate that light traveled about 10 thousand times faster than Earth’s orbital speed.
• In the late 19th century, French physicist Hippolyte Fizeau and American physicist Albert Michelson conducted various experiments using rotating mirrors or interferometers to measure the speed of light more accurately in air or vacuum.
• In the early 20th century, German-born physicist Albert Einstein proposed the special theory of relativity, which postulated that light speed was constant and independent of the motion of the source or the observer. He also showed that light speed was the maximum speed for any form of matter or energy in the universe.
• In the late 20th century, various methods and standards were developed to define and measure light speed more precisely and consistently. In 1983, the International System of Units (SI) adopted the exact value of 299,792,458 metres per second as the definition of light speed in vacuum.

Example Conversions of Light Speed to Other Units

Here are some examples of how to convert light speed to other units of speed, using the conversion factors given above:

• To convert c to kilometers per hour, we multiply by 3,600: c x 3,600 = 1,079,252,848.8 km/h
• To convert c to miles per hour, we multiply by 2.2369362920544: c x 2.2369362920544 = 670,616,629.384 mph
• To convert c to feet per second, we multiply by 3.2808398950131: c x 3.2808398950131 = 983,571,056.43 fps
• To convert c to knots, we multiply by 1.9438444924406: c x 1.9438444924406 = 582,749,918.284 kn
• To convert c to meters per second, we use the exact value: c = 299,792,458 m/s
• To convert c to meters per minute, we multiply by 60: c x 60 = 17,987,547,480 m/min
• To convert c to centimeters per second, we multiply by 100: c x 100 = 29,979,245,800 cm/s