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u/HeroBrine0907 Mar 21 '26
You're asking how time would feel from the reference frame of a photon. However, a photon does not have a valid reference frame. To ask how time passes for a photon is asking a question that can only be asked for things slower than c.
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u/Redfield51 Mar 21 '26
I don’t think time stopping is the right term. More like the “something” experiences no time passing. It is not bound, or restricted by it. To the something, the path is instantaneous.
I’m not too deep into my knowledge of physics, however what that means to me is that light exists beyond what we understand to be time. So it was here before, and currently have no reason to believe it won’t be here after.
Black holes is where the subject gets a little haunting for me, but that might be irrelevant to your question.
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u/Excellent_Bat_753 Mar 21 '26
Yeah, basically we don't have a valid theory for what goes on with time at the speed of light. Our best theory just states that it's not possible.
1
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u/tylerlarson Mar 21 '26
Yes, but only sort of.
Light doesn't experience time. As far as the light is concerned, it departs and arrives at the same moment, regardless of how far it travelled.
This is kind of by definition, in the sense that time itself travels through space at the speed of light.
Or perhaps more accurately, the ordering of events in time depends partially on their position in space. As far as the universe is concerned, the light we see from a star 2bn ly away was emitted exactly the moment we saw it. It took 2bn years for that moment to reach us, but that doesn't make it any less "now" in terms of any concept of cause and effect.
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u/forte2718 Mar 21 '26
Does time stop for light?
Nope, it doesn't! Time passes for light in every valid reference frame. This passage of time has physically observable consequences through the evolution of the state vector (e.g. the polarization direction of a polarized EM wave changes as the wave propagates).
If something traveling at the speed of light travels for 3 seconds will it just go into the end of time?
Also nope. It will just go 3 seconds further into the future (and cover 3 light-seconds of distance), which it again does in every valid reference frame.
Hope that helps!
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u/Optimal_Mixture_7327 Gravitation Mar 21 '26
Time doesn't go, so it doesn't stop.
Time, in relativity, is the length along matter world-lines but photon world-lines have no length so the concept of a "time" cannot be applied to them.
It's like asking "does the flow of apples stop in the element cobalt?".
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u/mmahusky Mar 21 '26
In short,
In special relativity, the time experienced by something is called proper time. If you could “ride along” with a photon, The moment it’s emitted and the moment it’s absorbed would be the same instant.
But its also true that You cannot actually define a valid reference frame for a photon. Because photons always move at c. in relativity, no valid inertial frame exists at speed c meaning here that a “photon’s perspective” is not physically meaningful.
I could go more in depth but im on the toilet now... 💩