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,then again, extra pickles would be nice.

I'm still working on it...

It's now Christmas! Per Paradoctor's request, and my response I have been reviewing and preparing my papers for publication, and I'm still not finished, ugh, but I will post here again when I am. In addition, I'll also be spending more of my time this holiday with my family than anything else, so have a Merry Christmas and New Year! --Modocc (talk) 10:27, 25 December 2013 (UTC)

Take your time, there is no WP:DEADLINE. ;) Merry Consumas! Paradoctor (talk) 17:16, 25 December 2013 (UTC)

I'm glad there is no deadline because other duties have kept me preoccupied, but I'm sure to make some progress on this in the near future. -Modocc (talk) 22:42, 22 January 2014 (UTC)

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Contractions

The following discussion is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.

(Continued from here.) "intrinsic to spacetime and matter" is so broad that it applies to everything. The problem is whether contractions is due to a physical change in the rod. Since contraction can be induced by merely accelerating the observer, there is obviously no change in the invariants describing the rod, its physical state. But if you accelerate the rod instead, the observer will still see contraction, despite the observer undergoing no physical change. So, if neither observer nor rod "cause" contraction, where does it come from? Solution: their relative motion changes, which means you need to consider the relationship between both physical systems to find the change. That's pretty abstract, but still physical, and has measurable consequences, i. e. contraction. So, yes, the pole will fit into the barn. Which then explodes from the impact of a relativistic projectile, but progress requires sacrifices. ;) Contraction is real, but is not due to a change of state of the rod. The mind boggles, but Einstein don't care. Paradoctor (talk) 21:25, 23 January 2014 (UTC)

Perhaps your conclusion that the state of the rod is unchanged can be backed up with citations? That the rod fits is because of proper distances which involve the non-simultaneity of events and not simply the lengths that are not invariant and would not allow a fit without the proper distances being involved. Moreover, when particles are accelerated they gain energy and their DeBroglie wavelength contracts as required by the Plank relation increasing their inertia. In other words, their physical state does change. -Modocc (talk) 01:03, 24 January 2014 (UTC)

The change you refer to is an artifact of the choice of reference system. How do you explain the presumed state change of the rod in the case where the observer is accelerated? Paradoctor (talk) 01:50, 24 January 2014 (UTC)

Physical state changes simply occur if an object is accelerated. Thus if the observer is accelerated, the coordinate system or reference frame map changes of course, and their local state changes. -Modocc (talk) 02:22, 24 January 2014 (UTC)

But the rod isn't acccelerated, hence there is nothing capable of changing its physical state. So, if contraction is to be due to a physical change of the rod, what causes that change? Paradoctor (talk) 03:26, 24 January 2014 (UTC)

In the problem example, it's measurably contracted not contracting, according to relativity. There was no change in its state, either stated or implied by the author. Thus if we are at rest with the rod and deaccelerate to frame S, we have to use the new map of the rod. -Modocc (talk) 03:36, 24 January 2014 (UTC)

So there is "no change in its state". If you admit that, then what are we discussing? This was what I said from the beginning. Paradoctor (talk) 03:58, 24 January 2014 (UTC)

I've only stated that there is no change in state when an object is not being accelerated. If an object is being accelerated that is a horse of a different colour. You started out claiming contraction is not a physical change at all, or it is not intrinsic, or it's in some abstract relation, or that it's merely an "artifact", and I happen to disagree on all these points, so bring a citation please. --Modocc (talk) 04:16, 24 January 2014 (UTC)

I'm trying to sort out what seems to be a confusion of words, lest we talk in different directions. Numbering a few simple statements might be helpful.

a) The observer is accelerated, the rod not.

b) The rod is accelerated, the observer not.

c) After acceleration, the rod is contracted for the observer in both cases a) and b).

d) "Physical state" is a set of invariants describing an object, the measures of which are independent of the observer.

e) Before acceleration, the rod is in the same physical state SA in both cases.

f) After acceleration, the rod is in the same physical state SB in both cases.

g) In case a), there is nothing that could influence the physical state of the rod, as no forces act on it.

h) Accepting e), f) and g) implies that SA=SB.

Do we both agree to these statements and definitions?

Paradoctor (talk) 04:44, 24 January 2014 (UTC)

Ideally, with a correct model d) is true, but it is a nonstarter with relativity (for me at least) since length contraction measurements, clock rate measurements and relativistic mass depend on the observer and you are excluding these by fiat. With classical theory, the invariants are simply event simultaneity and spacial distances. It's a far simpler paradigm to work with when it comes to d). -Modocc (talk) 05:45, 24 January 2014 (UTC)

"fiat"? That these are not invariants is an inescapable consequence of accepting relativity theory. Are you telling me you reject relativity?

"classical theory" Aren't you forgetting minor stuff like energy, impulse, angular impulse, electric charge and whatnot?

"simpler paradigm" The same could be said for the classical elements as opposed to the periodic table of today. Paradoctor (talk) 07:34, 24 January 2014 (UTC)

Ok, I'm looking forward to that. Paradoctor (talk) 17:25, 24 January 2014 (UTC)

Miraculously, I found a statement by Paradoctor (in the dispute resolution debate) which should help clarify that length contraction should not be understood as actual physical contraction of objects (or distances between them.) "Please note that I'm not talking about proper length, which is a physical property, and does not undergo contraction." There you have it. I am sure we can all agree that Earth's diameter would not contract as measured by observers/frames approaching at relativistic speeds. That leaves relativity's dictum, about "no preferred frames", i.e., that "all frames are equally valid" in dire need of being discarded and no longer taught in 'relativity school' or in Misplaced Pages articles. So at rest with an object is (should be) the "proper" frame from which to measure anything. In lieu of that, the Lorentz transformation formula is legitimately applied to correct for the difference between "apparent length" (measured from/at high speeds) and actual, physical, "proper length", which is always intrinsic to the object, stays the same, and is independent of variations in observational frames. Ps, the dictum that "length is not invariant" must also be discarded, though basic to SR's worldview. LCcritic (talk) 19:55, 24 January 2014 (UTC)

Yes, proper length is invariant. Didn't you know that? Perhaps you can have a look at the opening sentences of the lead of our article Proper length. - DVdm (talk) 20:14, 24 January 2014 (UTC)

If Modocc or DVdm still wish to engage you on their or your user talk pages, that is their choice. Pester anyone else, you cross the line. This is my final warning to you. Paradoctor (talk) 20:39, 24 January 2014 (UTC)

Yes Paradoctor, I knew that. So how does that long pole fit into the short barn again? SR insists on having it both ways, "length is not invariant" because length depends on variations in measurement... and "proper length is invariant." LCcritic (talk) 19:50, 25 January 2014 (UTC)

(Redacted)

Point in question: "length" and "proper length" are different measures measured by different processes. If this didn't occur to you, you either didn't read or didn't understand the definitions of these terms in relativity theory. (Redacted) Paradoctor (talk) 20:47, 25 January 2014 (UTC)

Please refactor per WP:AGF and wp:npa (and I'll remove this reminder if you do). I would imagine that LCcritic overlooked DVdm's signature and thought the unindented posts were one. --Modocc (talk) 21:26, 25 January 2014 (UTC)

AGF extends only so far, and I don't consider stating facts falling under NPA, WP:CIVIL is much closer here. But since you requested it, I'll comply. No need to remove your note, as far as I am concerned.

BTW, the indentation is correct. If you wish to have it handled differently here, just say so, no problem. Paradoctor (talk) 23:51, 25 January 2014 (UTC)

I'm not so sure about there being different processes. As an example, suppose the barn doors don't have to close or open, but the openings are enmeshed with continuous laser beams. According to the paradigm, the entry beams will be interrupted by rods of different proper lengths simultaneous, only if their lengths coincide because they have different velocities with near zero velocity being inclusive, and although relative motion does distinguish length from proper length, the measurement method doesn't seem to differ appreciably. Modocc (talk) 21:26, 25 January 2014 (UTC)

Hein? The very fact that different proper lengths result in the same length measurement unequivocally shows that the two are different beasts. The crucial difference is that proper length is always measured in a system in which the rod is at rest. Here, and only here, do the two measurements coincide. Put differently, "normal" length measurements lack determination of a factor that is required for measurements of the proper length: relative speed. Again, this is the same situation as in the angular diameter model. Add information about distance and orientation, and you can determine the proper diameter, as opposed to merely the angular one.

"Near zero" is simply not true, not if γ is not very close to 1. For γ=2, you need ${\displaystyle v>0.866c}$. Paradoctor (talk) 23:51, 25 January 2014 (UTC)

To clarify, I meant that the rods' lengths coincide and fit within the barn at the same time, but they enter/leave at different speeds (in the barn's frame of reference). -Modocc (talk) 00:38, 26 January 2014 (UTC)

Sure, but how does that change anything I said? That their lengths are the same despite having different proper lengths has the same reason as with the rods and the barn: relative motion. The barn is just a fancy rod. Replace the barn with a rod, and instead of closing the doors, clamp the ends together when they coincide. The implications are the same whethere you use two rods or two billion: One instant, they all line up, the next: BOOM.

"barn's frame" Not necessary to specify, the fact that there is relative motion is independent of the (inertial) frame of reference, only it's magnitude changes. Paradoctor (talk) 00:55, 26 January 2014 (UTC)

It doesn't change anything you said. In fact I agree with it for the most part. For the angular diameter analogy, the measure is a proper angle and not a length, so its not like the situation for apparent motion which is fictitious, but the measure's of lengths and angles don't ever coincide thus it's not a perfect analogy. I'm just saying that it's not obvious that at the instant they are together that any of them have proper length until the big bang. --Modocc (talk) 01:07, 26 January 2014 (UTC)

"have proper length" Erm, they do. You can measure it at any time please.

"proper angle" There is no such thing. Try to define a procedure for determining it. Like sound pressure, there is no non-arbitrary way of defining a standard. Paradoctor (talk) 01:35, 26 January 2014 (UTC)

By proper angle, it was just a figure of speech in the sense that it is the correct angle measured for a given geometry, I meant nothing else other than that. Aye we can take measurements, but if the big bang is a dud because the rods' speeds are nearly zero, it could take too long to distinguish between them. Modocc (talk) 01:59, 26 January 2014 (UTC)

"nearly zero" There, we are in the classical realm, and length contraction is no longer an issue. This has no bearing on the issue. I think it's best we wait for the real beef you have with relativity. ;) Paradoctor (talk) 02:08, 26 January 2014 (UTC)

I agree, thus I'll be closing this discussion. :-) -Modocc (talk) 02:18, 26 January 2014 (UTC)