Mass of Photon: Consequences & Experiments - L.C. Tu et al (2004)

[Andrew Mason]

Andrew what we are trying to tell you is that the idea that special relativity is dependent on electro magnetism is a misconception¹ and there are several derivations of the Lorentz transformations that do not use Einsetin's second postulate².

Thank you for the cites. I would be particularly interested in reading the Srivastava article which, I gather, is no longer available for free. Is it worth $30 (US)?

Clearly special relativity CAN handle a massive photon without any signifcant change, it is quite possible that the only change would be that we would no longer use derivaivations which assumed a massless photon like Einstein's original, few would agree that this would constitutes a major overhaul.

While electro-magnetism provided Einstein with the insight that led to his development of the theory of relativity, his theory applies to all energy and matter. So it is not dependent on EM.

Einstein concluded that there is a relationship between time, space and the nature of energy and matter. It can be viewed in different ways. One way is to say that the speed of light is a universal constant (ie the same to all inertial observers), which was Einstein's starting point. Another way is to say that the ratio of energy to mass is a universal constant, which is what Einstein concluded. The latter statement is non-EM dependent. That could have been Einstein's postulate. And his second postulate (frame independence of c) could have been one of his conclusions.

AM

 

[jcsd]

Thank you for the cites. I would be particularly interested in reading the Srivastava article which, I gather, is no longer available for free. Is it worth $30 (US)?

I wouldn't pay that much money for an artilce, you could get a book for that much! Your library may have a susbcription and your local university library defintely will (I really don't know how these things work in the US though)

While electro-magnetism provided Einstein with the insight that led to his development of the theory of relativity, his theory applies to all energy and matter. So it is not dependent on EM.

Einstein concluded that there is a relationship between time, space and the nature of energy and matter. It can be viewed in different ways. One way is to say that the speed of light is a universal constant (ie the same to all inertial observers), which was Einstein's starting point. Another way is to say that the ratio of energy to mass is a universal constant, which is what Einstein concluded. The latter statement is non-EM dependent. That could have been Einstein's postulate. And his second postulate (frame independence of c) could have been one of his conclusions.

AM

It's the wya with any theory, you can make results into postulates and postulates into results.

 

[Andrew Mason]

Again, the point here being that there ARE cases where we only have to readjusts the definitions and how we measure things, rather than throwing the baby out with the bathwater. These possible alternatives clearly proves that your "A must lead to B" scenario isn't correct.

I don't recall having said that "A must lead to B" as in "Discovery of photon mass must lead to SR being overhauled". If I did I wish to retract that. The Theory of Relativity is a human creation and I cannot predict what humans will do in the future. I meant that "A will likely lead to B".

In my view, C (tweaking SR) would make SR no longer a theory of principle and would reduce it to a constructive theory that will not provide a sufficient understanding of our physical reality to satisfy all theoretical physicists. I predict that at least one of them, at some future time, would provide a fundamentally different theory that would successfully explain relativistic phenomena (if all photons are found to have rest mass, which I doubt will occur).

For the same reason, I predict that at least one theoretical physicist, at some future time, will provide a theory that will elevate the Standard Model from a constructive (I will avoid saying 'ad hoc') theory to a theory of principle.

AM

 

[ZapperZ]

In my view, C (tweaking SR) would make SR no longer a theory of principle and would reduce it to a constructive theory that will not provide a sufficient understanding of our physical reality to satisfy all theoretical physicists. I predict that at least one of them, at some future time, would provide a fundamentally different theory that would successfully explain relativistic phenomena (if all photons are found to have rest mass, which I doubt will occur).

For the same reason, I predict that at least one theoretical physicist, at some future time, will provide a theory that will elevate the Standard Model from a constructive (I will avoid saying 'ad hoc') theory to a theory of principle.

AM

Again, I disagree. We "tweaked" Maxwell Equations to make it covariant under a Lorentz transformation. I don't hear you downgrade it to a "constructive" theory.

Again, this tweaking process occurs all the time in physics. We tweaked Einstein's photoelectric effect equation to now include the properties of the material. We tweaked electron transport equation to include a more generalized idea of "transport" in exotic material, etc... etc. We add to our knowledge of things that start off being "simple". This process does not diminish the original concept. What Einstein postulated as something that doesn't change in all reference frame may in fact has a more generalized or redefined idea (refer to my description of group velocity versus signal velocity). In the history of science, that has often been the path that is taken in forming a more comprehensive idea. I do not see this as being a problem

Zz.

 

[Andrew Mason]

Again, I disagree. We "tweaked" Maxwell Equations to make it covariant under a Lorentz transformation. I don't hear you downgrade it to a "constructive" theory.

Well it is not a matter of downgrading it. Constructive theories play an essential part in the evolution of science. Constructive theories, such as Maxwell's equations, quantum theory, and the Standard Model are very important and useful. There are no 'pure' theories of principle and few useful theories which completely lack principle. There is a continuum from 'constructive' to 'principled' theories.

I would put Maxwell's equations about midway between a purely constructive theory and a pure theory of principle. Quantum theory and General Relativity required tweaking EM theory but since Maxwell's equations were essentially empirically derived no fundamental change in principle was required. EM theory did not predict the existence of, or rule out the existence of, the ether, of energy quanta or of gravitational effects. So nothing fundamental had to be changed to accommodate QM, SR and GR. (I may be overstating that a bit, but I think it is essentially true).

Theories of Gravitation provide good examples of this continuum. Before Newton, the theory was basically "all things naturally fall down" - a purely constructive theory with no illuminating principle to help us understand "why" or to allow us to generalize to all of nature. Planets moved the way they did because of metaphysical crystal spheres - which didn't explain much. Newton was able to provide greater insight into nature. His law of universal gravitation was based on rough measurement and astonishing intuition. Newton took a more principled approach (mathematical) than his predecessors but still it was largely a constructive theory.

Einstein took gravitation much farther and, using the principle of equivalence and the principles of relativity and the constancy of c, he developed a theory that explained the nature of gravity and described in detail how gravity and inertia defined and affected space and time.

The more 'principled' a theory is the more difficult it is to make it adapt when it is discovered that the underlying principles are wrong. That is essentially the point I was trying to make.

AM

 

[ZapperZ]

Well it is not a matter of downgrading it. Constructive theories play an essential part in the evolution of science. Constructive theories, such as Maxwell's equations, quantum theory, and the Standard Model are very important and useful. There are no 'pure' theories of principle and few useful theories which completely lack principle. There is a continuum from 'constructive' to 'principled' theories.

But I think you missed the entire point of my reply. We DO continually tweak many theories along the way. This is a common practice in physics. Either new things are found, or that certain things have to be redefined. And all of them are as important theoretically as any other. It doesn't diminish or make them less useful, even conceptually, after they have been tweaked.

I will not be surprised if SR would follow suit.

Zz.

 

[Andrew Mason]

But I think you missed the entire point of my reply. We DO continually tweak many theories along the way. This is a common practice in physics. Either new things are found, or that certain things have to be redefined. And all of them are as important theoretically as any other. It doesn't diminish or make them less useful, even conceptually, after they have been tweaked.

I will not be surprised if SR would follow suit.

I actually agree with everything you have said (after the first sentence), even your last statement. I would be surprised, however, if it turns out that photons are found to have rest mass (ie. all photons).

AM

 

[T.Roc]

Andrew,

Why do you think all photons would have the same rest mass? They don't all have the same energy, and through quantization, gives out its' info in steps (even though continuous). With mass quanta, it could be non zero and still not "trigger" our "measuring devices" (calculators included). So, all photons would not have to have non zero mass. It's really just a question of how many zeros are in front of the # representing the loss of energy as the wavelength increases. It must be replaced by mass.

TRoc

 

[Andrew Mason]

Andrew,

Why do you think all photons would have the same rest mass? They don't all have the same energy, and through quantization, gives out its' info in steps (even though continuous). With mass quanta, it could be non zero and still not "trigger" our "measuring devices" (calculators included). So, all photons would not have to have non zero mass. It's really just a question of how many zeros are in front of the # representing the loss of energy as the wavelength increases. It must be replaced by mass.

I never suggested that they would have the same rest mass (if they had rest mass). I just said they would all have to have some rest mass. Since there is no lower limit on energy for a photon a photon's rest mass would have no lower limit. But the point is, it would not be zero.

AM