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What's Up With Gravity And Spacetime Curvature?

general relativity.

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#86 Moronium

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Posted 02 February 2019 - 07:59 PM

Take 2 clocks, slowly separate them both very slowly. Use 1 to trigger a laser and the other to measure when it arrives. Subtract t1-t2 and you have the speed of light over the separation between them. That's a 1 way speed of light measured. 

 

There are a number of physicists who have claimed to have measured a one way speed of light.  They have all been proven wrong.

 

The "one-way" speed of light, from a source to a detector, cannot be measured independently of a convention as to how to synchronize the clocks at the source and the detector. What can however be experimentally measured is the round-trip speed (or "two-way" speed of light) from the source to the detector and back again.

 

Experiments that attempted to directly probe the one-way speed of light independent of synchronization have been proposed, but none has succeeded in doing so.Those experiments directly establish that synchronization with slow clock-transport is equivalent to Einstein synchronization, which is an important feature of special relativity. Though those experiments don't directly establish the isotropy of the one-way speed of light, because it was shown that slow clock-transport, the laws of motion, and the way inertial reference frames are defined, already involve the assumption of isotropic one-way speeds and thus are conventional as well.  

 

Many experiments intended to measure the one-way speed of light, or its variation with direction, have been (and occasionally still are) performed in which light follows a unidirectional path.[30] Claims have been made that those experiments have measured the one-way speed of light independently of any clock synchronisation convention, but they have all been shown to actually measure the two-way speed...

 

...This experiment, carried out in 1990 by the NASA Jet Propulsion Laboratory, measured the time of flight of light signals through a fibre optic link between two hydrogen maser clocks.[31] In 1992 the experimental results were analysed by Clifford Will who concluded that the experiment did actually measure the one-way speed of light.[11]   In 1997 the experiment was re-analysed by Zhang who showed that, in fact, only the two-way speed had been measured.

 

The first experimental determination of the speed of light was made by Ole Christensen Rømer. It may seem that this experiment measures the time for light to traverse part of the Earth's orbit and thus determines its one-way speed, however, this experiment was carefully re-analysed by Zhang, who showed that the measurement does not measure the speed independently of a clock synchronization scheme but actually used the Jupiter system as a slowly-transported clock to measure the light transit times.[33]

 

The Australian physicist Karlov also showed that Rømer actually measured the speed of light by implicitly making the assumption of the equality of the speeds of light back and forth.

 

 

https://en.wikipedia..._speed_of_light

 

Try as hard as you like, but you'll never convince anybody that you have "proved" a conclusion by assuming it as a premise.  Such attempts are made daily in this forum, but, still...


Edited by Moronium, 02 February 2019 - 08:00 PM.


#87 ralfcis

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Posted 02 February 2019 - 08:37 PM

You can quote all the articles you want, show me the math. You start with the assumption the two way speed of light is correct which it is because it only involves 1 clock and hence clock sync between two clocks is not needed. But for 1 way, clock sync between 2 clocks is needed. However, relativity defines how the clock de-sync will affect the measurement between the 2 separated clocks. If the result matches what is expected taking into account the relativistic effects, then you have measured the 1 way speed of light. Show me in your articles where my reasoning is incorrect. 

 

I'll do it for you since you'll only post more irrelevant articles. What you're missing is why this is important to relativity which all your dumb articles won't tell you. This has to do with the contradiction between the relativity of simultaneity and the constancy of the speed of light from all perspectives. Separated clocks invite the problem that so long as clocks are separated, one can't make a definitive judgment from all perspectives on the clock readings in order to define what is the one way speed of light from all perspectives. Yet relativity makes the assumption that the speed of light is the same from all perspectives. Can you see the contradiction? These types of circular arguments are the result of the theory being based on inductive inference. The results support the hypothesis but the hypothesis must be assumed  true to prove the results. This is what you're trying to say but don't understand enough to say it. Most of what you post is garbage because it is not tied together by context and reason. It's wiki salad.

 

The conclusion I come to as a result of these facts is

1. You can measure the one way speed of light.

2. c is constant from all perspectives

3. the relativity of simultaneity is based on relativity's faulty definition of time and this is what causes the contradiction.


Edited by ralfcis, 02 February 2019 - 09:09 PM.


#88 Moronium

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Posted 02 February 2019 - 10:29 PM

You can quote all the articles you want, show me the math. You start with the assumption the two way speed of light is correct which it is because it only involves 1 clock and hence clock sync between two clocks is not needed. But for 1 way, clock sync between 2 clocks is needed. However, relativity defines how the clock de-sync will affect the measurement between the 2 separated clocks. If the result matches what is expected taking into account the relativistic effects, then you have measured the 1 way speed of light. Show me in your articles where my reasoning is incorrect. 

 

 

"Show me the math," eh?  Math has nothing to do with it.  The problem is a logical one.

 

1.  In order to measure the one way speed of light, you must know that the two different clocks you are using are actually synchronized.

 

Right?

 

2.  But, as it turns out, in order to know the two clocks are actually synchronized, you must first know (i.e, assume) the one way speed of light. 

 

In all these experiments, the one-way speed of light is assumed, usually tacitly, so that it may not be readily apparent. 

 

Take your simplistic example:

 

Take 2 clocks, slowly separate them both very slowly. Use 1 to trigger a laser and the other to measure when it arrives. Subtract t1-t2 and you have the speed of light over the separation between them. That's a 1 way speed of light measured.

 

 

How do you know that the two distant clocks are synchronized?     Because they have been "transported slowly?"  That proves nothing. Transporting them, at whatever speed, is deemed to generate a difference in the rate at which the two clocks tick.  You have simply assumed that they are synchronized.  Or that they have remained synchronized, if you prefer.  As pointed out in the wiki article, "it was shown that slow clock-transport, the laws of motion, and the way inertial reference frames are defined, already involve the assumption of isotropic one-way speeds and thus are conventional as well."

 

The crucial thing here is that the very definition of an inertial frame itself assumes an isotropic one way speed of light.

 

As required by the experimentally proven equivalence between Einstein synchronization and slow clock-transport synchronization, which requires knowledge of time dilation of moving clocks, the same non-standard synchronisations must also affect time dilation. It was indeed pointed out that time dilation of moving clocks depends on the convention for the one-way velocities used in its formula.[17] That is, time dilation can be measured by synchronizing two stationary clocks A and B, and then the readings of a moving clock C are compared with them. Changing the convention of synchronization for A and B makes the value for time dilation (like the one-way speed of light) directional dependent.

 


Edited by Moronium, 03 February 2019 - 01:26 AM.


#89 ralfcis

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Posted 03 February 2019 - 08:32 AM

Relativity is all about calculating what the reciprocal time dilation of each clock is to the other's perspective. If you separate them slowly, the relativistic effects on their time difference will be insignificant. (Moving both clocks alternately will get twice the distance at half the speed of just moving one clock.) Hence the known error this will cause in the measurement of the one way speed of light will also be insignificant, probably less than the margin of error allowed for any experiment. This tiny adjustment is not the issue. Hey, maybe accelerate them apart and that should cause no time dilation between them from what I've read here.

 

Einstein's clock sync method is some weird holdover from the nineteenth century that relativists still cling to for syncing clocks. Atomic clocks are universally accurate. Once they're sync'd together at the start, you don't need to send light signals to sync them when they're apart. That argument is old and tired and not relevant for many years. Their time difference from when they were together is calculable but even if you say that's cheating and using relativity to prove relativity, the tiny error in time is insignificant to what the two way speed of light is measured at.

 

I know you can't understand the important part of what I said about the contradiction between relativity of simultaneity and constant c because if that doesn't appear in a wiki article, it can't be important. So no discussion on that then.



#90 OceanBreeze

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Posted 03 February 2019 - 09:54 AM

Relativity is all about calculating what the reciprocal time dilation of each clock is to the other's perspective. If you separate them slowly, the relativistic effects on their time difference will be insignificant. (Moving both clocks alternately will get twice the distance at half the speed of just moving one clock.) 

 

Do you even realize what you just said?

 

You are claiming for absolute motion while trying to explain relativity!

 

That is priceless.



#91 ralfcis

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Posted 03 February 2019 - 03:56 PM

Just making sure someone was paying attention. No, that was a horrible careless mistake and I apologize to everyone who read it. I will now go bck and edit it out.



#92 Moronium

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Posted 03 February 2019 - 05:21 PM

You are claiming for absolute motion while trying to explain relativity!

 

 

It's actually fairly common, Popeye.  Relativists, out of necessity, frequently tacitly resort to assuming absolute motion to "explain" their positions (all while purportedly insisting that no such thing exists, of course).

 

Every branch of physics acknowledges absolute. motion, including astronomers, cosmologists, string theorists, particle physicists, or whatever.

 

It's only when they come to trying to explain (and apologize for) SR that they start trying to claim that the whole concept is "meaningless." Consistently applied, and taken to it's logical conclusion, this simply throws out the baby with the bath water.  It renders reasonable physics impossible.


Edited by Moronium, 03 February 2019 - 05:34 PM.


#93 ralfcis

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Posted 03 February 2019 - 06:20 PM

No. If you have 2 ships leaving earth in opposite directions at .33c, that is exactly the same relative motion between the ships as if you had one ship on earth and the other take off at .6c. But it is not the same "absolute" motion relative to any preferred frame such as the earth or distant stars or the electromagnetic medium of space for example. Unfortunately it is impossible to draw relative velocity on a spacetime diagram without including the background common cartesian reference frame and/or not avoid depicting one of the participants as stationary when neither of them are.



#94 Moronium

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Posted 03 February 2019 - 06:37 PM

Unfortunately it is impossible to draw relative velocity on a spacetime diagram without including the background...and/or not avoid depicting one of the participants as stationary when neither of them are.

 

Yeah, well, maybe that's one limitation to the usefulness of spacetime diagrams, eh?

 

On the other hand, it's perfectly consistent with SR's use of the Lorentz transforms, which also require one of the participants to be stationary, whether "true" or not.

 

Anyone who tells me the answer is given in a spacetime diagram obviously doesn't understand the question(s) I am raisisng.


Edited by Moronium, 03 February 2019 - 06:42 PM.


#95 Moronium

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Posted 03 February 2019 - 06:57 PM

 

On the other hand, it's perfectly consistent with SR's use of the Lorentz transforms, which also require one of the participants to be stationary, whether "true" or not.

 

 

 

This mathematical protocol serves to immediately establish a motionless preferred frame and, consequently, the absolute motion of the other guy.

 

Oh, wait, I forgot.  There are no preferred frames and there is no absolute motion in SR.


Edited by Moronium, 03 February 2019 - 07:08 PM.


#96 ralfcis

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Posted 03 February 2019 - 07:00 PM

No more limited than the use of schematics to build a building, you have to know how to read them. An even bigger problem is how light signals are depicted in an STD. Using relative velocity, they should travel equal time and distance between the two parties but they're depicted not to if the relative motion between the parties is depicted skewed as it is in the Minkowski STD. At .6c relative velocity, a light signal from Bob takes twice as long and travels twice as far as an equivalent light signal from Alice. This is not true if the same relative velocity is depicted in a Loedel STD where both light signals travel the same distance in the same time. The light propagation difference in the Minkowski is never taken into account if you use light signals to determine reciprocal time dilation from both perspectives because it's kind of an embarrassment to relativity. It may be that c is constant from all perspectives but how much distance and time used to make c is not the same from all perspectives when depicted in a Minkowski STD.



#97 ralfcis

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Posted 03 February 2019 - 07:06 PM

You must get confused when you talk to a photograph and the people in the photograph do not answer you back. It's because depictions of reality are limited in their depiction of reality.


Edited by ralfcis, 03 February 2019 - 07:19 PM.


#98 Moronium

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Posted 03 February 2019 - 07:18 PM

A picture isn't a live person!?

 

WHO KNEW!?

 

That may the most insightful, profound thing you've ever said, Ralf.


Edited by Moronium, 03 February 2019 - 07:19 PM.


#99 ralfcis

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Posted 03 February 2019 - 07:30 PM

I know I can't reach you but maybe someone else will find me insightful. but part of me really hopes when I do start my serious attack on relativity, you won't be participating?



#100 Moronium

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Posted 03 February 2019 - 07:42 PM

.... part of me really hopes when I do start my serious attack on relativity, you won't be participating?

 

I can certainly understand your hopes, and your reasons for them.

 

But, sorry, chances are I will be participating.


Edited by Moronium, 03 February 2019 - 07:42 PM.


#101 ralfcis

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Posted 03 February 2019 - 08:52 PM

My reasons are I always get shut down before I get my answers because I get sidetracked responding to non-answers. I may be against the theory of relativity but I totally agree with the facts of relativity which you do not. Plus I'm totally open to be convinced of the theory if all the contradictions can be explained away.



#102 Moronium

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Posted 03 February 2019 - 09:21 PM

My reasons are I always get shut down before I get my answers because I get sidetracked responding to non-answers. I may be against the theory of relativity but I totally agree with the facts of relativity which you do not. Plus I'm totally open to be convinced of the theory if all the contradictions can be explained away.

 

 

 

What exactly are "the facts of relativity," as you see it, eh, Ralf?

 

I see SR as a hypothetical theory which does not, as such, establish any facts.  As a theory, it just serves to "explain" facts external to it to a better or worse degree.


Edited by Moronium, 03 February 2019 - 09:23 PM.