Speed of light to Mach number Conversion Calculator: Free Online Tool
Convert speed of light to Mach numbers with our free online speed converter.
Speed of light to Mach number Calculator
How to Use the Calculator:
- Enter the value you want to convert in the 'From' field (Speed of light).
- The converted value in Mach number will appear automatically in the 'To' field.
- Use the dropdown menus to select different units within the Speed category.
- Click the swap button (⇌) to reverse the conversion direction.
How to Convert Speed of light to Mach number
Converting Speed of light to Mach number involves multiplying the value by a specific conversion factor, as shown in the formula below.
Formula:
1 Speed of light = 8.7403e+5 Mach numbersExample Calculation:
Convert 60 speed of light: 60 × 8.7403e+5 = 5.2442e+7 Mach numbers
Disclaimer: For Reference Only
These conversion results are provided for informational purposes only. While we strive for accuracy, we make no guarantees regarding the precision of these results, especially for conversions involving extremely large or small numbers which may be subject to the inherent limitations of standard computer floating-point arithmetic.
Not for professional use. Results should be verified before use in any critical application. View our Terms of Service for more information.
What is a Speed of light and a Mach number?
The speed of light in vacuum, commonly denoted by 'c', is a universal physical constant important in many areas of physics. Its exact value is defined as 299,792,458 meters per second.
The Mach number (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 Austrian physicist and philosopher Ernst Mach.
Note: The Speed of light is part of the imperial/US customary system, primarily used in the US, UK, and Canada for everyday measurements. The Mach number belongs to the imperial/US customary system.
History of the Speed of light and Mach number
The concept that light travels at a finite speed has been explored since antiquity. Early quantitative estimates were made by Ole Rømer in 1676. Increasingly accurate measurements were made over centuries, culminating in the 1983 definition by the General Conference on Weights and Measures, which fixed the speed of light to its current value, thereby defining the meter based on 'c' and the second.
The term "Mach number" was proposed by Swiss aeronautical engineer Jakob Ackeret in 1929. It gained prominence during World War II with the development of high-speed aircraft. The sound barrier (Mach 1) was famously broken by Chuck Yeager in 1947.
Common Uses for speed of light and Mach numbers
Explore the typical applications for both Speed of light (imperial/US) and Mach number (imperial/US) to understand their common contexts.
Common Uses for speed of light
- Physics: Fundamental constant in Einstein's theory of relativity (E=mc²), electromagnetism, and cosmology.
- Astronomy: Measuring vast cosmic distances (light-years).
- Telecommunications: Determining signal propagation speed in fiber optics and wireless communication.
- GPS: Accurate timing based on signal travel time from satellites.
Common Uses for Mach numbers
- Aerospace: Describing the speed of aircraft and spacecraft relative to the speed of sound (subsonic, transonic, supersonic, hypersonic).
- Fluid Dynamics: Analyzing high-speed flows in wind tunnels, jet engines, and rocket nozzles.
- Ballistics: Characterizing the speed of projectiles.
Frequently Asked Questions
Questions About Speed of light (c)
Is the speed of light always the same?
The speed of light in vacuum (c) is constant and independent of the observer's motion or the source's motion. However, light travels slower when passing through materials like water or glass. The ratio by which it slows down is the material's refractive index.
Can anything travel faster than the speed of light?
According to the theory of special relativity, no object with mass can be accelerated to the speed of light, and no information can travel faster than 'c' in a vacuum.
How is the speed of light related to the meter?
Since 1983, the meter is defined as the distance light travels in vacuum during a time interval of 1/299,792,458 of a second. This definition fixes the speed of light exactly.
About Mach number (Mach)
What does Mach 1 mean?
Mach 1 represents the speed of sound in the surrounding medium under specific conditions (temperature, pressure, altitude). At standard sea level conditions (15°C and 1 atm), Mach 1 is approximately 343 meters per second (1,235 km/h; 767 mph).
Is the speed of Mach 1 constant?
No, the speed of sound varies primarily with temperature. It decreases at higher altitudes where the air is colder. Therefore, the actual speed corresponding to Mach 1 changes with altitude and atmospheric conditions.
What are the different speed regimes related to Mach number?
- Subsonic: M < 0.8
- Transonic: 0.8 ≤ M < 1.2
- Supersonic: 1.2 ≤ M < 5
- Hypersonic: M ≥ 5
Conversion Table: Speed of light to Mach number
| Speed of light (c) | Mach number (Mach) |
|---|---|
| 1 | 874,030.49 |
| 5 | 4,370,152.449 |
| 10 | 8,740,304.898 |
| 25 | 21,850,762.245 |
| 50 | 43,701,524.49 |
| 100 | 87,403,048.98 |
| 500 | 437,015,244.898 |
| 1,000 | 874,030,489.796 |
All Speed Conversions
Conversion Formula
1 c = 874030.489796 Mach
Where 1 Speed of light (c) equals the calculated value in Mach numbers (Mach).