The speed of light in a vacuum is approximately 299,792 kilometers per second (km/s) or about 186,282 miles per second.
In standard scientific notation:
- Exact value: 299,792,458 meters per second (m/s)
This value is a universal constant, often represented by the symbol c, and it plays a crucial role in many physical theories, especially Einstein’s theory of relativity.
Key Points:
- It is the fastest speed possible in the universe.
- No information or matter can travel faster than this speed.
- It is the basis for defining the meter, the SI unit of length.
So, in a vacuum, light travels at this constant, maximum speed—unaffected by material properties.