Am I interpreting Einstein correctly?

[GrayGhost]

Samshorn,

Well, you do sound pretty sure of yourself. You're right, the ellipsoid cannot encompass the EM complex under Neuenschwander's interpretation of the section 8 scenario, assuming that the ellipsoidal surface per the moving system represents a spherical surface that precisely coincides with the leading edge of expanding spherical wavefront in the stationary system (at any arbitrary time t). Here's the thing though ...

Is Neuenschwander "that bad" that he does not know light is isotropic, or does his figure 3 maybe represent something a little different from what you assume it does? I must say, his figure 3 doesn't make sense to me either, and the related description seems bad at best. Let's face it, the rocketeer does not record anything indicative of what he depicts there. It suggests he does not understand the desynchronisation of moving bodies, however that's also hard to swallow. If he really does have some sort of intent that we don't quite realize, I cannot imagine teaching it as such. Who is this fellow, Neuenschwander, anyways?

EDIT: There is only 1 way to interpret Neuenschwander's figure 3b as drafted. However, it cannot exist as such per any frame's POV, including the rocket's POV, and is thus contrary wrt his assertion that the rocketeer sees it as such.

GrayGhost

 

[harrylin]

Samshorn,

There's little doubt that Neuenschwander could have done a better job in stating what his figure 3 represents. As worded, and as depected, there are indeed problems with it. I'm not yet convinced his paper is incorrect otherwsie though. I'll need a little more time with it. It's interesting that his paper obtains the same result while starting with the initial assumption I did, ie that the radius R represents and expanding lightsphere from origin. It would seem the result "should" be the same. If so, then the big question is ... which approach did Einstein envision when he wrote his paper.

GrayGhost

Isn't that clear by now? As discussed, everything(?) is consistent with the interpretation that Einstein continued his discussion of a planar wave originating from "an infinitely distant" light source, while more than a few things are inconsistent with Neuenschwander's interpretation.

Harald

 

[bcrowell]

I emailed Neuenschwander a few days ago to let him know about the error. He replied cordially and said he'd take a look at it. I don't think it's unpardonable that he made this mistake, since almost everyone who posted in this thread (including me) initially misread the paper in the same way. I think it's commendable that he wrote this commentary, complete with hand-drawn illustrations, and made it available for free on the web. It would only be really unfortunate if he failed to correct the error.

 

[GrayGhost]

harrylin,

It's clear to me, now. I had never looked at sections 7 and 8 before, except at glance. I too originally suspected the energy-enclosing-surface corresponded to the leading edge of an expanding EM lightsphere. Now, it seems to me that it cannot be the case. The plane wave appears the logical intention of Einstein, based on the eqn he drafted and the requirement that the spherical surface always enclose the EM complex in both systems.

I tried to follow it thru assuming my original interpretation. Say the enclosing surface is expanding and spherical. For any time t, the spherical surface maps to a moving contracted ellipsoid per the rocket POV. However, considering the spherical surface at time t ... then when the EM intersects it simultaneously per the LAB (let's assume this occurs after precisely 1 wavelength of EM was generated, as Neuenschwander did), we might consider each photon's intersection as "an event". The mapping of "all said events", would be an elongated ellipsoid (not moving) in the rocket POV, however the events would not all occur at once. The events would occur as follows ... imagine a plane-surface parallel to the Y/Z plane, and move this plane in the direction of +x such that it passes thru the elongated ellipsoid while considering only the intersection of the 2 surfaces. That's the order of event occurances. Just guessing here, but maybe Neuenschwander intended to draft something such as that? Yet, said ellipsoidal surface would not exist per the rocket observer in the way Neuenschwander depicted it.

GrayGhost

 

[GrayGhost]

I emailed Neuenschwander a few days ago to let him know about the error. He replied cordially and said he'd take a look at it. I don't think it's unpardonable that he made this mistake, since almost everyone who posted in this thread (including me) initially misread the paper in the same way. I think it's commendable that he wrote this commentary, complete with hand-drawn illustrations, and made it available for free on the web. It would only be really unfortunate if he failed to correct the error.

The cartoons are very good. I especially like how the lab rat raises his arms when the rocket flies by, and the CAPT of the starship wears a hat. He doesn't have to worry about windage blowing the hat off :) I also wonder what he meant by his depicted frame-rotation?

GrayGhost