Revenge of the Cranks by Chris Kennedy

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!)

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.

T. Garcia to Chris Kennedy 09/13/12

Like you, Chris, I wonder in my essay why no one had previous to me noticed my essay theme that speed determines the time rates for objects. You wrote a fine piece and included what could be valid arguments for your POV. We have found different viewpoints, however, in that you see the paradox as being the claim that each twin - if they could see each other's clocks - would see the other's clock as running slower. To me, the paradox is the so called "time dilation effect," which is resolved by my claim that time is a property of matter, etc.

Basics

A) Yes, I learned long ago A. Einstein (AE) took a lot of ideas from others without always giving credit where due, which often resulted in the public thinking he was not as great a genius as we were taught he was. But I think he was, really, since he maneuvered his way well through the lethal labyrinth of naked emperors who fought fiercely, as some still do, to hold on to whatever status they managed to win by hook or crook.

B) Here, he gave Galileo some credit. However, the statement that starts out with, "That is, all motion at constant velocity is to be considered relative...." puzzles me because constant velocity here seems out of place. Since all objects are in motion, all motion is relative, not just motion at constant velocity. What is your opinion on that?

To you, it seems the issue is the way AE concocted his explanations to resolve the TP, when all he had to say is that time is a property of matter and it passes inversely proportional to an object's speed. In order for the spaceship to leave earth and then return to it, it had to speed up. It did not have to turn around if it made a circular round trip, but if it did, the speeding up - relatively to the earth - is necessary to catch with the planet once more. Is that correct, or not?

The train experiment and others like it support AE's relativity also. So if he made up his math, it would not be the 1st time, but even so, the simplest explanation for any paradox is one like mine, I think, because it does not need any math to confuse the issue. If AE could have done that, we all would have been much smarter faster.

One thing to consider is that if someone is aging faster, ie. has a faster clock rate, they are not traveling into the future more rapidly, but into the past faster. They die sooner. Time is not a measure or dimension from past events to future ones, but the process by which the future becomes the past.

Knowledge is created inductively, future possibilities condensing into actualities, but it is used deductively, applying past experience to predict the future.

Tom,

I think it's more the velocity. As in traveling at the speed of light, time is stopped, since there is no internal activity to light, since the combination would exceed C. Acceleration also would slow the clock, ie. equivalence principle, but constant acceleration would quickly reach the speed of light, so that effect would be limited.

As Chris' essay shows, all these ideas are historically ambiguous and it's only tradition that canonizes them.

To Garcia from absolutely Nobody:

It's obvious why we need to get rid of all acceleration - this is the only way to simplify the TP so as to preclude any claims that acceleration has anything to do with the age difference.

Have you never heard of the KISS rule? We do not need overly-complicated examples for cases that are very simple. (This rule should also have been applied by Chris in his essay.)

Not to remention the fact that acceleration has *no* effect upon either clocks or twins anyway.

T. Garcia to Nobody:

Maybe this will help you see it is not acceleration that is needed to see the whole forest. It is needed to cause time dilation. In your Triplet Example, there is no time dilation because there is no acceleration on the part of the three ships in space. For time to "dilate," one ship has to change its speed from that which all three are moving at constant speed. That one ship's time rate will be different than the other two ships.

The effect of time dilation is a pardox which is clearly stated in the train experiment. There is nothing left to resolve unless one can sccessfully argue the time as measured by each observer is the same. Until then, the imaginary "time dilation" paradox does not exist anymore because we know now how it happens and why: It happens because time is a property of objects and passes inversely proportional to an object's speed.

What train experiment?

And, sorry to say, but you are simply ignoring all of the facts that I have already presented.

You wrote:

>In your Triplet Example, there is no time dilation because there is no acceleration >on the part of the three ships in space.

No, acceleration is not needed to cause time dilation because

[1] it cannot because it has zero effect upon clock rates (tested experimentally up to 10^18g) http://math.ucr.edu/home/baez/physics/Relativity/SR/clock.html

and

[2] As Throop said, Ann aged differently from Copy-Bob despite the fact that no one accelerated.

If you cannot digest these two simple facts (not given just by me, but by much more reputable people), then I will have to stop discussing this with you.

In any debate, one must not discard the facts at hand.