Why in the world would Einstein suggest....

@dalehileman,

Quote:

But the Twin Paradox (and now I believe I'm agreeing with you) seems to constitute evidence for the "preferred" frames. I'm just surprised that our SR bunch hasn't come up with a clear answer

They don't have a clear answer. I previously cited a website which discusses an "open letter" that a large group of scientists (and others) sent to the "physics community." They just asked for a clear, consistent, and meaningful explanation of the "twin paradox."

That site reviews all the unsatisfactory answers that have been advanced over the years. It also summarizes the results they have achieved, in the way of responses from phyicists. Unfortunately, no physicist provided them with what they asked for.

The problem is NOT that the answer is difficult. It isn't. It's really rather simple. Paul Langevin gave it, back around 1905. The problem the physicists have is that they try to give an answer AND simultaneously maintain that no preferred frame is being used.

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@layman,

Quote:

The same thing could be said about "germs," and many other things, which were posited long before we had any means of knowing they were true.

As has already been discussed in this thread, cosmologists now seem to (almost universally) agree that the physical existence of a preferred frame has now been discovered (i.e., the CMBR).

Of course the existence of the CMBR was unknown, undetected, and, in fact, undetectable back in 1905 when Al's and Lorentz's theories were originally being debated.

In case you don't recall, Dale, I cited (and quoted), among others, Dr. George Smoot, a physics professor at Berkeley, (who won the Nobel Prize for Physics in 2006) as support for the assertion that the CMBR establishes a "preferred frame."

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@layman,

Astrophysicists (and others) now routinely use the CMB as a "preferred frame" in making their calculations. They also use the lorentz transformations to assess time dilation, etc.

But they do NOT use SR (which also employs the lorentz transformations). SR purports to prohibit the use of a preferred frame.

Back around 1920 or so, Bertrand Russell, the famous mathematician and philosopher, said: "The theory of special relativity IS the lorentz transformations."

He was essentially right. But the converse is not also true. It is false to say that "The lorentz transformations ARE the theory of special relativity."

Nonetheless, physicists will now routinely say that "SR" has been confirmed by experiments and facts which do NOT use SR, but which use the lorentz transformations (e.g. the Hafele-Keating experiment and the functioning global positioning system).

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@layman,

Actually, it should be noted that the LT, taken from Lorentz by Einstein, were "adjusted" by him to include a term incorporating the (dubious) "relativity of simultaneity" which Lorentz himself unequivocally did NOT use. Therefore, the transformations used by each are not indentical (even though each is referred to as "Lorentz transformations').

The following excerpts are taken from a paper written a little over a month ago by a professor at the University of Georgia, Edward T. Kipreos. Kipereos makes this distinction by calling the original transformations, used by Lorentz, the ALT (Absolute Lorentz Transformation):

Quote:

The Absolute Lorentz Transformation (ALT) is an alternate Lorentz transformation that has similar kinematics to special relativity (SR), but is distinct in describing absolute simultaneity and invoking a preferred reference frame (PRF) relative to which time dilation and length contraction occur in a directional manner...

ALT differs from SR in several respects. ALT maintains absolute simultaneity for all observers, while SR implies local differential simultaneity [2, 3]. The corollary to this is that SR maintains light speed isotropy between inertial reference frames, while ALT implies anisotropies in the one-way speed of light, although the two-way speed of light for ALT is c [3, 9]. The two theories also differ in that time dilation between inertial reference frames is reciprocal for SR and directional for ALT. With directional time dilation, observers in a PRF will observe that
clocks moving relative to the PRF run slower, while observers in non-PRF
reference frames will observe that clocks in the PRF run faster (i.e., exhibit time contraction)...

...unlike ALT, SR cannot distinguish between an absolute reference frame and other inertial reference frames. This is because SR predicts equivalent, reciprocal time dilation and length contraction between any two inertial reference frames, including a potential absolute reference frame...

Experimental evidence from Hafele & Keating indicates that the Earth centered non-rotating inertial reference frame (ECI) can act as a local reference frame to direct time dilation (i.e., a PRF in the broader sense)....In the Hafele & Keating experiment, the time dilation was absolute and directional, as the flying and ground-based clocks showed different elapsed times when brought together for side-by-side comparisons. Hafele & Keating suggested that the directional time dilation arose within the context of SR... [but] clocks on GPS satellites undergo time dilation of ,7 ms per day relative to the Earth’s surface, which is calculated by applying the Lorentz/ALT time dilation formula independently to the speed of the satellite relative to the ECI and to the speed of the Earth’s surface relative to the ECI [17]. Correcting for the Lorentz/ALT time dilation is essential for proper positioning in the GPS system

http://news.uga.edu/documents/Kipreospone0115550.pdf

The author also explains that preferred reference frames are locally associated with centers of gravitational mass, suggests that experiments can be devised to distinguish between SR and LR, and explores the consequences of an absolute simultaneity theory (which he abbreviates as an AST) for cosmological phenomena.

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@layman,

One advantage that an AST has over SR is that it is NOT limited to inertial frames. Quoting from the same author:

Quote:

Historically, SR has not been used extensively in general relativistic cosmology (GRC)...These historical considerations would not apply to ALT, which is not encompassed by Minkowski spacetime or current GRC theories.

The Lorentz transformation/ALT equation can accurately calculate the time dilation of objects traveling in non-inertial frames [12]. It can also accurately predict the time dilation of muons traveling in a circular cyclotron using only the speed of the muons as input; and this motion is, by definition, accelerated motion [51]. Further, the Lorentz transformation/ALT equation accurately predicts the time dilation of subatomic particles traveling through Earth’s atmosphere [52], which is neither empty nor flat, with densities of matter and curvature of space that are significantly higher than that found in intergalactic space...The Sagnac effect is consistent with AST because light is predicted to propagate isotropically only in PRFs, but not in reference frames moving relative to a PRF, such as the rotation of the Earth’s surface relative to the non-rotating ECI [3]. The Sagnac effect does not conflict with SR because rotational movements are considered to be exempt from the relativity principle...This wide applicability is consistent with ALT for which there is no theoretical basis to limit its application to inertial reference frames.

In other words, an AST works in non-interial frames and frames which are rotating, whereas SR does not. The author is quite polite when he says, for example "The Sagnac effect does not conflict with SR because rotational movements are considered to be exempt from the relativity principle."

In this context he is using it, "exempt from" reduces to "fails in." SR falls apart, and its premises are shown to be false, when it is applied in accelerating and rotating frames. Therefore, it does not "apply" and is "exempt." Not true for an AST (which also avoids all the "paradoxes" generated by positing relative simultaneity).

That is the reason that SR is compelled to concede that non-inertial motion is absolute. SR can't even pretend that such motion is "relative." Likewise with rotational motion, which, according to SR, should be totaling undetectable. It isn't, even when applying SR. Just one more reason why it is incorrect to say that "you can't tell who's moving."

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@dalehileman,

Dale, I want to repeat what I said in response to one of your questions:

Quote:

Dale said: But the Twin Paradox seems to constitute evidence for the "preferred" frames. I'm just surprised that our SR bunch hasn't come up with a clear answer

I've posted a lot, and you might not care to read all of it (even though it's for you--nobody else seems to care). That's why I repeat this:

Quote:

In response, I said: In case you don't recall, Dale, I cited (and quoted), among others, Dr. George Smoot, a physics professor at Berkeley, (who won the Nobel Prize for Physics in 2006) as support for the assertion that the CMBR establishes a "preferred frame."

If you're waiting for an "expert" to come around to this thread, I'm afraid you will be sorely disappointed. If you have questions about the "existence" of a preferred frame, you might instead want to "consult" the real experts I have cited. This frame is not directly related to the preferred frame used in the twin paradox, of course, but it may help alleviate the "unease" you said you had about preferred frames in general.

I don't know how to create a link to the post I'm talking about, but it's on page 14 of my display, if that helps.

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You people are making the things so complicated, but once your vision is cleared it is extremely simple to see how irrational this whole thing is.
But then first you have to unlearn a lot, because now you are having conceptual blindness, that is why you can't see how simple it is.

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@layman,

layman wrote:

I think the question is purely a logical one. One does not need specific knowledge whatsoever of contingent, accidental facts in order to assess, and respond to, the assertion made.
Do you disagree with that? If so, why?

When an object changes from one frame of reference to another, all sorts of relativistic things happen to it.

When someone proposes a hypothetical model in order to better understand a concept, it is rather important that the model take into account all changes in frame of reference that occur within that model.

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@dalehileman,

dalehileman wrote:

oralloy wrote:
Does the traveler decelerate (change reference frames) when passing by again after circumnavigating the universe, or just speed on by a second time?

I can't see how it matters

It matters because having an object change reference frames introduces all sorts of relativistic effects.

Ultimately, it matters because your refusal to provide these details in your proposed models is the direct cause of your inability to get an answer to your questions.

dalehileman wrote:

oralloy wrote:
If you have a traveler who accelerates, and one person who is left behind without accelerating, the time relationship is not perfectly reciprocal.

True but of course the Twin Par asks, "if not the acceleration that stopped my clock then why not reciprocal"

Of course you reply, "preferred ref," but how and why

No. I reply that your questions are unanswerable because you steadfastly refuse to provide enough details in your proposed hypothetical models.

The reason why that model isn't reciprocal is: because one party has changed frame of reference and one party has not.

dalehileman wrote:

Getting back to the bigger Uni, again consider the case where our little visible part is traveling at (near) c through the bigger one, with which I come to a halt when I accelerate. Which one would be "preferred" and why; so when we meet again which one of us has aged

There is no such thing as a preferred frame of reference.

Further details cannot be provided due to the excessive vagueness of your proposed hypothetical models.

dalehileman wrote:

oralloy wrote:
If the traveler was already going fast from the start (i.e. stays in the same frame of reference), that would be reciprocal, as neither party will have accelerated in that case.

Without that "preferred frame" I don't see how there would be much diff

There is quite a bit of difference between "a hypothetical model where all parties stay in the same frame of reference that they started in" and "a hypothetical model where one party changes frame of reference".

dalehileman wrote:

In short Lay,

I'm not Layman. I do not reject Einstein.

dalehileman wrote:

I agree most wholeheartedly that the SR bunch is sloughing off that "preferred ref" and I have no idea how they justify doing so.

We justify it with the fact that there is no such thing as a preferred frame of reference.

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@oralloy,

You didn't answer the question, which was:

Quote:

Do you disagree with that? If so, why?

Quote:

When someone proposes a hypothetical model in order to better understand a concept, it is rather important that the model take into account all changes in frame of reference that occur within that model.

Nothing in the question has a damn thing to do with changing a frame of reference. Can't you see that? As I said before, you appear to be trying to answer some question THAT I'M NOT ASKING.

Once again, here's the question:

1. If 2 observers (any 2 observers, anywhere in the universe)

2. Are moving with respect to each other

3. and both claim they are at rest with respect to the other, then:

4. Would it EVER, UNDER ANY CIRCUMSTANCES, even be POSSIBLE, no matter how many million of times they both may have changed frames of reference, for BOTH of them to be right when they claim they are "at rest?"

Is that possible? Logically?

You don't need FACTS to answer a question of logic. Did you know that?

Here's what you're doing: I ask you whether, if Joe is taller than Jack, then could Jack also be taller than Joe.

Your response: I can't answer that until you tell me how tall Joe is.

That's irrelevant to the question. Whether Joe is one inch tall or 8 feet tall, or anywhere in between, it's totally irrelevant.

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@oralloy,

Oralloy said:

Quote:

We justify it with the fact that there is no such thing as a preferred frame of reference.

Great insight, and great "explanation" for Dale, Oralloy. Perhaps you should share your knowledge with Dr. George Smoot, the Nobel Prize winner for Physics in 2006. He said:

Quote:

This would seem to violate the postulates of Galilean and Special Relativity but there is a preferred frame...

http://able2know.org/topic/265997-14#post-5882554

=====
A similar statement, from another distinguished physicist:

Quote:

The theory of special relativity is based on the principle that there are no preferred reference frames. In other words, the whole of Einstein's theory rests on the assumption that physics works the same irrespective of what speed and direction you have. So the fact that there is a frame of reference in which there is no motion through the CMB would appear to violate special relativity! ....There clearly is a frame where the CMB is at rest, and so this is, in some sense, the rest frame of the Universe.

Emphasis is not mine, but comes from the original

Source: http://www.astro.ubc.ca/people/scott/faq_basic.html

This statement was made by Dr. Douglas Scott, a physics prof. at the University of California, Berkeley..

As you can see, he refers to the CMB as "the the rest frame of the Universe."

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@layman,

Quote:

I've posted a lot, and you might not care to read all of it (even though it's for you

I'm deeply flattered Lay that you should spend so much effort on behalf of a Common Blockhead

Quote:

--nobody else seems to care)

So it would seem. Either (1) a2k actually has no experts, (2) it does but we're considered beyond hope

…or at least I am

Quote:

If you're waiting for an "expert" to come around to this thread, I'm afraid you will be sorely disappointed

If someone who uses one could only send a link to this thread (and others involving you, me, and Al, to a legitimate science forum…..

Quote:

I don't know how to create a link to the post I'm talking about...

The blue just to the right of "Post:" at upper right in each posting, eg,

http://able2know.org/topic/265997-21#post-5887093

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@oralloy,

Quote:

When an object changes from one frame of reference to another, all sorts of relativistic things happen to it

So the SR folk assure us, Ora. However how about my circumnavigation where no second shift is involved

Quote:

It matters because having an object change reference frames introduces all sorts of relativistic effects….because your refusal to provide these details….

Sorry Ora if my account was inadequate. After me having circumnavigated the Universe when we meet again, presumably it's you and not me who has aged. But how can it matter whether I stop

Quote:

There is no such thing as a preferred frame of reference.

Yes that's how I had always understood it until just recently. It seems to me that Lay has a pretty firm argument. If instead I just pass by, we could exchange greetings whilst observing the other's age. The point was, that I hadn't left my frame and so why (Twin Par-Con) shouldn't we still be the same age

As I've proposed several other scenarios I'm unsure where I was unclear, but feel free to specify and I'll do my best..

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@dalehileman,

Quote:

(1) a2k actually has no experts,

I don't think there is any shortage of self-proclaimed experts here, but that's not really saying much. I haven't seen anyone make any real attempt to explain anything. They tend to just make unqualified assertions with no justifications being offered, then quickly retreat if you ask them a question. To save face, they may call you a name before departing, but....

I've seen a number of cases where true professionals, such as physics professors who teach SR, give the impression that they don't really "buy" SR. But that doesn't stop them from teaching it (nor should it). They are just careful to continuously preface their statements with phrases such as "if you accept the basic postulates of SR, then you must conclude...."

Of course, by that same token, I've seen some devout SR advocates with advanced physics degrees go so far as to declare that SR is "fact," that it is "true," and/or that it has been "proven." But any theoretician (as opposed to mere "teachers") knows such claims are wrong.

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@dalehileman,

dalehileman wrote:

But how can it matter whether I stop

It matters because having an object change reference frames introduces all sorts of relativistic effects.

dalehileman wrote:

feel free to specify and I'll do my best..

Does the traveler accelerate (change reference frames) at the start of the model, or was this traveler going at their current speed all along?

Does the traveler decelerate (change reference frames) when passing by again after circumnavigating the universe, or just speed on by a second time?

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@layman,

Thanks Lay but somehow I feel at 84 with incipient Alz's I'm misunderstanding Ora. Of course if I fire my retros instead of staying to visit with Marty, it's quite clear by classical SR that the 10-minute jump in the reading of your watch is caused by my second shift

Is it that Or maintains my circumnavigating is somehow equivalent, that I'm changing refs a second time

Or have I merely proven the Uni isn't finite after all

1 Reply

@dalehileman,

dalehileman wrote:

Thanks Lay but somehow I feel at 84 with incipient Alz's I'm misunderstanding Ora. Of course if I fire my retros instead of staying to visit with Marty, it's quite clear by classical SR that the 10-minute jump in the reading of your watch is caused by my second shift

Is it that Or maintains my circumnavigating is somehow equivalent, that I'm changing refs a second time

Or have I merely proven the Uni isn't finite after all

How about I craft a hypothetical, and you tell me if that hypothetical will answer what you are trying to understand?

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@oralloy,

Quote:

Does the traveler accelerate (change reference frames) at the start of the model, or was this traveler going at their current speed all along?

If there's no reference frame and if it's not my acceleration that stops my clock (to you back on Earth) then I don't see how it matters. However for sake of argument I launch from LA, achieving (nearly) c when I pass you by in NY on my way to visit Marty

Quote:

Does the traveler decelerate (change reference frames) when passing by again after circumnavigating the universe, or just speed on by a second time?

I remember addressing this q about 4 or 5 times Ora, but I can well understand your reluctance to spend all day scanning the thread. My answer is found directly above but asks why it should matter

Quote:

How about I craft a hypothetical...

Sure Ora, be my guest, I'll do my best on your behest

Forgive

Meanwhile tho yardwork beckons

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@dalehileman,

dalehileman wrote:

Sure Ora, be my guest,

See if this hypothetical will address what you are trying to figure out:

Hypothetical: We have two travelers, named A and B. Both travelers are the same age. Both travelers are one light year away from each other. At the midpoint between the two travelers we have a set of bleachers with an audience waiting to watch them pass by. The travelers and the audience are all at rest with each other.

Both travelers rapidly accelerate to very near the speed of light, both going directly towards the other traveler. Their acceleration rates are identical. They zoom past each other in front of the audience as planned, and then speed away from each other.

As the universe in this hypothetical is finite and loops on itself, eventually the travelers zoom past each other in front of the audience a second time. After they are separated by a distance of one light year, they rapidly decelerate until they are once again in the same frame of reference as the audience. Their deceleration rates are identical.

Both travelers then travel slowly towards the audience (too slowly for there to be any further relativistic effects) and meet to compare their ages.

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@oralloy,

Hell Ora that's an easy one They'd be the same youngsters they were when they launched. But I'm wondering why it would matter that they swished on past Earth (if it's still in existence)

I'd suppose they'd get about the same result braking anywhere roundabout Our Planet

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Why in the world would Einstein suggest....

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