Revenge of the Cranks by Chris Kennedy

From: Thomas Garcia 09/10/12

To: Nobody

Dear Nobody, I may have understood your points better now. I am not always as bright as I like to think I am, heh.

You and I, sitting at our desks, are observing 3 objects, 2 of which are moving at constant velocity wrt each other. The 3rd object is moving toward the first 2, at the same speed as they are moving toward object 3. In this case, I state in my essay that they all have the same time rate because they are moving at the same speed. I state also that all objects moving at the same speed will have the same time rate regardless of their location and the distance between them.

You state that in my train example (one I did not invent), my two observers are not moving at different speeds in space, but instead it is a reciprocal illusion of time dilation that causes each observer to see the other's clock "running slow." The only illusion, however, is that each observer can see the other's clock. I do not see how that is possible, and besides that, it is not relevant to the experiment. The experiment succeeds well enough in presenting relativity's case of so-called time "dilation" as fact without that illusory observation. It serves only as a distraction, I think.

You state that your Triplet Example shows acceleration has nothing to do with time dilations. I agree, but your example cannot be used to show the time differences incurred in the Twin Paradox because they are not the same experiments. One has acceleration in it while the other does not. The whole point of the TP is acceleration, which requires the spaceship to accelerate in order to return to earth. I will wait on our other points too so we can be clear about them.

My intention here is to learn that which I don't know. Several posts above refer to a multiplicity of frames in ways I don't clearly understand. I think science - physics for sure - uses words that are ambiguous by design at times, perhaps to hide some naked emperor's confusion.

Frames of reference are made up to illustrate a particular scenario. To me, the Twin Paradox is a single ref. frame which has in it the earth and a location in space where one twin goes to from earth and then returns to earth and upon meeting again, he sees that the stay-at-home twin is notably older than s/he, the space-traveler twin.

Now, all of that happens in a single frame, as I understand relativity. If that's wrong, please explain why.

Nobody to Garcia:

Garcia wrote re the Twin Paradox:

>Now, all of that happens in a single frame, as I understand relativity. If that's wrong, please explain why.

Well, now I see why we are having communication problems. There are at least 2 primary frames in the Twin Paradox, and most likely 3. Anyone moving at a different velocity from you is in a different frame. ("Primary" means that we are ignoring all the frames involved in the acceleration periods.)

2-frame case:

Only if Earth is at absolute rest in space, and only if the traveling twin moves at the same speed through space during both trips (outward and return) will there be only 2 frames.

3-frame case:

But the odds are against the Earth being at absolute rest in space, so this means that the "traveling" twin (the one who leaves Earth) must travel faster or slower when he returns than when he left, so this makes 3 frames.

Look at the last sentence on this page (the *very* last sentence):

http://mentock.home.mindspring.com/twins.htm

Why would anyone want to involve acceleration when talking about special relativity? And acceleration makes things much more complicated.

Garcia wrote:

>The whole point of the TP is acceleration, which requires the spaceship to accelerate in order to return to earth.

No, the whole point of the TP is the age difference, and this is the whole point because acceleration has no effect upon aging or intrinsic clock rates.

http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html

"... it has been verified experimentally up to extraordinarily high accelerations, as much as 1018 g in fact ...."

Thank you for your response, Nobody.

It took me awhile to find where I went wrong, but I found it. It was my error in mixing up my notes and not noticing they did not match. I had just finished a long explanation why your Triplet example is a - wait for it - single frame of reference. I typed up my response, sent it, and went to bed. I am often wrong about things, unfortunately for me, so I try hard not to mess up, but this was a doozy! I could not be more embarrassed.

One thing I need to clear up. You said "anyone moving at a different velocity than you is in a different frame." I may be wrong again, but I think it is not that simple. For one thing, we are usually observers of frames and not participants of one. Observers set the coordinates of a frame in order to measure the position, velocity, and acceleration of objects. I would say instead that any acceleration in a ref. frame creates a new frame of reference.

You asked, "Why would anyone...involve acceleration when talking about special relativity? And acceleration makes things much more complicated."

I would answer that it cannot be avoided. You avoid using that term by using "...a different velocity from you...." But that means the same thing, does it not? An inertial RF can have objects at rest or in motion, and an object's velocity is changed by any acceleration, as you said so yourself.

from Thomas Garcia to Nobody

I must disagree that the point of the TP is the age difference. To me, the whole point is Einstein's claim showing us there are time rate differences that occur between bodies when they move at different speeds. Two or more bodies moving at the same speed will accrue the same time rate.

Garcia wrote:

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One thing I need to clear up. You said 'anyone moving at a different velocity than you is in a different frame.' I may be wrong again, but I think it is not that simple. For one thing, we are usually observers of frames and not participants of one. Observers set the coordinates of a frame in order to measure the position, velocity, and acceleration of objects. I would say instead that any acceleration in a ref. frame creates a new frame of reference.

--------------------

Hello, Garcia, you are correct of course when you say that acceleration creates a new inertial frame, but, as I tried to get across, acceleration is not the important thing when talking about inertial frames. Indeed, one definition of an inertial frame is that it contains no acceleration, i.e., its observers and its objects feel no acceleration forces.

Garcia also wrote:

--------------------

You asked, 'Why would anyone involve acceleration when talking about special relativity? And acceleration makes things much more complicated.'

I would answer that it cannot be avoided. You avoid using that term by using 'a different velocity from you' But that means the same thing, does it not? An inertial RF can have objects at rest or in motion, and an objects velocity is changed by any acceleration, as you said so yourself.

--------------------

Garcia, did you not look at the cited web site? The whole point of using triplets was to avoid accelerations.

http://mentock.home.mindspring.com/twins.htm

Note that this website was fully endorsed by relativity experts; it is not my site. Even these SR experts fully agree that acceleration can indeed be avoided, even in the Twin Paradox case (by simply adding another person, making it Triplets).

Dear Criss

I really enjoyed your essay. I have nothing more to say that I agree with your view. Right now I am having a discussion with Daniel Wagner who supports relational motion, you may be interested in reading our discussion in my essay and his. From my part I hold that there is a preferred system of reference (PSR) which obviously eliminates all paradoxes of relativity. I am sure you will find my work interesting. By reintroducing the aether and the PSR I endeavor to build a stronger model and explain most physical phenomena (see also my discussion with Jaryl Danzen about the physical interpretation of the red shift in my entry and his). I would be glad if you could make some comments in my entry. Actually, my reference 17 in my essay implies a new paradox in relation to the isotropy of the one-way speed of light according to two observers. Please feel free to take a look at the discussion with Daniel Wagner in his entry and mine where we treat these topics. I will recommend your essay to him, so he gets a deeper feeling of how paradoxical SR is.

Congratulations for your work and best luck in the contest

best regards

Israel

Chris,

JM: Like I said, if you analyze it in any given inertial frame, you get the same result for the age difference.

CK: I'm not even sure what that means, since from the traveler's perspective, he is not in an inertial frame for the entire journey.

Pick *any* inertial frame. It doesn't have to be a frame ever used by either twin, though it could be. For instance you could use the frame initially comoving with the twin who accelerates; after he accelerates he won't be at zero velocity in that frame any more. Analyze the situation. Solve for the difference in proper time between the twins. You will get the standard answer, if you do the math correctly.

Or, pick any non-inertial coordinate system. Analyze it using the methods of GR like Einstein did to see things from the viewpoint of the accelerated twin. Once again you will get the same result. The wikipedia page I linked you to explains what Einstein did, which was correct and a good demonstration of the fancy methods of GR. Just as you can choose different coordinate systems in non-relativistic mechanics and get the same result, in GR you can use even non-inertial coordinate systems and still get the *same* result though you will then attribute that result to gravitational fields that don't exist in an inertial coordinate system describing the same situation. GR is like that. But you don't even understand SR so you'd better stay away from thinking too hard about GR right now.

Well, I have tried to help you. I doubt it will do you any good. It will not be worth my time to try to help you any further because you are not open minded. Ironic but not surprising that you accuse the establishment your own failings; it happens with all crackpots.

Regards,

Jack

Nobody, I searched 5 pages looking for the site, to no avail. Now this time I found it right away. It is completely different than your first one, though.

The gist of your citation seems to be "A lot of [TP] explanations,,have claimed it is necessary to include a treatent of accelerations,or involve [GR]. Not so." In their example, they, like you, also change the TP into a different experiment by saying SR "seems" to imply that either twin can be seen as being "at rest. Then they say yes and no,and that SR's implication is the reason it is a paradox.

Then they say "Bob must change his inertial frame" in order to avoid restating "the problem with [only] the names changed." They do not understand that is what SR says, that either twin can be at rest while the other leaves then returns! Wayne et al seems confused at this point since when they change Bob's frame on the planet, they accelerate him! But Ann is never accelerated wrt to Bob in SR's TP! Clearly, theirs is no longer the same TP experiment, and that invalidates their claims against SR's time dilation effect.

Let's say Bob stays home. The coordinates include earth, Bob, the spaceship, and Ann. All are at rest rest relative to each other. Primary I.F. 2 shows Ann accelerating as she takes off on the ship. P.I.F. 3 shows her return trip to earth. Yes paradox.

A question like "does acceleration affect light clocks?" would definitely make for an interesting discussion, but I don't know if I can quantify anything simple right now to give a yes/no answer. I've come close, by trying a few times to visualize what it would be like for a light clock to travel through a gravitational field, and the one thing that I notice that always automatically pops up is acceleration. I'll try to fiddle around with it some more to see if this acceleration would have a secondary effect.

I've attached a couple of pictures to illustrate the acceleration effect. The top image shows a light clock where the photon makes a 90 degree change in direction at every tick. The bottom image increases this angle based on height, and so the lower the photon goes, the closer this angle gets to 180 degrees, and the slower time runs. Just following this simple rule, one automatically gets acceleration.Attachment #1: accel.jpg

To Garcia:

The reason for my citing the web site was simple - it was to show how Triplets can remove all acceleration.

Here is a quote from the cited site that you finally sighted:

"To avoid accelerations in the thought experiments above, we can simply make the second Bob frame into a 'messenger' Carl that never accelerates, but passes by Bob as they set their watches together. Messenger Carl then travels to Ann and compares watches as they pass each other. That makes it clear that there are three distinct inertial frames involved."

Please note their key phrase "To avoid accelerations."

Nobody, we already agree there are 3 primary I.F.s. Our point of contention now is my claim that your citation is substituting the author's incorrect understanding of the TP which is not parallel to the TP and thus his is a false analogy to the TP, which makes it an invalid argument by the rules of logic.

An argument defeated in proper debate is an argument lost. Unless you can show I am wrong in my claim that it is an incorrect analogy to the TP, it remains an invalid argument.

Your turn, Friend.

Hi, Chris,

Yep, the clocks do slow differently due solely to their different speeds thru space (inertial motions only), but this does not obliterate Galileo's principle - only Einstein's. (Gal's mechanical relativity still stands, but E's optical rel. falls - but it never held in the first place - so no big loss there!)

To Garcia:

It really makes no difference what Throop said about the Twin Paradox because that case involves acceleration, which I am trying to avoid, and which can easily be avoided by simply adding a third person. This tells us in no uncertain terms that people age differently even sans acceleration. SR has no explanation.

Neo-Lorentzian interpretation of relativity is also not justified. I am looking forward ...

Eckard

T. Garcia to Nobody:

Nobody, I can only reply that the TP thought experiment has as its basic premise acceleration in it and if you take that out it is no longer the same experiment. Like if you want to measure the distance between earth & pluto but you can't because pluto is too far away. So you measure the distance to Saturn and say that is the same distance to Pluto.

Acceleration need not be a speed increase; it can a change of direction or up or down, or a slowing of speed. Acceleration is merely a change in motion. Why would anyone want to take acceleration out of the TP?

Without it, in fact, there can be no time changes, as per SR's explanation. An object moving at constant speed and direction is at constant velocity, while an object moving in a perfect circle is at constant acceleration.