Speed of light is measured by all observers

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  • #51
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[2clockdude wrote:]
Thinking people would want to know why light's one-way speed
is Lorentz invariant.

[Tom Mattson noted:]
You can think about it all you want, the question has no known
answer. And as has been noted, even if we did have the answer,
that explanation would have some unexplained phenomenon behind it.
... Einstein did not have the power to force the speed of light
to be absolute, "by definition", or any other means. The speed of
light is a Lorentz scalar because that's what it is measured to be.

[2clockdude replies:]
You need to read Einstein's 1905 SR paper before trying to
comment on his "theory."

Here are his own words (which you are probably now reading for
the very first time):

"2. Any ray of light moves in the "stationary" system
of coordinates with the determined velocity c, whether
the ray be emitted by a stationary or by a moving body.
Hence

velocity = light path/time interval

where time interval is to be taken in the sense of the
definition in Section 1."

Did you see the word "definition"?

If you will read Einstein's definition, then you will see that it
merely forces one-way invariance. (John Wheeler's book, Spacetime
Physics_, gives a good description of how clocks are forced to
obtain Einstein's baselessly chosen one-way invariance; I highly
recommend that you add that to your required reading list.)

I haven't got time to educate every Tom, Dick, and Harry about SR.

[Tom Mattson noted:]
... Whether you measure the speed of light one-way or two-way, you
get the same result, namely that the speed of light is a Lorentz
invariant.

[2clockdude replies:]
News Flashes to Tom:
You cannot measure light's one-way speed without two clocks, and
you cannot use two clocks to measure any speed unless they have
been correctly synchronized. Tell us how to correctly synchronize
two clocks.

As of today, no one has ever used two clocks to measure light's
one-way speed, so your above one-way claim is as bogus as the
day is long.
 
  • #52
23
0
[outandbeyond2004 noted:]
Let me concede that nobody has measured the one-way speed of light
directly by means of a non-rotating set of two relatively-at-rest
clocks that we know are synchronized. He predicts that (oh, my
honey, THEORY!!) we will find the speed of light to be variable,
contradicting SR.

[2clockdude responds:]
Well, you have taken one step in the right direction, but now you
need to concede that the reason no one has ever measured light's
one-way speed is that no one knows how to correctly synchronize
clocks.

Then you need to further concede that only experiment can decide
the laws of nature.

Then you need to concede that man cannot give the laws of nature
via definition, by math or by any other means.

Then you need to concede that SR has one-way invariance/isotropy
only via a definition from man, so this invariance/isotropy is
not a law of nature.

Then you need to concede that Einstein himself admitted openly
and mathematically that _given_ correctly synchronized clocks,
light's one-way, two-clock speed would vary.
["w is the required velocity of light with respect to the carriage,
and we have
w = c - v.
The velocity of propagation of a ray of light relative to the carriage
thus comes out smaller than c."][from Einstein's _Relativity_]

Then you need to realize that not only do I predict one-way variance,
but experiment shows it. And I am not even counting the experiment
given above by Einstein; all I need is two observers viewing a single
approaching light ray.

But I don't have the burden of proof. Einstein has made the claim of
one-way light speed invariance. Let him (or his followers) back this
baseless claim if they can.

Einstein has also made the claim that he has a scientific theory that
is based (solely) on his claim of one-way light speed invariance, so
if he cannot back up the latter, then he cannot back up the former.

In other words, unless one-way invariance is a law of nature, Einstein
has no scientific theory.

Put that in your pipe and smoke it!
 
  • #53
russ_watters
Mentor
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7,259
Lets try a different approach, 2clockdude - you tell us how to measure the speed of light without running into clock synchronization issues that make the outcome a foregone conclusion.
Put that in your pipe and smoke it!
:confused: You're not in junior high...or are you?
 
  • #54
1,440
1
protonman,

I would like to give you my idea why c is the same for all observers regardless of their state of motion in the vacuum.

To do that, I have to go back to the original formulation done by Maxwell.

[tex] c = \frac {1}{\sqrt{\epsilon_0 \mu_0}} [/tex]

[tex] \epsilon_0 [/tex] is the permittivity of the vacuum and

[tex] \mu_0 [/tex] is the permeability of the vacuum.

The permittivity and permeability of the vacuum is always a constant no matter where you are in the universal vacuum and no matter how fast or how slow your speed is at each of each location of your position and no matter how you are located in time: past, present or the future.

The permittivity and permeability is the interaction of the electric force and the magnetic force. To say that c is different is the same thing as saying the electric force and magnetic force interact differently but this can only happens if there is matter but not in vacuum.
 
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  • #55
1,440
1
Further, to relate this concept of the constancy of the speed of light to my research, the infinitesimal difference between electric and magnetic force is the force of gravity.

[tex] F_g = | F_m - F_e | [/tex]
 
  • #56
641
0
The speed of light is given by Electric field/magnetic field at a given point.
If one or both of these can vary the speed changes.This would also mean that the permeability and the permittivity can change.I think E/ B is different for a graviton and
so it moves faster than light and can account for "instantaneous action at a distance." If light emits gravitons then perhaps it interacts with a mass that it is moving relative to, and adjusts E/B to make it more or less, so that speed of light + speed of mass = constant.
 
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  • #57
1,440
1
I think you are getting the idea. Please add some more and make some equations or fundamental principles.

In other part of my research I'm theorizing the existence of a fundamental acceleration(s) subject to change at various distances of r.

[tex] \vec{a} \cdot \vec{r} = c^2 [/tex]

but the product of acceleration and the distance is always the square of c.
 
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  • #58
1,440
1
Furthermore, I am asserting a fundamental force that is equivalent to time and that mass is inversely proportional to the time rate of change of acceleration.

[tex] m = ( \frac {da}{dt} )^{-1} [/tex]
 
  • #59
Tom Mattson
Staff Emeritus
Science Advisor
Gold Member
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2clockdude said:
[2clockdude wrote:]
Thinking people would want to know why light's one-way speed
is Lorentz invariant.

[Tom Mattson noted:]
You can think about it all you want, the question has no known
answer. And as has been noted, even if we did have the answer,
that explanation would have some unexplained phenomenon behind it.
... Einstein did not have the power to force the speed of light
to be absolute, "by definition", or any other means. The speed of
light is a Lorentz scalar because that's what it is measured to be.

[2clockdude replies:]
You need to read Einstein's 1905 SR paper before trying to
comment on his "theory."

Here are his own words (which you are probably now reading for
the very first time):

I have read it. I've even worked out the details! I don't know what you think this proves, but it doesn't even address my comment. Einstein's definitions do not affect the outcome of experiments, which is what I was saying in the quote above.

"2. Any ray of light moves in the "stationary" system
of coordinates with the determined velocity c, whether
the ray be emitted by a stationary or by a moving body.
Hence

velocity = light path/time interval

where time interval is to be taken in the sense of the
definition in Section 1."

Did you see the word "definition"?

Sure did.

If you will read Einstein's definition, then you will see that it
merely forces one-way invariance. (John Wheeler's book, Spacetime
Physics_, gives a good description of how clocks are forced to
obtain Einstein's baselessly chosen one-way invariance; I highly
recommend that you add that to your required reading list.)

Not only have I read it, I taught a course based on that it.

Since neither Taylor nor Wheeler have any doubts about relativity, I'm sure I don't know what parrt you are referring to. Would you mind pointing me to the section that you believe de-bunks relativity?

I have the second edition right here on my bookshelf, and I will be happy to explain to you why you misunderstand that part of the text. :smile:

I haven't got time to educate every Tom, Dick, and Harry about SR.

That can only be for the best, because you don't understand it very well. :rolleyes:

[Tom Mattson noted:]
... Whether you measure the speed of light one-way or two-way, you
get the same result, namely that the speed of light is a Lorentz
invariant.

[2clockdude replies:]
News Flashes to Tom:
You cannot measure light's one-way speed without two clocks, and
you cannot use two clocks to measure any speed unless they have
been correctly synchronized. Tell us how to correctly synchronize
two clocks.

Clocks can be synchronized quite easily. Ahrkron explained how in your thread SR Question of the Century. I'm puzzled as to why you still don't know. :confused:

As of today, no one has ever used two clocks to measure light's
one-way speed, so your above one-way claim is as bogus as the
day is long.

Actually, the one-way speed of light has been measured, with decaying pions, just as I said. See T. Alvager et al., Physics Letters 12, 260 (10/1/64).
 
  • #60
1,525
10
protoman - your question is quite proper - it is always disheartening to get answers like "that is the way the world is made" While SR gives correct relationships as near as one can tell, many believe that the goal post can be moved back a few yards to find a physical reason why the Einstein-Lorentz transformations work (if they do in every case). This should be an object of physics - yes - ultimately we will probably reach a point where we must say there is an unanswerable question - at least a puzzle we cannot fathom with human minds - but I concur that SR does not represent the end of the quest - probably more like a beginning. Moreover, whether you have a degree in physics or science does not automatically diminish your contributions to the state of learning - ideas frequently come from the new kid on the block because his thinking is not so regimented. Relativity was the product of a mind that had no prior recognition, a lowly patent examiner. It caught on because of its mathematical elegance, and its symmetry. It is now endorsed as gospel, but not by its creator who, near the end of his life, said, to wit: "I cannot think of a single theory that will survive the test of time. Maybe I have been on the wrong track all along - feelings of doubt come from within" Quote not quite correct - but nearly so from memory
 
  • #61
641
0
Constancy of the speed of light.

Let’s suppose that a photon is moving slightly faster than c metres per second.
It emits a graviton which is also an EM wave and this is absorbed by a stationary particle with rest mass.
However because the graviton was emitted from a photon moving faster than usual
the graviton wave is blueshifted by the Doppler effect more than usual.So when it is absorbed it causes the particle to emit a graviton with a higher frequency than normal too.The photon absorbs this graviton and the ratio of E/ B gets smaller so that the photon moves at c metres per second.The graviton is not subject to Lorentz invariance
but it seems to be just because it moves so fast, 10^20 metres per second, that particle speeds which reach the speed of light at the most, are virtually the same relative to the graviton however they are measured.A photon moving slightly slower than c emits Doppler redshifted gravitons and these result in the particle emitting a redshifted graviton which causes E/B in the photon to increase.
The way to form an equation for this discussion is to consider momentum conservation for the particle graviton photon interaction.I'll give it a try sometime.
 
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  • #62
23
0
[russ_watters asked:]
Lets try a different approach, 2clockdude - you tell us
how to measure the speed of light without running into
clock synchronization issues that make the outcome a
foregone conclusion.

[2clockdude replies:]
Well, you need to clue in Tom Mattson because he sees no
problems with either SR's clock synchronization or with
the results thereof. (All of which, as you said, are merely
man-given foregone conclusions, including light's one-way
speed invariance and the SR transformation equations.)

As for your highly relevant question, here is the answer:

One need not quantify the relative speeds of one's
clock-starting entities; all one needs to do is to
simply ascertain their equality; therefore, one can
absolutely synchronize two clocks by simply using a
third (operating or running) clock to time the two
clock-starting entities speeds in order to confirm
their equality. This is known as a qualitative
comparison because neither entity's speed is actually
measured. (By analogy, I need not know the actual
lengths of two sticks in order to confirm that they
are either equally long or not. This can be done very
easily via a side-by-side comparison.)

(I hope that my description was deliberately vague enough
to protect my proprietary interest.)

Thanks for the question!
 
  • #63
23
0
[Tom Mattson noted:]
Einstein's definitions do not affect the outcome of experiments,
which is what I was saying in the quote above.

[2clockdude replies:]
I know what you were saying, and (as even 'russ_watters' openly
stated), Einstein's definition of clock synchronization yields
merely foregone conclusions (which of course have no place in
science, either theoretical or experimental).

[Tom Mattson noted:]
Since neither Taylor nor Wheeler have any doubts about relativity,
I'm sure I don't know what parrt you are referring to. Would you
mind pointing me to the section that you believe de-bunks relativity?

[2clockdude replies:]
You misread me; at no point did I even hint that the Taylor/Wheeler
'team' had 'de-bunked' SR; what I did say was that they had presented
an excellent description of Einstein's clock synchronization process,
a description which clearly shows the circularity involved. In other
words, Wheeler shows exactly how Einstein's clocks are merely forced
by man to obtain one-way light speed invariance. (Here is why this
is circular: If I force clocks to obtain one-way invariance, then,
by George, they will most certainly obtain it!)

[I can't afford their latest edition. I have the 1966 version, and
in it, said description starts on page 18 of the section entitled
"The Geometry of Spacetime."]

[Tom Mattson noted:]
Actually, the one-way speed of light has been measured, with decaying
pions, just as I said. See T. Alvager et al., Physics Letters 12, 260
(10/1/64).

[2clockdude responds:]
Nope, that was merely a source-independency test.
[See http://www.weburbia.demon.co.uk/physics/experiments.html [Broken] --
Section VII.]

[2clockdude continues:]
As both I and 'russ_watters' know, the critical goal is two
correctly (or absolutely) synchronous clocks, and we can be
sure that Einstein failed to find such things because he
admitted that he could not determine absolute simultaneity.
 
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  • #64
mee
213
1
Relativity

russ_watters said:
They are a reality, but like velocity, you can only measure it in relation to someone else. To date, there is no evidence of this "something" causing the motion of matter to slow. It is certainly possible, but without any evidence, it can't be assumed or even theorized. And it works perfectly well to use the current explanation: that time itself is slowing.

All of the laws of the universe 'just are' - either that or they were made by God for a reason only he knows. Either way, you do have to live with that answer.

Why does the time on the planet left not appear to slow from the spaceship as it is accelerating at great speed away from the spaceship, relative to the spaceships perception. I mean, could traveling at close to light speed also be viewed as slowing down the spaceship more and more so that the rest of the universe, traveling at close to light speed, :smile: rapidly moves in relation to the now practically "still" spaceship.
 
  • #65
DrChinese
Science Advisor
Gold Member
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protonman said:
I don't care about getting them published. Besides the world is probably not ready for my ideas and would most likely reject them due to their ignorance.

1. You are afraid someone else will steal your ideas and publish them as their own;
2. But you don't care about publishing them yourself;
3. And society is too stupid to appreciate them even if they were published.

Do I detect an inconsistency here?

By my count, protonman would rate an 85 on the Baez crackpot index from his statements on this thread. But please, don't assume I am calling protonman a crackpot. Or that you know what my motives are, or anything about my educational background...
 
  • #66
DrChinese
Science Advisor
Gold Member
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2clockdude said:
[2clockdude replies:]
I know what you were saying, and (as even 'russ_watters' openly
stated), Einstein's definition of clock synchronization yields
merely foregone conclusions (which of course have no place in
science, either theoretical or experimental).

[2clockdude continues:]
As both I and 'russ_watters' know, the critical goal is two
correctly (or absolutely) synchronous clocks, and we can be
sure that Einstein failed to find such things because he
admitted that he could not determine absolute simultaneity.

What do you think the significance of this is? It is basically of no import and arguing over semantics.

So what if absolute simultaneity cannot be determined? You still have the situation in which all "imperfect" measurements of the speed of light yield c. That doesn't happen for electrons, marbles, or other matter.

Hmmm. Maybe SR is useful after all, and not the definitional self-deception of stubborn scientists. Utility is derived from a good theory, and SR fits the bill. While you lament the foregone conclusion of the results of experiments, others are using SR every day. Got anything better? That would be a great way to convince just about anyone.
 
  • #67
Tom Mattson
Staff Emeritus
Science Advisor
Gold Member
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2clockdude said:
[Tom Mattson noted:]
[2clockdude replies:]
I know what you were saying, and (as even 'russ_watters' openly
stated), Einstein's definition of clock synchronization yields
merely foregone conclusions

No, it doesn't. Synchronizing the clocks in the way prescribed by Einstein merely forces clocks in the same inertial frame to tick at the same rate. This is required to be consistent with the relativity postulate (not the speed of light postulate).

[2clockdude replies:]
You misread me; at no point did I even hint that the Taylor/Wheeler
'team' had 'de-bunked' SR; what I did say was that they had presented
an excellent description of Einstein's clock synchronization process,
a description which clearly shows the circularity involved. In other
words, Wheeler shows exactly how Einstein's clocks are merely forced
by man to obtain one-way light speed invariance. (Here is why this
is circular: If I force clocks to obtain one-way invariance, then,
by George, they will most certainly obtain it!)

Uh-huh, so in other words you hinted that Taylor and Wheeler debunked SR.

[I can't afford their latest edition. I have the 1966 version, and
in it, said description starts on page 18 of the section entitled
"The Geometry of Spacetime."]

There is no such section in the second edition. But I did look up all the entries of "synchronization" up in the index, and they all say the same thing: that properly synchronized clocks tick at the same rate in the rest frame of the clocks. No surprises there.

[Tom Mattson noted:]
Actually, the one-way speed of light has been measured, with decaying
pions, just as I said. See T. Alvager et al., Physics Letters 12, 260
(10/1/64).

[2clockdude responds:]
Nope, that was merely a source-independency test.
[See http://www.weburbia.demon.co.uk/physics/experiments.html [Broken] --
Section VII.]

:rolleyes:

That's the same thing, silly.

[2clockdude continues:]
As both I and 'russ_watters' know, the critical goal is two
correctly (or absolutely) synchronous clocks, and we can be
sure that Einstein failed to find such things because he
admitted that he could not determine absolute simultaneity.

Einstein failed to find a pair of clocks that are synchronized in every frame, because such a pair of clocks doesn't exist in reality: Simultaneity is relative.
[/quote]
 
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