Do photons effectivley travel instantaneously?

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Discussion Overview

The discussion revolves around the nature of photon travel, specifically whether photons effectively travel instantaneously. It touches on Einstein's thought experiment regarding observing a reflection while traveling at the speed of light and the implications for the principle of relativity.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions if photons travel instantaneously, suggesting that if they did, Einstein's thought experiment about seeing a reflection would yield a "no" answer.
  • Another participant asserts that photons travel at the speed of light (c) and do not possess a rest frame.
  • A third participant provides a historical context by quoting Einstein's writings, interpreting them to suggest that if one were to travel at the speed of light, they would not be able to observe the light beam as stationary, thus supporting the idea that such a frame of reference is not permissible under relativity.
  • A later reply reflects on the implications of not seeing a reflection, suggesting that this would indicate knowledge of one's speed without external observation, which the participant believes contradicts the principle of relativity.

Areas of Agreement / Disagreement

Participants express differing views on the implications of photon travel and Einstein's thought experiment. There is no consensus on whether photons effectively travel instantaneously or the ramifications of this on the principle of relativity.

Contextual Notes

The discussion includes references to Einstein's early thoughts and the interpretation of his writings, which may not fully align with contemporary understanding of relativity. The nuances of how these concepts interact remain unresolved.

Pyrokenesis
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Do photons effectivley travel instantaneously? If not then the question posed by Einstein "If I travel at the speed of light and hold a mirror in-front of my face, do I see a reflection?" has the answer, no!

Although I'm not positive why but would say that because your in the same frame of reference as the mirror that you do see a reflection.

Befuddled!
 
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Photons travel at c, they don't have a rest frame.
 
Just for the record, here is what Einstein wrote.

""
Wenn ich einem Lichtstrahl nacheile mit der Geschwindigkeit c (Lichtgeschwindigkeit I am Vacuum), so sollte ich einen solchen Lichtstrahl als ruhendes, raümlich oszillatorisches elektromagnetisches Feld wahrnehmen. So etwas scheint es aber nicht zu geben, weder auf Grund der Erfahrung noch gemäss den Maxwell'schen Gleichungen.
""

Here is an English translation.

""
If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as a spatially oscillatory electromagnetic field at rest. However, there seems to be no such thing, whether on the basis of experience or according to Maxwell's equations.
""

If he were traveling at c behind the beam of light, then he would not be catching up to it. He said "nacheile", which means "lag". So it should be "If I lag a beam of light...". He didn't say "gehe mit" (go with) or "reise mit" (travel with) that beam of light. So he hasn't explained just how he thought he could experience those (for him) stationary oscillations, and he hasn't explained just how he might have transformed those Maxwell equations to that moving frame of reference. But this is just a remembrance of something from his early thoughts, before his theory of relativity. It would have been about 1895 and (he says) he was sixteen.

I think he agrees with the topic originator. It would be just like standing still (relativity principle), so the light beam can't be at rest even in this frame of reference. Relativity theory won't permit this (traveling at lightspeed)to be a frame of reference at all.

*autobiography from Schilpp Library of Living Philosophers
 
Last edited:
Thanx guys, I've read a bit more on the subject, and if he couldn't see his image then as I understand it he would know the speed he was moving at without having to look outside his own frame. This violates the principle of relativity. Makes sense!
 

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