Here are two of them:

Linking to an image does not demonstrate understanding.

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SeanF

"Ask to understand, but don't challenge unless you have the knowledge."--NEOWatcher

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Hey, if he can substitute the explanations for the math, he probably considers an image link as understanding.

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Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Neptune- The original Dark Matter.

The author feels that this technique of deliberately lying will actually make it easier for you to learn the ideas. - Donald Knuth

I know what you're thinking.

I realize that the way you look at the thought experiment, you think that the “A” clock “really is moving” and the “B” clock is “not moving”.

You need to keep in mind that in the SR theory, the two clocks are “moving relatively”, since we have no fixed place in space with which to judge their motion, both systems are absolutely equal, and they are not experiencing any “acceleration”. So the motion is only “relative”.

The “stationary system” is whichever system you fix your mind in and think that you travel with. It can be the K’ or the K system, it doesn’t matter, since the motion is only relative.

You need to study the origin of Einstein’s ideas. He got them mainly from the Lorentz theory and Lorentz’s 1895 book, which Einstein credits in a 1907 paper (see Volume 2 of “Collected Papers”).

In Lorentz theory, Lorentz had two “relatively moving” systems, but only one of his two atomic clocks really slowed down. Why? That’s because that system and that clock were moving through his “ether”. The ether put up a resistance to the motion, and this caused a force to be placed on the atoms, and as a result, their oscillation rates slowed down. The “stationary” system and clock in his theory were stationary with the ether, so that clock did not slow down. So it wasn’t the “relative motion” that caused the slowdown of that one atomic clock in Lorentz theory, it was its motion through the ether that caused it, because the motion caused a Lorentz type force to be placed on the atoms that moved through the ether.

Einstein took that theory and tried to work it around a bit, to try to get rid of the ether. He tried to attribute the slowdown in his “moving” clocks to “kinematical” effects. He tenaciously kept his mind oriented with the K system, I think because that system represented the earth to him in the Michelson Morley experiment. So, he never had the earth-clock (or K clock) slow down, since he always oriented his mind as being stationary with that system’s clocks in the SR theory.

He realized that the way he set up the theory would cause someone in the K’ system to see the clocks slow down in the K system, but he ignored that in the Section 4 thought experiments, as he set up the thought experiments for himself and his reader to think of only one clock was “stationary” and only one clock was “moving,” rather than both clocks moving “relatively”. Unfortunately, this was a geocentric or K-centric point of view, and this led to the paradox.

When other physicists read his theory in 1905, many of them saw the error and the paradox. That’s why we have so many attempted “twins paradox resolution” attempts today, and none are alike, and none are like Einstein’s own attempt in 1918.

The later GR theory has no paradox, because it is more like the original Lorentz theory. The atomic clock that experiences the most force is the one that slows down the most. The slow clock sees the fast clock running fast, and the fast clock sees the slow clock running slow. No paradox.

No insults please. That is not allowed.

Hey, Tensor, what ever happened to swansont and the two horses?

Don't know. I've only been able to pop in now and then ( AAMOF, I've been here for about 20 minutes tonight, which is the longest I've been on here in a month)

__________________
Some try to tell me, thoughts they cannot defend,... - Moody Blues.

Neptune- The original Dark Matter.

The author feels that this technique of deliberately lying will actually make it easier for you to learn the ideas. - Donald Knuth

Name three.
Electromagnetic theory obviously works, and when united with quantum mechanics it works with uncanny precision. Notions of "common sense" mean nothing, only concrete results. A century's worth of scientists and engineers have the results. And your three critics that you will be naming have ... ?
[-(

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The bar has been lowered for the promotion of ATM ideas; the bar for the acceptance of ATM ideas must remain high.

I now officially condemn CM's skits as smartaleck, ignorant, sophomoric, inflammatory and and a poor reflection on the level of discussion in BAUT. -- Bob Angstrom

Yes, Sam, you are correct. I inadvertantly switched them. I apologize for my mistake.

I can't help but notice that you responded only to the typo, and not to any of the conceptual issues.

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"I have a cunning plan that cannot fail."
S. Baldrick

Some contemporary SR critics, all PhD physicists (none of them YECs or Gs!):

Harvey, Renshaw, Lange, Rebigsol,Todoroff, Bartocci, Hecht, Ferrigno, Moch, Markweger, Neundorf, Babin, Galeczki,Hanks, Hille, Miller, Ott, Siepman, Apostol, Bjerknes, Dissler, Friebe, Munshi, Rado, Schmidt, Theocharis, Ahonen, Boersema, Aspden, Hatch, Jansen, Gaasenbeek, Kalanov, Keyser, Larsen, Marklin, Mehta, Marmet

Here's an example of the Twin Paradox resolved with SR alone
http://sysmatrix.net/~kavs/kjs/addend4.html

Sam5, I think you're still missing the fact that you can't set a coordinate system in motion under SR. While the K' and K axes y and z [1] overlap at the moment when the motion of the clock starts, the x and t axes do not. Nor have they, ever, because the two coordinate systems must be defined so that they've always been in motion wrt each other. The clocks may accelerate, move, be viewed from/switch between coordinate system, but the systems themselves cannot change their motion in any way at all. Even before the A clock has started moving, K' is already moving the way A is going to, expecting to "catch up with it" just as motion starts.

So, when motion starts:
The clocks A and B are synchronous and synchronised in K
The clocks A and B are synchronous, but not synchronised in K'
The clocks A and A' (the moving one) are synchronised in both K and K', however, they are not synchronous. K and K' views diverge on which is running slower, though.

When A' reaches B, observers in K and K' will both agree that A' lags behind B.
The K observer sees that A' is running slower than B; the K' observer sees the reverse, but also says that B was far ahead of A' (and A) when the motion started!

To switch to the other example, so far, Sam5 is actually correct. The race is a tie, simply because when considering simultaneity, you correct for signal travel time.
However, if a camera is travelling along the finishing line from horse B to horse A, it'll observe A winning. If it's travelling the other direction, B wins. This is regardless of where the camera is when the horses finish, and after correcting for signal travel time.

[1] y and z are perpendicular to the direction of motion, x, as things are normally defined.

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"We do not require reality to conform to the expectations of the ignorant"

Interesting that you should say that, because that’s also what Sean said. Give me some time to have a few cups of coffee this morning and I’ll respond with my point of view about it.

These are subtle effects we are talking about here, and the strength of the materials is enough to overcome them. But the answer is no.
Well, if you're going to push from behind, it's going to be hard to separate, I agree.

But if the front and the back had different engines such that each experienced the same acceleration, then they would separate.

That’s ok. I made a mistake on the other thread about a marble falling 32 feet the first second, when it actually falls only 16 feet.

I think we’ve settled who won the race and where to place a single camera to show that the race was a tie. That position above the finish line, and equal distance from each of the two horse’s noses.

The stuff I posted about the rules of horse racing were just sort of little jokes, since they only judge winners to an accuracy of about .01 of a second. So I suppose we could make up a joke about why two physicists didn’t enjoy a “photo finish” horse race that was a tie, because they both argued about the position of the camera and the travel time of the light signals, and they wanted nanosecond accuracy. I suppose if they were two quantum mechanics experts, they never could settle the answer because there would be a 50-50 chance the leading electron in one horse’s nose would be at the finish line or not at the finish line, and the same with the leading electron in the other horse’s nose, and that under QM rules, there is no such thing as a provable tie in a horse race.

There is no “Stella-come-Alf” in the 1905 paper. There are no three moving systems. There is no third party adopting a second party’s clock reading as they move in opposite directions relative to one another. There are no space buoys stationary relative to the earth. There is no earth. In the “closed curve” thought experiment of Section 4, the K observer sees the K’ clock move in the closed curve, while the K’ observer sees the K clock move in the closed curve, so there is no “turn-around” of any single clock in SR theory.

Let’s study what Einstein says at the beginning of Section 3:

”Let us in ‘stationary’ space take two systems of co-ordinates, i.e. two systems, each of three rigid material lines, perpendicular to one another, and issuing from a point. Let the axes of X of the two systems coincide, and their axes of Y and Z respectively be parallel. Let each system be provided with a rigid measuring-rod and a number of clocks, and let the two measuring-rods, and likewise all the clocks of the two systems, be in all respects alike.

Now to the origin of one of the two systems (K’) let a constant velocity v be imparted in the direction of the increasing x of the other stationary system (K), and let this velocity be communicated to the axes of the co-ordinates, the relevant measuring-rod, and the clocks.”

Ok, first, there is no such thing as “stationary” space. So we’ve got to consider whichever system Einstein’s mind stays with, to represent a limited kind of theoretical “stationaryness”.

Next, he “imparts a constant velocity” to the K’ frame. You notice that in this theory he leaves out acceleration effects, so here he imparts the “constant” velocity with absolutely no consideration of acceleration. This is not possible in real life, so we have a second situation that does not represent reality: 1) “stationary space”, and 2) “imparting a velocity” without an acceleration taking place.

Both concepts are both ok in theoretical physics, as long as we realize and fully accept the consequences of these two deviations from reality. But we must realize that the more real stuff we leave out of a thought experiment, the more our thought experiment is prone to give us false results.

Ok, so, the K’ system goes from no motion relative to K to a fixed velocity relative to K, and this disproves your statement, ”you can't set a coordinate system in motion under SR” since Einstein obviously sets the K’ system in motion, relative to K, in Section 3. First it is not in motion relative to K, and then it is in motion relative to K.

Let's not. You can't discuss Einstein's usage of coordinate systems until you understand what a "coordinate system," in general, is.

And you apparently don't.

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SeanF

"Ask to understand, but don't challenge unless you have the knowledge."--NEOWatcher

The contents of this post are ©2010 by SeanF and may not be copied or retransmitted in any form without the express written consent of SeanF

The front and rear of the space shuttle don’t have separate engines and so the front and rear don’t separate. The front might compress a little toward the rear due to the acceleration from the rear, much like tall buildings compress a little over the years, but I doubt if the top of the pyramids in Egypt have compressed toward the bottom more than a few mm during the past 4,500 years. The top certainly hasn’t separated itself from the rest of the pyramid and gone a few mm up into the air. Based on your theory of “separation” due to acceleration, the top stones of the pyramids should have stretched upward into space rather than downward.

“For example the U.S. capitol, Gregory says, has settled 5 inches during the last 200 years. But the Great Pyramid settled for less than 1.5 inches during the last 4500 years (Russel & Sellier 1994).”

Source

If that's what you think then nothing has been settled. If the race was a tie to the observer in the middle then the time difference would have been 10 ns to a camera on the end. I deliberately chose a different value.

But it is true that there is a camera position that will show it to be a tie.

The problem that you have avoided addressing is how does one decide beforehand - without knowing where the horses will end up - which camera is the correct one.

By saying that you have to put the camera in the middle of the two horses, you are essentially solving a simple equation to tell you what you want to know, and you are arbitrarily choosing a frame of reference to the jusge. But this camera position would change from race to race.

This is the same concept that applies to other aspects of relativity - there is no preferred frame. If you want to compare measurements, you have to choose a coordinate system, because measurements from different coordinate systems will disagree, even though they are observing the same event.

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"I have a cunning plan that cannot fail."
S. Baldrick

Well, let’s hear your definition of it.

You can’t simply remove the parts of the SR theory you don’t like and hide them away in a closet. The entire theory leads up to the paradox in Section 4.

I was basing my central camera position on your diagram, which clearly showed the two horses in a tie. Now you’re trying to claim your diagram wasn’t accurate and it wasn’t really a tie.


Yeah, so? Everyone already knows that. We don't need "relativity" to tell us that. Anyway, the races only judge accuracy within .01 of a second. They disregard nanoseconds.

You know as well as I do that you're not going to accept me as your "teacher," and I'm tired of trying. Find somebody else to explain it to you (a math course would be a good place to start).

Says the guy who ignores the math in the theory. :roll:

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SeanF

"Ask to understand, but don't challenge unless you have the knowledge."--NEOWatcher

The contents of this post are ©2010 by SeanF and may not be copied or retransmitted in any form without the express written consent of SeanF

You claim you understand what a coordinate system is and I don’t, so tell us what you think it is. Maybe it is you who does not understand what it is, since you don’t understand the paradox of SR theory. I remember back in the days when you claimed the paradox was “resolved” because the K’ clock “turned around”, until I pointed out to you that there is no “turn-around” in the SR thought experiment we have been discussing. So you learned that from me.

I don’t ignore the math in the theory. I’ve already pointed out that the two relatively moving clocks are supposed to see each other’s time dilate in the amount of:



So if both see this amount of time dilation in each other’s clocks, then both clocks will have the same reading at the end of the thought experiment. The paradox is caused by Einstein claiming that while both observers see this amount of time dilation in each other’s clocks, only one of the clocks “lags behind” the other at the end. This is a paradox caused by incorrect conceptual considerations.

You've a long way to go before you get to all the math in the theory. A simplified version of the dilation equation is not the entire theory.

Here it is, in the last paragraph of that Section 4: "If one of two synchronous clocks at A is moved in a closed curve with constant velocity until it returns to A"

You can't move in a closed curve without turning around. And "one" means "single".

Are you seriously saying that you think the top and the bottom of the pyramid experience the same acceleration due to gravity?

No, Sam5, your theory about how GR works is wrong.
Not all, but a lot. You've said that math leads to mistakes. It's not math's fault.
That's right, but not by Einstein's incorrect conceptual considerations. By yours. You haven't described the setup properly, even in that paragraph.

Note that he isn't using K' for anything whatsoever before the velocity is imparted. He's not describing a physical process here, but describing how K and K' work, step by step. You cannot use the same mathematics for a K' that isn't moving wrt K and one that is - physically, they're two different systems. So when you look at things in K', you must realise that this system is moving wrt K regardless of when you examine things in it. No accelerating coordinate systems are permitted in SR, so if you want to change the motion of an object and stay with it, you have to define another coordinate system.

As long as we're aware of what conditions must hold for our thought experiment to work, there should be no deviation of reality and our expectations.

About the twin paradox: You have to define which version you're working with, since there are several ones being tossed around. In the version I described above (I think this is Einstein's original one) there's one clock moving from a point some distance away towards us (points A and B, respectively, in my description previously). That one requires two coordinate system. If you want to have a clock travel outwards and come back for comparison, you need (at least) three coordinate systems to describe it under SR. GR will handle them all and gobble up geocentricity as well without breaking a sweat.


swansont, sorry, but you're wrong in this. You have to have the observing camera in motion to see any simultaneity effects; just changing its location won't affect simultaneity as relativity sees it. This is analogous to when we talk of measing time dilation with frequencies; the classical, "naive" effects have already been removed from the situation so that only the effects we're interested in remain.

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"We do not require reality to conform to the expectations of the ignorant"

He doesn’t consider acceleration in the 1905 SR theory, and the theory also has either system and either clock as being considered the “stationary” one to the observers that remain with it. If an observer remains with K then he sees the K’ clock move in the “closed curve”. If he remains with K’ then he sees the K clock move in a closed curve.

It was probably this thought experiment that caused him to start thinking about accelerative effects, and of course he later concluded, as Lorentz had done many years before him, that an accelerated atomic clock would tick slower than a non-accelerated one.

You can find his progression of papers related to acceleration in Volumes 2 through 5 of the “Collected Papers” series.

When he finally worked out the acceleration effects on atomic clocks, then the paradox disappears, since only one clock really accelerates and slows down, and the slow clock sees the fast clock tick fast, while the fast clock sees the slow clock tick slow.

But he hasn’t gotten that far yet in the premature, impetuous, an precociously erroneous SR theory of 1905, and his 1905 errors led to his 1905 paradox.


[correction for double post]