Minkowski Space Time Briefly Revisited

Your thought experiment is so delusional that it is not even worth any real consideration. There is no evidence that two energy pulses or EM radiation, maybe photons, to be a bit more clear, ever interact, under any conditions. How ever, if two beams of light intersect in any FoR they intersect in all FoR.

 

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I don't know what you're claiming. Is there experimental evidence?

I'm really stupid, so please, indulge me..

 

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No problem Dan. Also see this from Imperial

Yes, and the Higgs mechanism contradicts E=mc². The electron is a body. And the mass of a body is a measure of its energy content. If it's the measure of its interaction with some field, it isn't the measure of its energy content.

Replace the proton with an electron to make things simpler. The electron has a wave nature, you can diffract it, it has its magnetic moment, because it's a spinor, because something is somehow going round and round. And we made that electron out of light in pair production. So model the electron as a ring of light. Follow one point on the circumference, and when the electron moves fast, the path of that point looks helical. Repeat for all points and what was a ring of light is now a cylinder of light. The electron is lengthened, and if you were that electron, everything you passed would look length-contracted. Not because they changed. But because you did.

The photon doesn't change one iota. The tone of a siren doesn't change when you run past it. You hear it as changed, but it didn't change. You were running towards, now you're running away from it, so you hear it as having changed. But all the various bystanders can assure you it didn't change a jot.

 

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Sure. The experimental evidence is the Shapiro delay and optical clocks running slower when they're lower.

 

No it isn't.

 

Yes it is. Here, see the Wikipedia article on the Shapiro delay. See the quote by Irwin Shapiro:

"The proposed experiment was designed to verify the prediction that the speed of propagation of a light ray decreases as it passes through a region of decreasing gravitational potential".

Is there some part of that you don't understand?

 

You continue to cherry pick your quotes and explanations. A variation in speed is only one explanation. A variation in distance is another.., which retains the constancy of the speed of light. Read the whole of the Wiki reference.

There is also a variation in the distance explanation. And there really is no way to know with certainty which is real at present. However, I believe most physicists working in associated areas would go with the variation in distance traveled explanation. This has been addressed with you many times in the past. http://en.m.wikipedia.org/wiki/Shapiro_delay#Time_delay_due_to_light_traveling_around_a_single_mass

 

I'm not cherry picking. Shapiro said what he said. So did Einstein when his said this:

"Secondly, this consequence shows that the law of the constancy of the speed of light no longer holds, according to the general theory of relativity, in spaces that have gravitational fields. As a simple geometric consideration shows, the curvature of light rays occurs only in spaces where the speed of light is spatially variable."

 

This is finally getting to the crux of what vexed me most about the last Minkowski rotation discussion thread.

I keep finding these "let's pretend that I actually understand relativity" things on the internet that are like this:

http://www.math.upatras.gr/~weele/files/Beyond the pole-barn paradox (paper 64).pdf

and this:

http://en.wikipedia.org/wiki/Ladder_paradox

These analyses are both as wrong as they can possibly be. The pole and barn paradox has NOTHING whatsoever to do with "how rigid the ladder is", or even if it did, what is the point of discussing that issue without also discussing the complimentary issue of "how rigid the barn is"?

The issue is the simultaneity of the ladder entering, leaving the barn in the FoR of the runner+ladder vs. the FoR of the barn, not whether or not every atom that composes the barn or the ladder is traveling at the same rate as every other atom it is composed of, which is really no more of an issue than whether each and every atom of the barn is actually at rest. If you don't understand that, at least, I'm sorry, but I can't help you. There is no such thing as absolute motion or absolute time. This means that for a runner moving with a constant velocity less than c, the atoms in his own body and in that of the ladder are every bit as much "at rest" with respect to each other as they are for that barn. What if the barn was the thing that was moving? That's the point.

I've replaced the barn and the ladder with light pulses traveling identically at c, and the answers I'm getting are demonstrating that my assessment of the state of relativity education has dropped way below the level of sub-ignoramus into a pathetic pre-1905 state.

Back to the Pulse Paradox

The two photon pulses made simultaneous in emission by means of a beam splitter are separated in distance from each other by 1 light second. This would mean that in the lab frame, each pulse travels the square root of 2 light seconds before they intersect in the lab frame at t = 0. Are we OK so far?

You are all, or should be familiar with this:

http://en.wikipedia.org/wiki/Relativity_of_simultaneity

And more particularly, with this:

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But this diagram only holds for the two cases of material observers moving relativistically from the left or from the right in the case of the pulses, so that if the emission of the pulses occurs simultaneously FROM ANY DISTANCE in the lab frame, then they will miss each other because they are traveling at c, and so either they must travel an equal distance IN EVERY FoR, or else they will miss each other. They are traveling at c. This much is the same in every FoR. They don't both travel an 'equal' distance in every FoR, and so they don't 'intersect' in different FoRs, as they do in the lab frame. I for one think this is a pretty severe causality violation.

Oh. Now I see the right answer to my problem. Never mind.

 

yeah, explain the physics meaning of propagate in this sentence.
and also, what's the phase velocity ?

 

i'm also familiar with the wrods under that imgae, Events A, B, and C occur in different order depending on the motion of the observer. The white line represents a plane of simultaneity being moved from the past to the future.

 

That is a fascinating wikipedia reference, since that sentence does not appear in the actual article that Sharpiro wrote. The edit was done by PMB. A known crank?

Edit: Someone has already corrected the quotation! Just when I have an example of wikipedia failure, someone goes and corrects it.

I'm sure Farsight will just cite the past version of the page, like he has before.

 

This page was last modified on 30 December 2014 at 17:39.

• (cur | prev) 17:52, 30 December 2014‎ PaunchyCyclops (talk | contribs)‎ m . . (8,094 bytes) (-7)‎ . . (Author mistake) (undo)
• (cur | prev) 17:39, 30 December 2014‎ PaunchyCyclops (talk | contribs)‎ . . (8,101 bytes) (+540)‎ . . (Removed fabricated quotation and added relevant details.) (undo)

 

The page now says this:

"Because, according to the general theory, the speed of a light wave depends on the strength of the gravitational potential along its path..."

Not much different there then. But my oh my, I wonder who PaunchyCyclops is?

 

So, Farsight deigns to respond to one small part of one post, ignoring the actual scientific content of Shapiro's paper, and never addressing any of the questions I directly asked him.

Par for the course.

 

I've addressed plenty of your questions. And the moot point is that the speed of light varies with gravitational potential, just like Einstein said.

 

That is a lie. An obvious lie.

Would you please show us how your inhomogeneous space leads to any physics application? Would you please show us how inhomogeneous space leads to the correct calculation for a galaxy rotation curve? Would you please go through Shapiro's paper and show why he used a constant speed of light to calculate time dilation?

 

Does this mean you are finally, for this issue understanding the difference between how far each pulse travels, from emmission to intersection is the same in all FoR, even though because of time of light delays and Simutaneity of Relativity, the distances between an observer, and each emmission event, is does vary, diferent FoR?.... While, and I repeat.., the distance that each pulse travels between emmission and intersection remains constant in all FoR? So while you see the emission occurring at different times, they always intersect at the same time.

Emmission events are two specially separated events.., the intersection event is a single event, both specially and in time. This holds for all frames of reference.

 

It isn't a lie. An optical clock goes slower when it's lower. And there is no time flowing through that optical clock. The clock goes slower because the light goes slower, because the speed of light varies with position, just like Einstein said.

No, I can't show you how inhomogeneous space leads to the correct calculation for a galaxy rotation curve, because that rotation is what we observe. However I can show you Einstein referring to inhomogeneous space. Here is is. Try to understand that if space is homogeneous, there is no gravitational field, and your pencil doesn't fall down.

No, I won't go through Shapiro's paper because I don't have a copy of it.

 

from post #410,
can you explain the physics meaning of propagate in that sentence.
and also, what's the phase velocity ?