Relativity is broken"Relativity Broken: Uncovering the Mystery

[munky99999]

Ok so here it goes.

-As you approach the speed of light, time slows down. Shown with the atomic clocks, one in the plane, one stationary.
-at speed of light time would stop.
-above speed of light, time would reverse. unlikely but whatever

However isn't also the speed of light dependant on time. as speed is distance/change in(delta) time.

so if time has stopped for light itself, the speed isn't happening. and if no speed, no special mass and as light has no mass, it doesn't have rest energy.

so logically light doesn't exist if its true for the original -

 

[russ_watters]

The speed of light is not a valid reference frame for measuring/calculating speeds in other frames since nothing other than light can achieve it.

 

[DaveC426913]

so if time has stopped for light itself, the speed isn't happening.

Correct. Photons do not experience time at all.

However isn't also the speed of light dependant on time. as speed is distance/change in(delta) time.

No. Our measurement of something's velocity uses time (as in distance over time), but we are measuring it from our own reference frame, not the object's. Measuring an object's speed in our own reference frame does not require the object itself to experience time. In fact, note that the object CANNOT measure its OWN speed (except by referring to another reference frame.)

 

[Garth]

In fact, note that the object CANNOT measure its OWN speed (except by referring to another reference frame.)

Well, in its own frame an object's speed is zero, its clock is running at the rate one second per second and its metre rule is just one metre long.

i.e. in any object's rest frame clocks and rulers behave as you expect them to!

munky - why do you think relativity is broken?
Garth

 

[DaveC426913]

Well, in its own frame an object's speed is zero, its clock is running at the rate one second per second and its metre rule is just one metre long.

Right. Speed is a meaningful concept only when comparing to other things.

 

[Albrecht]

It results from an abstract structure

There is another view of this problem I like to point to.

According to Louis de Broglie, a photon does not move at the theoretical speed of light, but is a very small amount slower than that. Also the mass of the photon is not exactly zero but extremely small.

An object like a photon with zero mass is a singularity in a mathematical system. This is (most probably) not possible in a real physical system.

It is a speciality of the spiritual world of Einstein, that he understands physics as a structure (following the Greek philosopher Plato). It is remarkable that Einstein follows this way only in the context of relativity. In the context of quantum mechanics, which according to main stream physics is also based on structures, Einstein has always objected.

 

[munky99999]

actually I've thought of that i was going to add it. I've never heard of Louis de Broglie or anything of this before.

I don't know how he come to that conclusion. But once in high school physics we were taking up how light changes speeds in different materials. then i pointed out that space isn't true space, there is always some matter roguely flying around space thusly making untrue vacuum. it may be 99.99999% vacuum, but there is always that one particle or something. thusly making the speed of light just slightly less then the true exact limit.

then taking into above account, to the photons time goes extremely extremely slow, but there is time, then what I've stated makes sense.


Buuuuut.
if light in space is proportional to how true the vacuum is. then the true speed of light isn't a constant, its simply relative.

annnnnnd.
if light speed is relative to the trueness of the vacuum. back near the big bang, light would be very slow compared to now, since the space between atoms are moving apart basically because of the expansion of the universe.

exact opposite of what creationists want. http://talkorigins.org/indexcc/CE/CE411.html"

 

[ZapperZ]

actually I've thought of that i was going to add it. I've never heard of Louis de Broglie or anything of this before.
I don't know how he come to that conclusion. But once in high school physics we were taking up how light changes speeds in different materials. then i pointed out that space isn't true space, there is always some matter roguely flying around space thusly making untrue vacuum. it may be 99.99999% vacuum, but there is always that one particle or something. thusly making the speed of light just slightly less then the true exact limit.
then taking into above account, to the photons time goes extremely extremely slow, but there is time, then what I've stated makes sense.

No it doesn't, because you are ignoring the MECHANISM on why, in a medium, the speed of light differs from the vacuum value.

First of all, you need to understand what exactly is meant by the speed of light in a medium (hint: learn the meaning of phase and group velocity). Secondly, do you really think a scattering with an occasional particle in vacuum would truly affect the speed of light? Can you please show this, for example, in a Compton scattering? The optical transport in a more dense medium (such as gas) is also different than an optical transport in a solid medium (such as glass). Without understanding the mechanism on what causes light to change "speed" in such situations, you are opening yourself up to making unsubstantiated and unverified speculations.

Buuuuut.
if light in space is proportional to how true the vacuum is. then the true speed of light isn't a constant, its simply relative.
annnnnnd.
if light speed is relative to the trueness of the vacuum. back near the big bang, light would be very slow compared to now, since the space between atoms are moving apart basically because of the expansion of the universe.
exact opposite of what creationists want. http://talkorigins.org/indexcc/CE/CE411.html"

I would like to remind you that speculative posts are only restricted to the IR section, per our Guidelines. This has gone off from asking to speculating based on an incomplete knowledge of Special Relativity and Optics. If you wish to do that, then it should be done only in the IR section, not here.

Zz.

 

[Garth]

[Edit: crossed with Zz]
You have to distinguish between the nature of the space-time continuum with transformations between different frames of reference on the one hand and the physical behaviour of photons and particles within that continuum on the other.

If you are going to say that the velocity of light is variable then you have to describe precisely how you are making that measurement of velocity. You need rulers and clocks, so perhaps it is your ruler and clock that are varying w.r.t. to each other? This would mean the spatial and temporal structure of the atoms out of which your rulers and clocks are constructed are varying, which means most probably that the fine structure constant is varying.

Such Variable Speed of Light theories have been suggested, but they cannot be proposed in a naive way.

The fine dust and gas in ISM does not influence the speed at which light travels through it. The medium needs to constantly absorb and re-emit the photon to influence its speed, in the ISM the light path from star to observer for most photons is unbroken.

Garth

 

[munky99999]

Can you please show this, for example, in a Compton scattering?

To be honest i don't even know what your asking here. If its the old experiment with Light hitting gold that released electrons when they absorbed the light. Alright cool. Dont really know how to do that, but sure.

Secondly, do you really think a scattering with an occasional particle in vacuum would truly affect the speed of light?

Well I am not saying that the speed of light would be effected in any meaningful way. I am just saying that those very few particles must have an effect regardless to how negligable that is.

the result may be 99.999999999999999999999999999999999999999999999999999999999999999999999999999999999% still being transmitted fine, and that very tiny % means nothing, but its legitimately there.

Take this for example.
You take you density and measure the speed of light in 1 atmosphere on Earth through air.
Then you do the same thing with .75 atmospheres. a slightly more vacuum. and the speed of light will increase. even though its almost nothing. then keep lowering that # until u get to that .00000000000000000000000000000000000000001 atmospheres and you essentially have space. using the line of best fit you find the constant, speed of light: c

however. to actually say your at the speed of light would be one of those.

1/3=.333333333333333333333333333333333333333...
2/3=.666666666666666666666666666666666666666...
1/3+2/3=3/3=1
but
.333333333333333333333333333333333333333...+
.666666666666666666666666666666666666666...=
.999999999999999999999999999999999999999 which doesn't mean 1.

actually i don't recall what math says to this :)

in the ISM the light path from star to observer for most photons is unbroken.

true. but i dunno. i haven't figured that out. I was imagining as a star as reference, i emit light, and in the very large space between me and earth, there is a good chance for particles to play around, but all light wouldn't be guarenteed to be hitting anything. I don't know how to get around that obvious problem. Perhaps virtual particles come into it. I am pretty sure virtual particles can effect light, the whole pair production thing relates to using photons to making them real.

 

[Rade]

1/3=.333333333333333333333333333333333333333...2/3=.666666666666666666666666666666666666666...
1/3+2/3=3/3=1
but
.333333333333333333333333333333333333333...+
.666666666666666666666666666666666666666...=
.999999999999999999999999999999999999999 which doesn't mean 1.

Perhaps this is a mathematical expression of the concept that the whole is greater than the sum of its parts ?

 

[ahrkron]

0.9999... is exactly 1. You can search the forums for the explanation of this, which has been talked about many times.

 

[Albrecht]

Ive never heard of Louis de Broglie or anything of this before.
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Louis de Broglie was one of the founders of quantum mechanics. He found the wave nature of elementary particles and received in 1929 the nobel price for that.

DeBroglie assumed that a photon is composed of 2 neutrinos. There is no direct proof for this assumption but there is also nothing in conflict with it. A conclusion of this assumption is that a photon also has a small mass as the main stream physics believe since a few years that a neutrino does in fact has a small mass.

In one point you are right: The speed of light is not constant in vacuum. In the presens of matter at some distance the speed c is reduced. We call that effect "gravity".

 

[Garth]

In one point you are right: The speed of light is not constant in vacuum. In the presens of matter at some distance the speed c is reduced. We call that effect "gravity".

No, in the presence of matter when climbing out of gravitational curvature the speed of light remains c, but the energy is reduced, i.e. it is red shifted. We call the effects of that gravitational curvature "gravity".

Garth

 

[quantumdude]

There is another view of this problem I like to point to.
According to Louis de Broglie, a photon does not move at the theoretical speed of light, but is a very small amount slower than that. Also the mass of the photon is not exactly zero but extremely small.

For completeness, the current experimental upper bound on the photon mass is $6\times10^{-17}eV$.

http://pdg.lbl.gov/2005/listings/s000.pdf

An object like a photon with zero mass is a singularity in a mathematical system. This is (most probably) not possible in a real physical system.

Can you be more specific? What singularities are predicted by SR? If you are referring to the fact that the Lorentz factor blows up to infinity when $v=c$ then I don't see the problem, because massive particles don't move that fast.

DeBroglie assumed that a photon is composed of 2 neutrinos. There is no direct proof for this assumption but there is also nothing in conflict with it.

I would beg to differ on that. It is well known that a system of two spin-1/2 particles can form composites with 4 spin states $(s,m_s)=\{(1,1),(1,0),(1,-1),(0,0)\}$. But in countless experiments only 2 states have ever been observed for the photon: $(s,m_s)=\{(1,1),(1,-1)\}$, which is exactly what one would expect if the photon were massless.

 

[ZapperZ]

And to add to what Tom said, the suggestion that a photon is made up of 2 neutrinos has another fallacy: WHICH neutrino? Electron, muon, tau? And if it is made up of one of the neutrinos, by citing the mass evidence, one must also not ignore that the neutrinos has a mixing angle. This means that the electron neutrino can mix into another form. I'd like to see that being explained to light's properties.

This is where using snippets of outdated hypothesis while ignoring modern-day evidence can produce outrageously wrong guesses.

Zz.

 

[Albrecht]

No, in the presence of matter when climbing out of gravitational curvature the speed of light remains c, but the energy is reduced, i.e. it is red shifted. We call the effects of that gravitational curvature "gravity".
Garth

Already in the 1970ies Shapiro has proven by radar ranging to the planet Venus, that the speed of photons passing close to the sun is reduced. Later such experiments were performed with high precision. They all verify the equation about this reduction of c in a gravitational field given by the Schwarzschild formalism.

This reduction of can be applied to the internal motion within an elementary particle as it was described by Schroedinger in 1930. Then the consequence is an acceleration of this particle which we call "gravity".

 

[Albrecht]

For completeness, the current experimental upper bound on the photon mass is $6\times10^{-17}eV$.
http://pdg.lbl.gov/2005/listings/s000.pdf

... and how much is the mass of a neutrino please?

Can you be more specific? What singularities are predicted by SR? If you are referring to the fact that the Lorentz factor blows up to infinity when $v=c$ then I don't see the problem, because massive particles don't move that fast.

A theory like SR has to be valid for all particles. The photon is a real particle and should be covered. Otherwise SR can only be taken as an approximative theory and we have to find the correct one (what many physicists these days expect to be done).

I would beg to differ on that. It is well known that a system of two spin-1/2 particles can form composites with 4 spin states $(s,m_s)=\{(1,1),(1,0),(1,-1),(0,0)\}$. But in countless experiments only 2 states have ever been observed for the photon: $(s,m_s)=\{(1,1),(1,-1)\}$, which is exactly what one would expect if the photon were massless.

I understand this so, that the combination necessary to build the photon is possible, but not all combinations are used in nature.

 

[Albrecht]

And to add to what Tom said, the suggestion that a photon is made up of 2 neutrinos has another fallacy: WHICH neutrino? Electron, muon, tau? And if it is made up of one of the neutrinos, by citing the mass evidence, one must also not ignore that the neutrinos has a mixing angle. This means that the electron neutrino can mix into another form. I'd like to see that being explained to light's properties.
This is where using snippets of outdated hypothesis while ignoring modern-day evidence can produce outrageously wrong guesses.
Zz.

I do not have any more details about the statement of deBroglie. I guess that at his lifetime it was not known yet that there are 3 types of neutrinos. But I understand this as a hint to which direction we could look in order to understand the photon.

All elementary particles we know in present physics have spin=1/2. All bosons are composed of fermions. So it should be expected that also the photon is composed of something. What do modern days physics tell us about this?

The treatment of the photon also in SR is for my understanding incomplete. The whole theory of relativity (particularly GR) is not correct which is obvious through the unsuccessful discussions about quantum gravity since several decades.

This is when staying fixed to theories and ignoring the fact of unresolved problems.

 

[George Jones]

they all verify the equation about this reduction of c in a gravitational field given by the Schwarzschild formalism.

It depends on what what one means by the speed of light. Suppose a laser beam whizzes by an observer (freely falling or accelerated). The observer, independently of where she is located, uses an orthonormal frame to make measurements, and, with respect to this orthonormal frame, the observer always measures the speed of light to be c, just as Garth says.

Regards,
George

 

[quantumdude]

... and how much is the mass of a neutrino please?

Much, much higher. You should be able to look up the neutrino masses for yourself.

http://pdg.lbl.gov/2005/listings/contents_listings.html

A theory like SR has to be valid for all particles. The photon is a real particle and should be covered. Otherwise SR can only be taken as an approximative theory and we have to find the correct one (what many physicists these days expect to be done).

SR does cover photons. It just happens to say that the "rest frame" of a photon is a nonsensical concept. So far we have no reason to think that this understanding is wrong.

I understand this so, that the combination necessary to build the photon is possible, but not all combinations are used in nature.

Then what you are suggesting is that the normal quantum mechanical rules for addition of angular momenta are wrong.

 

[ZapperZ]

I do not have any more details about the statement of deBroglie. I guess that at his lifetime it was not known yet that there are 3 types of neutrinos. But I understand this as a hint to which direction we could look in order to understand the photon.
All elementary particles we know in present physics have spin=1/2. All bosons are composed of fermions. So it should be expected that also the photon is composed of something. What do modern days physics tell us about this?

I can easily argue that a photon is "field" particle, not an elementary particle. And since when are all bosons composed of fermions? Can you tell me what a phonon is composed of?

And you're just using THAT "rule" while ignoring all the other problems associated with that rule. You're ignoring the fact that by using neutrinos to make up one photon, you have introduced a whole boatload of problems that contradicts our experimental observations. This you have conveniently swept under the rug and ignored. All you cared about was that they add to spin of zero, which is in itself is already dubious based on what Tom has explaned. If you have looked at the Clebsch-Gordon coefficient for the addtion of 2 spin 1/2 particles, you would have seen a number of other eigen spin states that are possible for such a composite particle. So where are they?

The treatment of the photon also in SR is for my understanding incomplete. The whole theory of relativity (particularly GR) is not correct which is obvious through the unsuccessful discussions about quantum gravity since several decades.
This is when staying fixed to theories and ignoring the fact of unresolved problems.

How are you able to conclude that such a thing is unsuccessful when it is still a research front area? This is still a problem yet to be solved. We will NEVER reach a point where everything is solved. But you are using something that is still being worked on as "evidence" that things are not right. How about using the same argument that your incomplete understanding is also not right, by your reasoning?

Please, please, please keep in mind that physicsts, by definition, work on stuff that are new, unexplained, cannot be described by current ideas, etc. If we know everything, I would be unemployed. But it doesn't mean that there are things we simply don't know. I can prove that this is wrong simply by pointing out that ever expanding boundaries of our knowledge. But with each new things that we learn, we find other new things we never discovered before. Do not confuse such discovery with the fallacy that we understand nothing.

Zz.

 

[Albrecht]

It depends on what what one means by the speed of light. Suppose a laser beam whizzes by an observer (freely falling or accelerated). The observer, independently of where she is located, uses an orthonormal frame to make measurements, and, with respect to this orthonormal frame, the observer always measures the speed of light to be c, just as Garth says.
Regards,
George

Imagine you take an orthonormal frame which coveres the whole planetary system, at least however Earth and Venus, and you use a gauge to measure the distance between Earth and Venus which is far enough from the sun so that the gauge is not influenced by the gravity of the sun. And then perform the Shapiro experiment. Then you can use the distance and the travel time of the e.m. pulse to find the speed of the e.m. pulse. You will get the (almost) normal value for c if the sun is not in the way, but you will get a changed=reduced value for c if the sun is close to the e.m. beam.

So. you will in fact measure a different value for c.
(Einstein would say, even if the distance is the same, there is more "space" between Earth and Venus if the sun is there even if the distance is not changed. But that is a funny und unnecessary way to treat this case).

Regards, Albrecht

 

[Albrecht]

Much, much higher. You should be able to look up the neutrino masses for yourself.
http://pdg.lbl.gov/2005/listings/contents_listings.html

I have checked that. Most of the values given there are upper limits. The rest are definite values, but the error bars are greater than the value itself. So there is no information given by the authors usable here.

SR does cover photons. It just happens to say that the "rest frame" of a photon is a nonsensical concept. So far we have no reason to think that this understanding is wrong.

So you say it yourself: There are cases not covered. If you use the Lorentz transformation to calculate the mass of the moving photon from the rest mass, which is zero, that you have to multiply m=0 with the Lorentz factor (= infinite). This multiplication is not allowed in mathematics and it yields an undefinied result. - A complete theory does not have such cases.

Then what you are suggesting is that the normal quantum mechanical rules for addition of angular momenta are wrong.

It seems that also QM does not cover the photon.

 

[pervect]

I have checked that. If you use the Lorentz transformation to calculate the mass of the moving photon from the rest mass, which is zero, that you have to multiply m=0 with the Lorentz factor (= infinite). This multiplication is not allowed in mathematics and it yields an undefinied result.

This is correct.

- A complete theory does not have such cases.
It seems that also QM does not cover the photon.

Neither of these remarks are correct- relativity is a complete theory, and QM defintely does cover the photon.

 

[ZapperZ]

So you say it yourself: There are cases not covered. If you use the Lorentz transformation to calculate the mass of the moving photon from the rest mass, which is zero, that you have to multiply m=0 with the Lorentz factor (= infinite). This multiplication is not allowed in mathematics and it yields an undefinied result. - A complete theory does not have such cases.

Please show me (i) a "complete theory", and (ii) a "complete theory" that doesn't contain such a thing. Would you like to look at Coulomb's Law and figure out the value of the field at the position of the point charge?

This so-called incomplete theory is able to make corrections to the semiconductor band structure that requires relativistic effects to be accurate and useful in your modern electronics. Not only that, your life depends on it each time you fly in an airplane. Aren't you being a bit of a hypocrite for using it on one hand, and coming in here and making all those statements on the other hand?

Zz.

 

[quantumdude]

I have checked that. Most of the values given there are upper limits. The rest are definite values, but the error bars are greater than the value itself. So there is no information given by the authors usable here.

OK, fine. But it really doesn't matter because my main point here is your disagreement with the QM rules of angular momentum addition.

So you say it yourself: There are cases not covered.

No, I did not say that the photon is not covered. I explicitly said that it is covered.

If you use the Lorentz transformation to calculate the mass of the moving photon from the rest mass, which is zero, that you have to multiply m=0 with the Lorentz factor (= infinite). This multiplication is not allowed in mathematics and it yields an undefinied result. - A complete theory does not have such cases.

I have no idea of what you mean by a "complete theory", but your understanding of relativity is clearly wrong in this instance. I just got through explaining that one of the lessons of SR is that the rest frame of a massless particle is a nonsensical concept. But then here you are referring to the rest frame of a photon.

Why?

It seems that also QM does not cover the photon.

Of course it does. What QM does not cover is the idea that a photon is made up of two massive spin-1/2 particles.

 

[pervect]

Already in the 1970ies Shapiro has proven by radar ranging to the planet Venus, that the speed of photons passing close to the sun is reduced. Later such experiments were performed with high precision. They all verify the equation about this reduction of c in a gravitational field given by the Schwarzschild formalism.

The change in arrival time for radar signals is a prediction of relativity - it is not a result in contradiction with relativity.

You have misinterpreted the results of the experiments in a common (but unfortunately still incorrect) way when you claim that the increase in round-trip time of signals that past close to the sun (the Shapiro effect) is due to a change in velocity of light.

It is important to realize that any observer, using local rulers and clocks, will measure the speed of light to be equal exactly to 'c' at any point anwyhere along the path of the radar signal.

From the perspective of an observer at infinity, clocks appear to run slow near the mass due to gravitational time dilation, and rulers also appear to change length. From the perspective of an observer at infinity, the coordinate speed, dr/dt, of the path of a radar signal (aka a null geodesic) will not appear to be constant. However, from the perspective of any local observer along the radar beam, the rate of change of distance with time will always be constant and equal to 'c' when measured with local clocks and local rulers.

When we say the speed of light is constant, we mean that the speed of light as measured by a local observer with local clocks and local rulers is constant, not that the coordinate speed of light is constant. This is as it should be - we are in fact, free to chose any arbitrary coordinate system that we like in GR.

 

[Albrecht]

Neither of these remarks are correct- relativity is a complete theory, and QM defintely does cover the photon.

Since several decades physicists are looking for quantum gravity, which is assumed to unify relativity and QM. Without any success. I have read a statement of a known physicist that the lack of success till now is so great that the problem will not be solved just by correcting or extending either relativity or QM. Several others stated something like: We do need a new Copernicus who guides physics out of the present dead lock.
So either relativity or QM is wrong, probably both.

 

[Albrecht]

Please show me (i) a "complete theory", and (ii) a "complete theory" that doesn't contain such a thing. Would you like to look at Coulomb's Law and figure out the value of the field at the position of the point charge?
Zz.

I do not have a complete theory (even though I know something which I understand to be better than what we have; but that is not a point here). I do not know if a point charge exists, but two charges cannot be at the same position; so that mentioned case does not exist. The photon, however, exists and in any state of it we have the situation that the formalism of SR has a singularity when describing its internal state.

Please show me (i) a "complete theory", and (ii) a "complete theory" that doesn't contain such a thing. Would you like to look at Coulomb's Law and figure out the value of the field at the position of the point charge?
This so-called incomplete theory is able to make corrections to the semiconductor band structure that requires relativistic effects to be accurate and useful in your modern electronics. Not only that, your life depends on it each time you fly in an airplane. Aren't you being a bit of a hypocrite for using it on one hand, and coming in here and making all those statements on the other hand?
Zz.

A theory can of course be very helpful even if it is not complete. Also the theory of Newton was helpful, but not complete as we know. (Newton's theory is basically sufficient to build and fly an airplane). The point is a different one: It does not help the development of science if we ignore the problems which are still open. That is what I wanted to explain in relation to relativity.

 

[Albrecht]

OK, fine. But it really doesn't matter because my main point here is your disagreement with the QM rules of angular momentum addition.

No, I did not say that the photon is not covered. I explicitly said that it is covered.

I meant that you explicitly said "it is covered" but your further comment showed that it is not covered.
I understand that the solution is not as simple as to combine two neutrinos. But this shows that the photon is in fact a particle to be understood.

I have no idea of what you mean by a "complete theory", but your understanding of relativity is clearly wrong in this instance. I just got through explaining that one of the lessons of SR is that the rest frame of a massless particle is a nonsensical concept. But then here you are referring to the rest frame of a photon.
Why?

Do you really understand why a particle without any mass has a momentum? I do not mean that we have a formalism stating that. But to understand physics is in my view a bit more that to have a mathematical description.

I mentioned earlier that we have this problem with quantum gravity. I expect that this problem will not be resolved until we leave this (quite common) position und really understand physics rather that only describing physical processes formally.

In the historical understanding of the planetary system there was the successfull mathematical description by Kepler. But that only helped to a certain point. E.g. the influences of one planet onto the other could not be handled. Later Newton came and provided his law of motion as an explanation.

The corresponding theoretical background as with Newton is the point missing in modern physics (Relativity as well as QM).

 

[Albrecht]

From the perspective of an observer at infinity, clocks appear to run slow near the mass due to gravitational time dilation, and rulers also appear to change length. From the perspective of an observer at infinity, the coordinate speed, dr/dt, of the path of a radar signal (aka a null geodesic) will not appear to be constant. However, from the perspective of any local observer along the radar beam, the rate of change of distance with time will always be constant and equal to 'c' when measured with local clocks and local rulers.
When we say the speed of light is constant, we mean that the speed of light as measured by a local observer with local clocks and local rulers is constant, not that the coordinate speed of light is constant. This is as it should be - we are in fact, free to chose any arbitrary coordinate system that we like in GR.

Yes, here you say it yourself. The local observer observes always the same value for c because the clock and the rulers change. So, it is clear that this is a seeming result. As you state, not c is constant but the measurement result is.

This is a general point in relativity: Does the time change (as stated by Einstein) or do the clocks change? Does the space contract (as stated by Einstein) or do only the rulers contract? Is there any way to distinguish between both alternatives?

There is no way to decide this by an experiment. If you follow the other way (=non-Einstein) you will come to the conclusion that c is not at all constant, neither is SR not in GR. But we cannot measure the change by the causes mentioned.

I find this understanding better for the following reason:
If you assume that clocks change and rulers change, you will ask next, which is the physical cause for that change. If you on the other hand assume with Einstein that time and space changes then nobody does see a reason to ask for a cause.

In my view the latter point is the reason for our present problems in physics.

 

[ZapperZ]

I do not have a complete theory (even though I know something which I understand to be better than what we have; but that is not a point here). I do not know if a point charge exists, but two charges cannot be at the same position; so that mentioned case does not exist. The photon, however, exists and in any state of it we have the situation that the formalism of SR has a singularity when describing its internal state.

Then a "complete theory" doesn't exist and you bringing up such a thing is a fallacy. You cannot use that as an argument when you yourself cannot point to the existence of such a thing. You were using something that doesn't exist as an argument.

A theory can of course be very helpful even if it is not complete. Also the theory of Newton was helpful, but not complete as we know. (Newton's theory is basically sufficient to build and fly an airplane). The point is a different one: It does not help the development of science if we ignore the problems which are still open. That is what I wanted to explain in relation to relativity.

How can you say that it doesn't HELP the development of science after all the advancement SR has produced? Do you think think Dirac equation doesn't ADVANCE science? Do you think all those relativistic corrections to the semiconductor band structure did nothing to further science? What about all the new physics that came about as the result of SR? What do you call all those?

Furthermore, since when is a singularity of any kind is a hinderance to the physics involved? We know how to treat such a thing from mathematics. And you want to check up on something called van Hove singularity. You have it right in the electronics you are using. It doesn't hinder physicists, nor engineers, in making your electronics work. It does NOTHING. So why are you picking on SR only as if it is the only place where you have such divergence?

Zz.

 

[russ_watters]

This is a general point in relativity: Does the time change (as stated by Einstein) or do the clocks change? Does the space contract (as stated by Einstein) or do only the rulers contract? Is there any way to distinguish between both alternatives?

No, those are all just parts of a philosophical question you are asking: are the laws of the universe screwing with us? - or to put it another way, what is the difference between perception and reality? Those questions are all largely irrelevant to the scientists and engineers who use Relativity on a daily basis: for them, perception is reality. It must be because it is all we have to judge what is real.

Time is relative, not clocks, because, by definition a clock is a device that measures time. (However, to say "clocks change" or "does time change" is not a correct way to ask the question - in the stationary frame, no variation occurrs)

Space contracts, not rulers, because by definition rulers measure distance in space.

And is there any way to distinguish between the alternatives? As already said (ehh, maybe in another thread), you can make all the superfluous assumptions you want about invisible fairies and elephants pushing planets around, but they have no effect on what we actually observe. And as a result, a scientific mind must assume that invisible fairies, elephants, the aether, and laws of physics that conspire to trick us do not exist.

 

[ZapperZ]

IDo you really understand why a particle without any mass has a momentum? I do not mean that we have a formalism stating that. But to understand physics is in my view a bit more that to have a mathematical description.

Hint: Open Jackson's Classical Electrodynamics. Now there's no "particle" of any kind there, only classical wave theory for EM field. Guess what? There's MOMENTUM there too! And a complete explanation on where it came from.

This is an indication that you haven't done enough to understand what you are criticising, not just on SR, but even on classical physics. So if you have a problem with a particle with no mass, but having a momentum, then you should also be in the Classical Physics forum complaining about a "wave" that is not even a particle, with certainly no mass, but also have a momentum. Why aren't you doing that?

Zz.