http://www.geocities.com/sciliterature/RelativityDebates.htm

Interesting that none of the "million debunkings" have withstood the test of time or even experiment...

There are millions of debates, but debunkings, nah!

-J

Hi,

The problem with the relativity of simultaneity is not Einstein's conventions. That's fine. The problem--as is becoming increasingly clear--is that he was an advocate of "natural" mathematics (now known as "constructivism" in mathematics) and that he used it to embed a logical anomaly in the relativity of simultaneity. This wasn't nefarious--he actually did believe constructivism was necessary, as he plainly said. Such insertions--for example, the "natural" coincidence anomaly in the relativity of simultaneity--are not conventions. They are arbitrary and have no logical relation to the argument at all--that is, they are not hypotheses, assumptions or definitions.

It is "natural" coincidence which deprives the relativity of simultaneity of logical content. That's the way Einstein thought it had to be. However, if you are interested in scientific arguments with logical content, this will cause you problems.

We are only now--largely because of a renaissance in the historiography of set theory (see references in the paper below)--able to see precisely where Einstein inserted this logical anomaly in the relativity of simultaneity. It's identified in the paper.

Note that Einstein was not the only non-mathematician major twentieth-century figure seduced by the apparent suitability of constructivism for the expression of scientific ideas!

But an understanding of constructivism does bring the reign of relativity to an end. Sorry about that, but dreams do come to an end.

I strongly recommend you read Garciadiego's now-classic account of the murky origins of set theory which so influenced Einstein (although, as I suggest, Einstein imbibed "natural" mathematics--which seems to have been around since Aristotle--from sources other than Poincare).

Ryskamp, John Henry, "Paradox, Natural Mathematics, Relativity and Twentieth-Century Ideas" . Available at SSRN: http://ssrn.com/abstract=897085

Hi,

The problem with the relativity of simultaneity is not Einstein's conventions. That's fine. The problem--as is becoming increasingly clear--is that he was an advocate of "natural" mathematics (now known as "constructivism" in mathematics) and that he used it to embed a logical anomaly in the relativity of simultaneity. This wasn't nefarious--he actually did believe constructivism was necessary, as he plainly said. Such insertions--for example, the "natural" coincidence anomaly in the relativity of simultaneity--are not conventions. They are arbitrary and have no logical relation to the argument at all--that is, they are not hypotheses, assumptions or definitions.

It is "natural" coincidence which deprives the relativity of simultaneity of logical content. That's the way Einstein thought it had to be. However, if you are interested in scientific arguments with logical content, this will cause you problems.

We are only now--largely because of a renaissance in the historiography of set theory (see references in the paper below)--able to see precisely where Einstein inserted this logical anomaly in the relativity of simultaneity. It's identified in the paper.

Note that Einstein was not the only non-mathematician major twentieth-century figure seduced by the apparent suitability of constructivism for the expression of scientific ideas!

But an understanding of constructivism does bring the reign of relativity to an end. Sorry about that, but dreams do come to an end.

I strongly recommend you read Garciadiego's now-classic account of the murky origins of set theory which so influenced Einstein (although, as I suggest, Einstein imbibed "natural" mathematics--which seems to have been around since Aristotle--from sources other than Poincare).

Ryskamp, John Henry, "Paradox, Natural Mathematics, Relativity and Twentieth-Century Ideas" . Available at SSRN: http://ssrn.com/abstract=897085

Hi jrysk:

I read the paper you cited. I assume you are the author. No offense intended, but I found it to be a rambling, incoherent screed. The paper never defines what it means by natural mathematics, nor identifies which specific purported paradoxes or coincidences are supposedly so troubling. Or exactly what is wrong with Einstein's work. I for one am not seeking further explanation, because in light of the number of words already thrown at the subject with so little effect, more words are likely only to take me deeper into the realm of crackpot-ism.

Jon

I don't think you know any history of mathematics, but you should read some, because developments in the history of mathematics had tremendous influence on Einstein. If you knew anything about the history of set theory, you would have no question about what "natural" mathematics is. Don't blame your ignorance on me--educate yourself. I can't do it for you. You can read P. Maddy's book, Naturalism in Mathematics. That's a good summary. Just because you are ignorant, doesn't mean I'm a crackpot.

Also read Garciadiego's book. Also works on constructivism (the latter-day incarnation of "natural" mathematics) by Troelstra. All these were cited in the paper. You're just too glib and hasty to pay attention.

So just educate yourself. And dispense with flippant remarks. You don't know what you are talking about, and you've waded into an ongoing scholarly discussion like an idiot. Very embarrassing--to you.

Hi jrysk,

I apologize for using the word "crackpot." However, if your paper is intended to be intelligible only to specialists who've read 2-3 books on this arcane subject, then it strikes me as too broad-brush, argumentative and lacking substance. For example, the paper poses dozens of repetitive and seemingly rhetorical questions without providing justification for the questions' premises and without answering them. That writing technique is unpersuasive.

If the paper is intended as an introductory overview of the subject, then it falls short of crisply explaining the underlying theory, background and specialized terminology. The paper also rambles incoherently from subject to subject.

Sorry...

Jon

Hi jrysk,

I apologize for using the word "crackpot." However, if your paper is intended to be intelligible only to specialists who've read 2-3 books on this arcane subject, then it strikes me as too broad-brush, argumentative and lacking substance.

NO, YOUR PROBLEM IS THAT YOU SIMPLY REFUSE TO READ ANYTHING. YOU THINK YOU KNOW EVERYTHING. IT'S RIDICULOUS. YOU ARE PRESUMING TO TALK ABOUT RELATIVITY, BUT THERE IS NO QUESTION THAT THE MOST IMPORTANT TOPIC IN RELATIVITY STUDIES TODAY IS EINSTEIN'S EARLY INTELLECTUAL ORIENTATION. FOR JUST ONE EXAMPLE, READ STACHEL AND HOWARD, EDS., EINSTEIN THE FORMATIVE YEARS. THEY ARE BOTH WELL-KNOWN HISTORIANS OF SCIENCE. ARE THEY 'SPECIALISTS WHO'VE READ 2-3 BOOKS ON THE SUBJECT?'

YOU'RE JUST RIDICULOUS. WHAT ARE YOU, A LITTLE PRINCE SOMEWHERE?

For example, the paper poses dozens of repetitive and seemingly rhetorical questions without providing justification for the questions' premises and without answering them. That writing technique is unpersuasive.

ALL THE QUESTIONS POSED ARE THOSE WHICH SEEK TO RELATE THE ARGUMENTS OF THE AUTHORS--WHETHER GODEL, KIMURA, EINSTEIN OR SRAFFA--TO THE NATURAL MATHEMATICS BACKGROUND THEY BOTH SHARED AND SOUGHT. DON'T FORGET--THESE ARE THE NON-MATHEMATICIANS IN SEARCH OF MATHEMATICAL EXPRESSION FOR THEIR IDEAS. THEY TOOK THE RISK, THEY WANTED THE REWARD. IF IT DIDN'T PAN OUT BECAUSE THEY DIDN'T DO THEIR HOMEWORK--DIDN'T LOOK INTO THE FOUNDATIONS OF THE MATHEMATICS IN WHICH THEY CHOSE TO EXPRESS THEIR IDEAS--WELL THEN THAT'S JUST TOO BAD FOR THEM.

SO WHAT YOU ARE TELLING ME IS NOT ONLY DO YOU REFUSE TO LEARN ANYTHING NEW, BUT ALSO, YOU'VE NEVER READ ANYTHING BY KIMURA OR SRAFFA. SO WHAT YOU'RE TELLING ME IS THAT YOU DON'T REALLY KNOW ANYTHING ABOUT THE INTELLECTUAL HISTORY OF THE EARLY TWENTIETH CENTURY, THE MILIEU IN WHICH EINSTEIN DEVELOPED. AND YET YOU PRESUME TO SAY SOMETHING ABOUT EINSTEIN.

WHY NOT JUST GET OFF YOUR TUFFET AND SAY, 'GEE, I DIDN'T KNOW ANYTHING ABOUT THE HISTORY OF EINSTEIN'S MATHEMATICAL ORIENTATION. I'LL LOOK INTO IT.' BUT NO, YOUR ROYAL HIGHNESS IS JUST TOO VAIN. HOW SILLY.

If the paper is intended as an introductory overview of the subject, then it falls short of crisply explaining the underlying theory, background and specialized terminology. The paper also rambles incoherently from subject to subject.

HOW WOULD YOU KNOW IT FALLS SHORT OF ANYTHING, SINCE YOU HAVE NOT READ THE WORKS OF THE AUTHORS UNDER DISCUSSION, NOR ANY OF THE LITERATURE DISCUSSING THOSE WORKS.

DON'T WRITE ANYTHING MORE ON THIS SUBJECT UNTIL YOU HAVE STUDIED THE HISTORY OF SET THEORY EXTENSIVELY. READ GARCIADIEGO'S BOOK, THEN READ POINCARE'S SCIENCE AND HYPOTHESIS, WHICH HAD SUCH A TREMENDOUS INFLUENCE ON EINSTEIN. AND WHAT EXACTLY WAS THAT INFLUENCE? LET'S HEAR YOU TALK ABOUT THAT. IS POINCARE ALSO SOMEONE KNOWN ONLY BY '2 OR 3 SPECIALISTS?' WELL IF IT IS, YOU'RE SURE NOT ONE OF THEM. BECAUSE YOU'RE AN ANTI-INTELLECTUAL GOON. I FEEL VERY SURE YOU'VE NEVER READ SCIENCE AND HYPOTHESIS. TELL ME I'M WRONG.

RIDICULOUS RIDICULOUS RIDICULOUS. WE'RE IN THE MIDDLE OF A VERY SERIOUS REASSESSMENT OF THE MATHEMATICS UNDERLYING THE RELATIVITY OF SIMULTANEITY, AND ALONG COMES AN UNEDUCATED CLOWN LIKE YOU. DON'T EMBARRASS YOURSELF FURTHER.

Sorry...

YOU'LL BE SORRIER STILL WHEN YOU REALIZE YOU HAVE EGG ALL OVER YOUR SELF-SATISFIED THUG'S FACE.

Hi jrysk,

It was not my intent to attack the field of philosophy of mathematics. It seems to be a very interesting subject, particularly when examining great historical thinkers in the context of the developing ideas of their times. I would note, however, that the subject matter of this website is physics, not philosophy. (I suppose that observation will only lead to hair-splitting debates about whether the philosophy of mathematics is more like philosophy or more like math. Sigh.)

I see that I am not the only one you've critisized for being uneducated on this arcane subject. You accuse various published authors in this field of the same sin: http://www.amazon.com/gp/cdp/member-reviews/A4J6ZABMYLANK/ref=cm_cr_dp_auth_rev?ie=UTF8&sort%5Fby=MostRecentReview

In any event, as I said it was not my intent to specifically critisize the subject matter. Rather, I intended to critisize only the poor writing which renders your paper and accompanying posts rambling and unintelligible. I'll read some more about philosophy of mathematics, and you can take a critical writing course.

Jon

This it is a REAL debate ......please get deeper...

This it is a REAL debate ......please get deeper...

Hi I'm back. I haven't been here since August, not because I was basically told to stop posting (although I don't understand why nobody posting anything is preferable to me posting something), but because work has been really busy and I reserve my Relativity time to working hours only.

I'll just spend my time here responding to these blog entries.

Question 1 about the train/platform thought experiment. In the Brian Greene course I took on WorldScienceU, it is stated that the observer on the platform is able to peer into the future of a passenger riding at the back of the train approaching the light source and into the past of a passenger riding at the front of the train which is moving away from the light source. This is backed up by the slanted x' axis of the spacetime diagram which depicts all events in space on the x' axis line as being simultaneous from the x' axis perspective. So when receding from the lightsource, the x' axis includes a time that is past from the x axis (set as stationary) perspective as being simultaneous with the x' axis present. Similarly, when the rear passenger is moving toward the light source, the x' axis is tilted to include the passenger's future with the stationary observer's present.

Now the interpretation of this from the professor and his toadies on that forum is that the platform observer is able to see the light hit the rear passenger's eye "before" the rear passenger sees the light from his own perspective on the train. In essence, the platform guy is able to peer into the rear passenger's future. This is all just fine, according to them, because past, present and future are all equally real and concurrent.

I don't buy this for a second. I can't see how causality can be violated. I think the light hits the rear passenger simultaneously as the platform guy sees the light hit the rear passenger but because of the time dilation between the two frames, the time on the platform's clock is advanced relative to the time on the rear passenger's clock. There's no looking into the future of an event that hasn't happened yet from the train's perspective. How does one correctly interpret the spacetime diagram to disprove what they're saying?

Welcome back, Ralf!

This is a bit of a 'dead thread' resurrection (from ca. 2008) and people tend to unsubscribe from it, so replies do not get a wide audience. It is always better to start a new thread, where it gets some visibility again and people tend to subscribe (or even participate) if it sounds interesting.

If you give me a link to the Brian Greene forum thread, I will try to pick up some context and reply more fully. For now, I think they are probably perfectly correct, but may be playing 'word-games' to make it sound more interesting that it actually is...

-- J

worldscienceu.com . I don't really want a wide audience because, well, there's bad feelings between me and them.

Ralf, I just want to state two provisos: I will not go into a dialogue with any anti-relativist. You either want to learn proper relativity and digest/question what I offer, or I'm not interested. My experience is that to try and analyze every scenario and try to correct all the "wrongs" in anti-arguments leads to endless circular argument that leads nowhere - thus a complete waste of valuable time.

Secondly, 'private teaching' is not offered. We discuss it on an open forum where either more people can contribute, or more people can benefit. I will look at your scenarios and formulate the main problems with them in a new thread. Then you can either participate or not, taking into account my first proviso.

-J

Understood.

http://www.worldscienceu.com/courses/6/elements/DlA1UO

worldscienceu.com courses special relativity the reality of past,present, future module 14

Question 2 on the train/platform thought experiment. The propagation and speed of light through a substance depend on the substance's values of permeability and permittivity. A lack of substance cannot have values so space is indeed a substance just like water or glass. Light will propagate slower through those substances because the permittivity and permeability values are higher. The formula for the speed of light shows that light is an electromagnetic wave propagating through an electromagnetic medium much like the speed of a mechanical wave propagates through the inertia and elasticity of a mechanical medium. Why people assumed light has no medium because it is electromagnetic instead of mechanical is beyond me.

Further,the Fizeau experiment showed that the speed of the medium must be added, using relativistic velocity combination, to the speed of light through that medium. So, that said, I want to know if you agree that the results of using an open flatbed train would differ from the results of using an enclosed train, where the air is stationary in relation to the light source, by the relativistically combined velocity of the train?

Question 3 on the train/platform. Consider 2 light sources, one on the middle of the train and one on the platform that both light up at their closest approach to each other. From the rear passenger's perspective, the light on the train has further to travel to reach him than the light from the platform because he is moving toward the light on the platform. So he will see the platform light before he sees his on-board light even though both lights must behave as a single light with the same speed. So the rear passenger can't see the platform light first even though he is actually closer to it. I feel understanding what's happening in this example is the essence of understanding relativity.

Ralf wrote: "Consider 2 light sources, one on the middle of the train and one on the platform that both light up at their closest approach to each other. From the rear passenger's perspective, the light on the train has further to travel to reach him than the light from the platform because he is moving toward the light on the platform."

I understand your questions 1 and 2, but 3 seems absurd. Two light flashes that happen simultaneously in the same space location is one and the same spacetime event, whether one source is moving relative to the other or not. All observers in the universe will measure the two flashes as simultaneous and co-located.

What is the hidden agenda for having two flashes?

The hidden agenda is this. The passenger on the train doesn't need to know he's moving. The light on board the train has a half train length to travel to reach him no matter what his velocity. The light outside the train has vt less distance to travel. The speed of light is constant for both frames of reference so in order for both lights to hit him simultaneously from his perspective, he must know that time is moving slower outside his window so that it takes longer for the light to travel a shorter distance in order for the speed of light to be constant in that frame.

I'm confused what the platform guy saw. He must've known the train light had further to travel from the start. He also knows the time on the train is slower than his from his perspective.But both lights must hit the rear passenger simultaneously and the platform guy is seeing light take longer to travel a longer distance. Doesn't this mean the speed of light is slower on the train from the platform guy's view of the train's timeframe? I'm confused, I'll get back to you Monday.

Ooops I just realized how dumb I've been. The light is not travelling the full half length of the train from the rear passenger's perspective. Can I delete question 3 and my reply?

Unfortunately this is only possible in the first 15 minutes (your editing window). Thereafter you can only retract statements etc.

Here is a partial response to your scenarios. I will use this later in a new thread as a complete summary of problems and relativity solutions.

Maybe you are confused because of a poor statement of the problem. You have two inertial frames in the problem, the train frame and the station frame. You have two light flashes, the train flash and the station flash, happening simultaneously AND co-located in both frames (a very important point).

It is confusing to talk about "what does the train observer see?", or "what does the station observer see". Correct 'relativity speak' is "how do observers in the respective frames observe the progress of the light from the two flashes?" Provided that each frame's clocks are correctly synchronized (yet differently for each frame, because the frames are in relative motion^[1]), each frame's observers will find the light to propagate precisely in an isotropic fashion around the flashes, i.e. at c in all directions.

How do these observers, who are static in their respective frames and at a specific spatial coordinate, 'find' this fact? They simply record the time on their clocks when they see the flashes. Note that each observer on the train and on the station will see the train flash and the station flash happen together - it is as good as one flash. Later, at the debrief, they will find that the time of observing the flashes is exactly compatible with light propagation at c in all directions. And this holds for both frames.

This is usually where readers get confused and start thinking about why it cannot be like this. The answer is usually a 'shock and a let-down' - it is so because we ensured the outcome through the way in which we synchronized the clocks for each frame, assuming light to propagate isotropically in every inertial frame to start with.

Some people react to this with "cheating!", but there is nothing more to it. And BTW, the train and stain clocks are not recording different times due to time dilation and/or Lorentz contraction - it is a synchronization offset that is applied to the two sets of clocks; it is not even 'relativistic' in the usual sense, because it is a linear effect.^[2] It is simply the best convention for clock sync ever invented and it works perfectly in relativity. It makes proper physics as simple as it can be. ;)

-J

Notes

[1] In any inertial frame, you send any electro-magnetic signal to bounce of each observer (radar style) and find the round-trip time delay. Half that delay and you have the propagation delay for each observer to set his clock time. Now you send one time-stamped signal and each observer adds his delay to the time stamp when he receives it and set his clock accordingly.

[2] The sync offset between clocks in different frames is ΔT = ±vD/c², where v is the unsigned relative speed and D is the signed displacement between the clocks in the direction of movement.

i've always had a problem with understanding the deeper significance of your words. I tend to take them at face value and re-interpret them to suit me. For example I don't see it as a cheat to use light to synchronize clocks if you know beforehand that the speed of light is constant for all frames. But maybe Einstein didn't know that before he set his convention and because his convention didn't violate the experimental results, he felt that justified his convention.

The classic myth behind Einstein coming up with the theory of relativity is that he wanted to explain the results of the Michelson-Morley experiment and how the speed of light can be constant for all moving frames. I think the significance of your words is that history has it backwards, that the Michelson-Morley results had no more to do with Einstein formulating SR than the orbit of Mercury had in him formulating GR. I think he started with the Lorentz equations and his big insight was to strike out the words absolute motion and replace them with relative motion. History has it that his big insight was in order for the speed of light to be constant in all frames, then time and space must not be absolute. I think that fell naturally out of his joining Lorentz with relative motion. The experimental results didn't inspire the theory, the theory ended up not violating the experimental results. Hence using light to synchronize clocks to come up with the idea that the speed of light is constant for all frames could have been wrong except for the fact that it is independently supported by experiment. Is that what you were saying?

You wrote: "Hence using light to synchronize clocks to come up with the idea that the speed of light is constant for all frames could have been wrong except for the fact that it is independently supported by experiment. Is that what you were saying?"

I think the point that you miss (or which I miscommunicate) is that the one-way speed of light is simply due to the Einstein clock synchronization convention and cannot and has never been experimentally determined. We can only determine the two-way speed of light, where only one clock is used - hence no synchronization convention required.

We then synchronize clocks so that it also holds for the one-way speed - i.e. we 'force' the one-way speed of light in vacuum to be c. Its the theme of this very thread. Without this realization, SR (as simple as it is) will always seems to have 'mysteries' and apparent paradoxes (where there is none).

-J

I'm not getting the deeper significance of the unmeasureable one-way speed of light not being the same as the measureable 2-way speed of light. If it's unmeasureable, how does it make any difference if the 2 are not the same? Are you just correcting the precision of my statement or am I missing some epiphany that will make everything clear to me?

Oh and what about the bulk of my post, do you think history has it wrong on how Einstein came up with the theory?

We choose to synchronize clocks to make the one-way speed of light the same as two-way, simply because relativity is then simpler. We are free to choose a different clock convention, where the one-way speed of light is not c, but it complicates the mathematics of all physics horrendously.

On you second point, I have little to no interest in the history or the priorities of relativity. I once read through it all and thereafter concentrated only on the modern interpretations and developments. So, no comment.

Ok, can I move on to the length contraction is real thread or should I wait?

Feel free, but I would have appreciated a new thread and not another 'resurrection of the dead'!

Ok, any preferred name like, "Length contraction is not real and don't ever mention it again." That should get people interested.

Just one more point about clock sync. Can't the receiver of the clock just bounce the signal back and the guy at the origin can verify that the receiver got it at half the round trip delay? Isn't that using a single clock and two way speed of light? I can't remember if you mentioned this or not.

It will be fine to grab attention, but it might immediately destroy credibility because it begins with what borders on a false statement. Lorentz contraction is a measurable phenomenon, but it just happens to be frame dependent, i.e. it is not an absolute effect. The other problem is that the idea of "real" is not absolutely definable and lends itself to endless philosophical chatter.

On clock sync: no, unless we have sync'd the distant clock to the transmitter clock beforehand, its time stamp would be meaningless. You see the problem?

I'll call it "Realativity, what parts of relativity are real?" I chose to define reality as something that remains invariant across all frames. Length contraction, as you said, is an observational phenomenon that does not endure in the reference frame once it is brought into the reference frame by removing the relative velocity. There's not one example of the effects of length contraction (as listed in Wiki) that can't be explained by time dilation. Feynman was also out to lunch when he used length contraction to explain quark collisions. One can derive the length contraction formula from the time dilation formula so why even bring in the redundant concept of length contraction, they're the same thing. However, you said time dilation is also not real (because both frames see time dilation in the other) but using the criteria of the twin paradox, one can measure an age difference consistent with time dilation that remains once the relative velocity ends. Relativistic mass is also not real because it does not endure once the relative velocity ends.

Once you get rid of the concept of length contraction, then the concept of the speed of light as the limiting speed of the universe also disappears. What I mean is, total speed is a combination of the speed through time and the speed through space. If space is invariant then as one gets closer and closer to the speed of light, one can travel the length of the universe in shorter and shorter time, way beyond the speed of light (velocity of moving frame = gamma v = proper distance/dilated time of moving frame). All that the speed of light limits is the speed of information transfer to ensure causality. There's more to say, this is just a brief synopsis.

You wrote: "One can derive the length contraction formula from the time dilation formula so why even bring in the redundant concept of length contraction, they're the same thing. However, you said time dilation is also not real (because both frames see time dilation in the other) but using the criteria of the twin paradox, one can measure an age difference consistent with time dilation that remains once the relative velocity ends."

This is the crux of the matter. There is coordinate dependent time dilation and then there is proper time dilation. There is coordinate dependent Lorentz contraction, but there is no proper Lorentz contraction. In this sense, the two are different, not 'the same thing'.

However, Lorentz contraction is real in the sense that when you make a real measurement of the length of a passing spaceship, you get a Lorentz contracted value. In this sense Lorentz contraction is 'real', but then, 'real' means different things to different people - a debate that I have no intention of entering.

As long as you have standard synchrony, i.e. Einstein synchronization of clocks, you have Lorentz contraction and the limiting one-way speed is c. The limiting 2-way speed is c, irrespective of the clock sync convention used.

-J

I'm lost here, totally blank. What you said may be beyond my ability to understand. I can't even formulate a question.

Well, start a thread with some of your interpretations of SR. Firstly, in an open thread with more people participating, you may get more insights than just mine. Secondly. I may be more inclined to spend time on detail explanations when there are more than one person asking questions.

-J

Your proposed title for a thread is good. My advice is to keep it in this sort of tone and and try not to sound authoratative when promoting controversial ideas. This may keep readers interested and not unsubscribing quickly.

-J

Still amazing responses Jorrie. And amazingly Ralf is more tuned now in his newer posts.

Thanks for showing this spirit!

I went back and read my early posts. Boy was I prickly and ignorant. A year from now I'll probably be saying the same thing about my recent posts.

So why not change it now?

Ok I posted my 1st 2 threads, "Relativity: Coming to Terms" and "Relativity: Coming to Terms: Relative velocity and time dilation". I'll be writing a few more such as Relativity: Coming to Terms: The future, Relativity: Coming to Terms: Reality, Relativity: Coming to Terms: gamma Velocity, Relativity: Coming to Terms: Length contraction

Yeah, well done!

One hit the bin and no outcome so far.

I guess most genies go un-noticed because they cannot communicate the validity of their wisdom.

I think the problem here is that some people have a very fixed framework in which they can understand things. New information is sometimes contorted to fit into that framework and then they challenge the validity of the information, rather than the validity of their favored framework.

Ralfcis seems to run into 'trouble' on many forums and I think it is due to the above problem. He seems to quote what he has learned (or read) from what it appears to say after he has forced it into his framework of understanding. It then apparently makes sense to him, but to nobody else.

As you have noticed, I have given up trying to modify his framework - and so have many others, it appears...

-J

Yup I have a framework which you spent many months correcting. I thought that I had interpreted your patient teachings correctly (except for the question I posed on the Physics Forum) but apparently not one thing was correct. So I didn't even last 24 hrs on that forum for having "my own ideas" but it really started out well, I couldn't even keep up with the responses. Relativity is a very orthodox religion where blasphemy is dealt with immediate excommunication. I'll keep going though because I love Relativity and I'll find the answer to my question somewhere, I'm sure.

Ralf, since in order to defend your framework, you quote what I wrote in this Blog on other Forums (and mainly out of context), I respectfully request that in future you first run such quotes past me to check the context. Also as a check that you are not reinterpreting my statements to fit your framework.

As an example, here is a case that you have quoted out of this Blog on PhysicsForums, where it is unclear which were your statements and which were mine.

"You wrote: One can derive the length contraction formula from the time dilation formula so why even bring in the redundant concept of length contraction, they're the same thing. However, you said time dilation is also not real (because both frames see time dilation in the other) but using the criteria of the twin paradox, one can measure an age difference consistent with time dilation that remains once the relative velocity ends."

"This is the crux of the matter. There is coordinate dependent time dilation and then there is proper time dilation. There is coordinate dependent Lorentz contraction, but there is no proper Lorentz contraction. In this sense, the two are different, not 'the same thing'.

However, Lorentz contraction is real in the sense that when you make a real measurement of the length of a passing spaceship, you get a Lorentz contracted value. In this sense Lorentz contraction is 'real', but then, 'real' means different things to different people - a debate that I have no intention of entering.

As long as you have standard synchrony, i.e. Einstein synchronization of clocks, you have Lorentz contraction and the limiting one-way speed is c. The limiting 2-way speed is c, irrespective of the clock sync convention used".

The problem is this quote was preceded with 137 other replies in this thread that set the context. Even if you would have quoted the url of the thread, you cannot expect anybody to read through that lot.

You then asked the other forum members to tell you what I meant in that quote. Can you see the futility of that? So please stop that practice. I will open a new Blog post where we can discuss the questions around that "crux" quote.

-J

Yes futility but in my framework I said where the quote was and if anyone was interested they would have gone back to that thread to check the context. The whole point of my latest writings was to take things discussed in the dead threads out into the rest of the community. I won't do that anymore. I've tried to understand what you were telling me and I can make no headway. Of course, if that quote is the crux I'll do any desperate thing to try to understand it short of reading every book on relativity ever written.

The battles I've gone through have changed me. Ok that's a lie, they've made me aware that I need to change to get the answers I want. This doesn't mean I won't fall backwards into bad behavior from time to time even though I know it's crucial that I don't. I found a physics forum that has the worst of the worst in it. I'm going to enter that to see if I can keep my head under the worst abuse from people who have their own incomplete theories of relativity, mostly against it. I now understand the wisdom of the physicsforums in keeping personal theories out. Why would anyone want to handle thousands of interpretations of relativity, it would be chaos. I have to ask questions only within the context of relativity and not lose patience with answers that assume I know absolutely nothing because I asked a question and the answer is obviously inside the 2 volume Feynman lecture series and I should go look there. I'll just answer I have and couldn't find it.

I went over our past discussions and I see I've changed a lot and I've admitted to have been wrong about everything so far. I'm totally on team Jorrie and not at all on team Brian Greene. There's a similar sentiment on the physicsforums against Brian Greene so I feel there is still some room to discuss relativity. I wrote that series of threads to ensure I had interpreted you correctly by paraphrasing what I thought what you said in my own words. I'll change any part that you see as misinterpretation. It's difficult to interpret Relativity correctly and I just don't want to recite the Catechism blindly and get all the right answers without understanding what they mean.

We only differ on 2 points. The first is I didn't understand your answer on length contraction. I think when you say length contraction and coordinate length contraction you're talking about the difference between the formulas x'=Yx and x'=Y(x-vt). That's as far as I got.

The 2nd point is one I know you don't like. I phrased it as a question on the physics forum and within 5 minutes I was banned for life for even bringing it up. I simply asked if a ship was leaving for Pluto and he kept transmitting his time back to us and we compared it with our earth time time he would see that his clock was ticking slower. No problem there, verified by Hafele-Keating and GPS satellites. But I said no one has done the same experiment from the Pluto traveler's perspective. Nothing on an outbound ship has taken time transmissions from earth and compared them to the on board clock. Relativity says the Pluto traveler will also see our clock slowed in relation to his. Then I go into a lengthy spiel of why I think the opposite is true and why don't we just do the experiment to see who's right. The consensus is it would be a waste of time and money to do it. We don't need to do that experiment because there's no benefit to backing up Einstein's assumption with empirical data. End of discussion, I'll never bring it up again except on rogue forums.

Your point 1: No, this is not what I meant by: "There is coordinate dependent Lorentz contraction, but there is no proper Lorentz contraction." It simply means that length contraction is only a coordinate dependent phenomena. I contrast, one can say that time dilation can be either coordinate dependent or absolute, depending on the situation.

The 'twin paradox', where more than one inertial frame is involved results in absolute time dilation, or perhaps better stated as difference in elapsed proper time or 'difference in aging'. Perhaps one should steer clear from calling this 'time dilation' and stick to difference in elapsed proper time, which is the best description. Then one can reserve 'time dilation' for the coordinate type, which can be reciprocal, i.e. each observes the others time to be dilated.

Your point 2, specifically:

"But I said no one has done the same experiment from the Pluto traveler's perspective. Nothing on an outbound ship has taken time transmissions from earth and compared them to the on board clock. Relativity says the Pluto traveler will also see our clock slowed in relation to his."

No, this is done every time a signal from Earth is received by a spacecraft. In fact there is no need to test for it; we simply use relativity to correct the frequency of the Earth signals so that things on board the spacecraft stay in sync. The fact that things work as designed is enough to prove relativity right.

You must understand that the redshift between the spacecraft and Earth is also influenced by gravity, not only by velocity. The GPS system has proven the effects of speed and gravity to great accuracy, simply because we have corrected the spacecraft's clocks to agree with Earth clocks in accordance with relativity. The accuracy that is achieved would have been orders of magnitude poorer if the relativistic corrections were not correct.

I will post the new Blog thread after the long weekend.

-J

Well there it is, the answer clear as a bell. Thank you. Just a few comments:

1. Yes GPS has both gravitational and velocity time dilation components. The gravitational one does not depend on perspective. The people inside the gravitational one see that time is faster for those in a less gravitational environment. Astronauts will see our time moving slower. There is no need to differentiate between the terms "time dilation" and "absolute time dilation" aka "difference in elapsed proper time" when it comes to gravitational time dilation.

2.Yes GPS has both gravitational and velocity time dilation components. This is supposedly outside the realm of SR because gravity is involved, yet it is not too difficult to consider the velocity component separately and independently from the gravitational.

Another thing that is not supposed to be in the mix is acceleration. Yes, I know acceleration itself does not contribute to time dilation, only its average velocity does. The satellites are in a constant state of angular acceleration. Again supposedly outside the range of SR's applicability. Yet again no problem, no relevance to resolving the twin paradox.

As you said, what differentiates the twin paradox from time dilation is a jump in inertial frame speed, not acceleration or gravity per se. I think it's more. At the turnaround point of the twin paradox (aka absolute time dilation scenario) whether you consider actual deceleration or a hand off to a ship passing in the opposite direction, for a split second the earth twin and the ship twin are in the same "stationary" inertial frame relative to each other. Yet they are separated by a huge distance which automatically brings in the relativity of simultaneity. I think, maybe, the real reason that the twins must reunite in order to definitively determine who has aged less is the fact that this huge bank of time caused by simultaneity must be spent. My question is if the ship twin came to a complete stop (entered the earth's relatively stationary frame) at the halfway point, what would the messages between the twins say about each others ages?

3. The difference between my Pluto scenario and the GPS satellites is that the Pluto scenario is a one way trip and the GPS satellites is a round trip journey. According to the twin paradox, the round trip journey will always see our perspective of the satellite's time slowing and their perspective of us with out time going faster than theirs. The Pluto scenario is pure time dilation while the GPS scenario is "absolute time dilation." These have now been defined as two separate things.

4. I still contend time dilation and length contraction are different forms of the same formula. The formula for Yv applies to the relationship of "your space, my time." Yv is the velocity vector through spacetime. Yv=x/t' where t' is time dilation t=Yt'. If you group the Y with the x instead of the t in the same formula you get x'=Yx, the formula for length contraction. My question is if they're different forms of the same thing, why does the time dilation form get a permanent absolute form in the twin paradox and the length contraction form does not. i.e. the ship twin arrives as having aged less but why has he not also arrived much thinner in a pancake sort of way?

I'm not going into too much detail now, but here are some pointers to your mistakes.

Your point 3: The Pluto probe had to undergo at least 2 inertial frame changes, so purely based on speed, it will have less elapsed time recorded than Earth.

Your point 4: Please reread what I wrote last time in its full context (I just quote a snippet here):

"Perhaps one should steer clear from calling this 'time dilation' and stick to difference in elapsed proper time, which is the best description. Then one can reserve 'time dilation' for the coordinate type, which can be reciprocal, i.e. each observes the others time to be dilated."

-J

Point 3. The Pluto probe could've been launched off earth and whizz by it at speed.

Point 4. So time dilation is slowed time while the twin paradox is slowed aging which you want renamed to "difference in elapsed proper time" rather than "absolute time dilation."

So the Muon scenario is an example of time dilation and not a difference in elapsed proper time even though we see experimental and permanent evidence that they have aged slower than normal due to their velocity relative to us. The reason the Muon scenario is an example of plain old time dilation is because from their perspective our clocks are ticking slower than theirs. However, if the Muons began their journey on the surface of the earth and then fell back to it, then it would be an example of a difference in elapsed proper time. They will have recorded our clocks as having ticked faster than theirs. Just a thought experiment.

Maybe length contraction is not absolute like the absolute form of time dilation because there is no equivalent of simultaneity in the Lorentz transform equation for space coordinates?

Point 3: If the probe only whizzed by us and also whizzed by Pluto, we would have no idea about elapsed time difference (ignoring the obvious gravity influence in this hypothetical scenario). If it 'stopped' at Pluto there had to be a change of inertial frames and we would have known the absolute time aging difference, although we could not have directly measured it.

Point 4: Time dilation is just observed 'slowed time', which is reciprocal and this cannot be absolute. Yes, you need some form of 'twin experiment' to get differential aging in SR.

The Muon experiment is much more subtle - I will answer that later.

-J

Oh my god this is getting really deep. I need to take time to absorb this into my framework but it sounds really complete from a relativistic point of view. I miss correcting some typos because I'm very far from my screen and can't see my keyboard either. In one post I said with out and it should be with our.

"So the Muon scenario is an example of time dilation and not a difference in elapsed proper time even though we see experimental and permanent evidence that they have aged slower than normal due to their velocity relative to us."

We do not really see or observe time dilatation in the muons that come from high in our atmosphere. We simply count the number of muons that we get at a mountain top and at sea level and then we explain that difference due to time dilation (since we have measured their half-life on earth when they are moving very slowly). In other words, we calculate what we would have observed if we could read 'muon clocks'.

While this all sinks in, please allow me time to complete the "Time Dilation and Lorentz Contraction Revisited" Blog post and lets continue the discussion there.

-J

I have posted "Time Dilation and Lorentz Contraction Revisited" as a new Blog thread.

Please comment there - this thread has become too unwieldy.

-J