Does S-T Curvature Change Particle Shape?

[Hugh de Launay]

This is an inquiry about some of the details of the bending of the trajectory if a photon by curved space-time (S-T) from the perspective of general relativity (GR).

The environment in this scenario contains a black hole at its center, a photon passing by the black hole a km above the event horizon, a starship observation platform which is moving a few kms per second well off from the black hole, and a light speed observer platform traveling next to the photon with technology that makes the photon visible to the observer. There is also an imaginary two dimensional flat sheet that can track the photon's wave motion. The sheet intersects the center of gravity of the black hole, the center of the photon, and the center of the length of its trajectory.

The observer in the accelerated reference frame of the photon reports to the starship that the photon appears to be unaffected by the curvature of S-T because at each instant it is moving along a vector that is tangent to the curvature of S-T. The photon is further reported to be a disk of electromagnetic waves perpendicular to the direction of its motion.

The observer in the starship's inertial frame of reference focuses his or her attention upon the photon's wave pattern in segments of 1000 meters. The observer plots the photon's wave motions tracked on the imaginary flat sheet that intersects the black hole's center of gravity and the center of the photon. In the starship, a history of the photon's wave pattern in two dimensions is printed for examination by the starship observer.

The printout shows the starship observer what was suspected. The curved line which was parallel to the photon's trajectory and intersected the top points of all of the crests of wave motion was longer than the parallel curved line which intersected the lowest points of the troughs. The starship observer finds that the distance between the intersection points on the lower side are closer together than the distance between the equal number of points on the line that intersected the top points of the crests.

The starship observer concludes that the S-T curvature below the center of the photon was sharper than the S-T curvature above the center of the photon. So the sharper curvature of S-T below the photon had a relatively slower pace of time than the S-T curvature above the center of the photon. The reason the action of the troughs keeps up with the action of the crests, in spite of their difference in the pace of time, is that they have a shorter distance to execute their wave pattern.

In this hypothetical case the sharp curvature of S-T altered the shape of the photon. The question is, does this happen to all fundamental particles when they are viewed from a distant observer?

I am also interested in finding out if what I have just written is valid in GR. If it is not valid, I wouldn't mind hearing what modern or old GR has against this scenario.

 

[PeterDonis]

a photon passing by the black hole a km above the event horizon

I'm assuming you mean for the hole itself to be much larger than 1 km. If so, it is impossible for a photon to pass by 1 km above the horizon on a grazing trajectory (i.e., moving tangentially) and escape. The photon will fall into the hole. In order for a photon to escape from that close to the horizon, it has to be moving almost exactly radially outward. So you need to rethink your scenario with that in mind.

There is also an imaginary two dimensional flat sheet that can track the photon's wave motion.

If it's imaginary, how can you tell what it's supposed to be telling you?

the accelerated reference frame of the photon

There is no such thing as a "reference frame of the photon", accelerated or otherwise. I'm not sure what you're trying to capture here, but you need to take another stab at it using valid concepts.

the photon appears to be unaffected by the curvature of S-T because at each instant it is moving along a vector that is tangent to the curvature of S-T

I don't know what you mean by "tangent to the curvature of S-T".

The observer in the starship's inertial frame of reference focuses his or her attention upon the photon's wave pattern

You are mixing up models here. If you want to analyze a "photon", there is no such thing as a "wave pattern"; there is just a null worldline (what you are calling the "trajectory" of the photon in spacetime). If you want to analyze electromagnetic waves in curved spacetime, there is no "photon"; you need to be doing something like solving Maxwell's Equations on a curved spacetime. You can't do both in one model.

The observer plots the photon's wave motions tracked on the imaginary flat sheet that intersects the black hole's center of gravity and the center of the photon.

Since the flat sheet is imaginary, i.e., unphysical, I don't see how this can be done.

In this hypothetical case the sharp curvature of S-T altered the shape of the photon.

A photon has no shape. If you are talking about the "shape" of EM waves, and whether spacetime curvature affects it, it does, but the way you are imagining the scenario is too confused to be helpful in seeing how that works.

I am also interested in finding out if what I have just written is valid in GR.

It's too confused to even be invalid. See my comments above.

 

[Hugh de Launay]

Wow! I had no idea it would be this difficult to communicate ideas in modern physics. I will try to make some repairs to what I have said here, but I am not optimistic about succeeding. I am learning a lot about physics and the way physicists communicate every time I post something. It is not a bad way to learn, and the learning is very fast if you post an unacceptable idea or write something that is confusing. In the next few days or weeks I will try to tailor what I said to be less confusing. Thank you for the time you took to show me what kind of communication is unacceptable to today's physics.

 

[PeterDonis]

I had no idea it would be this difficult to communicate ideas in modern physics.

I don't think your primary issue is communicating the ideas. You need to understand the ideas first. Where are you getting your understanding of GR from?

 

[Hugh de Launay]

You need to understand the ideas first. Where are you getting your understanding of GR from?

I read about general relativity a few years ago and I am relying on my memory.

P.S. I plan to clean up the confusion I caused with post #1 in a post below.

 

[pervect]

Addressing only the title of this thread (good comments have been made about some of the other assumptions in the thread, most specifically the problems with assuming that light-speed observers exist).

What is the "shape" of a photon? And how do we measure it?

If we consider a photon to be a point particle, it doesn't make much sense to talk about its shape, other than to say that it's a point particle. Perhaps you have some other scheme in mind, but it's not clear what it might be. One might, for instance talk about coherence length. This could be interesting, but because I doubt you are talking about this I think it would be a mistake to go into details that would probably be off-topic.

If we don't share an understanding of what the "shape" of a photon is in flat space-time, , it doesn't make much sense to even talk about how curvature affects the "shape".

A very good alternative might be to get rid of the quantum notion of "photons", and rephrase the question in terms that don't involve quantum mechanics, if you can manage that. This is especially true since GR is a classical theory, so it does not directly include quantum phenomenon.

 

[PeterDonis]

I read about general relativity a few years ago and I am relying on my memory.

As should be evident from this thread, that is not a good strategy. You should consult a GR textbook and refresh your knowledge.

It would probably also be a good idea to consult textbooks on classical EM and possibly quantum electrodynamics (if you are really interested in the actual quantum "photon" model used by physicists, instead of just classical light propagation).

 

[Hugh de Launay]

If we don't share an understanding of what the "shape" of a photon is in flat space-time, , it doesn't make much sense to even talk about how curvature affects the "shape".

Agreed. I completely changed my representation of a photon in my writing below. Thanks for your input and time.

 

[Hugh de Launay]

You should consult a GR textbook and refresh your knowledge.

Agreed. I plan to study both GR and QM in 2019.

 

[Hugh de Launay]

Regarding post #1: If you cause confusion, it is your responsibility to dismantle it. I will change or delete the causes of the confusion in my scenario and then rewrite the scenario free of the elements of the confusion -- there is no guarantee that will make the needed difference.

First, the easiest item of confusion that can be changed is the black hole and its tangent path photon capture zone a km or more above the event horizon. In the scenario the black hole is changed to a black dwarf star, and the photon passes by the star 25 kms above its surface. Second, the starship is changed to an observer that is at rest relative to the black dwarf. Third, the imaginary flat sheet and its graph are deleted. Fourth, the accelerated frame of reference of the photon is deleted because there is no such frame of reference in GR or anywhere else. Fifth, the comments about the photon being tangent to the curves of space-time are deleted. Sixth, the salient error in my scenario and headline question was the use of the word "shape" when describing photons and other fundamental and elementary (baryons, etc.) particles. The word "shape" implies a macroscopic object like a golf club or golf ball, or the particles of classical thermodynamics. The fundamental particles do not have this kind of tangible form. Because of their rapid frequencies, there are no static edges or borders that could be viewed as a shape. The word "shape" has to be deleted from the headline question and the text of the scenario and replaced by fundamental particle wave form or some better expression. In light of this the, "disk" used to describe the shape of the photon is deleted. Seventh, the mixing of models needs the be unmixed. This will be done after the scenario is rewritten next.

The environment in the revised scenario contains a black dwarf star at its center, a photon passing by the black dwarf 25 kms above its surface, and an observer at rest relative to the black dwarf in a position to view the photon perpendicular to its up and down orientation with the center of gravity of the black dwarf. (The mix of models begins here.) The observer sees the photon follow a curved path as it passes the dark star. During the photon's presence in its curved path, the observer sees the that the troughs of the photon are closer to each other than the photon's crests. The observer concludes that since the photon's wave action below its center occurred closer together than its wave action above its center, gravity's gradient of sharp curvature of space-time compressed the photon's wave pattern more on its lower side than on its upper side. (end of the mixed models)

Back to the seventh item of confusion: the mixed models. It appears to me that after the models of QM and GR are unmixed, the question cannot be answered by either discipline. With GR there is no use adapting Maxwell's equations to the curvature of space-time because Maxwell was not working with fundamental or elementary particles. And further with GR, if the photon is just a point particle, as mentioned by Pervect in post #6, and its passage by the dark star is no more than a point pursuing its own null path along its worldline, there never will be any action features of the particle that can be observed in GR. Neither discipline is able to deal with the distance between the lowest points of the troughs being closer together than the distance between the highest points of the crests. But after such a long trip to a boring dark star, the observer is not ready to give up. He or she turns to QM, drops GR, and elicits the help of gravitons. There is just one more problem, gravitons are hypothetical, so he or she cannot use them either.

 

[PeterDonis]

The environment in the revised scenario contains a black dwarf star at its center, a photon passing by the black dwarf 25 kms above its surface, and an observer at rest relative to the black dwarf in a position to view the photon perpendicular to its up and down orientation with the center of gravity of the black dwarf.

All this looks fine. (You are making an implicit assumption that the black dwarf is not compact enough for there to be photon capture issues 25 km above its surface, analogous to those I raised for the black hole version of the scenario. Some neutron stars are this compact, but "black dwarf" implies a white dwarf star that has cooled to the point where its radiation is negligible compared to background, and such an object would not be anywhere close to compact enough to cause an issue.)

The observer sees the photon follow a curved path as it passes the dark star.

Why? With reference to what? Note that the observer, strictly speaking, can only directly observe events at his location. If you want a global "observation" of the photon's path, you need a fleet of observers at various locations that all can observe the photon as it passes them.

Also, "path" is ambiguous: do you mean path through spacetime (the photon's worldline) or path through space (in which case you need to specify "space" with reference to what system of coordinates)? Or are you modeling a "photon", again, as something other than a point particle? (See below.)

Also, there is only a "path" if you are modeling the "photon" as a point particle. But it doesn't look like you are; see below

During the photon's presence in its curved path, the observer sees the that the troughs of the photon are closer to each other than the photon's crests.

What you're describing here isn't a "photon", it's a classical EM wave packet. Again, you can't mix models; you need to pick one. A classical EM wave packet does not have a "path" through space or spacetime. A photon (point particle moving on a null worldline through spacetime) does not have wave crests or troughs.

It appears to me that after the models of QM and GR are unmixed, the question cannot be answered by either discipline.

You don't know this, because you haven't yet asked a well-defined question. First you need to be able to state a question that's well-defined to begin with. What do you actually want to know?

With GR there is no use adapting Maxwell's equations to the curvature of space-time because Maxwell was not working with fundamental or elementary particles.

That implies that you have some question about fundamental or elementary particles that you don't think can be answered by GR + Maxwell's Equations. But so far you haven't stated any such question. (Note, btw, that you can also do QED, quantum electrodynamics, the quantum field theory of which the classical Maxwell's Equations are the classical approximation, in curved spacetime.)

If it helps, forget about theoretical models altogether and focus on the actual experiment: what are you actually going to measure, and how? What equipment are you going to use, and what actual readings (pointers, dials, numbers, etc.) is it going to give you? Hand-waving about "observing a curved path" isn't enough, because you haven't explained how you're going to observe the path. Hand-waving about "crests and troughs" isn't enough, because you haven't explained how you're going to observe the crests and troughs.

If you find this request onerous because you're not familiar enough with the actual experimental devices that are used and how they work, then you should go fix that problem.

if the photon is just a point particle, as mentioned by Pervect in post #6, and its passage by the dark star is no more than a point pursuing its own null path along its worldline, there never will be any action features of the particle that can be observed in GR.

What do you mean by "action features of the particle"?

Neither discipline is able to deal with the distance between the lowest points of the troughs being closer together than the distance between the highest points of the crests.

How would you measure any such distance, and why do you think such measurements would even show what you're claiming?

He or she turns to QM, drops GR, and elicits the help of gravitons.

Why do you need gravitons for this? You're not worried about quantum aspects of gravity. The quantum aspects you seem to be worried about (though, as noted, you're not doing a good job of specifying exactly what those aspects are) are quantum aspects of electromagnetism, which are (a) much better understood theoretically--QED--and (b) much easier to see experimentally (experiments probing the quantum EM field have been done for decades).

 

[Hugh de Launay]

How would you measure any such distance, and why do you think such measurements would even show what you're claiming?

It seems to me that if what is in the scenario is the case, gravity might be the cause of the difference. If so, it would be an interesting relation between fundamental particles and gravity. How you would measure such a distance would likely require a new technology.

What do you mean by "action features of the particle"?

I had in mind the action that produces the wavelength and frequency.

What do you actually want to know?

I am afraid, with my lack of knowledge of the language of modern physics, no question I ask now on this subject will have a proper expression. My personal curiosity is about what gravity does to the inner workings of fundamental particles -- even if that is not to be known for an unknown number of years.With respect to your other notes, naturally I am going to agree with you because it all makes sense. I plan to go back over my two threads and draw up a checklist of how to present what I am interested in exploring. I hope this will make a big difference and reduce the mentors' burden with respect to my posts. I appreciate the time, analysis, and thought you put into this thread. I think I am learning fast how the modern physics culture wants inquiries to be presented.

 

[PeterDonis]

It seems to me that if what is in the scenario is the case, gravity might be the cause of the difference.

Why? You're just waving your hands here. Where are you getting this stuff from?

I had in mind the action that produces the wavelength and frequency.

What do you think this action is? Where are you getting this from? Can you give a reference?

I am afraid, with my lack of knowledge of the language of modern physics, no question I ask now on this subject will have a proper expression.

As I've said before, I don't think your problem is lack of knowledge of the language. I think it's lack of understanding of the concepts. You need to have at least some valid understanding of the concepts before you can even try to formulate a meaningful question. You don't seem to have that.

My personal curiosity is about what gravity does to the inner workings of fundamental particles

Then my advice to you is to first build a good understanding of "the inner workings of fundamental particles" without gravity. You don't seem to have that. If you don't have that, you won't even be able to get a start on understanding how, if at all, gravity changes those workings.

I think I am learning fast how the modern physics culture wants inquiries to be presented.

Again, I think you are focusing on the wrong thing here. I think you need to stop worrying about how you are presenting things, and start worrying about the fact that you don't understand the concepts you're trying to ask about.

 

[Ibix]

What do you mean by "action features of the particle"?

I had in mind the action that produces the wavelength and frequency.

I think I can guess. There are plenty of diagrams of electromagnetic waves looking like a pair of waves on strings, one waving horizontally and one vertically. And if you wrapped such a pair of strings around the Earth, the troughs would, indeed, be closer together than the peaks. So you wouldn't quite have a sine wave on the string, you'd have something else.

Unfortunately, this model is not relevant to light in a gravitational field. Probably the biggest misconception is the image of something waving up and down. There is no such thing in an electromagnetic wave. The values of the fields at a point change sinusoidally with time as the wave comes through, but nothing is displaced. Connect an oscilloscope to an AC source and you'll get a wave on the screen. Is the wire bumping up and down? The diagrams of electromagnetic waves as things waving up and down are like that - pictures, not reality.

Assuming I've guessed your mental model correctly (and you would be far from the first person to think of electromagnetic waves that way), then as Peter says, you need to learn what the physics actually is before you can do any useful speculation.

 

[Hugh de Launay]

you need to learn what the physics actually is before you can do any useful speculation.

I can see that you are guessing correctly what I had in mind. I can see from what you said that what I had in mind was wrong. You are right by suggesting I learn to find a realistic model of the EM field's action. I will do that in the coming year. Thanks for your comments and good advise.

 

[PeterDonis]

if you wrapped such a pair of strings around the Earth, the troughs would, indeed, be closer together than the peaks.

In addition to the valid criticisms you make of this picture, it's worth noting that it is a picture of a wave in space, not spacetime. But the latter is what needs to be understood in the context of relativity.

 

[Hugh de Launay]

Why? You're just waving your hands here. Where are you getting this stuff from?

You are right in your assessment, that I can see now. I believe I have projected pictures into the concepts I was reading about in books of physics which did not belong there. I plan to fix this during 2019.

start worrying about the fact that you don't understand the concepts you're trying to ask about.

This I will do and correct in the coming year.

Then my advice to you is to first build a good understanding of "the inner workings of fundamental particles" without gravity

I will take your advice and work on it next year.

As I've said before, I don't think your problem is lack of knowledge of the language. I think it's lack of understanding of the concepts.

Now I see what you mean. So, again, I plan to work on GR and QM with the new perspective about having inadequate concepts in mind.

What do you think this action is? Where are you getting this from? Can you give a reference?

Since I am recognizing the ignorance I have about the photon and other concepts involved with what I want to investigate, I can say no more about the details associated with them until I have appropriate mental pictures of what is going on. Thanks a lot for the excellent guidance you have given me. The guidance will be invaluable to me while I continue my study and investigations. During my studies I will read a lot of INSIGHT articles.