SUMMARY
The speed of light is defined as 186,282 miles per second, a value that arises from the definitions of the mile and the second. This speed is invariant, meaning it remains constant across all inertial reference frames, a principle central to Einstein's theory of relativity. The numerical value of the speed of light is not a fundamental property of the universe but rather a consequence of our unit definitions, particularly in the SI system where it is defined as exactly 299,792,458 meters per second. The underlying constants, such as the permittivity and permeability of free space, contribute to this definition but do not provide a deeper explanation for why the speed of light is what it is.
PREREQUISITES
- Understanding of the principles of electromagnetism, particularly Maxwell's equations.
- Familiarity with the concepts of invariance and reference frames in physics.
- Knowledge of unit systems, especially the SI system and its definitions.
- Basic comprehension of relativity and its implications on speed and measurement.
NEXT STEPS
- Explore Maxwell's equations and their implications for electromagnetic wave propagation.
- Study the principles of relativity, focusing on the concept of invariant speeds.
- Investigate the definitions and roles of permittivity and permeability in different unit systems.
- Research the fine structure constant and its significance in modern physics.
USEFUL FOR
Physicists, students of physics, and anyone interested in the fundamental constants of nature and their implications in theoretical and experimental physics.