On the idea of time in physics-relativity

[Aqueous Id]

Addendum:

If the two beams of light in MME were actually simultaneous, there would be no interference pattern (coherence). So it's not even relevant on the grounds of "simultaneity".

 

[Write4U]

Aquous ID,

Posted by Write4U,
One thing I am not clear about. The thought experiment proposes a simultaneous flash of light at two specific spacetime coordinates. When the light flashes (simultaneously) does it make a difference if the train is in motion or if there is a train at all?

It makes a difference as to whether the folks in the train will get a different result. If the train is parked there (or gone, they're us standing trackside) they get the same result as the person on the platform, provided they are each located midway from the flashes.

a) The difference is that, if the train is gone, they are standing "inside" the tracks in a straight line between the Flashpoints. The other observer, by virtue of standing outside the tracks, receives the flashes at an angle from each other, which means the flash always has to travel a longer distance to reach observer O outside the tracks than O' (on a straight line) inside the tracks.
I stipulate this would be a very small amount of Planck time, but non-negotiable. It is a mathematical contradiction. A straight line is the shortest distance between points. Any point along this straight line is the shortest distance between the two ends. Any point outside the straight line would present a longer path between the source and observer, if that observer is also located "half-way" between the flashpoints.

Even if there is simultaneity between the flashes at different locations, there will never be simultaneity between the observer's observations.
They occupy different spacetime coordinates.

IMO, the relevancy of the train is that it moves the observer (O') who is ON the train, nothing else.

That's the whole point. Since they're in motion, they have left the inertial reference frame where simultaneity was assured.

But there never was simultaneity between when O and O' receive the flash. In every instance the light MUST travel a longer distance to O than to O' (on the train), even if the train was standing still.

When the light flashes can this event have momentum? Seems to me a flash is
(a) stationary event at a specific spacetime coordinate.
(b) even in motion, it still occurs at a specific spacetime coordinate and is a stationary event.

Physical momentum? The product of mass of a body times its velocity? I don't see a connection.

Thus the simultaneous flash events are "fixed" in a specific spacetime coordinate, which is now independent of the movement of the train. The flash event itself is not connected to the train at all.

But I thought that C is constant in all frames of reference. You can't add momentum, only intensity (blue shift)

Only the observer O' (on the moving train) has a relative movement to the light flashes. But that only creates a frequency shift, no?

It does not affect when the light is perceived. It alters the path length each ray has to travel to reach him since the train bends spacetime.

ok

But allow me a introduce a condition which seems to be missing from all illustrations. No one has paid any attention to the distance each observer is removed from the points of the light flash.

If the train were 200' long, observer O' (in the middle of the train) would be 100' removed from both flashpoints.
However, observer O (by virtue of standing alongside the tracks) would be more than 100' removed from both flashpoints.

It seems reasonable to expect each observer to receive the light flashes at different times (even at SOL). Keep in mind that there is a plane between the two foci (flash points) in which every point is equidistant from the flashes. Wherever the plane intersects a person's position (forming a line across the platform, down the stairs, across the tracks and cutting through the train) any such location is guaranteed to be equidistant from the flashes -- until:

ok

LOL, the introduction of a moving train is just to make the problem a little more difficult....

Yep - until SR kicks in and that plane just got twisted. Take a sheet of paper, hold it perpendicular to the ground and at eye level looking into the edge, now rotate until you can see some girth. The line projected by the paper onto (say a tabletop below) that was orthogonal to you is now slanted. This means that where it cuts across the tracks, the "center of simulaneity" has shifted to some other aisle farther back.

But - herein lies the paradox - it only gets twisted on the train, and only because it's moving, and to a degree that depends on the velocity relative to the platform (and especially as the speed becomes close to c).

ok.....

 

[Write4U]

Aqueous Id , please forgive the spelling error. ( I am unable to edit)

 

[Prof.Layman]

Addendum:

If the two beams of light in MME were actually simultaneous, there would be no interference pattern (coherence). So it's not even relevant on the grounds of "simultaneity".

LOL! LOL! LOL! You still don't get it!

THE BEAMS ARRIVAL TIMES ARE SHOWN TO BE SIMULTANEOUS BECAUSE THERE WAS NO INTERFERENCE PATTARN IN THE EXPERIMENT!!!

Do yourself a favor and get a life why don't you.

 

[Aqueous Id]

LOL! LOL! LOL! You still don't get it!

THE BEAMS ARRIVAL TIMES ARE SHOWN TO BE SIMULTANEOUS BECAUSE THERE WAS NO INTERFERENCE PATTARN IN THE EXPERIMENT!!!

Do yourself a favor and get a life why don't you.

Go read your own link and stop trolling. An actual interference pattern from an MM device, from your own source:

Note: interferometry is concerned with measuring phase differences. The best way to calibrate is to bring the objective into fringing. The fringe bands give a visual cue and phase differences can be estimated as some fraction of the band width. This is still off topic BS that does not excuse you for repeat posting nonsense.

 

[Prof.Layman]

Go read your own link and stop trolling. An actual interference pattern from an MM device, from your own source:

Note: interferometry is concerned with measuring phase differences. The best way to calibrate is to bring the objective into fringing. The fringe bands give a visual cue and phase differences can be estimated as some fraction of the band width. This is still off topic BS that does not excuse you for repeat posting nonsense.

OMG! This must mean that there really is an aether! The beams didn't actually arrive at the same time and the experiment was a complete success!!!

 

[Aqueous Id]

Aqueous Id , please forgive the spelling error. ( I am unable to edit)

I had that problem once and put in a request to have it corrected and it was taken care of that same day. (My reason for harping on Prof L. about his spelling and language is that he's pretending to be a master of a subject that would obviously require a college education at a minimum. The assumption there being that you have to know how to spell basic technical terms even before you can claim to profess what they mean and how they work. )

You are right that the difference in position from O to O' alters the outcome, since, as drawn, they're not both lined up on that plane which lies midway between the foci. And so naturally they can not be expected to get a similar result compared to each other whether moving or not. I may have misunderstood this point earlier, but that's certainly correct.

The key thing that changes when the train is in motion is that the spacetime rotation changes the symmetry of the path length. Here I'm referring to the apparent distance from the front flash to center of train now becoming shorter than the apparent rear path length. While it's true that we expect a blue shift in the forward flash and a red shift in the rear flash, it's quite surprising, until we contemplate what "spacetime rotation" actually means-- to stumble onto the meaning of "Lorentz rotation" only to find the "cause" that the path length of the forward flash to the center of the train has been shortened while the path length for the rear flash has been elongated. This of course is what Prof L is remaining utterly blind about. He simply refuses (or is probably incapable of) removing the blinders.

I think this essential fact got lost in the endless noise from our resident crank. It's an interesting way of looking at spacetime rotation because it's the transverse view, like watching a car pop a wheelie as it passes you from left to right. That tilt on spacetime is what the Lorentz transformation models. In the diagrams I posted the red lines were the path lengths that light has to travel to get from each focus (far left and right of each diagram) to the center of the train (vertex of each V). What this means is, whenever you pass a fixed observer in a vehicle, you are tilting spacetime slightly as compared to his perspective. And for that reason, there can not be the seemingly expected overlap of simultaneity. We have a paradox, and without the paradox there would be no warping of spacetime, and vice versa. But of course all of this has been physically verified, most notably in the Global Positioning System, which -- even as we speak -- is up there popping wheelies.

Thanks for your patience. It's refreshing to converse with someone who's actually thinking about this stuff. It still blows my mind everytime I think of it.

(Heh heh . . . Perfect smiley to reflect my post. I tend to get long-winded!)

 

[Aqueous Id]

OMG! This must mean that there really is an aether! The beams didn't actually arrive at the same time and the experiment was a complete success!!!

More trolling. More repeat posting nonsense. As clearly explained to you in my response to your last childish outburst, and in the link you seemed to think I wasn't aware of, the aether would have been detected if the bands had narrowed from full out-of-phase fringing. Gawd, how long do you get to keep trolling?

 

[Pete]

LOL! LOL! LOL! You still don't get it!

THE BEAMS ARRIVAL TIMES ARE SHOWN TO BE SIMULTANEOUS BECAUSE THERE WAS NO INTERFERENCE PATTARN IN THE EXPERIMENT!!!

Do yourself a favor and get a life why don't you.

Layman, you said you're familiar with the Michelson Morley experiment. It's now clear you that you've only read about it at a vague pop science level, and you don't actually know the details of how it is performed.

Please, do some reading.

 

[Prof.Layman]

More trolling. More repeat posting nonsense. As clearly explained to you in my response to your last childish outburst, and in the link you seemed to think I wasn't aware of, the aether would have been detected if the bands had narrowed from full out-of-phase fringing. Gawd, how long do you get to keep trolling?

I guess for as long as you revel in your own ignorance. You just didn't understand it, and misinterpreted that to mean that there was an interference pattern that shows that they did not arrive at the same time. I don't know how much stupider this conversation could get. If you cannot accept the results of the experiments for what they actually where then you got serious problems. I wonder how long you have been trolling people in the name of this so called "science" that you claim to know.

 

[Prof.Layman]

Layman, you said you're familiar with the Michelson Morley experiment. It's now clear you that you've only read about it at a vague pop science level, and you don't actually know the details of how it is performed.

Please, do some reading.

So I guess that means that you know what the actual results of the experiment was? Could you explain to Aqueous ID that the beams arrive at the same time?

 

[Aqueous Id]

Layman, you said you're familiar with the Michelson Morley experiment. It's now clear you that you've only read about it at a vague pop science level, and you don't actually know the details of how it is performed.

Please, do some reading.

Better yet,"Reading for Understanding"!

Of course we always knew it would come to this, we'd call his bluff, he'd pull a card from his sleeve and it would be the 2♣.

(hey pete: Thoreau has an old-timers role call going - I took your name in vain there )

 

[Aqueous Id]

So I guess that means that you know what the actual results of the experiment was? Could you explain to Aqueous ID that the beams arrive at the same time?

No they do not. All they know for sure is that there is 180° phase incoherence when they set it up. In 1887 no one had access to a network analyzer, so get with it and stop flapping your trap. You've been harping on the same tripe ad nauseum.

if you want to know how interferometry works, just ask. But cut the crap.

 

[Aqueous Id]

I guess for as long as you revel in your own ignorance. You just didn't understand it, and misinterpreted that to mean that there was an interference pattern that shows that they did not arrive at the same time.

What do you think "out of phase means"? More moronic nonsense.

A phase interferometer doesn't care about absolute path lengths, not to within a wavelength of the actual zero crossing. It only cares about relative phase between two beams.

I don't know how much stupider this conversation could get.

As stupid as your crank posts.

If you cannot accept the results of the experiments for what they actually where then you got serious problems.

I have no problem with the way things are. I have a problem with the way your posts are.

I wonder how long you have been trolling people in the name of this so called "science" that you claim to know.

I claim to know nothing about the science of repeat-posting nonsense, other than the learning I get about mod patience when you get popped.

 

[Prof.Layman]

No they do not. All they know for sure is that there is 180° phase incoherence when they set it up. In 1887 no one had access to a network analyzer, so get with it and stop flapping your trap. You've been harping on the same tripe ad nauseum.

if you want to know how interferometry works, just ask. But cut the crap.

So you expect me to believe that all of pop science is wrong in giving the same interpretation of the MME? I think it is far more likely that your interpretation of the wiki page is wrong. And that there isn't an interference patteren between the two beams from them arriving at different times.

I don't know if you have ever heard this, but the MME proved that there wasn't relative motion between the beams of light in the experiment and the motion of the Earth. Then other experiments have been done that test this same thing that where actually in motion relative to the Earth.

How could I ever sleep at night knowing that I would be leaving what is actually science in your hands? And that you would be wrong about such a basic thing. Even layman know this stuff, come on give me a break.

If actual scientist say, they arrive at the same time, then they arrive at the same time. If they say, they arrive at the same time even in motion in this type of experiment, then they arrive at the same time while in motion in this type of experiment. You are no better than every other scientist in the world that has written about this topic. You don't even have a laymans understanding of this.

I don't know what you are trying to prove. You clearly do not follow what mainstream science has to say about this experiment. Get a clue, look it up in a pop science book if you have to.

 

[Aqueous Id]

So you expect me to believe .......

No. I expect you to stop posting nonsense. I expect you to ask how things work, since you have no experience, from the folks here who do have the knowledge and experience. I expect you to retract all of your insults and bogus invented claims. In short, I expect you to comply with site rules.

Contrary to your asinine remarks, interferometry is a measurement of phase difference only. It has nothing to do with measuring a time-of-arrival (although there are modern devices which do precisely that, but for an entirely different purpose). No one cares when the leading pulse of the lamp hits the objective; all they care about is what happens after they get it set up. The lamp could have been burning for hours before the first measurement is made. In fact they will purposely let the device warm up and temperature-stabilize so it doesn't expand or contract in use. First they make a delay adjustment in one of the legs until it comes into full deep saturated fringe lines. At this point the beams are not only imperfectly "arrived" but now a full half wavelength of difference is added to the cumulative amount. Again, no one cares about how long it took the leading edge of the beam to get there on one side vs the other. That's ancient history, and it's worthless information. All that matters now is what happens when they rotate the legs. If an aether is present, they expect it to "blow" the "light corpuscles" a little faster at the leg that's "pointing into the wind". And they would know this would happen because they would see the fringe pattern slip from 180° to 179° to 178° and so on, causing the bands to get narrower. Carefully measuring the width of the main fringe band with a graticule is how they arrive at the phase change. They plot these values as a function of the turntable position (compass angle). If an aether wind is present, they expect a sine wave to appear in their plot as the fringe band graticule measurements walk through the phase changes . . .3°, 2°, 1°, 0 359°, 358° . . . etc. back to . . . 182°, 181° then finally settling at the home orientation at 180°.

At no time was any measurement of beam "time-of-arrival" made, nor could it be made in 1887. All they are concerned with is phase difference. I suppose you can read the link you thought I needed to read until you are blue in the face and you will still never comprehend the most fundamental principles of a basic test apparatus. And this of course is the one that you keep whining about as the device that shut down AE's train thought experiment. Here we are thousands of lines of text after you made that bogus claim, and even with the evidence staring you in the face you have no clue what it means and how to arrive at a correct physical interpretation.

The MME was a flop, to their credit. All they were able to plot was the error in their measurements, nothing at all sinusoidal, so the gig was up. Aether was toast. However, from cradle to grave, none of these measurements had anything to do with time of arrival or simultaneity, much less relativity.

All of you claims to the contrary all repeat-nonsense posts. So you're trolling infractions are all part of he record.

Let the record speak for itself. Space time is relative, relativity in experimental scenarios requires two frames of reference and in all observations done to date all of the predictions of Lorentz-Maxwell-Einstein have be repeatedly verified. One that is laughing at you while you post nonsense is your GPS which is constantly acting under the constraints of SR/GR and yet able to make precision location measurements - precisely because the relativistic effects have been calibrated out.

 

[Prof.Layman]

No. I expect you to stop posting nonsense. I expect you to ask how things work, since you have no experience, from the folks here who do have the knowledge and experience. I expect you to retract all of your insults and bogus invented claims. In short, I expect you to comply with site rules.

Did you ever think about trying to lead by example? You say you don't believe in aether, but you keep trying to make an argument for it. I guess it was a good thing they didn't have you running the experiment. Still wondering how something can be measured to travel the same speed, but then can arrive at different times from traveling the same distance, in that kooky brain of yours.

 

[Cheezle]

Did you ever think about trying to lead by example? You say you don't believe in aether, but you keep trying to make an argument for it. I guess it was a good thing they didn't have you running the experiment. Still wondering how something can be measured to travel the same speed, but then can arrive at different times from traveling the same distance, in that kooky brain of yours.

It is very obvious you don't know what you are talking about. In the case that you might want to learn something, here is a good description of the Michelson Interferometer.

http://www.cis.rit.edu/class/simg232/lab8-20033-michelson.pdf

 

[Syne]

Exactly, as Syne has wonderfully shown the diagram above. If you tried to apply the logic in the TE to the MME, then the particles would not arrive at the same time, as shown above to the right. The experiment found that what actually happens is what is shown on the left. The left simulation has been shown to also be true when the experiment is considered to be in motion. So if I said the right diagram was on a train, then it wouldn't agree with experiment.

MMX does not compare two frames, so it is lacking the one thing in the TE that exposes relative simultaneity. Again, the emission and detection events of each path occur at the same places and times, which no observer would disagree on. The expectation of the waves being out of phase has nothing to do with the train in the TE.

But then the depth of your ignorance is no longer surprising.

Time would actually have to be dilated and different in other frames so that the beams reach the detector at the same time. I don't believe in variable speed of light, and I have refuted it many times in the past. I don't know why you keep saying that I would think there is a variable speed of light.

I said, the observer on the train can assume that he is at rest. Then two beams of light are sent to him at the same time. They are the same distance away. They would then travel the same distance, at the same speed so then they would arrive at the same time. His direction of motion would not change the arrival times, because the observer on the train would measure the speed of light to be the same speed even though he was in relative motion to where the beams are sent.

It would be like saying that in the right simulation, the beams are sent from the back of the train and then one is reflected off the top of the train and the other is reflected from the front of the train. They both then meet at the bottom of the train. The right simulation is what happens in Einsteins thought experiment, the left simulation is what happens in actual experiments. The two do not agree with each other. The left simulation would be what should happen on the train! That has been what was found by actual experiments!

The only way both flashes could be observed as simultaneous in both frames would be if there were a variable speed of light. Regardless of whether you have claimed this, your argument logically and physically demands it. You are just to blithely ignorant to bother looking at the facts. You know, the real world everyone tells you your woefully inadequate memory of simple pop-sci analogies is at odds with.

The train observer can and does assume himself to be at rest. But the only way for the flashes to be "sent to him at the same time" is for them to originate from the train frame. Reversing the TE to assume they do, the platform observer will then not see them as simultaneous.

It is physically impossible for both observers to receive the signals simultaneously when equidistant from their sources.

MMX and this TE are in complete agreement. You just do not readily see it because MMX does not address the factor in this TE which expose relative simultaneity.

 

[Aqueous Id]

Hey Cheezle, my man! Wussup? Thanks for that. But will he ever even begin to understand? I doubt it.

Did you ever think about trying to lead by example?

There's no lead here. There's just this constant suction coming from the vacuum of your mind. Yet nothing that goes in finds its way back to the speech centers, so all we get is a vacuous diatribe. You've had ample time to regroup and formulate your questions but you're still acting stuck on stupid, afraid to eat crow and ask somebody how something you've never used actually works. And you have the audacity to sneer at Einstein. You should be ashamed of yourself.

You say you don't believe in aether,

There's nothing to believe. It's only significance is that it helped usher in the era of Modern Physics since it had no basis in fact and folks wanted to be sure, so they went off and designed the MME which has nothing to do with simultaneity and/or perfectly equal path lengths.

but you keep trying to make an argument for it.

Liar. Prove that I ever made an argument for aether. You repeatedly lie about what I've said. And you persist in this moronic quest for disrupting intelligent dialogue.

I guess it was a good thing they didn't have you running the experiment.

As you've well established this is nothing about me. You, however, have done a bangup job of making the thread all about you.

Still wondering how something can be measured to travel the same speed,

At least now you admit your ignorance. For the umpteenth time: it's called phase interferometry. Two paths will be known to channel light at the same speed if the phase between them stays constant. The preferred calibration is at 180°. No one cares about absolute path length and no one cares if the leading edge of the beams arrived at the same time or not. Get that through your thick skull and you'll be on your way to the free pony rides at the end of the quiz.

but then can arrive at different times from traveling the same distance, in that kooky brain of yours.

Because the paths are not exactly the same "distance", and they don't have to be. No one cares about the path length. It's measuring phase, for the 900th time. I realize you have no idea what that means, but your willful ignorance is no excuse to insult me or anyone else here who is trying to get basic concepts from their freshman physics classes into your thick skull.

Go to question #4 in the nicely done lab handout that Cheezle got for you. Just answer the freaking question or the prof is going to throw you out of the lab without a ticket to the pony ride.

Somewhere you latched onto the bogus idea that the MME relies on the time of arrival of the beams when the lamp is turned on.(Laser in Cheezle's modern day apparatus.) That only applies to the case of the flash in the TE. It has nothing to do with keeping the lamp on and rotating the turntable a degree or two at a time while measuring the fringe width. All phase measurements are within ±180°. There is no information available about how many bazillion Angstroms long each path is, and no one cares, and the experiment doesn't utilize this information.

It's a phase measurement, you fool, and no one gives a whit how you think it works. You've got all the documentation here and all the longwinded explanations to puff yourself up on til the pony bucks and you're back on the ground kicking and screaming 'cause you didn't get your way.