Absolute Frame Fallacies

It looks as though your long-running battle will be yet longer.

Hi Jorrie,

I believe that a reply to sjw would be fruitless. I think the problem is that there is a lot of conflicting 'information' on the internet. Some of it is written by people who appear to have good credentials. It is difficult for people like me who have been working in a field which is very different from rocket science and aeronautics to determine what is correct. You, on the other hand have made this your life's endeavor. After several years of discussions with you, I trust your opinions on relativity and the like. I would like your response to this link, if it is not too much trouble. I can't even understand the summary.

-S

Hi S, looks like an interesting link. An old (1967) paper, but very professional, is my first impression. Will give it a read and let you know.

-J

Hi S, "... would like your response to this link, "

I have read it, but to stay closer to topic, I have replied on the Sagnac Blog post.

-J

Two airplanes traveling at a constant velocity in opposite directions around the Earth, no Sagnac affect. Two GPS satellites traveling at a constant velocity in opposite directions around the Earth, no Sagnac affect. Two beams of light traveling at a constant velocity in opposite directions around the earth, Sagnac affect. So tell me, what causes this for light but not any other thing? Does not your non-rotating lab also report different travel distances for airplane and GPS? Why do you not use this lab frame to explain the Sagnac affect for airplane and GPS satellite? Should not according to this lab frame one of the airplanes and one of the GPS satellites have longer to travel?

Ooops, I wasn't supposed to ask those questions, sorry.

SJW, this thread is not about the Sagnac effect - you are immediately off-topic again. I had two recent Blog entries on the Sagnac effect, where these questions of yours have been answered more than once, actually.

BTW, the Sagnac effect is there for all objects traveling in closed loops, be it airplanes, satellites, electrons or photons. It is just not there in every frame of reference. This has also been discussed in the Sagnac threads.

-J

PS: I have no delete rights on the General section, but the moderators have that and worse. So do not relax too much...

Shall I go get your answer to a previous blog where you state two planes traveling in opposite directions travel the same distance regardless of the earth's rotation? Double talk Jorie. You want it to be one way to answer one theory and then another to answer a different set.

No I am off topic because you don't want to have to answer why you must choose an absolute frame and use its measurements to explain the Sagnac affect for light. You must choose a third frame of reference and prefer it over the results of the other two. This is about frames of reference is it not? If your third frame the lab frame is not an absolute frame then why must you use it to explain the results? Why can you not use either of the clock frames since its all relative? Smoke and mirrors.

"This is about frames of reference is it not? If your third frame the lab frame is not an absolute frame then why must you use it to explain the results? Why can you not use either of the clock frames since its all relative?"

Obviously it is about reference frames, which you have demonstrated to not understand before, despite more than one participant trying to give you insight. You remember? It seems that you still are not understanding them. Best to go read those post again carefully, including perhaps some references.

You can choose any reference frame you fancy, including the rotating frame, for your calculations. Some are just much easier to work with than others, but not absolute frames in any way. This is the topic of this thread, not the Sagnac effect.

If you have a problem with what I wrote on the equivalence principle, let's discuss it. As Solar wrote: "What is the problem you are trying to solve that incorporates these principles?"

If no problem, you are wasting your time here (and other reader's).

What is the problem you are trying to solve that incorporates these principles?

If there is no problem, then you are just arguing semantics...imo

Reality is the same for everybody, it may be interpreted differently but it's the same thing...The reason we as humans are capable of solving some of the most complex problems that confront man, is because we have different points of view...If we were all of one point of view, when we hit a problem we would be stumped, but instead somebody else comes along and proposes a different approach, this repeats until there's a breakthrough and progress continues...Embrace the diversity of thought...$.02

The problem is that GPS shows the one way speed of light does not travel at the same velocity relative to the rotation of the Earth. But in order to make that experiment fit the flawed concept that light travels at c regardless of observer motion they attempt to throw in a third frame of reference, prefer that frame above all others to justify their reasoning and at the same time claim their is no preferred frame. Double talk and sleight of hand, smoke and mirrors. They are unable to accept the fact that light travels at c relative to a vacuum (not relative to moving objects) and at other speeds relative to the transparent medium it propagates through. That v+c or v-c relative to moving objects has always been supported by the data, and only by arbitrarily choosing two different starting points for measurements can they obtain length contraction and time dilation. If they choose the same starting points they get length contraction and time contraction, or length dilation and time dilation. They then must further twist things and multiply one and divide the other, and even though they claim it is based on the same Lorentz equations they do not do this consistently, but use unrelated correlations.

Arbitrary starting Points

unequal application of the same Lorentz formula

Double talk and sleight of hand, smoke and mirrors.

The speed of radio signals (identical to the "speed of light") is the same from all satellites to all ground stations at all times of day and in all directions to within ±12 meters per second (m/s).

Hi Solar; what you said is true, but only because GPS was designed with clocks synchronized in a way that ensured the one-way speed of light between the satellites and receivers to be identical in all directions. This includes the relativistic clock-rate offset employed in the satellites.

There is no known way of measuring the one-way speed of light without dependence on a clock synchronization protocol. Hence, if there exists an underlying absolute frame (ether) for light, it is not detectable. To paraphrase Einstein: "if we can't detect an ether, we can just as well forget about it".

I.e., choose the clock synchronization that makes your life the simplest and get on with the job at hand. This is really what I wanted to get at with this thread and my prior one.

-J

" GPS was designed with clocks synchronized in a way that ensured the one-way speed of light between the satellites and receivers to be identical in all directions. This includes the relativistic clock-rate offset employed in the satellite."
Yes, that was my point...

Thinking about it again, the clincher in what you wrote was "... at all times of day and in all directions...".

Add to that "all year round", and we have fairly strong evidence that the one-way speed of light in Earth's frame does not change with different speeds (of Earth) relative to some external reference frame, like the CMB frame. The fact that it is clock-sync dependent is then irrelevant.

The Michelson-Morley experiment checked this only for the two-way speed of light.

"The fact that it is clock-sync dependent is then irrelevant."

General Relativity (GR) predicts that clocks in a stronger gravitational field will tick at a slower rate. Special Relativity (SR) predicts that moving clocks will appear to tick slower than non-moving ones. Remarkably, these two effects cancel each other for clocks located at sea level anywhere on Earth. So if a hypothetical clock at Earth's north or south pole is used as a reference, a clock at Earth's equator would tick slower because of its relative speed due to Earth's spin, but faster because of its greater distance from Earth's center of mass due to the flattening of the Earth. Because Earth's spin rate determines its shape, these two effects are not independent, and it is therefore not entirely coincidental that the effects exactly cancel. The cancellation is not general, however. Clocks at any altitude above sea level do tick faster than clocks at sea level; and clocks on rocket sleds do tick slower than stationary clocks. FWIW

You are correct, but just to make sure that other readers do not misunderstand the facts you have stated here. My statement: "The fact that it is clock-sync dependent is then irrelevant" is not related to the geoid effect that you mentioned; and also not to the fact that the satellite clocks are tuned to tick at the same rate as geoid clocks.

This is the only clock synchronization protocol that ensures that the one-way speed of light between satellites and the ground is isotropic. What I intended with "The fact that it is clock-sync dependent is then irrelevant" was to show that this one-way speed of light does not change with Earth's changing cosmic velocity (relative to the CMB). Even if a different protocol, with non-isotropic light speed, were adopted, that speed would still not have changed with Earth's relative velocity. Hence the "then irrelevant".

Sorry for laboring this, but I could sense a miss-quote coming from certain quarters. We have enough of that already.

Perhaps you can show the relevance of this reply of yours by telling us clearly how you propose to measure the one-way speed of light "relative to a vacuum (not relative to moving objects)".

"The problem is that GPS shows the one way speed of light does not travel at the same velocity relative to the rotation of the Earth."

Could you be more specific here?

Your first link refers to Einstein's book Relativity pages 40-42. I have that book. Pages 40-42 spans 2 chapters. Neither talks about rod lengths or clock speed. You have taken Einstein out of context and worse.

Reality is the same for everybody, it may be interpreted differently but it's the same thing...

I'd be careful with such statements....the whole point of relativity is that what's observed in one reference frame may be observed differently in another. Since we know that neither frame is a preferred frame of reference (except by human preference) both are correct. That suggests that reality is also relative to the reference frame and although the differences might be slight, reality is similar but subjective.

"reality is similar but subjective."

I was speaking objectively, and from the same point of reference, obviously...

I'm not smart enough to offer anything revolutionary to this discussion, except to say that I've been around this forum long enough to know that sjw40364 has brought a dull knife to a gun fight.

Yet with such clock corrections employed GPS clocks still measure luight speed differences. Your contentions are misplaced.

http://arxiv.org/ftp/physics/papers/0703/0703123.pdf

http://www.worldnpa.org/pdf/abstracts/abstracts_3053.pdf

http://vixra.org/pdf/1008.0035v1.pdf

http://www.newtonphysics.on.ca/illusion/index.html

The fact is that no matter your clock synchronization light speed is inconsistent east to West. Your radio waves appear to travel the same speed because the calculations in the GPS satellites account for the discrepancies of the rotational aspect of the earth. They fudge the equations. Since GPS clocks are supposed to be accurate within nanoseconds over thousands of years, it is inconceivable that they would need to be adjusted every 1.5 seconds, yet that is exactly what is done to hide the fact that light speed is inconsistent.

They have to be adjusted because manufacturers prefer to build inexpensive GPS receivers for mass markets...not because of light speed variance... at the risk of throwing fuel on the fire here, how do you account for recent binary star observations...

It's not your handheld GPS device that is adjusted, it is the clocks on board the GPS satellites that are updated with the permanent ground clocks on a constant basis, this is the updating I am referring to. Even Jorie's vaunted Ashby in his papers actually admits the discrepancy then tries to double talk himself around the paradox. He fails miserably to those that actually read his words and not skip over those parts with preconceived ideas already set.

Please provide the link to your binary star article or paper. many observations regarding binary stars have been made, to which do you refer?

While most clocks are synchronized to Coordinated Universal Time (UTC), the atomic clocks on the satellites are set to GPS time (GPST; see the page of United States Naval Observatory). The difference is that GPS time is not corrected to match the rotation of the Earth, so it does not contain leap seconds or other corrections that are periodically added to UTC. GPS time was set to match Coordinated Universal Time (UTC) in 1980, but has since diverged. The lack of corrections means that GPS time remains at a constant offset with International Atomic Time (TAI) (TAI - GPS = 19 seconds). Periodic corrections are performed on the on-board clocks to keep them synchronized with ground clocks.^[89]

The GPS navigation message includes the difference between GPS time and UTC, which as of 2011 is 15 seconds because of the leap second added to UTC December 31, 2008. Receivers add this offset to GPS time to calculate UTC and specific timezone values. New GPS units may not show the correct UTC time until after receiving the UTC offset message. The GPS-UTC offset field can accommodate 255 leap seconds (eight bits) that, given the current period of the Earth's rotation (with one leap second introduced approximately every 18 months), should be sufficient to last until approximately the year 2300. GPS time is accurate to about 14 nanoseconds.^[90]

http://www.allanstime.com/Publications/DWA/Science_Timekeeping/TheScienceOfTimekeeping.pdf

From your first link in post 19 on page 1:

"The assumption that the speed of light, c, is constant is completely proved in the GPS experiments..."

This is exactly the opposite of what YOU have been saying.

Only with respect to a stationary ECI frame, read it, not just one line. With respect to any other frame they show light is not constant, yet relativity has no frame preference. They show it is constant because the corrections for rotation are already added, yet they do not add the Lorentz corrections, required for all moving frames, and it is clear the Earth is moving in space.

Ashby states: "The fundamental principle on which GPS navigation works is an apparently simple application of the second postulate of special relativity-namely, the constancy of c, the speed of light."

Clearly, the GPS range equation does not depend on the constancy of the speed of light relative to the receiver, which is the SRT claim. Yes, the GPS equation depends on the constancy of the speed of light relative to the earth-centered inertial (ECI) nonrotating frame-but that is contrary to SRT. A receiver moving in the ECI frame does not see an isotropic light speed of c.

Ashby: "Observers in the nonrotating ECI inertial frame would not see a Sagnac effect. Instead, they would see that receivers are moving while a signal is propagating."

This claim is a bit humorous. It would have been nice if this were the last claim in contention-since Ashby in effect concedes the argument here. Receiver motion during the transit time is the Sagnac effect. The only way that Ashby can claim that the Sagnac effect is not seen by a receiver in the ECI frame while admitting that the receiver moves during the transit time is to define the effect of a moving receiver differently depending upon the description of the receivers position-a bit of a sophistry.

Ashby: "Of course if one works entirely in the nonrotating (sic) ECI frame there is no Sagnac effect."

The only way this claim can be true is if we adopt the definition sophistry of the prior claim. But we have even more convincing data that Ashby's claim is false. NavCom Technology, Inc. has licensed software developed by the Jet Propulsion Lab (JPL) which, because of historical reasons, does the entire computation in the ECI frame. Because of some discrepancies between our standard earth-centered earth-fixed solution results and the JPL results, we investigated the input parameters to the solution very carefully. The measured and theoretical ranges computed in the two different frames agreed precisely, indicating that the Sagnac correction had been applied in each frame.

As the discussion of the Sagnac effect indicates the fundamental question regarding the speed of light is the following: Is the speed of light constant with respect to the observer (receiver) or is it constant with respect to the chosen inertial (isotropic light speed) ECI frame? Clearly the GPS range equation indicates the speed of light is constant with respect to the chosen frame. The receiver position in the range equation is its position at the time the signal is received. This means that the pattern of motion of the receiver during the signal transit time is completely immaterial. The receiver could have moved in a huge series of loops during the transit time. It would not matter-it is the receivers position at the time of reception of the signal which matters.

See: http://www.worldnpa.org/pdf/abstracts/abstracts_3053.pdf pg 5

Ashby is quite good at double talk and sleight of hand, smoke and mirrors too.

sjw40364 to StandardsGuy: " read it, not just one line".

From your quoted Sato paper, the final conclusion, p. 5: "The GPS should be interpreted by the theory of general relativity as well as special relativity."

Quite an enlightened conclusion for 2007. This is what GPS people said from the beginning.

On your attacks on Prof. Ashby's papers. Dude, it is best to refrain from comments on a subject that you are demonstrably clueless about. Nobody here has the time to educate you; with your frame of mind, it will take an infinite time...

-J

P.S. to StandardsGuy: If you wish, read the new "Wang/Hatch paper" that SJW referred to, but be warned about it's dissident nature. The authors attach their own meaning to "the constancy of the speed of light relative to the receiver", which has no foundation in relativity. I can refute it page by page, but is it worth it?

Yet it isn't, Lorents equations are required, but not used in relativity, you missed the whole point of the paper, you read only what you want to see.

So Ashby claims we should not see a Sagnac affect in the ECI frame, yet GPS clocks are adjusted for the Sagnac affect. How do you justify that? If there is no Sagnac affect in the ECI frame then why are GPS satellites adjusted for that affect? Double talk and sleight of hand, smoke and mirrors.

Crosstalk with smoke screens by sjw. Always unwanted phenomenon in engineering.

I think AH and Jorrie has shown before that sjw does not comprehend reference frames. Looks like they have given up on this guy.

How he can think that there must be a Sagnac effect in the non-rotating ECI frame is beyond me. Also, he misses the point that GPs satellite are not adjusted for the Sagnac effect. They are adjusted for time dilation and gravity effects. Sagnac effects are included in the receiver calculations, AFAIK.

"How he can think that there must be a Sagnac effect in the non-rotating ECI frame is beyond me."

SJW frequently quotes Ron Hatch, an absolute-framer. In their minds, the Sagnac effect is also present in co-linear movement. As such, they have their own definitions of 'local speed of light', clock synchronization and the Sagnac effect. I guess that's why they 'crosstalk'.

And why we can't get any signal through to them (smokescreen? - cute metaphor ;)

Yea, and they would surely claim that it's our "smokescreens" that keep us blind, e.g. not accepting some of their papers in say arXiv.

What do you think of the Wang-Hatch "crucial experiment" in www.worldnpa.org/pdf/abstracts/abstracts_3053.pdf ?

Wang and Hatch have both published in reputable papers, but that was before they started to misrepresent Einstein's theory of relativity in a variety of ways. The latest that I know of is their efforts to show that the Sagnac effect also exists in linear (non-rotational) movement. In essence, they describe Einstein's clock synchronization offset as a Sagnac effect, which it patently is not.

The "crucial test" that you referred to is a proposal for a (sort of) co-linear Sagnac effect measurement, which in fact is just based on a clock sync offset. This offset is coordinate-choice (reference frame) dependent and hence can never detect absolute movement.

If they somehow manage to perform such a test and analyze the data properly, they will get a (statistical) null result. Things that they claim to add up when going in two opposite directions, will actually cancel out.

It would be sensational if they were correct, but don't put money on it. AFAIK, so far nobody seemed to be willing to do so...

See wiki: http://en.wikipedia.org/wiki/Sagnac_effect

Practical uses of the Sagnac effect

The Sagnac effect is employed in current technology. One use is in inertial guidance systems. Ring laser gyroscopes are extremely sensitive to rotations, which need to be accounted for if an inertial guidance system is to return correct results. The ring laser also can detect the sidereal day, which can also be termed "mode 1".

Global navigation systems, such as NAVSTAR, GLONASS, COMPASS or Galileo, need to take the rotation of the Earth into account in the procedures of using radio signals to synchronize clocks.

So who is blowing smoke and mirrors and using double talk and sleight of hand???? No Sagnac affect taken into account? Lol, I'll put my money on that!

And Nasa if that isn't good enough: http://ilrs.gsfc.nasa.gov/docs/timing/gpsrole.pdf

Path delay computations. The total signal path transmission delay computation begins with the range from the SV to the receiver. Using the speed of light, one can convert the range to a time delay. This delay is then corrected for the ionospheric delay using a model provided in the navigation message, for the "Sagnac" effect (the result of transmission in a rotating inertial reference system), and for hardware delays in cables and receiver circuitry. The difference between the computed and measured millisecond time marks will give the relationship between the receiver clock and GPS time.

Gonna delete this post too?

According to standard definition: "It generalizes Galileo's principle of relativity-that all uniform motion is relative, and that there is no absolute and well-defined state of rest (no privileged reference frames)-from mechanics to all the laws of physics, including both the laws of mechanics and of electrodynamics, whatever they may be. Special relativity incorporates the principle that the speed of light is the same for all inertial observers regardless of the state of motion of the source."

Since emitter or receiver can be considered at rest, there is no grounds to base a conclusion that it only affects the receiver, since according to relativity the receiver can be considered to be at rest and the GPS to be moving. How conveniently we forget that when we want to define frames of reference to match ones thoughts on a subject. Then you also want to claim the GPS are part of the ECI frame, so are not both frames at rest relative to each other and the ECI frame?

Read the prior post, "it begins with the SV to the receiver" not receiver to SV.

"Since emitter or receiver can be considered at rest, there is no grounds to base a conclusion that it only affects the receiver, since according to relativity the receiver can be considered to be at rest and the GPS to be moving."

Read NIST Technical Note 1385

It may perhaps be useful if you can point us to where Wang and Hatch went wrong in their Appendix calculations (p 10).

No need to analyze the Wang calculations. They are correct, but prove nothing but that Einstein was right. Let's start early in the 'crucial experiment', page 6.

"To examine whether or not the speed of light measured in the system changes when a system changes its translational speed relative to the ECI frame, a crucial experiment could be conducted."

The speed of light in any system depends on the clock synchronization method adopted for that system. The 'Wang test' clock synchronization method (or lack thereof)^(a) for the two aircraft guarantees that the observed 'speed of light' will differ from c in both directions. And it will differ because the time in each direction will differ by exactly the Einstein clock synchronization offset: ±vL/c², which is standard special relativity.

Note that the 'speed of light' as observed by these non-synchronized clocks does not feature in that value - the 'c' below the line is the constant c, the speed of light in vacuum for every inertial frame, with synchronized clocks, obviously. So, this value has nothing to do with the 'speed of light' in the non-synchronized frame of Wang's two aircraft. It cancels out. You can use any old inertial frame to do the calculations in and the result will be the same. This is what I meant by 'null result'.

Quite humoristic is a statement just above the helicopters: "This experiment is crucial also because if the experiment shows that the speed of light in a system moving relative to the ECI frame is different from that in another system, we can invent a new kind of speed detectors that can measure the translational speed of the system relative to the ECI frame directly."

Sure, but we have plenty of instruments to measure the speed of one frame relative to any other. Rods and clocks, laser, Doppler radar, you name it. What we don't have are instruments measuring the speed of any frame relative to an 'absolute frame'. The Wang test does not do that either.

-J

(a) One must assume that the clocks on the two aircraft were synchronized when they were next to each other on ground and that their clocks were affected identically by the takeoff and climb to constant altitude and speed. However, if they were to do a relative clock synchronization during the test, they will find their clocks to be out of sync with each other by vL/c². Wang's test does not adjust them now, but use those readings to find a 'difference in the speed of light'. As shown above (and by Wang), those differences cancel out, thus defeating the purpose of the test. It essentially becomes a "two-way" speed of light test.

So quit deleting my posts and answer the my question.

1) Do GPS clocks show light to be isotropic before or after adjustment?

Answered. See Einstein Clocks and Sagnac #24

Which of your posts have been deleted?

(Maybe you need to reset your proferences to show all posts, including any hidden ones that may have been voted OT.)

Hi Tornado

I did delete a few 'flames' from SJW on my own Blog - some were totally disruptive and rude. I obviously have no more than a single OT vote here in the general section.

-J

Rude? If i was rude at any time it was only AFTER being spoken to rudely in the first place. Just asked questions you didn't want to answer.

SJW, I am puzzled as to why you apparently are not reading what people here wrote. You rarely ask a specific question to clear up a point that someone else made. Instead, you either repeat some rhetorical questions that have already been answered, or you attack. It is not contributing positively to the forums.

Still waiting for a direct reply to post #31 without runaround.

Post #31 is off-topic.

See #28 (http://cr4.globalspec.com/comment/796019/Re-Einstein-Clocks-and-the-Sagnac-Effect)

and #24 (http://cr4.globalspec.com/comment/795266/Re-Einstein-Clocks-and-the-Sagnac-Effect)

If there is anything in there that's not clear, please ask a specific question related to those posts.

One more time: is there anything in

http://cr4.globalspec.com/comment/796019/Re-Einstein-Clocks-and-the-Sagnac-Effect, or

http://cr4.globalspec.com/comment/795266/Re-Einstein-Clocks-and-the-Sagnac-Effect

that you do not understand?

Yet our clocks measure light as isotropic in the rotating frame of the earth without any adjustments. Then simply because you change altitude you say they cannot be synchronized, yet they are highly synchronized with clocks on earth. If all clocks on earth show light to be isotropic then GPS clocks should as well since they are synchronized in the same ECI frame. If GPS clocks show the sagnac affect then clocks on earth should as well, since they are all in the same ECI frame.

"Yet our clocks measure light as isotropic in the rotating frame of the earth without any adjustments."

Who told you such nonsense? For the benefit of other readers, who have actually read what was written before:

Globally, we apply the Sagnac correction for clock sync in Earth's rotating frame and that does not yield isotropic light propagation. In laboratories, we can synchronize clocks the Einstein way and we will get isotropic light propagation by definition, due of the clocks sync scheme that we used in the lab. However, we cannot string such laboratories around the globe and expect the clocks to agree at the point where we complete the circle.

"Then simply because you change altitude you say they cannot be synchronized, yet they are highly synchronized with clocks on earth."

Aircraft and satellites are in different rotating frames than Earth's (geoid) surface. Without adjustment of their inherent rates, we cannot perfectly synchronize their clocks with Earth clocks.

"If all clocks on earth show light to be isotropic then GPS clocks should as well since they are synchronized in the same ECI frame."

Misrepresentation or ignorance? There are no clocks in the ECI frame. Let us know if you find one.

No clocks in the ECI frame?

http://books.google.com/books?id=DH7jEf48KjgC&pg=PA13&lpg=PA13&dq=are+gps+clocks+set+in+the+eci+frame&source=bl&ots=A9WrR47QKq&sig=d3HxCnNtwv-fJZWc2RZ1alMQVkY&hl=en&ei=fl7KTujPK-642QXHq5ziDw&sa=X&oi=book_result&ct=result&resnum=3&ved=0CE0Q6AEwAg#v=onepage&q=are%20gps%20clocks%20set%20in%20the%20eci%20frame&f=false

http://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=ADA357062

Can post a few more if you need them.

SJW, try to comprehend in context. From your first ref:

As mitigation, I must say that the paragraph starts with a confusing statement, which is only clarified later. In any case, there are no clocks in the ECI frame, only 'fictitious' ones, used in calculations. Those imaginary clocks can be Einstein-synchronized, because light propagation is isotropic in the ECI frame. The real clocks sit in the ECEF frame, subject to the Sagnac effect and light is not isotropic there.

From your second ref:

"The ECI frame moves with the Earth but maintains its orientation with respect to the distant stars."

By definition, it orbits the Sun with Earth, but it does not rotate.

Semantics are often the enemy of science, because it is imprecise. "Clocks are synchronized" is often used to only mean "clocks are Einstein-synchronized". However, it can also be stated the GPS clocks are synchronized to the master clock cluster in Boulder, while they can obviously not be Einstein-synchronized, since they are all in rotating frames of reference. Such semantic difficulties cause a lot of the confusion in relativity.

So your calculations are based upon fictitious clocks in the ECI frame, therefore any results from those calculations read time in the ECI frame whether you like the idea or not. You cannot base your calculations on the ECI frame then claim it doesn't apply. Stop with the smoke and mirrors already. Doubletalk is all it is.

Not my calculations. Your GPS receiver does the same thing (e.g. for orbit deviations of a specific satellite) and then it transforms the values to the ECEF frame where you, me and most real clocks sit (some are in flying aircraft, which are not strictly in the ECEF frame).

But what has it to do with this thread? This one is about 'absolute frames', not GPS.

In your end-note: "However, if they were to do a relative clock synchronization during the test, they will find their clocks to be out of sync with each other by vL/c². Wang's test does not adjust them now, but use those readings to find a 'difference in the speed of light'. As shown above (and by Wang), those differences cancel out, thus defeating the purpose of the test. It essentially becomes a "two-way" speed of light test."

This does not make sense to me. I suppose they have GPS receivers on board and all GPS receivers are supposed to have clocks running at the same rate. Why would they now be out of sync in the two aircraft?

Further, you said that Wang's calculations are correct, but he finds that the vL/c² time differences add up, not cancel. Please clarify this.

My endnote was a bit cryptic, sorry about that. The topic is slightly complex, but I'll try to be brief and as clear as possible.

"I suppose they have GPS receivers on board and all GPS receivers are supposed to have clocks running at the same rate."

Yes, within the accuracy required by GPS, they run at the same rate, even if they are at low altitude and at low speed (not something like low Earth orbit - too high and too fast).

"Why would they now be out of sync in the two aircraft?"

Ground station clocks (and aircraft on the runway) are not synchronized in the (ECI) inertial frame; they are synchronized in a (ECEF) rotating frame, taking into account the Sagnac effect caused by Earth's rotation. The speed of light is not isotropic in this frame, nor is it isotropic in the rotating frame of Wang's two aircraft. If they try an 'Einstein clock sync check', using light/radio beams, their clocks will show an additional sync offset, proportional to their separation and ground speed, as predicted by the Sagnac effect.

"Further, you said that Wang's calculations are correct, but he finds that the vL/c² time differences add up, not cancel. Please clarify this."

In Wang's complete thought experiment, the difference in time adds up to 4vL/c², which you will notice does not include any c±v terms or factors. Hence the "one-way speed of light as 'measured' between his two aircraft" cancels out and disappears from the calculations. Just like Galileo and Einstein would have predicted.

In fact, the 4vL/c² is not exact, but for aircraft speeds, the second order effect (v²/c²) is so small that special relativistic effects are utterly negligible. It is effectively just a Galilean effect that we need to consider.

-J

Apart from what S pointed out in #24, your Sato link simply states a known fact - that the GPS satellite clocks are offset by the full general relativity suite (velocity and gravity, relative to Earth). They are hence not "ideal clocks" orbiting at 20,000 km altitude. This is exactly why there is no Lorentz contraction or time dilation observed when using GPS - it has been taken care of in the clock rates already - part of the specific GPS clock sync protocol.

This often misunderstood fact is the source of many a misconception...

No, there has been no Lorentz corrections at all, that is where you are mistaken.

Sato's conclusion, chopped into more paragraphs for readability:

"6. Conclusion

The GPS, which constructs the local gravitational system, is considered in the absolute stationary state. The isotropic constancy of the speed of light, c, is sustained. There is no Lorentz contraction detected.

The GPS precisely works in the ECI coordinate system. If only the theory of special relativity is applied to the interpretation of the GPS experiment, the deviation on the car navigation system by the Lorentz contraction of 700 km/s in the CMB is maximally estimated as 54 m. However, there is no such deviation.

The gravitational field drags the relative permittivity, ε_r, and permeability, µ_r, around the earth. Furthermore, the theory of general relativity should be taken into consideration. The GPS should be interpreted by the theory of general relativity as well as special relativity."

Sato: "There is no Lorentz contraction detected".

Of course not, what did he expect? Only an observer stationary in the CMB frame would have observed Lorentz contraction of the type Sato discussed.

Sato: "The GPS should be interpreted by the theory of general relativity as well as special relativity."

It is. All relevant relativistic corrections for the GPS are included in the system. Sato was barking up an empty tree.

P.S., I almost forgot: Sato's example must rate close to the no. 1 "absolute frame fallacy".

Yet you just contradict yourself as previously you posted: "This is exactly why there is no Lorentz contraction or time dilation observed when using GPS - it has been taken care of in the clock rates already - part of the specific GPS clock sync protocol."

So you say its taken care of in the clock rates already and they say its not observed.

Smoke and mirrors.

If you still see it through "smoke and mirrors" it must mean that I have completely failed to teach. Sigh...

Where to start now (at this late stage)?

The first thing that I'm sure you realize is that velocity time dilation and Lorentz contraction go hand in hand - if you have the one, you have the other. So the fact that one of the components of the 'tuning' of the GPS satellite clock rate is for velocity time dilation relative to the ECI frame, it means that Lorentz contraction relative to the ECI frame has also been taken care of ('tuned out').

The second thing is that Lorentz contraction is just observable between two frames in relative motion, each with perfect free-running clocks, Einstein-synchronized in their own frames respectively. Hypothetically, we can put an observer with a system of such clocks in the CMB frame (as used in cosmology). Such an observer will observe time dilation and Lorentz contraction in our ECI frame and we will observe the same in his frame. No side actually Lorentz contracts - it is just an observed effect, never absolute.

Let's use Sato's example of 700 km/s for Earth's movement relative to the CMB, together with an ensemble of CMB frame observers, whom Earth just happened to pass by. They will observe Earth's diameter as Lorentz contracted by some 35 m in Earth's direction of travel relative to them. This is in the sense that if we told them that we have measured Earth's diameter as (say) 12,740,000 m, they would get 12,739,965 m, using their own set of synchronized clocks and distance markers.

Likewise, if they had claimed their spaceship to be 12,740,000 m long and we measure it passing us length-wise, we would have measured that thing as 12,739,965 m long, using our own set of synchronized clocks and distance markers. There is absolutely no magic or smoke here: the differences are simply caused by both sides adopting Einstein's clock sync method for inertial frames - which is not mandatory, but simply the best.

In the GPS, a different sync protocol has been adopted, because we are not working in a purely inertial system with free-running clocks, so we use what is best for this case. All GPS clocks are "disciplined" to agree with the time of the majority, irrespective of whether they are in orbit or sitting on the ground - a true time-democracy.

If this does not clear the smoke somewhat, we must restart somewhere else.

-J

Yet that still does not explain why I have to specifically choose two different starting points and ending points to get 1) length contraction and 2) time dilation. If I choose the same starting point and end point I get time contraction and length contraction or time dilation and length dilation, depending on which point you start your measurement from. You must purposely choose opposite starting and ending points for each, not the same which is totally inconsistent. I measure the front of the rod and then the rear of the rod to get length contraction. But to get time dilation I measure the rear of the rod and then the front of the rod. It can never be done the same way, ever. Smoke and mirrors.

Still "smoke and mirrors"?

This seems to be true only for "absolute framers" (AFs). In fact, you have just provided a better argument against an absolute frame than what I could have dreamt up. Good answer!

You see, special relativity (SR) defines simultaneity in a way that completely removes the inconsistencies that AFs are faced with. Once clocks are Einstein-synchronized in every inertial frame, no one cares from which reference point you measure distances or whose clock you are using. Everything stays consistent, provided that you apply SR correctly. It goes without saying that you must understand SR before using it.

Not so easy for the AFs. Remember, they do not Einstein-synchronize their clocks, so they must first of all know how fast that rod of yours is moving relative to their AF, whatever that may mean. Then they are faced with the observable anisotropy of light propagation in various directions, making every calculation for high speed a thriller. Can you think what the radar equation for relativistic speeds must look like in an AF-world? Possible, but extremely messy…

This is why AFs nowadays employ the Lorentz transformations, i.e., they use the modern version of Lorentz ether theory (LET), with Lorentz transformations. This makes LET (observationally) indistinguishable from SR. AFAIK, some inconsistencies still pop up in LET if you are not carefully orchestrating your reference point - also a serious drawback, from which SR sets you free.

Then there is the problem of making LET consistent with all the various gravitational tests that support general relativity (GR, which fully embodies SR). AFAIK, Ronald Hatch has tried with his modified LET (MLET), but failed (at least no one else uses it). All of this while GR is completely consistent and everyone use it.

I find this dialogue interesting, but as we have seen, the CR4 readership is getting bored. So maybe we should consider our closing arguments and let the jury go out to decide.

You keep on referring to a rod with some A and B ends, which I never mentioned and then you ask me: "Why do you find it necessary to pick two seperate starting points to measure the same rod?"

If you have referred to the Justin Jacobs "treatise" 'Relativity of Light', then ask him. I do not read that kind of quackery and hence cannot comment on it.

In a proper treatment of relativity, you can choose either point A or point B, whatever they are, as reference and you can do all your calculations in that frame. Then pick the other one as reference and you will get the same results. Simple.

If you have a problem, please state it clearly, and without requiring our readers to consult a cranky document. If you cannot clearly state the problem yourself, then this conversation will be over.

Duly reported.

Because you never pick the same frame as a starting point to get your time dilation and length contraction. You say you can choose either yet you know this is not true. If you start your length measurement in frame A you must start your time measurement in frame B, all choice is taken away. If you choose frame A for both starting points you get length contraction and time contraction, not dilation.

For the benefit of readers who may be confused by these hand-waving arguments that make little sense. SJW wrote about "time contraction".

Such a thing is not defined in SR and LET. There are Lorentz contraction and velocity time dilation, as defined in the Lorentz transformations (LTs), that's all.

To be precise, we must specify whether we are talking about the LTs in the standard configuration (SC), or in general. In the SC the origin of the two inertial frames coincide at time t=t'=0 and the relative movement is along the x-axis. Here we are concerned with just v, x,t and x',t' and things are simple.

In general, we may have different origins and the movement may be in any relative direction, so we are forced to work with more complex mathematics. But, everything stays consistent - all inertial reference frames are still equivalent, if we know what we are doing.

Yes if you know what you are doing by confusing people so they don't know what's up or down. But you and I both know they do not choose they same starting point on the rod to get length contraction and time dilation. Call it hand waving, whatever, but you know it is impossible for you to choose the same starting point on the rod for both measurements. You claim you have the freedom to choose when in reality you are forced to choose different ends of the rod to take your measurements so the results end up to be what you want. Smoke and mirrors and sleight of hand.

How you must measure different ends to get your results

How you do not even apply the Lorentz equations consistently

You may of course claim slight of hand and I agree, you apply it quite well. You must divide one and multiply the other. Choose one starting point for one and a different starting point for the other. And then you have the nerve to claim I am applying sleight of hand. That's a good one, lol.

I think the CR4 readership may understand better if they know where SJW's superior knowledge comes from. He regularly quotes (like the two links above) out of a website titled "Relativity of Light" by Justin Manning Jacobs. The synopsis is already quite something. I quote:

"SYNOPSIS OF THE TREATISE

This treatise will demonstrate in great detail that Einstein's Special Theory of Relativity was based on several false premises, and why such Special Theory and its mathematical consequences are physically invalid. It will also demonstrate that, in fact, there are no experimental confirmations of Special Relativity and its consequences, and that other mathematical theories which purport to confirm Special Relativity and its consequences are themselves either highly dubious, unconfirmed or invalid. Finally, it will disclose and explain answers to many paradoxes of phenomena that have baffled the scientific community for decades."

In a way entertaining, but use with discretion.

Facts are facts, you may choose to ignore them as you will. I do not disagree with all of GR or SR, but parts of it are clearly in error. Anyone who believes a theory is perfect without needing any revision from the day it was first conceived is deluding themselves.

Let me ask two simple questions that will solve the issue.

1) Does anyone here disagree that the GPS clocks show light is isotropic in the ECI frame, i.e. it travels at c?

2) Now, before the clocks were adjusted does anyone believe that they also showed light to be isotropic?

According to SR and GR all inertial frames will show light to be isotropic. Do you actually believe that they showed light to travel at c both before and after adjustment? if I choose the GPS as a frame of reference they show light to be isotropic in the ECI frame which they are part of, but only after adjustment. So it is not with respect to the receiver and its velocity, but with respect to the frame chosen. Yet SR demands it be isotropic on the receiver, yet the receiver's frame shows this is false until it is adjusted to the ECI frame.

In retrospect, post 2 seems prophetic. I would opt for closing this thread.

As the timekeeper kid on the IgNobel Awards chants, "I'm bored, please stop" [Repeat....]

True

My own Blog threads I have closed, so there will be less distractions, I hope.

This one is up to CR4 admin. Will talk to them if it gets out of hand.