Measuring The Relative Velocity Of Light

[grounded]

Your case would be greatly strengthed if you could give the mathematical formulation of your distance ideas.

Did you happen to read post #52?

 

[russ_watters]

Wasn't it Einstein who claimed it [C] must be the same for all frames of reference?

Einstein didn't "claim" it, he used the already known fact as the first postulate in his new theory. Big, big difference.

I like Tom's way of listing your predjudices here. I think this one (#1) is the most serious: That the speed of light is constant is not simply some arbitrary assumption made for for convenience in the math of SR. It is high precision experimental fact and you need to accept that.

I still don’t think you understand my point. In order for you to measure a relative effect, you have to take something out of a formula that we know works.

Take what out of what formula?

 

[wespe]

Did you happen to read post #52?

Have you read #53?

Let me try again:

"The distance the passing car travels in one second". This is speed.

"The amount of time it takes ONE car to fully pass you". This is 1/frequency.

So, you are calculating the wavelength by dividing speed by frequency.

OK. Here is your mistake:

This is what happens when you DO NOT include your distance traveled:

(Only the distance the passing car travels in one second) (80.66 Feet)(This is a known value)

What is this "known value" of 80.66? It is in fact the speed of the car wrt the road. The answer comes out wrong because of dividing the speed wrt the road by the frequency wrt the observer. You can't mix measurements made wrt different frames. And nobody is making such a mistake as you imagine.

To calculate the wavelength of light:
1- Measure the speed of light wrt yourself.
2- Measure the frequency of light wrt yourself.
3- Divide the speed by frequency.

Please note that at step #1, we don't just use a speed measurement made in some other frame (as "known value"), we really measure it wrt ourself. Therefore the mistake you imagine is not being made.

But, the value we measure wrt ourselves turns out to be the same value measured made in any other frame, c. So, no, we aren't neglecting the extra speed or traveled distance, it is light itself doing this.

And to make it really clear:

You don't have to assume speed of light constant wrt all frames. You just measure it in those frames. It just turns out to be always equal to c. Back to your car example, it would be funny if you measured the relative speed of the car to be constant. But this is the case with light. This is experimentally supported.

 

[quantumdude]

Tom, where did Maxwell discuss relative measurements of light? I was under the impression that Maxwell only discussed light from an, at rest relative to the source point of view.

To tell you the truth, I don't know what Maxwell thought about light propagation under coordinate transformations. It really doesn't matter (except perhaps for historical interest) because today we have better information than he ever could have had.

Wasn't it Einstein who claimed it must be the same for all frames of reference?

Yes, he was the first to claim that. And since then, it has been confirmed by experiment.

Didn't Maxwell basically say that since space offers no resistance to light, than no matter how fast the source is traveling, the light would always travel away from the source at the speed of light? Which one of MAXWELL'S equations (please try to keep it in layman terms) describes what we will measure if the light source is traveling towards us?

I've already explained this. Will you please try to pay attention?

It isn't anyone of Maxwell's equations that tells us that the speed of light is independent of the speed of the emitter. It is the requirement of the invariance of all of them[/color] that leads to the prediction.

I still don’t think you understand my point.

Look in the mirror.

I understand your point perfectly. It's just that you are wrong. Try to get over your ego and see that.

In order for you to measure a relative effect, you have to take something out of a formula that we know works.

And pray tell, what formula is that?

 

[svitenti]

Hum...

Every time i enter this part of the forum i laugh a lot, but this time there is something i cannot understand, why Tom Mattson and russ_watters are still trying to convince these insane people about things already founded 100 years ago. IF SR is wrong, the error will be only apparent near some cut off like plank lenght. You see, all those equations like dirac's and klein gordon and others, come just from representations of poincare group, so if you don't like SR you have to give us other group so we get the equations and test it against the experiment, hum... i talked too much

 

[ram1024]

you'll get to laugh soon, because special relativity falls this weekend.

it will be hysterical to set science back a 100 years. we'll all have a good chuckle I'm sure

 

[geistkiesel]

proper inmformation exchange processes crucial to defining SR

Some observations on the corfrectness of information exchange re om_Mattson v Grounded.

Grounded, we all understand it. That's because we all studied non[/color]relativistic physics before learning SR. It's just that you aren't understanding what we are saying. Let me explain.



What Russ and I have been telling you, and what you aren't understanding, is this:

The wavelength of the light in the rest frame of the source is not special. There's no reason to think that it is the "correct" wavelength, while all others are only "apparent". There's no reason whatsoever to use any correction for the distance the observer has traveled, and I'll explain why later on.

It does make sense to use SR to prove you wrong, because you yourself deduced from your hypothesis that the speed of light is not the same in every frame. And indeed, if your hypothesis is true, your deduction would be true also.

Grounded is saying that current system (SR) for measurement of wave length is flawed by not taking ino account the motion of the observer. A counter argument using SR is, therefore, pecipitous, premature at this point in the exchange. You repeatedly claim Grounded doesn'yt understand what you are etelling him, which isn't a scientific arguement, or reasoning.

But the deduction is not true: The speed of light is the same in every frame.

I don't think you are seeing exactly how SR connects to your argument.



But the theory was not developed to account for wavelength measurements. The theory was developed for the exact reason I said it was developed: To maintain the invariance of the equations of electrodynamics when transforming from one inertial frame to another.

Same basic observation. You try to submerge Grounded before you have understood his complete argument. Your intervention as he goes along voids your responses as having scientifically value. All your history rationale etc do not go to Grounded's thesis. I cannot understand why you have been unable to see what G is saying. Your misunderstanding is manifest with premature interjection of SR arguments, prior to the defined completion of the developing thread.

This not a minor point, none are. If you look closely Tom you will see Grounded does not assume SR is wrong befoe he starts, but you assume SR is correct and from this you make the assumption that Grounded has started with an asumed contradictiion with SR..

How many times do you have to observe that your intense application of SR themes does not attractg all the curious scientists, nor is it convincing?

You said you came here to talk to professionals about this, yes? Please take the advice of this professional: You are never going to get out of these circles you are stuck running around in until you understand the problem above.



No problem on my end. The question is, will you do the same?



Understanding it is no problem. Your points are nothing new to me: physicists have to study nonrelativistic physics before learning SR. It's not that I don't understand you, it's that I understand that you are wrong.

Tom look at this exchange and point to scientific worth. Grounded understands you, but he didn't approach you as a "professional" to hear you echo SRT. He wanted a critique of his system and he wanted the criitique fully void of attempted refutations and corrections such as "Because SR says so [etc].

You are trying to obtain a surrender . The "circles" are your ["standard model"] insertions into this thread, not Grounded. At no instant have you made an attempt to analyze a completed "model" by Grounded ,in his tems. Try hard to see your approach to solutions to these situaitions is problematics

And now we come to Prejudice #1, that you must abandon if this is to make any progress. When you say that the speed of light is not the same to all observers, the logical implication is that Galilean relativity is correct and Special relativity is wrong. That is why I attempted to explain to you why this cannot be so. You can't state what you state on the one hand, and then refuse to listen to why it's wrong on the other, and expect this discussion to get anywhere.



I wish you were more interested in learning physics, because you would know that you would not be ridiculed for saying this. Do you know why?

I know the "why" answer. From the example here :the illogical insertion of counter arguments before a structure is dynamically defined is sufficient to negate the worth of the counter point at tha position in the new theory.

Because I used the exact same approach in my post on Maxwell's equations.[/color]

I started with classical EM theory, and I assumed that SR was wrong, and I derived a prediction that is contrary to what we observe.



OK



OK again.



Not OK.

You are wrong when you say that this is the "only way", and I know that I have explained it more than once in this thread. Please do what you ask of the rest of us and listen[/color] to our responses.

Again, with emphasis: There is no reason whatsoever to state that the observer has traveled any distance. Your statement reflects Prejudice #2, which you also must abandon: There is no way to even define[/color] absolute motion. We are not forced to say that the obserer is moving 10 MPH. We are perfectly free to say that the observer is at rest, and that the car under observation is moving towards him at 65 MPH (notice that I'm not taking SR into account). All the observer has to do is take the 65 MPH, multiply by the time required to pass, and we get the correct length.

when a SRT makes a claim that a train can make the assumption that the platifrm is moving and the train is motionless may have an appetizing appeal for SRT, but it is unambiguously more than irrational, especially when we see that the passengers on the train are seen as the ones reacting to acceleration, the motion involved frame.. SR says the acceleration is of no consequence to SR under the conditions just described, that the train, the frame the people, the seats and weels and coffe tables are not in a higher energy state than the obsjects on the platform. You can use your theory all day long, but when you get to the "we can look from the train frame of the stationary frame equivalently, that I drop out of the conversation, becuse any assumption that ignores the accelertation, at the very minimum, is incomplete.

What seems so beautiful to your math mind make my mind reject and I ain't changing until the model is presented in a full rational mode.

All you have to do is use the relative velocity, and the time required for the car to pass, and you get the correct car length.

That is exactly what we do when we make measurements.[/color]



Yes. But unlike you, I also notice the differences[/color]. This brings us to Prejudice #3, which you also must abandon if you are to see your way out of this error. Specifically, you are prejudiced towards the opinion that a stream of light pulses can be treated in the same way as a stream of cars. It can't![/color].

You are correct in saying that an observer errs in making a measurement of the length of the car using its ground speed of 55 MPH when the observer's own ground speed is 10 MPH in the other direction. The reason you are correct is that there is (according to pre-relativity) a relative velocity[/color] of 65 MPH between the two cars, and that is what must be used to get a correct result.

But what happens when we look at light? The relative speed never changes[/color], no matter what the speed of the source. The relative velocity between a light pulse and any observer is c. And since the speed of light is the same for everyone, no frame has any special claim to knowledge of the "correct" wavelength of any light pulse. All measurements are equally valid for their respective frames.

Your entire case rests on a rejection of that fact, and that is why you are wrong.

edit: typo

Same basic flaws.

I f you looked at light like Grounded suggests you don't get the same answer as SR, as you measue somthing other than you would if you were doing some SR experiment.

try to see the problem. not from the eyes of an attorney who is trained to scrutinize through an adersarry process. Science is an objective , empathetic process, where Tom, there aren't any winners. Even if, EVEN IF, SR were to suffer a manifest blow, even a fatal one, so what?

It appears that your collective scientific position is the injection of SR theory for all problems. Tom, this is my observation, my perception.


You aren't seeing the pocess here as a practical model.

You should be as helpful as possible in assisting Grounded in every conceivable angle in developing his thread and model. You aren't meeting his stated request. He was looking for assistance, and you demand he learn SR, when he wants to lern his ownm model, which he wants to develop in the theory development forum..

 

[grounded]

OK Tom... let's say we do an experiment with some known values.

The distance light travels away from the source in one second = 186,000 miles
The distance the observer travels towards the source in one second = 4,000 miles
The wavelength of the light while at rest relative to the source = 1 mile
The above are known because we set up the experiment.

The relative frequency of the light measured by the observer while in motion = 190,000 cycle per second

The relative distance traveled in one second, divided by the relative frequency, equals the relative wavelength, right?

So (186,000 + 4,000) divided by 190,000 equals the wavelength (1 mile) Agree?

The part of the formula that you throw out is “the distance the observer has traveled relative to the source”.
You throw it out by not including it into the scale of the equipment used to measure the speed or wavelength, which is why you will always measure the total relative distance traveled by the light and the observer to be 186,000 miles.
I agree that you are not consciously throwing this out; you just never realized it was missing.

If you do not include the 4,000 miles the observer has traveled you will measure the following:
THIS NUMBER IS CAUSED BY INCORRECT MATH; IT IS NOT CAUSED BY SR.
(186,000 + 0) divided by 190,000 = .9789 miles

Is not that the wavelength you predict the observer will measure due to SR?

If you tell me that you are dividing the frequency into 186,000 miles because that is what you measured, then I’m telling you that you are measuring it wrong. Since we set up the experiment, we know the observer is traveling towards the source at 4,000 miles per second. We also know that light will travel away from the source at 186,000 miles per second. We do not really even have to measure these values. We know the total relative distance traveled is 190,000 miles per second.

The observer knows he is traveling towards the light source at 4,000 miles per second.
The observer knows the light will travel 186,000 miles away from the source in one second.
The observer knows the relative distance traveled is 190,000 miles per second, this is a fact.

If and when the observer measured the total relative distance traveled in one second to only be 186,000 miles, he was smart enough to know that he has some how measured it incorrectly. He knows this for a fact because he knows the distance he was from the source when he started the experiment, and he knows the distance he is from the source when he completed the experiment. Again, he knows this because we set up the experiment. He also knows the light is traveling 186,000 miles per second away from the source. Knowing all that for a fact, he KNOWS the total relative distance traveled must equal 190,000 miles per second regardless of what he measured.

When the observer takes the total relative distance traveled in one second (190,000 miles) and divides it by the total relative frequency (190,000 cycles per second) he will get the relative wavelength (1 mile), which is the same length he measured before the experiment while at rest relative to the source.

You claim the observer will measure a change in wavelength due to SR.
Your proof is that we do.
My claim is that you and everyone else has measured the total relative distance traveled incorrectly by not including the distance the observer has traveled. After all, isn’t the total relative distance equal to the sum of the distance light has traveled relative to the source, added to the distance the observer has traveled relative to the source?

If you measure a ray of light with an oscilloscope while in motion relative to the source, where is the distance you have traveled relative to the source? How do you account for it? You don’t, and that is why you will never measure a change in speed.

Your measured change in the wavelength (.0211 miles) will be equal to the distance the observer has traveled (4,000 miles) divided by the measured frequency (190,000 cycle per second). This works BECAUSE the measured change in wavelength is caused by ignoring the distance the observer has traveled.

There is no change in the measured wavelength when you account for the distance the observer has traveled.

If SR exists, then it should be measurable after we include the distance the observer has traveled relative to the source.

 

[grounded]

The answer comes out wrong because of dividing the speed wrt the road by the frequency wrt the observer. You can't mix measurements made wrt different frames.

EXACTLY

The frequency wrt the observer equals the number of cycles that pass by you due to the velocity of the light, added to the number of cycles passed caused by your speed towards the source.

The total distance traveled per second (speed) wrt the observer equals the distance light has traveled relative to the source, added to the distance the observer has traveled relative to the source

 

[geistkiesel]

But we can see that he isn't transcending anything. He is making choices that lead to the physics of the 19th century, and we know that those choices are wrong.

You forgot the disclaimer "choices are wrong wrt SR" (asming SR "right"

 

[swansont]

The relative frequency of the light measured by the observer while in motion = 190,000 cycle per second

The relative distance traveled in one second, divided by the relative frequency, equals the relative wavelength, right?

So (186,000 + 4,000) divided by 190,000 equals the wavelength (1 mile) Agree?

No. Tell me how this doesn't imply that I am measuring the light to be moving at 190,000 miles/s

The part of the formula that you throw out is “the distance the observer has traveled relative to the source”.

...
THIS NUMBER IS CAUSED BY INCORRECT MATH; IT IS NOT CAUSED BY SR.

If you shine laser light of the right wavelength on an atom, it will absorb that light. If the atom starts moving, that absorption slows and stops as the light moves out of resonance - the color has changed. How is the atom "ignoring" the amount that it has moved? It isn't doing any math, AFAIK.

 

[grounded]

No. Tell me how this doesn't imply that I am measuring the light to be moving at 190,000 miles/s

That is exactly what I am saying.

If you shine laser light of the right wavelength on an atom, it will absorb that light. If the atom starts moving, that absorption slows and stops as the light moves out of resonance - the color has changed. How is the atom "ignoring" the amount that it has moved? It isn't doing any math, AFAIK.

I don't think the atom cares about the length of the wave, it only cares about the amount of time it takes to complete one wave.

 

[wespe]

EXACTLY

But nobody is making this mistake, only you imagine so!

By MEASURING the relative speed of light wrt ourself, we already account for the traveled distance.

Clasically, when approaching a light source with v, the value we measure should have been c+v. But experiments reveal it is really c.

You want to make it c+v again by adding v to the MEASURED RELATIVE speed c. Therefore you want to account for the traveled distance TWICE.

 

[quantumdude]

The distance light travels away from the source in one second = 186,000 miles
The distance the observer travels towards the source in one second = 4,000 miles
The wavelength of the light while at rest relative to the source = 1 mile
The above are known because we set up the experiment.

OK

The relative frequency of the light measured by the observer while in motion = 190,000 cycle per second

It is if you use the pre-SR Doppler formula.

The relative distance traveled in one second, divided by the relative frequency, equals the relative wavelength, right?

So (186,000 + 4,000) divided by 190,000 equals the wavelength (1 mile) Agree?

Right here is where you are directly contradicting both the experimental evidence, and SR. Please try to understand why.

According to pre SR theory, the wavelength will be 1 mile. That is because the speed that the light approaches the observer is 186,000 mps+4000 mps=190,000 mps. So, according to the observer, the wavelength is:

λ=(relative speed of light)/(relative frequency)=(190,000 mps)/(190,000 Hz)=1mile

But we now know that that is false[/color]. The Galilean velocity addition formula simply does not hold! Yet you keep happily applying it as though it does, and that’s why you go wrong.

Also, You don’t have to use the “relative distance traveled”. It’s the relative speed that counts. Your numbers for the relative distance and the relative speed happen to have the same magnitude because you are considering the motion over a time of 1 second. But the observer could have moved twice that distance in twice the time, and the above analysis would still give the same result.

What you should take away from this part:

1.Forget about relative distance traveled, and start thinking about relative speed.
2. You can’t simply add velocities like you have been doing.

The part of the formula that you throw out is “the distance the observer has traveled relative to the source”.
You throw it out by not including it into the scale of the equipment used to measure the speed or wavelength, which is why you will always measure the total relative distance traveled by the light and the observer to be 186,000 miles.
I agree that you are not consciously throwing this out; you just never realized it was missing.

I’m not throwing it out at all, because I don’t even work in terms of relative distances. As I keep telling you, relative distance is irrelevant to this analysis. What I do throw out is the increase in relative velocity between the detector and the light.

If you do not include the 4,000 miles the observer has traveled you will measure the following:
THIS NUMBER IS CAUSED BY INCORRECT MATH; IT IS NOT CAUSED BY SR.

No, you are mistaken. The discrepancy is due to the feature of SR that says that the relative speed between light and an observer is always the same.

(186,000 + 0) divided by 190,000 = .9789 miles

Is not that the wavelength you predict the observer will measure due to SR?

No, it isn’t. You are using the classical Doppler formula. When SR came along, the Doppler formula had to be rederived, and it is :

f=f₀((1+β)/(1-β))^1/2

when the source and detector are approaching.

If you tell me that you are dividing the frequency into 186,000 miles because that is what you measured, then I’m telling you that you are measuring it wrong.

I know what you are telling me. You are mistaken.

Since we set up the experiment, we know the observer is traveling towards the source at 4,000 miles per second. We also know that light will travel away from the source at 186,000 miles per second. We do not really even have to measure these values. We know the total relative distance traveled is 190,000 miles per second.[/color]

You have to be careful here, especially about the part in blue[/color]. First, relative distance is not measured in miles per second, it is measured in miles. What you mean is that the relative speed is 190,000 miles per second. And second, you are wrong about that: it is 186,000 miles per second. You will only get your result if you assume that SR is wrong, and that the Galilean velocity addition holds. It doesn’t.

The observer knows he is traveling towards the light source at 4,000 miles per second.
The observer knows the light will travel 186,000 miles away from the source in one second.

OK so far.

The observer knows the relative distance traveled is 190,000 miles per second, this is a fact.

No, it is a falsehood.

The rest of your post just seems to be more of the same, so I’m not going to continue. Grounded, please open your mind to the possibility that you are wrong. You say that you want us to listen to you , and I am. But you aren’t returning the favor.

edit: fixed quote bracket

 

[grounded]

By MEASURING the relative speed of light wrt ourself, we already account for the traveled distance.

Where? Can you tell me where the oscilloscope, or the interferometer, or what ever you used to measure the speed accounted for the distance traveled relative to the source?

 

[quantumdude]

Where? Can you tell me where the oscilloscope, or the interferometer, or what ever you used to measure the speed accounted for the distance traveled relative to the source?

The distance traveled relative to the source is irrelevant. What you are talking about is the relative speed (edit: between the source and the observer), but that is also irrelevant. When measuring the speed of light, all you need to do is measure the spacetime coordinates of absorption and emission.

 

[quantumdude]

Some observations on the corfrectness of information exchange re om_Mattson v Grounded.

It must be awfully hard to make any observations at all, with your head shoved so far up your hind end.

This post of yours contains such asinine misrepresentations of both SR and myself, that I find them unworthy of any detailed response.

You said:

You can use your theory all day long, but when you get to the "we can look from the train frame of the stationary frame equivalently, that I drop out of the conversation

I wish you would. Either that, or get your brain in gear, because you aren't helping, and you certainly aren't here to learn anything.

 

[svitenti]

Hum...

I'm anxious to see what could replace SR, but you known that all the dependent theories of it like QED, QCD, Eletroweak, GR, would fall, but remember that these theories give good results, and like i said one replacement to SR has to give THE SAME results to the energy used today.

 

[wespe]

Where? Can you tell me where the oscilloscope, or the interferometer, or what ever you used to measure the speed accounted for the distance traveled relative to the source?

What do you think relative speed is?

Consider please:

You are in a spaceship x meters long. There are windows on the front and back. Someone far away sends a light signal. You let the signal pass through your windows. You take note of the times when light enters the front window and exits from the back window. So you can calculate deltaTime. Now you can calculate speed of light as x/deltaTime. You find it to be 300.000 km/sec. That is the relative speed of light wrt you. Because all of them were your measurements. You don't care about the distances anyone traveled wrt something else, you just measure how long it took for light to pass the distance on your ship. So you measured the relative speed of light wrt you.

Now, you fire your thrusters, and start approaching the light source. You repeat the experiment. Oddly, you find the same relative speed of 300.000 km/sec! Light doesn't seem to care how fast you are approaching it!

Suppose, you wanted to measure the relative speed of a rock, instead of light. Same procedure. But, after you fire the thrusters, you find the relative speed of rock increased. For light, it does not increase, experimentally shown. Please do a google search how light speed was measured.

 

[wespe]

Where? Can you tell me where the oscilloscope, or the interferometer, or what ever you used to measure the speed accounted for the distance traveled relative to the source?

I guess you didn't like my answer above.

OK I try again: the distances traveled are accounted by the moving objects themselves, when relative speed is measured. Because, relative speed is the approach speed, if you will understand that term better. Approach speed is directly measured by the observer. If you try to calculate it by adding or subtracting speeds of the objects wrt something else, then the answer you get will not match the directly measured speed. This mismatch becomes more and more as the speeds approach c. And relativity describes why this mismatch occurs, and how to do it correctly. Is there anything not clear?

 

[grounded]

What do you think relative speed is?

Consider please:
You are in a spaceship x meters long. There are windows on the front and back. Someone far away sends a light signal. You let the signal pass through your windows. You take note of the times when light enters the front window and exits from the back window. So you can calculate deltaTime. Now you can calculate speed of light as x/deltaTime. You find it to be 300.000 km/sec. That is the relative speed of light wrt you. Because all of them were your measurements. You don't care about the distances anyone traveled wrt something else, you just measure how long it took for light to pass the distance on your ship. So you measured the relative speed of light wrt you.

This is a theoretical experiments created off SR, but if it was done it would agree with what I am saying. Currently we calculate the relative speed of light from measurements of the frequency or the wavelength, but we always divide them into 186,000 miles.

Relative speed is the sum of the distance traveled by both objects in one second.

The relative speed between car “A” and car “B” is equal to the sum of the distance car “A” has traveled in one second, added to the distance car “B” has traveled in one second.

60 miles in one second, added to 40 miles in one second, equals a relative speed of 100 miles per second.

How do you define relative speed?

People say we can’t measure the speed of light like this because of SR. Fine.

If that is so, we should be able to measure the speed of light, as done above, and clearly see the effect of SR. But we won’t.

We currently do not include the distance traveled by the observer (speed) when we calculate the relative speed (total relative distance traveled per second), which guarantees a constant speed of light, no matter what.

Don’t you think it’s odd that we have to change the formula in order to measure SR effect?
By change I mean, replace “relative speed” with “speed of light” as shown below.

SPEED OF LIGHT divided by RELATIVE FREQUENCY equals RELATIVE WAVELENGTH

Instead of:

RELATIVE SPEED OF LIGHT divided by RELATIVE FREQUENCY equals RELATIVE WAVELENGTH

If SR is valid, why can't we measure its effect using normal means.

 

[grounded]

the distances traveled are accounted by the moving objects themselves, when relative speed is measured. Because, relative speed is the approach speed, if you will understand that term better. Approach speed is directly measured by the observer. If you try to calculate it by adding or subtracting speeds of the objects wrt something else, then the answer you get will not match the directly measured speed.

Can you put this in a car "A" and car "B" perspective with math and show how the distance car "B" travels is accounted for?

 

[wespe]

Currently we calculate the relative speed of light from measurements of the frequency or the wavelength, but we always divide them into 186,000 miles.

Where did you get that idea? Relative speed is measured directly, similar to what I described. By letting light pass a known distance, and dividing the distance by the time it took light to pass it (of course, assuming speed of light does not vary while it passes the distance). There is an issue with one-way / two-way measurements, but you first have to understand these before you get to that point.

Google search "how is the speed of light measured"
http://216.239.41.104/search?q="how+is+the+speed+of+light+measured"&ie=UTF-8&hl=en

 

[quantumdude]

This is a theoretical experiments created off SR, but if it was done it would agree with what I am saying.

No, it wouldn't.

Currently we calculate the relative speed of light from measurements of the frequency or the wavelength, but we always divide them into 186,000 miles.

No, that is wrong. We can measure the speed of light just by knowing the times and places of emission and detection in our frame of reference. There is no need whatsoever to do speed of light measurements using either wavelength or frequency.

Relative speed is the sum of the distance traveled by both objects in one second.

The relative speed between car “A” and car “B” is equal to the sum of the distance car “A” has traveled in one second, added to the distance car “B” has traveled in one second.

"Distance traveled" according to whom? You keep ignoring the fact that I am not obliged to regard the observer as moving at all. I can consider him to be at rest if I want.

But in any case, the relative speed of a light pulse is simply its change in position divided by the time it took to cover the distance. It will come out the same no matter if I regard the observer as moving or stationary. This is true either in Galilean relativity, or in SR.

60 miles in one second, added to 40 miles in one second, equals a relative speed of 100 miles per second.

That is the Galilean velocity addition formula again. It doesn't apply in the real world.

How do you define relative speed?

I define it as the rate at which the distance between other objects and myself changes as a function of time.

People say we can’t measure the speed of light like this because of SR. Fine.

Nobody says that. We say that when we do measure it, it confirms SR and contradicts what you are saying.

If that is so, we should be able to measure the speed of light, as done above, and clearly see the effect of SR. But we won’t.

Of course we will. In fact, we have. The speed of light has been measured to be 'c', even from very fast moving sources.

We currently do not include the distance traveled by the observer (speed) when we calculate the relative speed (total relative distance traveled per second), which guarantees a constant speed of light, no matter what.

Right. We calculate it that way because it agrees with measurements.

Don’t you think it’s odd that we have to change the formula in order to measure SR effect?

Will you please try to open up and learn some actual physics? The whole point of my post on Maxwell's equations was to explain why it's not odd.

By change I mean, replace “relative speed” with “speed of light” as shown below.

SPEED OF LIGHT divided by RELATIVE FREQUENCY equals RELATIVE WAVELENGTH

Instead of:

RELATIVE SPEED OF LIGHT divided by RELATIVE FREQUENCY equals RELATIVE WAVELENGTH

We do that because the relative speed of light is the same for everyone.

If SR is valid, why can't we measure its effect using normal means.

This is a bogus question. SR is valid, we do make measurements with normal means, and the effect is observed.

 

[wespe]

Can you put this in a car "A" and car "B" perspective with math and show how the distance car "B" travels is accounted for?

But the correct math will have to be SR math. If you do it as Galilean, the answers will be different, but wrong. Wrong because experiments don't agree with it. So, math doesn't prove anything, only experiments can decide. But if you are just asking to see the SR math, I guess I can do it (if you give me some time, I'm a bit slow, or there are people here who can show it quickly, I'd appreciate their help)

Edit: With Galilean math, the traveled distance is still accounted for. When working with slow speeds, the answers are approximately correct. So if you want that, I can show it quicker. Please let me know.

 

[quantumdude]

Can you put this in a car "A" and car "B" perspective with math and show how the distance car "B" travels is accounted for?

Whether you are using Galilean relativity or SR, the equation is the same.

I can calculate the relative velocity between and a light pulse and myself by measuring the following:

Event 1: Pulse Emitted
x₁=Location of emitter on x-axis at time t₁.
t₁=Time of emission.

Event 2: Pulse Detected
x₂=Location of detector on x-axis at time t₂.
t₂=Time of detection.

The speed of the pulse relative to me is then:

v=(x₂-x₁)/(t₂-t₁).

For light, this will always come out to be c. And as you can see, that result is not "built in" to the way we calculate relative speed. It is a simple, undeniable experimental fact.

 

[wespe]

Whether you are using Galilean relativity or SR, the equation is the same.

Yes. I was thinking of first defining the scene from a third perspective, then transforming for A and B as Galilean. And show that the traveled distance is accounted for, despite approximately correctly for low speeds.

 

[grounded]

We currently do not include the distance traveled by the observer (speed) when we calculate the relative speed (total relative distance traveled per second), which guarantees a constant speed of light, no matter what.

Right. We calculate it that way because it agrees with measurements.

That is my whole point...

Whether you are using Galilean relativity or SR, the equation is the same.

v=(x2-x1)/(t2-t1)

The above formula has nothing to do with calculating relative speed. Integrate the formula. All this formula does is calulate the amount of time it takes light to travel from the source to the point it was detected. Your speed has nothing to do with anything in this formula except that it will alter the distance light can travel before you detect it.

 

[quantumdude]

That is my whole point...

What, that we construct our theories so that they agree with experiment? Guilty as charged!

Now the real question is, Why do you have a problem with that?

The above formula has nothing to do with calculating relative speed.

Wrong. That formula is the very definition of relative speed.

Integrate the formula.

What?

All this formula does is calulate the amount of time it takes light to travel from the source to the point it was detected.

Right. And the ratio of those two quantities is the speed of the light relative to me.

Your speed has nothing to do with anything in this formula except that it will alter the distance light can travel before you detect it.

That's because my speed is zero. I am always free to regard myself at rest if I am not accelerating.

 

[grounded]

Right. And the ratio of those two quantities is the speed of the light relative to me.

That formula is the very definition of relative speed.

No it isn't, it is the speed of light relative to the source. Can't you see that? It simply measures the amount of time it takes light to travel a specific distance determined by the location you detect the light.

If you run into the light at a distance of 100,000 miles from the source, what does your speed have to do with anything as long as the experiment ended at 100,000 miles form the source. Think about it... It doesn't matter how fast you are traveling when you end the test, all you are doing is marking a specific distance from the source and measuring how long it took light to get to that spot. If you traveled for two seconds, then no matter what your speed is, you will be 372,000 miles from the source.

Does that make sense?