Unravelling the Mystery of Light's Constant Speed: Challenges and Proofs

[M1keh]

M1keh, light could logically be able to travel at speed greater than light while all frequencies still initially went the same speed. I think sound waves are like this, all frequencies travel 334 m/s (not sure) but can be viewed as going faster from different reference frames.

michael879. That's sort of what I've been trying to get at. All of the 'evidence' that the speed of light is constant seems to be from experiements that confirm that all frequencies of light reach us from distant events at the same time ?

Surely, as I think you suggest above, this isn't evidence of anything of the sort ?

 

[ZapperZ]

wish I had checked on this earlier, I got a lot of comments..

first, aether, I just omitted the word inertial its what I meant, you didnt answer my question u just pointed out a mistake in it. I know what a postulate is but people don't just go around making up postulates out of nothing and use them in new theories. There must have been a significant amount of evidence that the speed of light is constant for einstein to create all of special relativity around it.

Then you must have not read ANY of Einstein's biography, or any history of physics. The formulation of SR was due to several issues of 19th Century physics, the biggest of which is the non-covariant nature of Maxwell Equations at that time under galilean transformation. This is a big deal since Newton's Laws maintain their covariance. And since light is a product of the Maxwell equations, it was natural that it has to be addressed. That was the impetus of SR!

M1keh, light could logically be able to travel at speed greater than light while all frequencies still initially went the same speed. I think sound waves are like this, all frequencies travel 334 m/s (not sure) but can be viewed as going faster from different reference frames.

zapper, the frequencies don't separate because they travel different speeds in a vacuum, just because they travel different speeds in a medium which is pretty irrelevant since the photons are still going the constant speed of c (just being absorbed and reabsorbed by molecules).

Er.. the frequencies don't separate because they travel different speeds in vacuum? Come again?

All you need to do is measure this and get it over with. We have measurements of c in vacuum ranging from low freq. radio waves all the way to gamma range. You demanded experimental evidence for the validity of SR. Now it is my turn to demand from you experimental evidence for what you are claiming. It is fair, is it not?

It is also ironic that you are using "photons are still going the constant speed of c" in your explanation of optical transport through matter, since you are arguing that they DON'T!

Zz.

 

[M1keh]

Then you must have not read ANY of Einstein's biography, or any history of physics. The formulation of SR was due to several issues of 19th Century physics, the biggest of which is the non-covariant nature of Maxwell Equations at that time under galilean transformation. This is a big deal since Newton's Laws maintain their covariance. And since light is a product of the Maxwell equations, it was natural that it has to be addressed. That was the impetus of SR!



Er.. the frequencies don't separate because they travel different speeds in vacuum? Come again?

All you need to do is measure this and get it over with. We have measurements of c in vacuum ranging from low freq. radio waves all the way to gamma range. You demanded experimental evidence for the validity of SR. Now it is my turn to demand from you experimental evidence for what you are claiming. It is fair, is it not?

It is also ironic that you are using "photons are still going the constant speed of c" in your explanation of optical transport through matter, since you are arguing that they DON'T!

Zz.

Zz. Although my id was mentioned this wasn't originally posted by me.

That said, can the fact that, all frequencies of light from a single source turn up at the same speed, be used as evidence of a constant speed of light ?

 

[clj4]

If LET uses the Lorentz transforms, then how is it an ether theory?

You'll need to figure that one for yourself, I am not interested in restarting a multi-hundred post thread with you.

Then please give one example of an additional ad-hoc assumption required to make GGT empirically equivalent to SR.

You got that in the CMWill paper that was recommended to you hundreds of posts ago. I am not interested in running another multi-hundred post thread with you on the same exact subject. It was already discussed ad nauseaum with you in more than one thread. Several other posters tried (and apparently failed) to explain the same thing to you. Try reading CM Will on your own.

 

[M1keh]

... the biggest of which is the non-covariant nature of Maxwell Equations at that time under galilean transformation. This is a big deal since Newton's Laws maintain their covariance. ...
Zz.

A bit more interesting. Can you recommend a good URL that gives the details ... preferably in 'an idiots guide ...' approach ?


Thanks.

 

[Aether]

You'll need to figure that one for yourself, I am not interested in restarting a multi-hundred post thread with you.

Your claim is absurd, and your reply is not responsive to my question. Unless someone else here agrees with you, then your claim is dismissed by unanimous consent.

You got that in the CMWill paper that was recommended to you hundreds of posts ago. I am not interested in running another multi-hundred post thread with you on the same exact subject. It was already discussed ad nauseaum with you in more than one thread.

Again, your reply is not responsive to my question. Unless someone else here agrees with you, then your claim is dismissed by unanimous consent.

Several other posters tried (and apparently failed) to explain the same thing to you. Try reading CM Will on your own.

Does anyone else remember it this way?

 

[alpaolo]

c costant

2. http://www.aip.org/enews/physnews/20...t/pnu484-1.htm . This is the most recent and accurate determination that the speed of light is independent of the speed of the source.

I don't know why are needed some experiment, I think is natural that the light speed is indipendent by the speed of the source.

Like a rain that fall down to the clouds.
If the cloud go down to sky with a certain speed, the drops fall at its speed, or not?

 

[ZapperZ]

2. http://www.aip.org/enews/physnews/20...t/pnu484-1.htm . This is the most recent and accurate determination that the speed of light is independent of the speed of the source.

I don't know why are needed some experiment, I think is natural that the light speed is indipendent by the speed of the source.

Like a rain that fall down to the clouds.
If the cloud go down to sky with a certain speed, the drops fall at its speed, or not?

OK, now this is strange. Usually people can't understand why the speed of something isn't dependent on the speed of the source.

The speed of "raindrops" is governed by many things, including drag forces. This puts a limit on how fast it can move through air, regardless of the initial speed of the clouds. If you remove the air, then it DOES matter. So if you do galilean transformation, as in speed of a bullet shot on a moving train, you'll see that a person on the ground will see a different speed of the bullet than the person on the train who fired it. You go from one frame to another via galilean transformation (under v<<c).

 

[alpaolo]

c costant

Another strange question.

If the source S of light run with speed vs is on train with a speed Vt, the observer watch the speed as like a sum vs+vt, but the generated run with speed c.
Is not because the source of light lies on the train and the force drag the source, but the light is indipendent, is, in fact "suspended"?

The source of light don't contrast the gravity (lies on the floor) but the light have a force that contrast the gravity?

 

[ZapperZ]

Another strange question.

If the source S of light run with speed vs is on train with a speed Vt, the observer watch the speed as like a sum vs+vt, but the generated run with speed c.
Is not because the source of light lies on the train and the force drag the source, but the light is indipendent, is, in fact "suspended"?

No, it is because gallilean transformation doesn't work when v~c. At that range, only Lorentz transformation works for all of mechanics, not just light.

Zz.

 

[alpaolo]

c costant

The speeed sum formula: (u+v)/[1+(u*v/c2)] for me appears a little trick to include a c in the formula.

About me there is a possibility to include gravity in the gallilean transformation.
Every object that don't lies on the "train" ( and stay suspended ) don't suffers the drag force.Then the ext observer can watch only the single speed...

I know I'm crazy, but this idea is a loop on my mind.

 

[ZapperZ]

The speeed sum formula: (u+v)/[1+(u*v/c2)] for me appears a little trick to include a c in the formula.

About me there is a possibility to include gravity in the gallilean transformation.
Every object that don't lies on the "train" ( and stay suspended ) don't suffers the drag force.Then the ext observer can watch only the single speed...

I know I'm crazy, but this idea is a loop on my mind.

Before you get carried away, pay attention to these:

1. The Lorentz transformation has been formulated BEFORE Einstein's SR. Einstein made a physical connection to it, and electrodynamics.

2. Re-read the PF guidelines regarding personal and speculative theories. We strictly enforce it.

Zz.

 

[alpaolo]

c costant

Thanks zz,

but where is a place where submit an idea?

I know it's impossible follows all idea. I'm not a genius but only watching the nature behaviour, is possible to get a a new idea.

Many people don't understand the costant speed of light because there is no way top accelerate it, but this not means that the speed of light is a limit...


thanks again zz

 

[michael879]

Er.. the frequencies don't separate because they travel different speeds in vacuum? Come again?

All you need to do is measure this and get it over with. We have measurements of c in vacuum ranging from low freq. radio waves all the way to gamma range. You demanded experimental evidence for the validity of SR. Now it is my turn to demand from you experimental evidence for what you are claiming. It is fair, is it not?

It is also ironic that you are using "photons are still going the constant speed of c" in your explanation of optical transport through matter, since you are arguing that they DON'T!

Zz.

Im not arguing that the speed of light isn't constant, I am asking for experimental evidence since the only proof I have is that a bunch of teachers have told me its constant. In my comment I was just telling you would a textbook would say: all frequencies of light travel at c in a vacuum. In media however they "travel" at different speeds. Its misleading to say that since in reality they are still traveling at c, they just are absorbed and reabsorbed by atoms in the medium that slow down different frequencies different amounts.

 

[ZapperZ]

Im not arguing that the speed of light isn't constant, I am asking for experimental evidence since the only proof I have is that a bunch of teachers have told me its constant. In my comment I was just telling you would a textbook would say: all frequencies of light travel at c in a vacuum. In media however they "travel" at different speeds. Its misleading to say that since in reality they are still traveling at c, they just are absorbed and reabsorbed by atoms in the medium that slow down different frequencies different amounts.

But in all practical sense, they DO travel at different speeds in a medium. This is because the "light pulse" that is measured is always the group velocity. You don't measure the phase velocity, nor do you have a direct probe of the "photon velocity". The same is true for speed of light in a vacuum. Do you think you measured the "photon velocity" here? Thus, the comparison is perfectly valid.

You were already given the experimental evidence that is consistent with SR. Yet, you continued to counter it with some made-up scenario of some "drag", which is neither formulated carefully, nor backed by any experimental evidence. Why aren't you as skeptical towards this scenario as you are with your textbooks and your teachers? To me, you're already nitpicking things that you don't like, while you turn on your blinders towards your explanation that is riddled with holes.

I have given you tons of experimental evidence. There are more. You haven't shown even one. Unless there's something you haven't told me, I'm sure you'll understand that I no longer wish to continue with this "discussion", because what I asked for, you refuse to provide.

Zz.

 

[michael879]

But in all practical sense, they DO travel at different speeds in a medium. This is because the "light pulse" that is measured is always the group velocity. You don't measure the phase velocity, nor do you have a direct probe of the "photon velocity". The same is true for speed of light in a vacuum. Do you think you measured the "photon velocity" here? Thus, the comparison is perfectly valid.

maybe its valid but its kinda irrelevent.

You were already given the experimental evidence that is consistent with SR. Yet, you continued to counter it with some made-up scenario of some "drag", which is neither formulated carefully, nor backed by any experimental evidence. Why aren't you as skeptical towards this scenario as you are with your textbooks and your teachers? To me, you're already nitpicking things that you don't like, while you turn on your blinders towards your explanation that is riddled with holes.

I have given you tons of experimental evidence. There are more. You haven't shown even one. Unless there's something you haven't told me, I'm sure you'll understand that I no longer wish to continue with this "discussion", because what I asked for, you refuse to provide.

Zz.

huh? when have I countered SR? I think SR is right I am just trying to understand its postulates and get some clear evidence of it. what drag scenario are you talking about? I havnt mentioned anything like drag and I havnt given my own theory to counter SR... I think your confusing me with alpaolo..

 

[ZapperZ]

maybe its valid but its kinda irrelevent.

Why? You ARE measuring the group velocity in BOTH, because at best, you measure "pulses". I'd say it is valid AND relevant.

huh? when have I countered SR? I think SR is right I am just trying to understand its postulates and get some clear evidence of it. what drag scenario are you talking about? I havnt mentioned anything like drag and I havnt given my own theory to counter SR... I think your confusing me with alpaolo..

You're right. I apologize. However, you DID counter SR. Did you forget that you said the following:

M1keh, light could logically be able to travel at speed greater than light while all frequencies still initially went the same speed. I think sound waves are like this, all frequencies travel 334 m/s (not sure) but can be viewed as going faster from different reference frames.

zapper, the frequencies don't separate because they travel different speeds in a vacuum, just because they travel different speeds in a medium which is pretty irrelevant since the photons are still going the constant speed of c (just being absorbed and reabsorbed by molecules).

You said that even AFTER being pointed out the experimental evidence that contradict what you just said. So not only are you contradicting the postulate of SR, you also made claims that did not match any experimental evidence.

Zz.

 

[michael879]

I said logically, which means if light were like sound different frequencies would still travel at c but they could appear to travel at speeds greater than c from different reference frames. I didnt say light IS like sound I said logically it could be. I was just saying that the fact that all frequencies travel at the same speed doesn't prove that c is constant in all inertial frames.

also, all frequencies do travel at c in a vacuum, its only when they are in some medium that they separate.

The fact that the speed of light can vary in different media is irrelevant to this thread because the photons in that case never travel slower than c. The overall light "wave" has an average speed slower than c.

 

[ZapperZ]

I said logically, which means if light were like sound different frequencies would still travel at c but they could appear to travel at speeds greater than c from different reference frames. I didnt say light IS like sound I said logically it could be. I was just saying that the fact that all frequencies travel at the same speed doesn't prove that c is constant in all inertial frames.

Logically, IT CAN'T! You cannot DERIVE such a thing, so there's no logic to this. It is why this is physics and not mathematics. At some point, you use physical values that are not derived, but measured! So what you claim to be "logical", isn't!

also, all frequencies do travel at c in a vacuum, its only when they are in some medium that they separate.

So I actually imagined you saying what I quoted in BOLD?

The fact that the speed of light can vary in different media is irrelevant to this thread because the photons in that case never travel slower than c. The overall light "wave" has an average speed slower than c.

You don't have to teach me that, especially if you have read our FAQ in the General Physics section. However, and I'm saying this again for the umpteeth time, you do NOT measure the speed of a photon. You detect the GROUP VELOCITY, be it in vacuum or in a medium. That is what we measure in optical transport measurement, it is what is measured in the paper that was cited, and it is what is being measured in that apparent superliminal NEC experiment a few years ago.

And where do you think are the sources of the gamma rays that were measured in the cited paper? In the Earth's reference frame? How about you give the paper a careful reading FIRST and figure out if they somehow managed to sneak into PRL with simply just that one result, or if they actually had a few more things to say?

Zz.

 

[michael879]

So I actually imagined you saying what I quoted in BOLD?

sorry I just reread what I wrote. I think my lack of commas made it mean something different from what I meant.

the frequencies don't separate because they travel different speeds in a vacuum

I meant that the reason the frequencies separate in a medium isn't because they travel different speeds in a vaccuum. We both saying the same thing arent we?

You don't have to teach me that, especially if you have read our FAQ in the General Physics section. However, and I'm saying this again for the umpteeth time, you do NOT measure the speed of a photon. You detect the GROUP VELOCITY, be it in vacuum or in a medium. That is what we measure in optical transport measurement, it is what is measured in the paper that was cited, and it is what is being measured in that apparent superliminal NEC experiment a few years ago.

And where do you think are the sources of the gamma rays that were measured in the cited paper? In the Earth's reference frame? How about you give the paper a careful reading FIRST and figure out if they somehow managed to sneak into PRL with simply just that one result, or if they actually had a few more things to say?

Zz.

what paper are you talking about? I havnt cited any paper... and I get that the group velocity isn't c in a medium but it really has nothing to do with my original question. All I asked was for experimental evidence that the speed of light was constant. Since relativity is based around that fact I am just curious why einstein thought that. Why are you being so aggressive towards me? and why do you keep acting like I made most of these posts? I've only posted 3 or 4 times and I havnt said half of the things youve accused me of.

 

[clj4]

I get the theory of special relativity, it is the logical conclusion drawn from the two facts that:
a) the laws of physics are the same in all reference frames
b) the speed of light is constant in all reference frames

what I don't get is why einstein thought the speed of light was constant in all reference frames. What proof of that is there even now? I know maxwell came up with c which is like 1/(m0*e0) or something which kinda suggests it but why couldn't that just be the initial velocity of light if the emitter was at rest with the "global reference frame".

Also, I am not convinced that theory is true. I mean, I've heard of all these experiments "proving" general and special relativity, but I've never seen any documentation of any or any real numbers. I've searched to... Can someone please give me some good links before I start talking about a giant physics conspiracy?

Here is a good synopsis of the experiments confirming relativity:

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html

The actual list is about 10x bigger.

 

[michael879]

thanks man, Ill read that

 

[Aether]

first, aether, I just omitted the word inertial its what I meant, you didnt answer my question u just pointed out a mistake in it. I know what a postulate is but people don't just go around making up postulates out of nothing and use them in new theories. There must have been a significant amount of evidence that the speed of light is constant for einstein to create all of special relativity around it.

There is no physical evidence that the one-way speed of light is isotropic. What the postulates of SR are designed to exploit is the fact that there isn't any phyiscal evidence to the contrary. This is a mathematical issue, not a physical issue.

 

[clj4]

There is no physical evidence that the one-way speed of light is isotropic. What the postulates of SR are designed to exploit is the fact that there isn't any phyiscal evidence to the contrary. This is a mathematical issue, not a physical issue.

You know that this isn't true, we went over this issue before, there are quite a few experiments that limit any potential anisotropy to very low limits. The experiments figure prominently in the list that I just gave. And you have been told that you are supporting an incorrect view countless times.

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#one-way tests

 

[Aether]

There is no physical evidence that the one-way speed of light is isotropic. What the postulates of SR are designed to exploit is the fact that there isn't any phyiscal evidence to the contrary. This is a mathematical issue, not a physical issue.

You know that this isn't true, we went over this issue before, there are quite a few experiments that limit any potential anisotropy to very low limits. The experiments figure prominently in the list that I just gave. And you have been told that you are supporting an incorrect view countless times.

http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#one-way tests

3.2 One-Way Tests of Light-Speed Isotropy
Note that while these experiments clearly use a one-way light path and find isotropy, they are inherently unable to rule out a large class of theories in which the one-way speed of light is anisotropic. These theories share the property that the round-trip speed of light is isotropic in any inertial frame, but the one-way speed is isotropic only in an ether frame.

What is your major malfunction, clj4?!? Can you not read your own references?

 

[JustinLevy]

There is no physical evidence that the one-way speed of light is isotropic.

You can define some coordinate systems where the speed of light is not isotropic. But the question becomes, is that an inertial frame?

You might also be interested in this very recent conference talk:
http://www.zarm.uni-bremen.de/2forschung/gravi/laemmerzahl/MG11exp/
I came across it when searching for "one way light speed measurements".

All you can read is the abstract by Dr. Adrian Sfarti, but it seems to state that he strengthened some old data to experimentally prove the one-way light speed is isotropic. Strangely, the abstract doesn't describe the experiment at all.


Update: When searching to try to find the paper that goes with the abstract, it looks like this Dr. Sfarti may be a crackpot. Also it appears that the conference preceedings haven't been published yet. So we'll have to wait to see the paper (assuming that the referees don't decide he's a crackpot as well).

 

[clj4]

You can define some coordinate systems where the speed of light is not isotropic. But the question becomes, is that an inertial frame?

You might also be interested in this very recent conference talk:
http://www.zarm.uni-bremen.de/2forschung/gravi/laemmerzahl/MG11exp/
I came across it when searching for "one way light speed measurements".

All you can read is the abstract by Dr. Adrian Sfarti, but it seems to state that he strengthened some old data to experimentally prove the one-way light speed is isotropic. Strangely, the abstract doesn't describe the experiment at all.Update: When searching to try to find the paper that goes with the abstract, it looks like this Dr. Sfarti may be a crackpot. Also it appears that the conference preceedings haven't been published yet. So we'll have to wait to see the paper (assuming that the referees don't decide he's a crackpot as well).

Kevin,Looks like the best you could muster in place of a scientific answer is a personal attack. This is what you learn at UCUI?
Last time we had a conversation on the same exact subject you were a pair of "sockpuppets" called "gregory_" and "NotForYou".
When "both" of you were banned you promptly re-registered yourself as "JustinLevy" and you "progressed" to personal attacks and cyberstalking as "scientific arguments". Looks like this type of unethical behavior is your standard mode of operation.

 

[clj4]

What is your major malfunction, clj4?!? Can you not read your own references?

The statement is made by Tom Roberts and is patently incorrect, sorry to disappoint you. It is refuted (multiiple times) by the papers of the much more respected expert in the field CMWill. Though Tom Roberts has been made aware that his statement is wrong, he never got around to editing his website. The same exact issue was refuted in a pair of multihundred posts threads between the two of us. How quickly you forget...
You need to read:

http://prola.aps.org/abstract/PRD/v45/i2/p403_1

I recommended it for you about 30 times.

 

[Aether]

The statement is made by Tom Roberts and is patently incorrect, sorry to disappoint you. It is refuted (multiiple times) by the papers of the much more respected expert in the field CMWill. Though Tom Roberts has been made aware that his statement is wrong, he never got around to editing his website.

You are the one who referenced this website in post #54, and I don't see any problem with the passage that I quoted from it.

The same exact issue was refuted in a pair of multihundred posts threads between the two of us. How quickly you forget...

No, you lost that debate. You simply refuse to accept that.

You need to read:

http://prola.aps.org/abstract/PRD/v45/i2/p403_1

I recommended it for you about 30 times.

I would be happy to discuss C.M. Will's paper with you, but you won't make any specific points nor will you answer any of my questions. Therefore, your reference to this paper stands dismissed by unanimous consent. How can it be otherwise?

 

[clj4]

You are the one who referenced this website in post #54, and I don't see any problem with the passage that I quoted from it.

Well, physics is about precision. had you read the referenced paper you would have understood that the complete quote is:

"Note that while these experiments clearly use a one-way light path and find isotropy, they are inherently unable to rule out a large class of theories in which the one-way speed of light is anisotropic provided that additional, ad-hoc assumptions are being made "The "provided that additional, ad-hoc assumptions are being made " are the Achille's heel of all the alternative "aether" theories.
That was the gist of my original counter from post 26. It is this exact "aetherist" position that you repeat every several months, only to be refuted every time, with the same arguments.

No, you lost that debate. You simply refuse to accept that.

Really? this is why you went away for such a long time? Just to come back with the same antiscientific statements that originated the threads? I

I would be happy to discuss C.M. Will's paper with you, but you won't make any specific points nor will you answer any of my questions.

Then read it and try to undewrstand it. CM Will makes his points quite clearly.

Therefore, your reference to this paper stands dismissed by unanimous consent. How can it be otherwise?

It can be otherwise if you took the time to read and understand rather than simply repeat stuff that you do not understand. As to the "unanimous", we have seen this from you in the past: it means you and yourself?