Can a photon travel forever without interacting with matter?

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A photon can theoretically travel indefinitely in a vacuum without interacting with matter, but its frequency may decrease due to gravitational redshift as it moves away from massive objects. The question remains whether a photon can decrease in frequency without any gravitational influence, and if it eventually "flat-lines" after extended travel. Currently, there is no experimental evidence to confirm these ideas, leaving them as open questions in physics. The discussion touches on the "Tired Light" concept, which suggests a potential mechanism for frequency decrease, though it lacks credible support. Overall, the fate of a photon in empty space continues to be a topic of speculation and inquiry.
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If there's nothing to interact with, will the photon attenuate and disappear after some distance, or will it continue to exist and travel forever?

For example, in a hypothetical universe where all matter is within a sphere and spacetime continues outside the sphere without limits, if a photon exits the sphere will it last forever?
 
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In your scenario it will indeed last forever, although it will be gravitational redshifted while moving away from the sphere.
 
That red-shift denotes a decrease in the photons original frquency over time and through it's pasages through gravitational influences.
I believe that what is not known at this time is if a photon decreases in frequency without gravitational influence.
Does a photon eventually "flat-line" by virtue of extended travel without any other influence?
I've heard that this is a good question with no experimental evidence to suggest an answer at this time.
 
If it decreases in frequency, ie if the e/m wave is getting closer and closer to dc, then this is not equivalent to going out of existence, is it.

Does the gravitational bending of spacetime extend all the way to infinity? Or does gravity, consisting of particles that cannot have less energy than a quantum quantity, disappear completely after some distance?
 
pallidin said:
That red-shift denotes a decrease in the photons original frquency over time and through it's pasages through gravitational influences.
I believe that what is not known at this time is if a photon decreases in frequency without gravitational influence.
Does a photon eventually "flat-line" by virtue of extended travel without any other influence?
I've heard that this is a good question with no experimental evidence to suggest an answer at this time.

This is the "Tired Light" idea, you might be interested in the wikipedia article http://en.wikipedia.org/wiki/Tired_light and especially the corresponding discussion http://en.wikipedia.org/wiki/Talk:Tired_light (the discussion is very "lively", if you want to see it in a positive way - including the identification of a sockpuppet :biggrin:)

my personal opinion is, that at the moment there exists no credible mechanism that would predict such a "tiring" effect.
 
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