Photon "reference frame" and determinism

[bennyboy]

If there is no distance, then there is no reason to think the photon's time was stopped while it covered that distance.

That's right. The photon didn't experience time because from its perspective the journey is infinitely short. WE see it as timeless because it literally is. Therefore. . . all things related by light are immalleable, therefore determinism. Ta da!

[wiploc]

If there is no distance, then there is no reason to think the photon's time was stopped while it covered that distance.

That's right.  The photon didn't experience time because from its perspective the journey is infinitely short.  WE see it as timeless because it literally is.  Therefore. . . all things related by light are immalleable, therefore determinism.  Ta da!

I can't make sense of that.  Let's use a situation that won't make physicists laugh at us: 

Joe and Sara are traveling (relative to each other) at a speed that makes each of them see the other's time pass at half speed. 

Now, if I understand you, you are saying that one of them experiences less time because his journey is shorter, and the other one seems slow because it literally is?   Is that your position?  If so, I think you are confused. 

Each will see the other as having slow time, and each will see the other as spatially distorted.  Neither view is privileged. It isn't true that one of them is "really" slowed down and the other is "really" physically distorted.

[InquiringMind]

I'll give you my understanding of it according to special relativity. An observer always experiences time passing normally in their own reference frame, but observers in different reference frames can disagree on the passage of time. But this is not why a photon is "timeless." At speed c, length contraction becomes infinite, so in the photon's frame of reference, the distance travelled is zero. The photon can still experience time, but it never does, because in the photon's reference frame, the distance to the atom that will absorb it is zero. But in our reference frame these distances are not zero, and a photon lives for a finite about of time, so experiments with light can work (and they do).

And for determinism, look into the idea of light cones. It's been a little while, and I don't remember off the top of my head how to apply that to this situation.

[bennyboy]

Yeah, that's my understanding, too.

However, I don't think a photon can actually experience time under any scenario because it instantly reaches light speed upon emission. So it seems to me that a photon is really a kind of wormhole, connecting two points in space, from its reference frame. In essence, it's connecting an atom in the sun to an atom in my eye, rather than a thing that moves, intercepts my eye, and is noticed by me.

[bennyboy]

That's right.  The photon didn't experience time because from its perspective the journey is infinitely short.  WE see it as timeless because it literally is.  Therefore. . . all things related by light are immalleable, therefore determinism.  Ta da!

I can't make sense of that.  Let's use a situation that won't make physicists laugh at us: 

Joe and Sara are traveling (relative to each other) at a speed that makes each of them see the other's time pass at half speed. 

Now, if I understand you, you are saying that one of them experiences less time because his journey is shorter, and the other one seems slow because it literally is?   Is that your position?  If so, I think you are confused. 

Each will see the other as having slow time, and each will see the other as spatially distorted.  Neither view is privileged. It isn't true that one of them is "really" slowed down and the other is "really" physically distorted.

Twin paradox.

[Alex K]

Why would you say that no time passes for a photon?

Because it's moving at the speed of light. I'm pretty sure as Alex said, that it's just considered "broken" because of a /0. But while I'm pretty poor at math, it seems to me that you can see that the limit of things moving closer to the speed of light is that the passage of time is approaching a zero rate. The same goes for stuff stuck in a black hole, no? That they are essentially frozen in time relative to our perspective?

There's a difference between stating that no time passes for a photon, and going to its rest frame though. Following the path of a photon and calculating its proper time is a mathematically unproblematic operation which simply yields a 0. Going to a reference frame where that photon is at rest, that's where you get the /0.

The time passing for an object falling into a black hole is super subtle, because in General Relativity, comparing the time passing at different points in space to the time passing for you is not a unique procedure. What one can say is that objects falling onto a black hole appear to freeze on its event horizon to a hovering observer. Whether it "actually" falls in or not in finite outside observer time is not a well-defined question.

[LastPoet]

Yeah, that's my understanding, too.

However, I don't think a photon can actually experience time under any scenario because it instantly reaches light speed upon emission.  So it seems to me that a photon is really a kind of wormhole, connecting two points in space, from its reference frame.  In essence, it's connecting an atom in the sun to an atom in my eye, rather than a thing that moves, intercepts my eye, and is noticed by me.

Still takes 8 minutes.

[bennyboy]

Yeah, that's my understanding, too.

However, I don't think a photon can actually experience time under any scenario because it instantly reaches light speed upon emission.  So it seems to me that a photon is really a kind of wormhole, connecting two points in space, from its reference frame.  In essence, it's connecting an atom in the sun to an atom in my eye, rather than a thing that moves, intercepts my eye, and is noticed by me.

Still takes 8 minutes.

In our frame of reference, yes.