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Photon path ..
#91
(06-07-2016, 11:22 AM)ALT Wrote: Yes, sloppy speech. I would suppose that in the world of particle physics, at that fundamental level of reality, instantaneous or not makes a world of difference. I can't see how it could not. But it seems you are saying  that 'in no time/space' is approximately the same as 'in some time/space' ? I have difficulty in accepting that.
No, what I'm saying is that there are no such things which happen in no time and no space. A point particle cannot be a point particle, it can only be something too small for us to measure its size. As well, nothing happens in no time, all we can say is that it happens in an amount of time too short to be observable.

Our mathematical models can have points. But these are mathematical idealizations.
(06-07-2016, 11:22 AM)ALT Wrote: A single photon fired from a laser emitter has velocity, and, consistent with the second postulate, is independent of emitter motion. Thus, absolute motion / rest can be proven.
Which is false. It is a clear misunderstanding of the second postulate, which tells that the speed of light is independent of the motion of the emitter. Frequency as well as the velocity do depend on the motion of the emitter.

And for the simple model - radial source in the center of a sphere, a small hole at the border - it is easy to see how the direction depends on the velocity of the whole emitter construction.
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#92
Hi Schmelzer, thanks for the comments. I'm on the road - hope to get back to this in a few days.
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#93
hi ALT, to reinforce my (and Schmelzer's) stance I went ahead and asked your question on PF forum. I didn't do it before because I knew what they'd say. But with that point about "velocity" in SR second postulate I felt the question would be interesting enough, maybe get them confused. Took them only 3 posts to get it straight. And I learned that "velocity" vs "speed" distinction dates from 1901, good to get that straight.

Anyway here's the thread, this should convince you that the photon direction is affected by transverse emitter motion!

https://www.physicsforums.com/threads/sr...er.875162/
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#94
(06-07-2016, 12:17 PM)Schmelzer Wrote:
(06-07-2016, 11:22 AM)ALT Wrote: Yes, sloppy speech. I would suppose that in the world of particle physics, at that fundamental level of reality, instantaneous or not makes a world of difference. I can't see how it could not. But it seems you are saying  that 'in no time/space' is approximately the same as 'in some time/space' ? I have difficulty in accepting that.
No, what I'm saying is that there are no such things which happen in no time and no space.   A point particle cannot be a point particle, it can only be something too small for us to measure its size.  As well, nothing happens in no time, all we can say is that it happens in an amount of time too short to be observable.  

Then you can equally say that the photon is emitted in an amount of time too short to be observable in the motion of the emitter.

Our mathematical models can have points.  But these are mathematical idealizations.  

I know this. I said so in previous posts .. in different words.



(06-07-2016, 11:22 AM)ALT Wrote: A single photon fired from a laser emitter has velocity, and, consistent with the second postulate, is independent of emitter motion. Thus, absolute motion / rest can be proven.
Which is false.  It is a clear misunderstanding of the second postulate, which tells that the speed of light is independent of the motion of the emitter.  Frequency as well as the velocity do depend on the motion of the emitter.  

This is not according to versions of the second postulate I'm seen. All say 'speed' and seem to be silent on 'velocity'

And for the simple model - radial source in the center of a sphere, a small hole at the border - it is easy to see how the direction depends on the velocity of the whole emitter construction.

Secur mentioned this earlier in similar form. Now, I gotta say, I'm not too sure what this really proves. Let's firstly imagine that radial source (in inertial movement of course) without the sphere.

It obeys the second postulate.
It emits a sphere of light in all directions.
That sphere of light is a multitude (an infinity ?) of photons.

Now, we include the encasing sphere. With a tiny hole in it, letting out ONE photon.

What of it ?

This is almost a rewrite of my initial thought experiment in the OP, in that in creates an emitter of one photon.

(06-12-2016, 01:07 AM)secur Wrote: hi ALT, to reinforce my (and Schmelzer's) stance I went ahead and asked your question on PF forum. I didn't do it before because I knew what they'd say. But with that point about "velocity" in SR second postulate I felt the question would be interesting enough, maybe get them confused. Took them only 3 posts to get it straight. And I learned that "velocity" vs "speed" distinction dates from 1901, good to get that straight.

Anyway here's the thread, this should convince you that the photon direction is affected by transverse emitter motion!

https://www.physicsforums.com/threads/sr...er.875162/

Hi securer, thanks for the link and I will check it out shortly. Very unlikely that I would get involved though - those guys have a habit of shutting down any apostate thought very quickly.

More importantly, did you make any progress with tracking down that evidence you said you were going to, in previous posts ?


PS: secur, I just read your post there. Very well put. And it does seem that there is some uncertainty.

W
e have to now de-construct the 'wiggle room' between the meaning and intention of the words momentum and velocity.

Anyway, need to think more on this.
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#95
(06-14-2016, 06:21 AM)ALT Wrote:
(06-07-2016, 12:17 PM)Schmelzer Wrote: No, what I'm saying is that there are no such things which happen in no time and no space.   A point particle cannot be a point particle, it can only be something too small for us to measure its size.  As well, nothing happens in no time, all we can say is that it happens in an amount of time too short to be observable.  
Then you can equally say that the photon is emitted in an amount of time too short to be observable in the motion of the emitter.
The emitter is moving all the time, with roughly constant velocity, and velocity is defined as the limit \(\lim_{\Delta t \to 0} \frac{q(t+\Delta t )-q(t)}{\Delta t }\), thus, is well-defined even if only an arbitrary short amount of time is known. So there is no "too short" in this sense.

(06-14-2016, 06:21 AM)ALT Wrote:
(06-07-2016, 12:17 PM)Schmelzer Wrote: Which is false.  It is a clear misunderstanding of the second postulate, which tells that the speed of light is independent of the motion of the emitter.  Frequency as well as the velocity do depend on the motion of the emitter.
 
This is not according to versions of the second postulate I'm seen. All say 'speed' and seem to be silent on 'velocity'
If the velocity would not be influenced, you would be able to see a difference - the laser in the moving train would not hit the target. So, even if possibly not explicitly stated, it is a trivial consequence. And in full agreement with the relativistic formula for addition of velocities.

(06-14-2016, 06:21 AM)ALT Wrote:
(06-07-2016, 12:17 PM)Schmelzer Wrote: And for the simple model - radial source in the center of a sphere, a small hole at the border - it is easy to see how the direction depends on the velocity of the whole emitter construction.
Now, I gotta say, I'm not too sure what this really proves. Let's firstly imagine that radial source (in inertial movement of course) without the sphere.
It obeys the second postulate.
It emits a sphere of light in all directions.
That sphere of light is a multitude (an infinity ?) of photons.
Now, we include the encasing sphere. With a tiny hole in it, letting out ONE photon.
What of it ?
This is almost a rewrite of my initial thought experiment in the OP, in that in creates an emitter of one photon.
Yes, and this was the intention: As close as possible to your original construction. But it allows, on the other hand, to identify the direction of the photon flight. We do not have to guess in which direction the photon flies in above cases - train at rest resp. moving train - but we can compare this, and see that the hole is in above scenarios at different places when the photon reaches the surface of the sphere.
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#96
Hi all.

Apologies for the delay. It does not seem there's anything in recent comments that hasn't been discussed in previous posts.

Would be interesting to see if / what secur comes up with, in actual experiments referred to earlier, which I think he said he was going to try to find.
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#97
Hi ALT, I hate to tell you, but there don't seem to be any experiments explicitly verifying photon path affected by emitter motion. When I asked the q. on PhysicsForums I realized the establishment does agree it's "thrown forward" (I thought maybe they would try to deny it). It becomes clear that, basically, nothing would work right if it weren't the case. Stellar aberration for instance; even in the space station they'd notice effects; and GPS wouldn't work. Every high-performance system confirms that relativity, whether Einsteinian or Lorentzian, simply works that way. The only mystery is "why", not whether. Mr. Calkin was thrown off because it's hard to get a straight answer, but that doesn't mean the answer's not there. If I ever figure out "why" light does that I'll let you know.
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#98
Big Grin 
Hi secur, noted, thanks.

If it is 'thrown forward' (sideway motion) then why also not rectilinear ? That's the aporia that hits me whenever I think of this, and not shallowly.

But no matter.

In recent times I have had much more stuff going on in real life to even think of this stuff for a minute, thus my absence.

But in comes in waves - I either have a huge amount going on, or very little.

I will have the luxury of 'very little' several months hence, and my obstinacy is sure to resurface, at which point I hope to even participate in the fine PF thread you created.

I will leave you with this quote from a great (if sometimes tortured) mind, which does have a degree of literal irony to our little topic;

"The greater danger for most of us is not that our aim is too high and we miss, but that it is too low and we reach..." (MICHELANGELO)

Big Grin Big Grin Big Grin

Cheers for now.
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#99
ALT wrote:

" ... instead of a rifle we have a photon emitter, and scale the speeds, etc., to suitable measurements for this to be considered.

The emitter. fires one photon. Does the photon hit the target (now a photoelectric receptor) or does it miss it ? "

We have to look for hidden assumptions. The first you are making is that a photon is a particle independent of its field.

Is it?
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Hi everybody, and thanks for your question Alt!

I have exactly the same, but I found a different answer than those that we find on the net. In fact, I have a particular theory on mass that is quite different than the Higgs, and that links mass to motion as with the inertia's principle. That theory needed that the inertial frame principle be reexamined, so I did, and I found some interesting things.

That principle comes from Galileo, who didn't know that light had a limited speed, so he didn't know of course that it could behave differently than massive bodies. Now we know, but we still stick to the idea that it behaves the same as massive bodies when the source and the observer are in the same reference frame, and then we disagree with that idea when they are not. We know that the stars are no more there when we look at them, but we think that they would still be there if they were traveling in the same direction and at the same speed than us. Its a flagrant contradiction, but contradictions do not convince relativists.

My theory on mass needs doppler effect and aberration to be not only produced by motion, but to also act on it, so I added those to the light clock mind experiment to see where I could get. Here is a drawing from wiki about SR that shows a light clock in motion, and its comment that I have translated from french:
Quote:[Image: 1200px-Time-dilation-002-mod.svg.png]
If the setting with two mirrors A and B is seen at rest, the distance that light travels is 2*L. If the setting is seen in motion, the distance traveled is 2*D, longer than 2*L, but traveled at the same speed by light. Thus, the phenomenon takes more time when seen in motion.

If we consider that the real ray is at the right side of the drawings, then it suffers aberration and doppler effect because it is at an angle to the motion. But if that ray suffers doppler effect at the source, then it is automatically nullified at the observer, and if it is sent from the source in the direction of the future position of the observer, then this direction is changed at the observer because the ray suffers aberration, and it is changed in such a way that it appears to come from the actual position of the source whatever the speed of the mirrors, as on the left side of the drawings.

This analysis implies that the flagrant contradiction I was talking about would depend on the reference frame principle, which uses the bodies as a reference for motion, whereas there would be no contradiction if we would take light as a reference instead. The relativists refuse to analyze that possibility because it implies that the light clock might suffer no time dilation. If light has a speed and a direction that are independent of the motion of the source, then it seems natural to use it as an absolute reference. In my theory on mass, light is not only a reference for our measures, it is also a reference for particles' motions. Since its speed is constant, it gives them their constant speed during their inertial motion, and since its direction is constant, it gives that motion a constant direction. I will open a specific thread on that mechanism later on.
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