Speed of light measured in/by a parallel frame moving at c

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SUMMARY

The discussion centers on the paradox of measuring the speed of light from the perspective of two observers, Alice and Bob, both moving at the speed of light (c) alongside their respective photons. It concludes that the concept of a "rest frame of a photon" is nonsensical, as no observer can truly "sit" on a photon. The resolution lies in understanding that as Alice attempts to accelerate towards photon A, she will never reach it, as it continues to travel at c, reinforcing the constancy of the speed of light as dictated by the principles of relativity.

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  • Understanding of Einstein's theory of relativity
  • Familiarity with the concept of inertial frames
  • Basic knowledge of the speed of light as a universal constant
  • Awareness of the implications of relativistic physics
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San K
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Scenario:

Alice is "sitting" on photon A
Bob is "sitting" on photon B

both are moving in same direction, their paths are parallel to each other.

Per relativity the speed of light is constant

So Alice will measure Bob's speed to be c
and Bob will measure Alice's speed to be c

yet they are both moving at constant velocity c

how is this (paradox?) resolved?
 
Physics news on Phys.org
If Alice accelerates, trying to catch up with photon A, she finds that it still eludes her, traveling at c.
 

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