Unravelling the Mystery of Light Speed (c)

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SUMMARY

The speed of light, denoted as "c," is defined as 299,792,458 m/s and is a fundamental constant in Maxwell's equations of Electromagnetism. Special relativity asserts that nothing can exceed this invariant speed, establishing it as the maximal speed for any object. The relationship between c and electromagnetic waves confirms that light propagates at this speed, reinforcing its significance in both theoretical and experimental physics. Various measurements and interpretations of c highlight its critical role in understanding the nature of light and speed limits in the universe.

PREREQUISITES
  • Understanding of Maxwell's equations in Electromagnetism
  • Familiarity with the principles of Special Relativity
  • Basic knowledge of the speed of light and its measurement
  • Concept of invariant speed in physics
NEXT STEPS
  • Study the derivation of the speed of light from Maxwell's equations
  • Explore experimental methods for measuring the speed of light
  • Investigate the implications of invariant speed in modern physics
  • Learn about the relationship between electromagnetic waves and light propagation
USEFUL FOR

Physicists, students of physics, and anyone interested in the fundamental principles of light and speed in the context of Special Relativity and Electromagnetism.

eoghan
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Hi!
Special relativity states that nothing can travel faster than c. But how do we know that c is the speed of light?
 
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c is a constant in Maxwell's equations of Electromagnetism.
A simple derivation shows that this constant, c, is the speed of EM waves which describe the propagation of light.
 
eoghan said:
Hi!
Special relativity states that nothing can travel faster than c. But how do we know that c is the speed of light?
c is defined as the speed of light in vacuum and is exactly 299792458 m/s.
 
eoghan said:
Hi!
Special relativity states that nothing can travel faster than c. But how do we know that c is the speed of light?

SR asserts that there is a invariant speed. One consequences is that this is a maximal speed.

Light happens to travel at this speed (for good reason).
 
eoghan said:
Hi!
Special relativity states that nothing can travel faster than c. But how do we know that c is the speed of light?
Special relativity states that nothing can travel faster than the speed of light. Which we happen to call "c".
 
Just to chime in, we have measured the speed of light, and it is c.
 
Drakkith said:
Just to chime in, we have measured the speed of light, and it is c.

Lols
 
eoghan said:
Hi!
Special relativity states that nothing can travel faster than c. But how do we know that c is the speed of light?
What, then, is your understanding of the meaning of c?
 
  • #10
eoghan said:
Hi!
Special relativity states that nothing can travel faster than c. But how do we know that c is the speed of light?

As you can see, there are different opinions as to what c officially stands for. This is because both in theory and experiment, Maxwell's electromagnetic constant equals the speed of light and this speed also equals the maximal speed.
 

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