At Rest with our Hubble view

[Grumpy]

Q-reeus

If and it seems clear that 'by geometry' you mean simply a changed length of light path owing to deflection

No, I am talking about a longer path due to the path's curvature, caused by the effects of mass. Every curved path through spacetime is longer than a direct geometrical path, thus every curve gives longer transit times. And those curves are caused by mass. Two identical photons emitted similtaineously from the same source will have a delay between their arrival times if one passes a large mass closer than the other passes, simply because the closer path is more curved. That effect is well known in Relativity, I'm pretty sure that's what Shapiro is chasing.

well no the unequivocal answer is that cannot anywhere near explain the delay

It seems, from the cite, that the effect is so minute it is in the noise, the Wiki article had a plea for an actual cosmologist to revue the article and, as I said, I will be waiting to go further than that on such speculative and unconfirmed data. If there is a single exception to light always travelling at lightspeed we would have seen photons travelling at less than lightspeed in a vacuum, that simply has not happened(believe me, it would be front page news). I do not accept Shapiro's work or paper as being valid, it has no experimental confirmation. Again, no one has ever measured lightspeed in vacuum in or from any frame as being slower than that in any other frame in vacuum.

Grumpy

 

[Undefined]

Hi Grumpy.

Yes. Motion gives similar TIME dilation.

I'm glad we still agree, along with Aqueous Id and everyone else here ('crank' and 'expert' alike), that the "t" used in each frame varies from other different frames.

Now, from this mutual understanding about varying "t" between different frames, I again proceed to point to what I see as the likely source of the confusion of the discussion between the 'takes' on lightspeed per se in this context.

There are two 'parts' to the likely source of the problem:

First part: I already explained, in this context, the subtle but crucial difference between the term 'invariant c' and the term 'constant c'; and the consequent confusions/misunderstandings brought about by those who still insist on treating treating them as "equivalent things/concepts" in logic/physics/maths. I have already pointed out why the two terms are not equivalent things in this context, such that any conclusions about lightspeed based on this incorrectly attributed equivalence' cannot be sustained in the context.

Second part: I have already mentioned elsewhere how the length contraction assumption 'buried' in the 'interpretation' of the observations leads to circuitous reasoning which makes some 'interpreters' quite prepared to abstractly attribute the observation results to "length contraction" rather than accept "non-constant lightspeed" (as distinct from "invariant lightspeed", as per the distinction I explained already).

Once one 'chooses' to interpret the result of "t varying across frames" as being "compensated for by length contraction", then one automatically shuts one's mind to the other interpretation; namely, that:

Varying "t" compensates for 'non-constant lightspeed' (as distinct from 'invariant c') such that the calculation in each frame always gives that 'invariant c' "measurement" even while the lightspeed has varied and is therefore not 'constant c' as still confusingly believed as equivalent to 'invariant c' by some.

But still some will continue to stick with 'length contraction compensates for varying "t"!....because they still mistakenly believe that 'constant c' is equivalent to 'invariant c'.....and all this tortuous, circuitous and biased reasoning in order to sustain a stubborn assumption that 'lightspeed is constant' (again, as distinct to 'lightspeed invariant c' as already explained is different and not equivalent to 'contant c') in order to 'justify' their 'interpretation' of the observed phenomenon in this context as being due to "length contraction plus time dilation" in preference to the other alternative interpretation of "time dilation plus non-constant lightspeed".

Once we 'prefer' length contraction as the 'compensatory factor' for the time factor for the calculated 'invariant c' measurement in each different frame, then one is trapped into the 'interpretation' by a unwarranted 'belief' that "lightspeed is constant because the other two factors time and length variations compensate to give invariant calculated c".

I hope after you read this and my prior posts in this context/issue, you will see what I am getting at; both as to:

- the crucial distinction which must be made between 'invariant c' and 'constant c' when discussing all the lightclock/lightsphere scenarios; and also to

- the unwarranted 'preference' for an ad-hoc assumption of 'length contraction' over the other logically indicated 'non-constant c' (but still 'invariant c', as already explained) as the explanation for observed phenomena in this context.

Once one drops the bodgied up belief in 'length contraction' as the compensatory factor for varying "t" in the calculations, and starts to consider the possibility that it is the 'lightspeed' that varies, then it is not outrageous to interpret the phenomenon in the context as "varying t compensates for varying lightspeed in the calculations (so hiding the fact that lightspeed does the varying and not length).


PS: By the way, Grumpy, just so you don't think I have nothing else to back up my observations so far, I will here mention, ahead of my publication, that I have the naive and 'real' answer (ie, the physical mechanistic and not just the current abstract geometric answer) as to why the photons in the light clocks depicted by Farsight behave as they do irrespective of the GR-orientation/SR-motion etc states (vertical or horizontal or anywhere in-between) of the parallel-mirror assembly. But please forgive me for not giving the answer here, for if I gave out all the answers now, I would have nothing to publish in respected science journals and books! Thanks for your respectful and friendly exchanges, Grumpy! I hope you and your sister and family are well as can be. I am very busy, so I don't know when I will post again. Bye for now.

 

[Tach]

I already explained, in this context, the subtle but crucial difference between the term 'invariant c' and the term 'constant c';

There is no "difference" . The difference exists only for cranks like you. Since the thread has been moved into "Pseudoscience", your posts are now in the appropriate forum because this is what you post: crackpottery.

Second part: I have already mentioned elsewhere how the length contraction assumption 'buried' in the 'interpretation' of the observations leads to circuitous reasoning which makes some 'interpreters' quite prepared to abstractly attribute the observation results to "length contraction" rather than accept "non-constant lightspeed" (as distinct from "invariant lightspeed", as per the distinction I explained already).

Nice word salad, I'll have ranch with it.

Once one 'chooses' to interpret the result of "t varying across frames" as being "compensated for by length contraction", then one automatically shuts one's mind to the other interpretation; namely, that:

Varying "t" compensates for 'non-constant lightspeed' (as distinct from 'invariant c') such that the calculation in each frame always gives that 'invariant c' "measurement" even while the lightspeed has varied and is therefore not 'constant c' as still confusingly believed as equivalent to 'invariant c' by some.

The standard crackpot fare. You go, RC.

But still some will continue to stick with 'length contraction compensates for varying "t"!....because they still mistakenly believe that 'constant c' is equivalent to 'invariant c'.....and all this tortuous, circuitous and biased reasoning in order to sustain a stubborn assumption that 'lightspeed is constant' (again, as distinct to 'lightspeed invariant c' as already explained is different and not equivalent to 'contant c') in order to 'justify' their 'interpretation' of the observed phenomenon in this context as being due to "length contraction plus time dilation" in preference to the other alternative interpretation of "time dilation plus non-constant lightspeed".

Are arguing with yourself or with your own hallucinations?

- the crucial distinction which must be made between 'invariant c' and 'absolute c' when discussing all the lightclock/lightsphere scenarios; and also to

No one talks about "absolute c" in the mainstream physics. Still fighting the windmills, Don Quixote?

- the unwarranted 'preference' for an ad-hoc assumption of 'length contraction' over the other logically indicated 'non-constant c' (but still 'invariant c', as already explained) as the explanation for observed phenomena in this context.

"Non-constant c" is a fabrication of your own ignorance. Doesn't exist in mainstream physics, you are evolving into a full blown crank.

Once one drops the bodgied up belief in 'length contraction' as the compensatory factor for varying "t" in the calculations,

No mainstream physicist has this "belief", you are making strawmen and beating them to death. Give it a rest.

and starts to consider the possibility that it is the 'lightspeed' that varies, then it is not outrageous to interpret the phenomenon in the context as "varying t compensates for varying lightspeed in the calculations (so hiding the fact that lightspeed does the varying and not length).

Light speed doesn't vary. Correction: it varies only in the minds of crackpots.

PS: By the way, Grumpy, just so you don't think I have nothing else to back up my observations so far, I will here mention, ahead of my publication, that I have the naive and 'real' answer (ie, the physical mechanistic and not just the current abstract geometric answer) as to why the photons in the light clocks depicted by Farsight behave as they do irrespective of the GR-orientation/SR-motion etc states (vertical or horizontal or anywhere in-between) of the parallel-mirror assembly. But please forgive me for not giving the answer here, for if I gave out all the answers now, I would have nothing to publish in respected science journals and books!

This is hilarious.

Thanks for your respectful and friendly exchanges, Grumpy! I hope you and your sister and family are well as can be. I am very busy, so I don't know when I will post again. Bye for now.

So, you think that you'll get published, eh? Full blown crank.

 

[Undefined]

No one talks about "absolute c" in the mainstream physics.

Still depending on typos and other trivial excerpts to "correct" while ignoring the full context that would have made it clear to you that it should have read "constant c', not as the obvious (to anyone else) typo 'absolute c'?

The rest of your post is eminently ignorable, as usual. Others will be more genuine in their discourse, so I will engage with them and leave you alone to enjoy your self-made pedantry-and-malice stew. Thanks anyway for your trouble though. Bye.

 

[quantum_wave]

... I don't know when I will post again. Bye for now.

Good luck, and thanks for helping keep the thread civil.

 

[Tach]

Still depending on typos and other trivial excerpts to "correct" while ignoring the full context that would have made it clear to you that it should have read "constant c', not as the obvious (to anyone else) typo 'absolute c'?

There was no typo but your whole post was , your standard fare, pure crackpot material.

 

[Undefined]

There was no typo but your whole post was , your standard fare, pure crackpot material.

Just so you can't switch-and-bait your way out of this latest silliness of yours, I came back in just to say:

It's too bad the whole context of the exchange/post obviously indicated a typo for any genuine reader.

But that never stops your pedantic nasty game playing.

That you should go to all the trouble of playing your silly games in the pseudoscience forum says it all about your ego-compulsive need to "correct" others, even when you yourself have been the one who needed the correction.

Too sad. Bye.

 

[Undefined]

Good luck, and thanks for helping keep the thread civil.

Thanks, and good luck to you too. Can any thread remain civil whenever the pedantic Tach comes in a-playing nasty? Let's see. Catch ya later, q_w, everyone. Play nice!

 

[Tach]

Just so you can't switch-and-bait your way out of this latest silliness of yours, I came back in just to say:

It's too bad the whole context of the exchange/post obviously indicated a typo for any genuine reader.

It isn't just the "typo" it is a whole collection of crank statements. They are dissected and exposed for what they are, pure crackpottery.

 

[Undefined]

Hi Tach. Just came in to check a PM, and caught your latest eminently ignorable opinionated post:

It isn't just the "typo" it is a whole collection of crank statements. They are dissected and exposed for what they are, pure crackpottery.

Sure, sure, anything you say, Tach. After all you are always 'right' about 'everything' and never 'wrong' about anything. Never been known to misunderstand or misconstrue or ignore the context before kneejerking without really understanding what is being said, and then trying to cover your embarrassment by using trivial/strawman "corrections" and personal games and insults to distract from your compulsive silliness and to sooth your whatever-it-is that-ails-you so deep down.

Let the genuine discoursers who engage honestly and politely discuss the points at issue with me, for you are not the stuff that real enlightenment is made of. Dishonest engagement and insults is no substitute. Good luck though; and thanks anyway for your interest at least. Bye again, Tach.

 

[Q-reeus]

The link you provided cites the paper from 1911. Give it a rest, cranko, the calendar says year 2013, only you and Farsight are still stuck in 1911.

How nice of you to ignore the derivation cited from AE's 1955 Published book. But what else to expect from cranky Tach.

This nonsense is what you've learned at crank university? The very links you cite contradict your wacko claims.
"Why doesn't gravity change the speed of light?

How come that the speed of light "c" doesn't change at all, even slightly, when the light passes closely to a star or some similar big object. We know that light bends in those situations, but what about "c"?

Yep, although light bends around a massive object like a black hole, the speed of that light in a vacuum is always the same. This is because the speed of light is directly dependent on the speed of the interaction between the electric and magnetic fields (light is an electro-magnetic wave, after all!). That speed of interaction is the same no matter where the light is or who is watching it. Therefore, the speed of light is the same for all observers at all points in space-time.

In other words, the light bends around the massive object, but the graduate students all along the light's path will always measure it moving at the same speed: the speed of light. "

Again, how nice of you to ignore that I cited that article as an honest attempt at 'balance' and pointed out it adopts a particular and imo artificial interpretation/definition in order to arrive at an invariant c.
How nice of you to utterly ignore the other articles I furnished providing a quite different perspective.
Well I can only heartily concur with sentiments expressed by Undefined in #1290. There are apparently some really good mood mellowing meds out there now - try them soon, very soon.

 

[Farsight]

Frustratingly Baez, after giving an unequivocal nod to Einstein's position there, never qualifies his following and apparently contradictory stance that |c| does not vary. My suspicion is he/they choose to interpret using some projection method that 'factors out' variation in coordinate length scale and clock-rate. Which amounts to saying the locally observed value is trivially going to always be c - on that basis. My second linked article in answer to Grumpy suggests that is the case.

All points noted, Q-reeus. If you take a look at an old version of the Wikipedia Shapiro delay article the Einstein quote is there.

What's strange about all this is that you can show people the Einstein quotes, and you can tell them about the Shapiro delay and the NIST optical clocks, and the coordinate speed of light varying in a gravitational field, and they just won't have it. Make it simple with the parallel-mirror gif and they still won't have it. They can't explain it either. Instead they become abusive. Once you realise how people can be like automatons, it's a bit scarey.

NB: have a read of The Other Meaning of Special Relativity by Robert Close. This explains why we always measure the local speed of light to be the same. It's because of the wave nature of matter.

 

[Q-reeus]

No, I am talking about a longer path due to the path's curvature, caused by the effects of mass. Every curved path through spacetime is longer than a direct geometrical path, thus every curve gives longer transit times. And those curves are caused by mass. Two identical photons emitted similtaineously from the same source will have a delay between their arrival times if one passes a large mass closer than the other passes, simply because the closer path is more curved. That effect is well known in Relativity, I'm pretty sure that's what Shapiro is chasing.

Well Grumpy this gets down to how one wishes to define things. What is unequivocally true is that when allowance is made for the Pythagorean path length increase owing to beam deflection, the great majority of experimentally confirmed to high accuracy Shapiro delay is owing to 'something else'. And that something else is a mix of slowed clock-rate and contracted length scale en-route.
From the Schwarzschild line element one directly reads off transverse and radial speeds that vary according to factors 1+φ and 1+2φ respectively (φ<<1). That was all explained in the third linked article I cited last time (and further in a link in that article itself). The former is owing purely to clock-rate, the latter is equally owing to clock-rate and contracted radial spatial metric component. Now there is some artificiality in that split in that one could choose to use say the so-called isotropic Schwarzschild metric, and there one will obtain transverse as well as radial length contraction factors. However it's customary to stick wit the standard Schwarzschild metric. Regardless though there is always in general a slowing of c owing to clock-rate and length scale. Howbeit as per that article, if one is in the lower gravitational potential, one calculates a higher c elsewhere, but the former situation is the normal perspective as per typical Shapiro delay experiments.
And I consider above pov the obvious and natural perspective, and many GR authors agree.

However evidently there is a push to make certain quantities like not just mass but also light speed invariant in relativity. Hence this convention/interpretation/definition that insists we view c as an invariant c under all circumstances but where altered spacetime path length accounts for things. That appears to be your choice and if so well fine I just prefer the other view for reasons given. And plenty of other articles could be cited to back either view. Peace.

 

[Q-reeus]

All points noted, Q-reeus. If you take a look at an old version of the Wikipedia Shapiro delay article the Einstein quote is there.

What's strange about all this is that you can show people the Einstein quotes, and you can tell them about the Shapiro delay and the NIST optical clocks, and the coordinate speed of light varying in a gravitational field, and they just won't have it. Make it simple with the parallel-mirror gif and they still won't have it. They can't explain it either. Instead they become abusive. Once you realise how people can be like automatons, it's a bit scarey.

NB: have a read of The Other Meaning of Special Relativity by Robert Close. This explains why we always measure the local speed of light to be the same. It's because of the wave nature of matter.

Farsight - one has to accept that certain conventions and interpretations are adhered to, and that 'ideological climate' is simply a fact of life, like it or not. Old school or new school, I don't care.

 

[przyk]

What's strange about all this is that you can show people the Einstein quotes, and you can tell them about the Shapiro delay and the NIST optical clocks, and the coordinate speed of light varying in a gravitational field, and they just won't have it. Make it simple with the parallel-mirror gif and they still won't have it.

That's because "they" want the one thing that's conspicuously absent from your list: logical (which usually means mathematical) arguments for why your claims are true.

Example: if you claim that inhomogeneous space is "equivalent" to curved spacetime, then it is up to you to 1) explain precisely how you are characterising/modelling the "inhomogeneity of space" and how that affects matter and light, and then 2) prove that the resulting model is mathematically equivalent to GR as described in, say, MTW (since this is the text you keep taking pot shots at).

Of course, you don't have the level of mathematical literacy needed to do this, and you know you don't, and even if someone else had already done all the work for you you wouldn't know it because you wouldn't be able to make your own independent assessment of it. That is your fault and nobody else's.

 

[Tach]

How nice of you to ignore the derivation cited from AE's 1955 Published book. But what else to expect from cranky Tach.

Again, how nice of you to ignore that I cited that article as an honest attempt at 'balance' and pointed out it adopts a particular and imo artificial interpretation/definition in order to arrive at an invariant c.
How nice of you to utterly ignore the other articles I furnished providing a quite different perspective.

I simply quoted from the very link you cited <shrug>.
It is not my fault that you are pushing the same crackpottery as Farsight and Undefined.

Well I can only heartily concur with sentiments expressed by Undefined in #1290. There are apparently some really good mood mellowing meds out there now - try them soon, very soon.

Well, you crackpots agree, good for you.

 

[Tach]

Hi Tach. Just came in to check a PM, and caught your latest eminently ignorable opinionated post:


Sure, sure, anything you say, Tach. After all you are always 'right' about 'everything' and never 'wrong' about anything. Never been known to misunderstand or misconstrue or ignore the context before kneejerking without really understanding what is being said, and then trying to cover your embarrassment by using trivial/strawman "corrections" and personal games and insults to distract from your compulsive silliness and to sooth your whatever-it-is that-ails-you so deep down.

Well, it isn't my fault that the crank stuff that you, Farsight and Q-reeus have been posting about "variable speed of light" landed the thread in "Pseudoscience". Take a hint.

 

[Grumpy]

Q-reeus

Regardless though there is always in general a slowing of c owing to clock-rate and length scale.

Such slowing has never been measured, period, and the light we see from even the deepest gravity well(just short of an Event Horizon)is not the least bit slower than any other photons(reddened, yes, slowed, not one bit), from any other source, in any relativistic frame of reference. Your statement is simply false, no matter how often repeated by you or anyone else(cough)Farsight(cough), it means that anything else you say BASED on that error is also false. C does not change, the length scale and time rate change so that the speed of light is always the same, in all frames and from all frames. It is a basic property of spacetime that massless photons travel at lightspeed in a vacuum, it is not a property that is affected by ANYTHING(gravity, energy density of the spacetime being crossed, how much spacetime expands between source and observer or the rate of speed through local spacetime of the source or the observer. That is an observed fact.

Shapiro is simply barking up the wrong tree(his measurements were well within the noise, as have all attempts to measure any such effect have been). His work has not passed peer review and no headline has appeared in the New York Times announcing the failure of Einstein's Relativity(SR or GR). Remember the "Faster than light" neutrinos? Front page. Same thing applies to "Slow light".

Grumpy

 

[Tach]

Shapiro is simply barking up the wrong tree(his measurements were well within the noise, as have all attempts to measure any such effect have been). His work has not passed peer review and no headline has appeared in the New York Times announcing the failure of Einstein's Relativity(SR or GR).

This is really bad, on multiple accounts.

1. Shapiro's work was published in a very reputable journal (PhysRevLett):

- Irwin I. Shapiro (1964). "Fourth Test of General Relativity". Physical Review Letters 13 (26): 789–791. Bibcode:1964PhRvL..13..789S. doi:10.1103/PhysRevLett.13.789

- Irwin I. Shapiro, Gordon H. Pettengill, Michael E. Ash, Melvin L. Stone, William B. Smith, Richard P. Ingalls, and Richard A. Brockelman (1968). "Fourth Test of General Relativity: Preliminary Results". Physical Review Letters 20 (22): 1265–1269. Bibcode:1968PhRvL..20.1265S. doi:10.1103/PhysRevLett.20.1265.

2. Shapiro never claimed that his work shows "light speed slowing". It is Q-reeus who makes this gross misinterpretation of his work. You won't find this crackpottery in any textbook (MTW , Rindler, Taylor and Wheeler, etc)

3. The whole issue has nothing to do with light speed, it is simply an issue of calculation of radar time delay in the context of light following a geodesic path. That's all.

 

[Q-reeus]

Such slowing has never been measured, period, and the light we see from even the deepest gravity well(just short of an Event Horizon)is not the least bit slower than any other photons(reddened, yes, slowed, not one bit), from any other source, in any relativistic frame of reference. Your statement is simply false, no matter how often repeated by you or anyone else(cough)Farsight(cough), it means that anything else you say BASED on that error is also false. C does not change, the length scale and time rate change so that the speed of light is always the same, in all frames and from all frames. It is a basic property of spacetime that massless photons travel at lightspeed in a vacuum, it is not a property that is affected by ANYTHING(gravity, energy density of the spacetime being crossed, how much spacetime expands between source and observer or the rate of speed through local spacetime of the source or the observer. That is an observed fact.

Shapiro is simply barking up the wrong tree(his measurements were well within the noise, as have all attempts to measure any such effect have been). His work has not passed peer review and no headline has appeared in the New York Times announcing the failure of Einstein's Relativity(SR or GR). Remember the "Faster than light" neutrinos? Front page. Same thing applies to "Slow light".

Grumpy
Strangely enough Tach has done me a favor in #1299. By rebutting your unwarranted doubt about Shapiro's ability and validity of effect he measured, even though Tach emphasizes it's 'just time delay'. Well in my book if there is time delay, then 'going slow' is a good explanation for that. But again there is this thing about interpretation, definition, convention.
Look, as I wrote before, authorities in GR take different positions on this one, and at least acknowledge that is the case - as the articles I provided amply demonstrate. You may feel your position is the only 'right' one. I see it differently, and just as well none of our opinions effects in the least the running of the local sewerage works.