Experiments Supporting Relativity Theory

[BurtJordaan]

With LET, we can know which frame is dilated only if we know which body has accelerated, and if we know where and when the acceleration started with regard to the observer.

The same for SR. The only difference is in the philosophy of what the role of the aether. In SR it is absent and AFAIK, LET still clings to an existing, yet unobservable aether.

[Inchworm]

If we can't make a simulation of the MM experiment with SR, then we can't teach SR as easily as we can teach LET. But there is another reason why LET is easier to grab: some events may not mesh with SR while they do with LET. Here is how Cooper presents his third simulation on his page:

«Everything in a Spacetime diagram has to move up the diagram over time even if it is stationary in space, but objects which are moving rapidly through space will have to move upwards more rapidly than slower objects if they are taking shortcuts into the future. In mode 1 we have a 1:1 tick-to-tick ratio for clocks on all paths, and this allows you to see some objects taking shortcuts into the future by moving more quickly up the diagram than other objects. You can also see the event-meshing failures that result, e.g. rockets reaching reunion points with their planets before their planets have arrived there and thus having to attempt to interact with them even though they're not there! If you change the frame of reference, you can see though that at least the actual events which have taken place are not changed by this change of frame: you are merely seeing the same moment in the generation of the future from the past with a different slant. In short, mode 1 displays Lorentz invariance and does not produce contradictions, but the event-meshing failure is a major problem for it (which I will comment on further below because there is actually one way to make it work, but it is most certainly not Einstein's model and it requires a kind of time to be added which is clearly Newtonian in nature). If you then switch to mode 2, the first of the variable ratio modes, the shortcuts are avoided and all events will now mesh together correctly, but you can also see that the Lorentz invariance has been lost: if you stop the action at any point and then change the frame of reference in this mode (for example, when the time counter reaches 360 or 550), events are changed as a result of switching frame, some events being undone while other events which hadn't happened before have suddenly happened. That can't be allowed to happen if this is a single frozen moment in time during the growth of a block universe (or the generation of future from past in any part of a model of a universe), but it is the direct result of trying to treat all frames of reference as equally valid when in reality they cannot be, so this is just another way of seeing the contradictions in the accounts of events from different frames.»

Take a look at the simulation to see what really happens when we change modes.
http://www.magicschoolbook.com/science/relativity.html

[BurtJordaan]

If we can't make a simulation of the MM experiment with SR, then we can't teach SR as easily as we can teach LET. But there is another reason why LET is easier to grab: some events may not mesh with SR while they do with LET.

Well firstly, there is no simulation that cannot be done in SR; The MM experiment is one of the simpler ones to do.

Second, Cooper's writings are full of holes, apparently stemming from gross misunderstandings of SR and GR, e.g. from his "Magic School" page:

"What we see then with Einstein's model is a problem of event-meshing failure: fast moving objects take shortcuts into the future and try to interact with other things which have taken longer paths through time to get there, and they are supposed to meet up and interact with each other even though some of them will get there too early for this to be possible. (You will see this more clearly when you play with the interactive diagram further down this page.) The big problem is that the only kind of time that's officially allowed in Einstein's model is the "time" dimension, so if we are to respect this sole kind of time that the theory allows for, we are forced to have clocks tick at the same rate on all paths: the rocket's clocks must tick once for every tick of the clocks on Earth, and that gets the rocket back to the point of the reunion with the Earth a full two years too soon. The events simply don't mesh together correctly, so that version of the model is immediately in severe difficulty. The only solutions to this problem are either to allow clocks moving on different paths to tick at different rates relative to each other (but that means allowing tick-to-tick ratios other than 1:1 for different paths through Spacetime) or to tolerate event-meshing failure during the construction phase, though that leads to events at any single Spacetime location changing there over Newtonian time. If we use ratios other than 1:1, we are also forced to bring in a Newtonian time to work in combination with the "time" dimension that's already in the model so as to allow some clocks to tick more slowly than others, but that's not something that Einstein's followers are at all keen to allow into the model as it breaks his rules. However, they have come up with a stunningly elegant solution to resolve this difficulty: they simply smuggle in this Newtonian time to allow tick-to-tick ratios other than 1:1, but they then deny that they have done so and claim they aren't using any kind of time other than the "time" dimension that's allowed in the model. With this added Newtonian time (which they claim they aren't using even though they depend on it), events can now mesh together properly with the rocket being united with the Earth after two years of the "time" dimension's time for the rocket, after four years of the "time" dimension's time for the Earth, and after a bit more than four years of Newtonian time for them both (and it's a bit more because the Earth is moving too: its clocks must run a bit slower as a result). "

I have read up to this part and then decided it is not worth further perusal. Quite dissident, it seems.

Readers who have started from the 'Cooper base' with SR must surely have real difficulties coping with relativity.

[Inchworm]

If we can't make a simulation of the MM experiment with SR, then we can't teach SR as easily as we can teach LET. But there is another reason why LET is easier to grab: some events may not mesh with SR while they do with LET.

Well firstly, there is no simulation that cannot be done in SR; The MM experiment is one of the simpler ones to do.

The MM experiment was about ether, so if we make a simulation of it, we have to see the interferometer moving through ether, and there is no ether in SR, so how would you explain that to the students. Would you use Cooper's simulation to help people understand SR here? Wouldn't you be afraid they keep imagining ether is part of SR? If you had done so here, I might have understood more rapidly why I was wrong in the example I presented with the star, the observer X and the earth. What I did not understand is the beaming phenomenon, and as I said, it is easy to understand when we look at the photon going through the telescope in the simulation. There is not much difference between LET and SR since they give the same numbers, but LET is easier to understand. Look at the way we can resolve the Twins' problem for instance: there can be no interminable discussions on the basics when ether is in the background.

Second, Cooper's writings are full of holes, apparently stemming from gross misunderstandings of SR and GR, e.g. from his "Magic School" page:

For the moment, I didn't find any hole in his writings. It even helps me to understand SR. Maybe you could point out one so that I can change my mind for SR. :0)

I have read up to this part and then decided it is not worth further perusal. Quite dissident, it seems.

He sure shows he was severely rejected by SR people, but I can testify that it's usually the way those things work, so I don't think he is exaggerating. He is just showing his feelings a bit.

Readers who have started from the 'Cooper base' with SR must surely have real difficulties coping with relativity.

As I said, it helps me to understand some features of SR, and also why laymen in the field have so much difficulties to admit its consequences even if there is data to back them up. No need to say shut up and calculate anymore with LET, just to take a look at the simulations again. A guy on Physics Forum told me LET was a bad way to approach GR properly. If you also think so, can you tell me why? The thread was closed before I had the time to ask.

[BurtJordaan]

The MM experiment was about ether, so if we make a simulation of it, we have to see the interferometer moving through ether, and there is no ether in SR, so how would you explain that to the students.

Only if you go to the historical LET of a century ago. LET gradually lost its aether flavor, until with modern LET one simply choose any convenient inertial frame as representing the aether frame. So it is simply SR's inertial frames A and B. Not surprising that they give the same results for all experiments. It is fairly trivial to write a simulation that shows the situation as viewed from either frame. Historical LET does not agree with experiments, so unless I need to give a 'history of relativity' lesson, I would rather avoid LET.

There is not much difference between LET and SR since they give the same numbers, but LET is easier to understand. Look at the way we can resolve the Twins' problem for instance: there can be no interminable discussions on the basics when ether is in the background.

But there is no ether observable in the background, so for most students it creates quite a conundrum. In my opinion, the "interminable discussions" are all rooted in an "aether mindset", which one should rather avoid from the outset.

A guy on Physics Forum told me LET was a bad way to approach GR properly. If you also think so, can you tell me why? The thread was closed before I had the time to ask.

As I have attempted to show in my "Bead-on a-string" thread, GR follows quite naturally out of SR (which boils down to just a special case of GR, when gravity is absent). AFAIK, one can also develop GR out of LET, but AFAIK the process is quite laborious and with a very 'unnatural feel' to it. But I must confess that I have never felt the urge to investigate that process deeper.

[Inchworm]

It is fairly trivial to write a simulation that shows the situation as viewed from either frame.

I never saw such a simulation showing a photon going along the telescope, and it is crucial to understand the beaming phenomenon. The first time a guy used a simulation of the MM experiment is at Anti-Relativity forum, and it was only to show that the photon's path was longer in the parallel arm than in the orthogonal one. I was still skeptic because I had not understood the beaming phenomenon yet, but as soon as I questioned Cooper about that, he told me to have second look at the telescope, and I saw the photon coming out of it sideways even if it was still pointing upwards. At Wiki on aberration, they show the photon getting into the tilted telescope sideways, but they never show it popping out sideways from a straight one.

They then say that aberration is related to relativistic beaming, and at relativistic beaming, they refer us to aberration to know why «most of the photons are emitted along the object's direction of motion»: why that buck passing? On the MM page, we can see an animation showing the parallel photon taking more time, but they don't show the trajectory the other one follows, so it looks as if it was traveling sideways to the motion. If it is so easy to make a good simulation, why don't they show one? Is it because simulations are too close to LET? Cooper has a good one, but I doubt that they would accept to use it since it is directly related to LET. I'm happy to finally understand something, it might even improve my small steps, but I'm still wondering if I am dumb or if SR is badly presented. (I know what you think, no need to say it. :0)

Historical LET does not agree with experiments, so unless I need to give a 'history of relativity' lesson, I would rather avoid LET.

What experiments are you talking about? Afaik, historical LET gave us length contraction and time dilation, and we still need them to explain the experiments. (Enjoy, I was far from thinking this way two weeks ago! :0)

[BurtJordaan]

Historical LET does not agree with experiments, so unless I need to give a 'history of relativity' lesson, I would rather avoid LET.

What experiments are you talking about? Afaik, historical LET gave us length contraction and time dilation, and we still need them to explain the experiments.

No, historical LET had no time dilation. It used Newtonian absolute time and physical length contraction, i.e. atoms would have been physically squashed in the direction of motion through the aether. It can explain the M&M experiment, but with all experiments that depend on time dilation it fails, e.g. relativistic Doppler shift, the correct aberration, beaming etc.

BTW, the M&M experiment had nothing to do with time dilation - the diagrams were simply 2D space-space, not spacetime. Modern LET did gradually (as one physicist put it) "saw off the branch that it sat on", because it had to accept time dilation and hence it has effectively abandoned the aether as well (by declaring it exists, but is undetectable).

We never "see" or detect a light beam coming "sideways" out of a telescope, because if the internal light beam moves at an angle relative to the vertical in any inertial frame, so does the telescope, even in Newton's dynamics. So relative to the telescope frame, it always goes "straight up". I still fail to understand your issue with it.

Lastly, LET can be extended to include first order approximations to GR, but it becomes a big mess when the second order effects have to be 'forced in' there.

[edy420]

I've tried explaining a contradictory thought experiment before, but I have poor explanation skills :P
My experiment makes a direct connection between travelling twins, using a flashing laser as a time reference.

If Bob walks away and holds his hand out while Alice flashes a laser on it, we can measure the difference in time dilation by using the laser flashes as a time reference.

We can do this by looking at Alice's clock and tapping the laser off and on for one tick per second.
Bob can then look at his hand and count the laser signal of Alice's one flash per second, and compare that to his own experience of time.

At walking speed, they won't notice much difference.
For each flash per second that Alice emits, Bob will witness one flash per second on his hand.
But if he sticks his hand out of a spaceship while flying away, he should notice the laser flashes speeding up, according to theory.

My problem with this experiment is that light speed is constant, and lasers are light, therefore Bob will witness the flashes on his hand at the same rate as the ticks on his clock, of one flash per second.

Or does he witness the flashes at a faster rate?
Would this not mean that light speed is variable, because Alice's emitted light signal is speeding up from Bobs point of view?

[Dave_Oblad]

Hi Edy,

Your concept gets very complicated very fast because it must include Doppler Effects and a host of other effects wrapped around Velocity Differentials, Speed of Light Limitation, and Dilation Factors. The best way to prove that velocity through Space-Time doesn't involve Temporal Displacement is the Centrifuge Experiment.

By Temporal Displacement, I'm referring to the idea that the Twin Paradox is explainable by allowing one Twin to move into the future faster than the other Twin while both maintain identical clock rates. Obviously, I don't buy into that viewpoint.

In the Centrifuge Experiment we have two super clocks, one located at the Center and one located out on the Arm of the Centrifuge. The key point here is that we never change the distance between the two clocks. Right off the bat.. that kills any issues with the Speed of Light over distance and Doppler Effects.

Both Clocks can communicate with each other as well as to an observer nearby. The effect we will see is that the Arm Clock will run slower than the Center Clock. Both clocks can measure the clock differentials between them because light Transit Time is a constant. For any Carrier Wave, the Arm Clock will have to auto adjust its Transceiver Frequency to maintain communication with the Center Clock.

1. The Center Clock will measure the Arm Clock running slower.
2. The Arm Clock will measure Center Clock running faster.

Even when the Arm Clock indicates it has slowed down by 24 hours relative to the Center Clock, you can request a Special Ping from the Center Clock and the Arm Clock with echo that Ping Immediately.. not 24 hours later.

This will prove that there is no Temporal Displacement between their Temporal Coordinates.

This will prove that Clock Dilation is strictly an accumulative function of Velocity Differentials.

NO time travel Involved! Just simple Clock Dilation due to pure Velocity Differential.

This isn't even an especially difficult Experiment to perform. When somebody finally does so and publishes such, there will be a lot of red faces around.. IMHO.

It's basically the Twin Paradox in a can.. minus the cloud cover.. lol.

Best Regards,
Dave :^)

[BurtJordaan]

Hi Dave, I'm not sure where you reckon that your "results" will differ from what standard SR predicts and has physically shown many times.

Both Clocks can communicate with each other as well as to an observer nearby. The effect we will see is that the Arm Clock will run slower than the Center Clock. Both clocks can measure the clock differentials between them because light Transit Time is a constant. For any Carrier Wave, the Arm Clock will have to auto adjust its Transceiver Frequency to maintain communication with the Center Clock.

With "auto adjust its Transceiver Frequency to maintain communication with the Center Clock", do you mean changing the 'tuning' as you go around the circle at constant angular speed, or does it mean setting the tuning only once in advance for a given arm-length and angular speed (as SR allows)? I suspect that you meant the prior, because I think that you reckon the receiver must continually compensate for its velocity change relative to the absolute frame.

If my suspicion is right, the red face is on you, because it has been done multiple times in one form or another. See e.g. http://www.exphy.uni-duesseldorf.de/ResearchInst/FundPhys.html, a little down the page, where you see the rotating platform graphic. That platform could be rotated and also moved linearly. The results were quite devastating for 'absolute framers'.

[BurtJordaan]

At walking speed, they won't notice much difference.
For each flash per second that Alice emits, Bob will witness one flash per second on his hand.
But if he sticks his hand out of a spaceship while flying away, he should notice the laser flashes speeding up, according to theory.

No, he will notice the opposite: the laser flashes will arrive at longer intervals than when walking. This is the Doppler redshift effect. If his away ship flew at 0.6c, he would only notice half the number of Alice-flashes per second. Should he turn around and fly back to Alice, he will see double the amount of flashes per second.

For both Alice and Bob, the speed of light is 'c' in their own frames, as measured by their own clocks and meter-sticks. What confuses beginners is when they start using Bob's clock and Alice's stick to measure the speed of any light pulse. Or vice-versa.

[Dave_Oblad]

Hi Jorrie,

I meant that as the Centrifuge ramped up to its maximum rotation in RPM, the Arm Clock would have to adjust for all of its clocks slowing down and that would include its Radio Transceiver.

The experiment you have pointed out was not setup to detect Frequency/Clock Dilatation but rather a variation of the M&M experiment for detecting our velocity through the Aether. We both know it's near impossible to detect our velocity through the Universe by Experiment due to the collective factors that add together to mask such measurements into a null result.

I had thought I had found a work around with my Light-Tube idea, but somebody has already tried that and got a null result.. due to the aberration of Light as it turns out. Meaning a radial lamp will direct more light to the front than to the back when in motion, thus the reflected light remains a constant in all directions.

My reference to red faces was in regards to the often stated effect that two travelers will "both" perceive the other travelers clock as being slower than their own, disregarding Doppler effects. A simple thought experiment would show the absurdity of such a concept. Also, the notion that a traveler (twin paradox) is moving into the future at a different rate than the stationary twin is ridiculous. As I've stated many times, we all are progressing into the future at the exact same rate (speed of light) but with variations of individual clock rates due to variations in individual absolute velocity relative to light speed. The Lorentz Equation shows that in no uncertain terms.

At 0.8660254037844386% the speed of light, your clocks will tick at exactly 50% of a stationary (0.0c) clock in flat space. The speed of light is the only anchor velocity that all other velocities are relative to. Only knowing the differential velocity between two travelers is utterly worthless because the Lorentz Conversion is non-linear.

Best Regards,
Dave :^)

[Inchworm]

Hi Edy,

Firstly, as everybody said, you're neglecting doppler effect. We already use such laser beams to measure the speed of cars, you can buy one if you wish, and it is based on doppler effect.

Secondly, if the cars were traveling at relativistic speeds, because of time dilation, we would measure more doppler redshift than at low speeds if the car was going away from us, or less doppler blueshift if it was coming towards us, and the dilation correction in the calculation depends on speed, which is unknown, so we could simply not know the speed with precision. That phenomenon arises when we measure the speed of particles in accelerators.

This will prove that there is no Temporal Displacement between their Temporal Coordinates.

This will prove that Clock Dilation is strictly an accumulative function of Velocity Differentials.

Hi Dave,

Do you mean that you don't believe the traveling twin will be aging slower? If you think so, then how do you explain the muon experiment?

[BurtJordaan]

The experiment you have pointed out was not setup to detect Frequency/Clock Dilatation but rather a variation of the M&M experiment for detecting our velocity through the Aether.

Nope, the rotating disk experiment tested both. There were others that specifically measured only the so-called "transverse Doppler effect" on a rotating arm, which is exactly the same as the time dilation of SR.

There is however a big difference between a clock at the rim of a rotating disk (or arm) and a purely inertially moving clock, e.g. a rim clock will observe the speed of light as different in different directions, while an inertial clock will not. Although the actual clock rate of the rim clock is exactly the same as the central (inertial) clock, the rim clock moves through a different spacetime than the inertial clock. In your own words of some time ago, the rim clock took a "shortcut" through time. From another p.o.v., one can say that the rim clock had to cover a larger 'space-distance' and hence has covered less "time-distance". The same thing.

The concept of "moving clocks slow down" is a perpetual misconception of relativity. We can only observe the amount of time that has elapsed for each clock (the number of ticks), never its absolute "rate of ticking" - because that always simply depends on who was looking at it...

[BurtJordaan]

... and the dilation correction in the calculation depends on speed, which is unknown, so we could simply not know the speed with precision.

I suppose you mean that speed relative to the mystical "absolute frame" is unknown? Relative speed between inertial observers is known with precision from the Doppler shift.

[Inchworm]

... and the dilation correction in the calculation depends on speed, which is unknown, so we could simply not know the speed with precision.

I suppose you mean that speed relative to the mystical "absolute frame" is unknown?

No, I was only talking about measuring relative speed from a distance, with a laser speed gun.

Relative speed between inertial observers is known with precision from the Doppler shift.

I may still make mistakes since I'm sort of new to the field of relativistic phenomenon, but since doppler effect is impossible to differentiate from time dilation, how could we measure a relativistic speed with precision?

[BurtJordaan]

I may still make mistakes since I'm sort of new to the field of relativistic phenomenon, but since doppler effect is impossible to differentiate from time dilation, how could we measure a relativistic speed with precision?

You are doing well when you are asking these sort of questions!

Time dilation is fully incorporated into the relativistic (or LET, if you wish) Doppler factor:

, where is positive for opening relative velocity and negative for closing relative velocity.

It is as precise as you can make your frequency measuring equipment.

[Dave_Oblad]

Hi Inchworm,

Do you mean that you don't believe the traveling twin will be aging slower? If you think so, then how do you explain the muon experiment?

Huh? The Centrifuge Experiment is a representation of the Twin Experiment. Yes, the (More) moving twin will age slower and his/her clocks will tick slower than the Stationary Center Clock (less moving). Both Clocks in the Centrifuge Experiment co-share an intrinsic speed through the Universe, so the differential dilation will have that in common.

Also note that the Radar Gun uses the two-way speed of light, which is always the full value (round trip) of the Speed of Light divided by 2.. minus a bit.. because of our atmosphere.

One other complex minor effect is dependent on the axis plane of the Centrifuge relative to the intrinsic Velocity of both Clocks through the Aether. Meaning the Arm Clock is not maintaining a constant Velocity relative to one-way Light Speed. A Clock wobble should appear in the data stream maintained between Clocks whose amplitude will be dependent on the velocity of the Arm Clock. But Length Dilation Oscillation of the Arm caused by its oscillational velocity relative to its intrinsic velocity through the Aether added to the oscillational One-Way Speed of Light issues would probably all cancel each other.

The only reliable aspect would be an accumulative one that the Arm Clock will eventually show a significant difference with the Center Clock. It might take years to accumulate a 1 hour differential between both super clocks, even though both always occupy the same Parallel Temporal Coordinate through out the entire experiment.

Regards,
Dave :^)

[Inchworm]

...Time dilation is fully incorporated into the relativistic (or LET, if you wish) Doppler factor:

, where is positive for opening relative velocity and negative for closing relative velocity.

It is as precise as you can make your frequency measuring equipment.

OK, I think I understand: the doppler effect is related to speed, so we can calculate the dilation directly from it. We can thus determine the relative speed this way, but we still cannot determine if it is the source or the observer that is moving, and we need that information for certain problems to be coherent. Particles and detectors cannot both be aging less for instance, and both twins neither. Why not then state that knowing which one has accelerated determines which one is moving then? Apart from modifying the relativity principle a bit, would it cause any other problem to SR?

[BurtJordaan]

Hi Dave, you said:

A Clock wobble should appear in the data stream maintained between Clocks whose amplitude will be dependent on the velocity of the Arm Clock. But Length Dilation Oscillation of the Arm caused by its oscillational velocity relative to its intrinsic velocity through the Aether added to the oscillational One-Way Speed of Light issues would probably all cancel each other.

Sure they are canceling, because picking that up should be trivial with modern technology. A better view is that there is nothing there to cancel in the first place!

BTW, there is no "length dilation of the arms" in a centrifugal type experiment. What you do get is centrifugal lengthening of the arms, but that is uniform and plays no role in the experiment.

You are right that such an experiment is equivalent to the twins Alice and Bob in the much discussed "paradox". Alice starts out stationary relative to Bob and then sets off on a long circular (spatial) journey, until she eventually come to rest relative to Bob again. Her clock never "ran slower" than Bob's, she just covered a spacetime path that took less time (and more space) than what Bob did.

PS:
Inch, I hope your efforts to learn SR are not derailed by Dave_O's stubborn clinging to the long dead old aether-horse... ;)

[BurtJordaan]

Apart from modifying the relativity principle a bit, would it cause any other problem to SR?

A modification of the relativity principle (that all inertial frames are equivalent, irrespective of their motions and of their place in the universe), would have major ramifications for physics. For one thing, experiments done in accelerators like CERN, would have to bring in the "movement of the day" of the facility relative to the "absolute frame", in order to achieve any accuracy. As I have said before, "quelle horreur".

Yes, acceleration is a different case and easily distinguishes frames from each other, because it changes the ratio of space vs time traveled (the structure of spacetime that I have written on before). But, once the acceleration stops, the frames are equivalent once again, thank goodness!

[Dave_Oblad]

Hi Jorrie,

Stubborn clinging to an Aether?

We may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an aether. According to the general theory of relativity space without aether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense. But this aether may not be thought of as endowed with the quality characteristic of ponderable media, as consisting of parts which may be tracked through time. The idea of motion may not be applied to it.

It is ironic that Einstein's most creative work, the general theory of relativity, should boil down to conceptualizing space as a medium when his original premise [in special relativity] was that no such medium existed [..] The word 'ether' has extremely negative connotations in theoretical physics because of its past association with opposition to relativity. This is unfortunate because, stripped of these connotations, it rather nicely captures the way most physicists actually think about the vacuum. . . . Relativity actually says nothing about the existence or nonexistence of matter pervading the universe, only that any such matter must have relativistic symmetry. [..] It turns out that such matter exists. About the time relativity was becoming accepted, studies of radioactivity began showing that the empty vacuum of space had spectroscopic structure similar to that of ordinary quantum solids and fluids. Subsequent studies with large particle accelerators have now led us to understand that space is more like a piece of window glass than ideal Newtonian emptiness. It is filled with 'stuff' that is normally transparent but can be made visible by hitting it sufficiently hard to knock out a part. The modern concept of the vacuum of space, confirmed every day by experiment, is a relativistic ether. But we do not call it this because it is taboo.

And by Length Dilation.. is was referring to Length Contraction. A rigid object of mass becomes shorter in the direction of travel.. thus when the arm of the Centrifuge is pointing away from or towards its direction of travel.. it becomes shorter than when the arm is at a right angle to its direction of travel. This was one of the reasons the M&M experiment produced a Null Result, since it was on a rotating base.

The Centrifuge Experiment:

That platform could be rotated and also moved linearly. The results (Null) were quite devastating for 'absolute framers'.

You are right that such an experiment is equivalent (not Null) to the twins Alice and Bob in the much discussed "paradox".

As said previously, Clock Functions in Moving Frames only works on paper when Absolutes are plugged in.

In the real world, Absolutes are hard to come by. Given Bob is moving at speed (X) and Alice is moving relative to Bob at 100,000 Kilometers Per Second faster than (X), one can not discern the clock differential (ratio) between them because the Lorentz Equation is Non-Linear.

https://en.wikipedia.org/wiki/Time_dilation

So, I have no issues with Relativity itself, but find it ironic that it only works when one knows Absolutes and Relativists defend to the death.. that Absolutes can't be known. Want further proof? Look at any Relativity problem and you will see Absolutes or.. implied Absolutes.. are employed. (Ie: Alice is stationary)

Obviously, I'm what Relativists call an Absolutist. And like Einstein (and most of real world physicists) we accept the concept of an Aether or Space-Time.. as Einstein renamed it to.

Regards,
Dave :^)

[ralfcis]

Words without math to back them up are just philosophy. Put your model in an STD and lets all see what the real answer is. Without that, you should post in the philosophy phorum.

[BurtJordaan]

Hi Dave; and still you are clinging to the old dead horse aether!

Obviously, I'm what Relativists call an Absolutist. And like Einstein (and most of real world physicists) we accept the concept of an Aether or Space-Time.. as Einstein renamed it to.

Einstein's 'new aether' and even more so 'Laughlin's ether' have very little, if anything, in common with the old luminiferous ether, which provided an absolute frame of rest.

Einstein replaced that medium with fields (gravitational and electromagnetic) and has clearly stated that it gave no notion of absolute motion to itself, or anything else. All motion was still only relative to other matter, or more precisely, to arbitrary frames of reference.

Laughlin (as a particle theorist and a champion of 'emergent' phenomena) included matter fields in his 'medium', but unlike particles of matter, matter fields did not provide anything that you can measure movement against. The book that you have quoted from is more about philosophy of science than about hard science, so one cannot expect precision there.

It was unfortunate that they both have used a similar term for these concepts than for the old defunct term 'luminiferous ether'. It has caused an immense amount of confusion later, and up to this day, it seems.

[Dave_Oblad]

Hi All,

When I might mention Planetary Orbitals.. no one jumps in with the Earth Centrist View.
When I might mention the surface of the Earth.. no one jumps in with the Flat Earth View.
So why.. when I mention the Aether (same context as Einstein) does everyone jump in with the "Luminiferous Ether" View?

I don't mind calling it Space-Time. But it is still an Aether. It is more than Nothing. Motion through it by Mass has a profound effect(s) on said Mass. Aether can be Curved, Twisted, Stretched and Compressed. You can't do those things to a Nothing. It has a Metric by which all other things are measured by and constrained by. It is Granular. It has a minimum non-divisible pixelated Resolution.

Ralfcis..

Given Alice has an unknown non-zero velocity and given Bob flew past her at 100,000 Kps in the same direction where they synced clocks. Given Alice has waited by her proper time of 1 year then how much Proper Time has Bob experienced for that same Alice Proper Time Interval?

Now that is a straight Relativity Problem because all you have to work with is the Relative Velocity between Alice and Bob.

There is no single correct answer.

Best that can be done is a Graph for all Possible Velocities of Alice vs Bob's Results. Without knowing Alice's absolute Velocity, nothing can be known about Bob's Proper Time. Again.. because the Lorentz Equation is NON-LINEAR.

Best Wishes,
Dave :^)

[BurtJordaan]

Hi Dave.

When I might mention Planetary Orbitals.. no one jumps in with the Earth Centrist View.
When I might mention the surface of the Earth.. no one jumps in with the Flat Earth View.
So why.. when I mention the Aether (same context as Einstein) does everyone jump in with the "Luminiferous Ether" View?
I don't mind calling it Space-Time. But it is still an Aether. It is more than Nothing.

Nobody said it is nothing. The problem lies in the way you tried to use spacetime in the past - something that you can measure movement against. Something that influences the clocks and physical length of moving bodies. Something that makes space locally anisotropic.

Motion through it by Mass has a profound effect(s) on said Mass. Aether can be Curved, Twisted, Stretched and Compressed. You can't do those things to a Nothing. It has a Metric by which all other things are measured by and constrained by. It is Granular. It has a minimum non-divisible pixelated Resolution.

Spacetime curvature has effects om masses. Flat spacetime has no effect on masses. I think we all agree that spacetime if full of fields: electromagnetic, gravitational, quantum, you name it. But it is not the aether that you try to endow with properties like being an absolute reference frame and make physical things contract in their direction of movement through it, etc.

@Ralfcis, please do not get derailed by Dave_O's absolutist views. Please show him how we define a scenario properly, without referring to the aether, and that there is only one right outcome predicted by SR and that it is what we measure/observe in our experiments.

[ralfcis]

Only a defector from his consortium of scientists from the future could convince him or if someone can hack into the line between his microphone and his ear piece.

[Inchworm]

Given Bob is moving at speed (X) and Alice is moving relative to Bob at 100,000 Kilometers Per Second faster than (X), one can not discern the clock differential (ratio) between them because the Lorentz Equation is Non-Linear.

Does that have anything to do with what they say at wiki about relative velocity time dilation?

«If Ship A and Ship B both think each other's time is moving slower, who will have aged more if they decided to meet up? With a more sophisticated understanding of relative velocity time dilation, this seeming twin paradox turns out not to be a paradox at all (the resolution of the paradox involves a jump in time, as a result of the accelerated observer turning around). Similarly, understanding the twin paradox would help explain why astronauts on the ISS age slower (e.g. 0.007 seconds behind for every six months) even though they are experiencing relative velocity time dilation.»

They put a question and never answer it! They refer us to the twins paradox instead. But if the ships don't turn around, which one will be aging less? Maybe there is no need for an answer because it is a useless problem, but at least, with LET, we can imagine that it is the one that has more speed with regard to ether. It is one thing to observe that clocks slow down with speed, but it is another one to consider that nothing but relative speed can slow them down. There has to be some kind of linkage between two things for them to be able to act with regard to one another, otherwise it is pure imagination.

[BurtJordaan]

They put a question and never answer it! They refer us to the twins paradox instead. But if the ships don't turn around, which one will be aging less? Maybe there is no need for an answer because it is a useless problem, but at least, with LET, we can imagine that it is the one that has more speed with regard to ether. It is one thing to observe that clocks slow down with speed, but it is another one to consider that nothing but relative speed can slow them down.

It depends... I have described the relativistic scenarios and answers somewhat in this post on Ralfcis' thread.

BTW, modern LET (the one compatible with all SR's predictions) do not have an absolute 'ether'. You just choose any inertial frame and call it 'ether', as I have said a few times before. It does not help us in any way to decide which one ages less.

[ralfcis]

Isn't that then the cartesian coordinates on all STD's assuming the role of a stationary reference frame? That makes LET kind of already inherent in SR.