How to reconcile photon not experiencing time with it's travel time?

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    Photon Time Travel
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Discussion Overview

The discussion revolves around the nature of photons, particularly addressing the concept of time as experienced by photons and how this relates to their travel time from the sun to Earth. Participants explore theoretical implications, properties of photons, and the reconciliation of their behavior with established physics concepts.

Discussion Character

  • Exploratory
  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • Some participants question whether a photon, not experiencing space-time, can "degrade/fray" during its travel, suggesting that conservation principles may be more relevant to its behavior.
  • There is a proposal that photons do not have clocks and do not care about time, leading to the assertion that there is nothing to reconcile regarding their travel time and experience of time.
  • One participant suggests that to describe a photon's world line, one should use coordinate time in a reference frame, noting that photons do not have a rest frame.
  • Another participant introduces the idea of perturbations within a photon, questioning whether these perturbations freeze in time when the photon is moving in a vacuum.
  • There is a discussion about the existence of photons in free space, with some arguing that photons must exist to traverse the distance from the sun to Earth, while others suggest that photons may only appear when light interacts with matter.
  • One participant emphasizes that photons have properties such as wavelength and polarization but should not be treated as small lumps of matter, indicating that their behavior is frame-dependent.
  • Concerns are raised about the decay of photons into other particles, with specific references to conservation laws that would prevent certain decay processes.
  • A participant expresses frustration over repeated questions regarding the experience of time by photons, directing others to a FAQ for further reading.

Areas of Agreement / Disagreement

Participants express multiple competing views regarding the nature of photons, their experience of time, and their properties. The discussion remains unresolved, with no consensus reached on these complex topics.

Contextual Notes

Limitations include the dependence on definitions of time and space, unresolved questions about the nature of photons in free space, and the implications of conservation laws on photon behavior.

San K
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If a photon does not experience space-time does that mean it cannot "degrade/fray"?

Is there a way to reconcile the, say, eight minutes, time
the photon (approx) took to travel from sun to Earth
with
the zero time that passed in the (frame of reference of) photon?

Where was the photon, in a sense, during those 8 minutes?
 
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San K said:
If a photon does not experience space-time does that mean it cannot "degrade/fray"?
What does this mean ? Split ends ?

Is there a way to reconcile the, say, eight minutes, time the photon (approx) took to travel from sun to Earth with the zero time that passed in the (frame of reference of) photon?
There's nothing to reconcile. Photons ( if they exist at all in free space ) do not have clocks and don't care about time.
Where was the photon, in a sense, during those 8 minutes?
Where do you think it was ?

You can resolve all these questions using Maxwell's equations and if necessary, GR.
 
To describe the world line of a photon, just use the coordinate time in some handy reference frame. That's all you need to know. A photon does not have a rest frame. (Is there an echo in here?)
 
Mentz114 said:
What does this mean ? Split ends ?

thanks Mentz114

a photon is a quanta of energy, within that quanta, i guess, there could be perturbations.

i guess, those perturbations would be created/initiated/caused during the prior interaction of the photon with matter-energy.

however would these perturbations (within the photon) freeze in time-space, when the photon is, say, moving in a vacuum (and not interacting with anything)?
 
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Mentz114 said:
Photons ( if they exist at all in free space )

Don't photons need to exist (in free space) so as to, say, reach from the sun to earth (while traversing the free space between the sun and earth)?
 
San K said:
a photon is a quantum of energy, within that quantum, i guess, there could be perturbations.
This is quantum mechanics but photons have wavelength and possibly a polarization state - but no other properties. And the wavelength is frame dependent. It is not useful to think that photons can be treated as small lumps of matter. When you've seen one photon you've seen them all.

See this article http://en.wikipedia.org/wiki/Photon#Physical_properties

Don't photons need to exist (in free space) so as to, say, reach from the sun to Earth (while traversing the free space between the sun and earth)?
It is possible that photons only appear when light interacts with matter. In this case we can't say anything except that light goes from A to B. Maybe while it is in transit it is an em wave. But it is not crucial because we can't detect light unless it interacts with matter.
 
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San K said:
If a photon does not experience space-time does that mean it cannot "degrade/fray"?
I think that conservation principles are more important for this. For a photon to decay into other particles those other particles would have to conserve energy, momentum, spin, charge, etc. It cannot decay into an electron because then it would violate conservation of charge. It cannot decay into an electron and a positron because then it would violate conservation of momentum. It cannot decay into a pair of photons because then it would violate conservation of spin. Etc.

San K said:
the zero time that passed in the (frame of reference of) photon?
We have had a rash of this question recently, and frankly I am getting tired of scratching. Here is the FAQ, please read through all of the other posts on the topic before continuing it here.

https://www.physicsforums.com/showthread.php?t=511170
 

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