Measuring The Relative Velocity Of Light

[David]

David,

If you are going to put so much weight on AE own words, why don't you at least use the version that he regarded as the best way to put things together? otherwise, you seem to be trying to advocate for the ideas that AE, and many others now, understood to be faulty.

Then why can’t this be discussed on this board’s SR pages? The management says we can’t post anything that challenges the validity of the 1905 paper. I got banned from those pages because I proved that Einstein changed his mind and corrected some of the errors of the SR theory, but management here is pretending there are no errors in SR and that Einstein never made any changes in it.

The Einstein cult that runs the board doesn’t want anyone to quote any later papers in which Einstein changed his mind about things he said in the SR theory. These guys are essentially carrying out a hoax, pretending that there are no flaws in SR theory and that Einstein never made any changes in it.

This is part of the political promotion of Einstein as the “world’s smartest man”. It’s a hero-worship cult. I run into this on other message boards too.

 

[wespe]

Yes, you’re right. The problem is, he lied in some of his books and papers. He flip-flopped many times on many issues, saying one thing in one paper and the opposite in a different paper. The book you are talking about was published in Germany in 1916, and many German physicists were mad at him because of his lying and deceptions.

I’ve been investigating this for years, and I’ve got a lot of his early papers that not too many people know about.

Well, okay, let's say he took ideas from other people and he changed his mind a few times, etc. But it would be wrong to say his contribution was null. I think he was the only one to combine all the ideas and dismiss aeather. Also he got nobel prize for explaining photoelectriic effect. I may be wrong in these. Anyway, that's history. The important thing is that there is currently a standard theory. There may be textbooks with erros, even professors may disagree with each other. It's not like a holy book you know. In the end it is the experiments that decide what is right and what is wrong. Therefore, in my opinion, your attacks on a dead man is not too beneficial.

[
sorry if I sound cocky.
regards.
]

 

[David]

Well, okay, let's say he took ideas from other people and he changed his mind a few times, etc. But it would be wrong to say his contribution was null. I think he was the only one to combine all the ideas and dismiss aeather. Also he got nobel prize for explaining photoelectriic effect. I may be wrong in these. Anyway, that's history. The important thing is that there is currently a standard theory. There may be textbooks with erros, even professors may disagree with each other. It's not like a holy book you know. In the end it is the experiments that decide what is right and what is wrong. Therefore, in my opinion, your attacks on a dead man is not too beneficial.

[
sorry if I sound cocky.
regards.
]

You don't sound cocky at all.

Of course his contributions were not “null”.

In my opinion his best work was in early atomic physics. His early atomic papers are absolutely brilliant. This is actually what he was famous for in the physics community and why he received the Nobel Prize. I don’t have any problem with that. He was quite smart about atomic physics.

What I have a problem with is all the Einstein-worship websites and books that say there are no flaws in SR theory, and so many cultists on the internet teaching teenagers the wrong physics information based on SR theory.

There is no current “standard theory” because it keeps changing. For example, just 10 years ago universities taught that the most distant galaxies were not moving at faster than the speed of light relative to the earth, but now many of the universities are teaching that they do move faster than light relative to the earth.

A type of “ether” theory has been re-introduced to astronomy with “co-moving local space” acting as a “local ether”.

It is not good in any science field when someone is banned from science forum topics because they point out that the SR theory contains errors and that Einstein himself corrected some of the errors.

This is not “science”, this is a “science cult”. The quest is not for “truth” or “knowledge”, but to promote the Holy Worshipped One. This is pseudo science masquerading as mainstream science.

My “attacks” are not on the dead man. If he were alive today he would be astounded at the amount of false information being spread on the internet in his name. He would be outraged.

He didn’t have the benefit of certain astronomical information we have today, so he had to guess about a lot of stuff a hundred years ago. He thought the universe was not “expanding” because virtually all the astronomers in the 1916 era said it wasn’t expanding. If he were alive today there would be plenty of things he would clear up about his early time and motion papers, because at last he would have the necessary observational information to make some final decisions. He flip-flopped on some issues a hundred years ago, but so did other physicists. But for Einstein cultists today to claim that he was always perfect, never flip-flopped, never fibbed or fudged, then that is just gross “hero worship”, which has no place in physics or science. It’s like Elvis worship. But Elvis worship does not belong in science.

 

[Hurkyl]

Gasp, Einstein didn't come out of the womb already knowing the form of GR and SR we use today? My entire worldview has been shattered.


If I may hazard a guess, the reason you are banned from the relativity forums because your topic is Einstein, not relativity. Worse, you have this nasty habit of hijacking threads to start this discussion, instead of giving it its own thread.

 

[swansont]

x₂=Location of car on x-axis at time t₂

t₂=Time of detection

x₂ is where you and the car will be at t₂ (you are the detector, you detect it when you run into it)

OK, thanks for clarifying. I wasn't sure you were actually measuring the car by collision - now I am.

x₂ and t₂ is simply the place and time you run into (or detect) the car. If you are moving towards the car, then the distance the car has to travel before hitting you is decreased since you are closer to it, and since the distance is decreased so is the amount of time it takes the car to travel that distance. 60 MPH is the same thing as 30 Miles Per 1/2 Hour.

If you are traveling away from the car, the car will have to travel a further distance from x₁ to run into you (x₂ - x₁). Since it travels a further distance, it will take more time to run into you (t₂ - t₁). The relative speed never changes.

Is that how you see it?

Post #141

I think I understand your point. But x₂ is where I am, so it's actually fixed in my coordinate system. If you want to look at it from another point of view, you have to properly transform everything.

 

[grounded]

But x₂ is where I am, so it's actually fixed in my coordinate system. If you want to look at it from another point of view, you have to properly transform everything.

x₂ and x₁ are specific spots on the highway.

x₁ = Location of car on the highway at time of acceleration.

x₂ = Location of car on the highway at time of detection.

I'm not sure what point of view you are talking about, since the locations on the highway are the same for everyone, we could mark them with a flag at the time of measurement.

I also don't know what transformation you're referring to, if you do change the distance then you must equally change the time, else the answer will vary. SR equations are designed to always give the same answer; they were created off from Einstein's two postulates. The idea came first, then the math, that is why the math always proves the idea.

 

[grounded]

What you are saying is approximately correct for slow trains. But if you increase the relative speed of a train close to the speed of light, it isn't correct anymore.

Because, as the speed increases, length contraction effect becomes more, and the length of the train cars are no longer measured the same; it is measured much less.

What you have not yet understood is that the amount of change in the length of the boxcar due to your "length contraction", is equal to the change in distance between the source and the observer per second (caused by the change in relative speed), divided by the number of boxcars that now pass you in one second.

It may help you to see my logic by viewing the train while it is not moving (relative to the ground).
If the observer is also not moving (relative to the ground), then the observer will measure the frequency to equal zero, since no boxcars are passing him.

If the observer travels towards the train at some constant speed, then the observer will measure the frequency to equal the number of boxcars he passes in one second. The distance he has traveled per second, causes the frequency.

Multiplying the frequency by the length of the boxcar will equal the observer’s speed towards the train.
If the observer knew his speed (relative to the ground), he could divide it by the frequency and get the length of the boxcar.
Do you see how the observer’s speed causes the frequency and speed to change but not the length?
The frequency equals the distance the observer has traveled (relative to the ground) in one second, divided by the length of the boxcar.

Now if the train starts moving at some constant speed (relative to the ground) towards the observer, the observer will measure an increase in frequency equal to the distance the train travels (relative to the ground) in one second, divided by the length of the boxcar.

The relative frequency that the observer now measures is equal to the sum of the frequency created by the distance the observer has traveled (relative to the ground) towards the train in one second, added to the frequency created by the distance the train has traveled (relative to the ground) towards the observer in one second.

In a confusing but simple statement… The relative frequency equals the number of boxcars that the observer passes in one second, added to the number of boxcars that pass the observer in one second.

When calculating the length of the boxcar using the relative frequency, it must be divided into the sum of, the distance the observer has traveled (relative to the ground) in one second, added to the distance the train has traveled (relative to the ground) in one second.

The reason we measure a change in length is because the distance the observer has traveled (relative to the ground or the source) is never included.

The methods currently used to measure or calculate the relative speed of light were created to match Einstein’s two postulates. Einstein stated his postulates then created the math to match it. That is why current measurements and SR calculations used to find the relative speed of light will always equal the speed of light. For example see post #14 and post #141.

And when you reach exactly light speed (not possible for trains), the relative speed becomes constant, wavelength and frequency becomes variable [for light] *

So is it just that you don't buy length contraction? What about time dilation?

I think you made a typo above, SR shows that the wavelength and frequency are always inversely proportionate at any speed, which is why the speed of light is constant.

I do not believe in length contraction or time dilation. Both are tools used to keep the speed the same in order to validate Einstein’s two postulates. If you have the time, all my ideas are described in my first post.

 

[swansont]

x₂ and x₁ are specific spots on the highway.

x₁ = Location of car on the highway at time of acceleration.

x₂ = Location of car on the highway at time of detection.

I'm not sure what point of view you are talking about, since the locations on the highway are the same for everyone, we could mark them with a flag at the time of measurement.

I also don't know what transformation you're referring to, if you do change the distance then you must equally change the time, else the answer will vary. SR equations are designed to always give the same answer; they were created off from Einstein's two postulates. The idea came first, then the math, that is why the math always proves the idea.

x₁ and x₂ are in a reference frame of an observer that is stationary with respect to the ground. If he wants to measure the relative speed between me and the car, he needs to know where I am at t₁ -call that x₃. Then the relevant distance is x₁-x₃. But I don't think that's the measurement you were describing.

I think that the math came first, actually, with Maxwell's equations and the Lorentz transformation.

 

[swansont]

I do not believe in length contraction or time dilation. Both are tools used to keep the speed the same in order to validate Einstein’s two postulates.

But moving clocks do indeed run according to relativity, as witness by GPS and other spaceborne clocks.

 

[wespe]

It may help you to see my logic by viewing the train while it is not moving (relative to the ground).
If the observer is also not moving (relative to the ground), then the observer will measure the frequency to equal zero, since no boxcars are passing him.

OK
relative speed=0
length of the train=100 km
measured frequency=0

Now change relative speed to 0.5c=150,000 km/sec
gamma=1.16
Due to length contraction, measured length will now be 100/gamma=86 km

Measured frequency will be = relative speed/measured length=1744 Hz

What you have not yet understood is that the amount of change in the length of the boxcar due to your "length contraction",

That is 100-86=14 km

is equal to the change in distance between the source and the observer per second (caused by the change in relative speed),

That is 150,000 km

divided by the number of boxcars that now pass you in one second.

That is 150,000 km /1744= 86 km

86 <> 14 therefore your statement was wrong.

Please clear this up before we can go further.

 

[grounded]

86 <> 14 therefore your statement was wrong.

I actually predicted a change of 50 km since my observer would measure 1500 Hz, but either way, you are right, and I am wrong.

Accounting for the distance the observer has traveled relative to the source, does not account for or equal the change in length predicted by SR.

The focus of my paper was to point out that the scale of an oscilloscope or an interferometer must account for the distance traveled by the observer in order to accurately measure the light. If the observer’s distance is not accounted for, the wavelength will change, and the speed will remain constant. This is a fact and you should agree with it.

My error was to assume that this type of error was equal to, or related to the change predicted by SR. If the observers distance is not included, than at half the speed of light, an observer would measure the length to be half what it originally was. Clearly this is not what SR predicts.

My measurements come straight from the observer approaching the train. If the observer is traveling towards the train at 150,000 km per second, then he will pass 1500 individual 100km trains per second, relative to himself, else he would know he wasn't traveling 150,000 km per second.

After working through your example I realized that your measurements come from the perspective of an observer watching another observer who is approaching the train. The train and the observer traveling towards the train are in the moving frame that is being contracted by the Lorentz Transformation relative to the observer watching them.

Is that correct?

If this is so, it would explain why it could not be measured by an oscilloscope or an interferometer. You can’t use an oscilloscope to measure the length that an object would appear to be to an observer viewing the object in a moving frame, it can only be calculated.

Right?

 

[wespe]

..Clearly this is not what SR predicts.

I'm glad we found the source of the disagreement. Honestly, I don't want to screw this up, I too get confused sometimes, but your statements below indicate there is more misunderstanding.

My measurements come straight from the observer approaching the train.

So were mine. I considered only a train and one observer. The measurements/calculations were the observer's.

If the observer is traveling towards the train at 150,000 km per second, then he will pass 1500 individual 100km trains per second, relative to himself, else he would know he wasn't traveling 150,000 km per second.

Actually, in the example, he will pass 1744 individual 86km trains per second. The length contraction is not an illusion, it is real for the observer. That is, if the observer was a sitting in a 100km train, and if compared the passing train next to his train, he would find the passing train really shorter and contracted to 86km. What's more, the contraction is mutual: the passing train would claim it was the other train that became shorter.

After working through your example I realized that your measurements come from the perspective of an observer watching another observer who is approaching the train. The train and the observer traveling towards the train are in the moving frame that is being contracted by the Lorentz Transformation relative to the observer watching them.
Is that correct?

As noted above, a second observer was not present. But if you mean a second observer stationary wrt the first observer, his perspective would be the same as the first observer, since they are in the same frame of reference.

You can’t use an oscilloscope to measure the length that an object would appear to be to an observer viewing the object in a moving frame, it can only be calculated.
Right?

If you mean: the observer can't directly measure 100km., yes. He measures 86km, it's real. But also knowing the relative speed, he can calculate 100km by multiplying the measured 86km by gamma.

 

[geistkiesel]

But moving clocks do indeed run according to relativity, as witness by GPS and other spaceborne clocks.

Swansont, you are wrong. Of course the measurements will run slower as the observer has not used her own velocity wrt to the velocity of the source of the photons. The error "the speed of light is always measured as c in all inertial frames" and will always be reflected by the error in failure to include the observer's velocity.

Read grounded's posts again, until you understand them and then attack those posts on their own merits. Very diffilcult isn't it, to not have to fall back on SR dogma?

 

[David]

If I may hazard a guess, the reason you are banned from the relativity forums because your topic is Einstein, not relativity. Worse, you have this nasty habit of hijacking threads to start this discussion, instead of giving it its own thread.

Not so.

The “relativity” threads are Einstein-worship threads, for GR and SR. The moderators don’t allow anyone to point out that SR is wrong and contains major errors, some of which Einstein corrected later.

If they want to talk about modern real relativity theories that actually work, then I’ve got no gripe or complaint.

But guys like Russ are SR believers and he refuses to recognize any errors in that 1905 paper, even though Einstein wrote other papers later correcting SR theory. Those are papers that Russ has not read. I can't even quote from Einstein's later correction papers, even if Einstein himself made changes in SR theory later, because guys like Russ believe completely in the original 1905 SR theory.

That’s why I was banned from the “relativity” threads, because they are SR and GR Einstein relativity threads designed to promote only Einstein’s old, obsolete, and out of date SR and GR versions of relativity.

 

[grounded]

If you mean: the observer can't directly measure 100km., yes. He measures 86km, it's real. But also knowing the relative speed, he can calculate 100km by multiplying the measured 86km by gamma.

I thought the observer couldn’t measure a change since his measuring stick has also contracted?

Quoted from the Microsoft Encarta Encyclopedia, (I hope this isn’t illegal):
In the 1890s FitzGerald and Lorentz advanced the hypothesis that when any object moves through space, its length in the direction of its motion is altered by the factor beta. The negative result of the Michelson-Morley experiment was explained by the assumption that the light actually traversed a shorter distance in the same time (that is, moved more slowly), but that this effect was masked because the distance was measured of necessity by some mechanical device which also underwent the same shortening, just as when an object 2 m long is measured with a 3-m tape measure which has shrunk to 2 m, the object will appear to be 3 m in length. Thus, in the Michelson-Morley experiment, the distance which light traveled in 1 sec appeared to be 300,000 km (186,000 mi) regardless of how fast the light actually traveled.
Microsoft® Encarta® Reference Library 2002. © 1993-2001 Microsoft Corporation. All rights reserved.

This is how I see it, what is your opinion?

The Michelson-Morley experiment was conducted to measure the resistance light encountered when traveling against the hypothesized ether.

No matter how or when they did the test, they couldn’t measure any resistance (ether).

Not wanting to let go of the ether, Lorentz hypothesized that the ether does exist, you just can’t see, feel, or measure it.

The Lorentz contraction explains why Michelson-Morley could not measure the resistance. The effect was masked because the distance was measured of necessity by some mechanical device that also underwent the same shortening.

Einstein took it another step and said the speed of light is the same for all observers. If the speed of light is constant, then so is Maxwell's equations. Michelson-Morley couldn’t measure a change in speed because the speed of light was constant and it was lengths and time that must be changing, which is why we couldn't measure it.

To me, it seems like the Michelson-Morley experiment proves that relative to the source, a ray of light will travel in any direction, away from the source, at the same speed. They were expecting it to be slower in the direction that was against the flow of the ether, which was the reason for the experiment. When they couldn't measure it, they had to explain why.

When they could not measure the effects of the ether, they said, the ether does exist, you just can’t measure it.

According to classical physics, one of the two observers was at rest, and the other made an error in measurement because of the Lorentz-FitzGerald contraction of his apparatus
Microsoft® Encarta® Reference Library 2002. © 1993-2001 Microsoft Corporation. All rights reserved.

I have to assume by the above, that they still believed there is a resistance to light, it just can’t be measured. Another words, they still refuse to believe the results of the Michelson-Morley experiment.

According to Einstein, both observers had an equal right to consider themselves at rest, and neither had made any error in measurement. The equations for this transformation, known as the Lorentz transformation equations, were adopted by Einstein, but he gave them an entirely new interpretation. The speed of light is invariant in any such transformation.
Microsoft® Encarta® Reference Library 2002. © 1993-2001 Microsoft Corporation. All rights reserved.

I believe Einstein meant the "both observers" to be, one traveling with the ether, and one traveling against the ether. Another words, one of the observers was measuring the light that was reflected and sent against the ether flow in the Michelson-Morley experiment, and the other observer was measuring the light that went with the ether flow.

In the above quote, it seems like Einstein too refuses to believe the results of the Michelson-Morley experiment. I am not sure if Einstein believes that the constant speed of light causes the Lorentz contraction, or if the Lorentz contraction causes the speed of light to remain constant. In either case, to prove that what Michelson-Morley measured was wrong, a contraction had to be applied that could not be measured by the observer. Both Einstein and Lorentz seem to be giving us a theory for why what we measured in the Michelson-Morley experiment is wrong.

To me it seems like Einstein is stating that SR applies to the ether and the source. No matter how fast or what direction the source moves through the ether, the speed at which light travels away from the source will remain constant whether moving with or against the ether flow. SR predicts the change we couldn't measure with the Michelson-Morley experiment. Is that right? SR says that when the light reflects off the mirror in the interferometer, and starts traveling against the ether flow, the reason we can't measure it is because the lengths and time have changed. Is that right?

The Michelson-Morley experiment did not have two observers moving relative to each other. The source of light was at rest with the interferometer, the light traveled from the source, then reflected off a mirror as to travel against the ether flow. The motion of that ray of light is what was assumed to be moving relative to the ether. The relative motion is between the source and the ether, what other relative motion is there?

If a ray of light is moving through space at 300,000 km/sec (186,000 mi/sec), and an observer is moving in the same direction at 29 km/sec (18 mi/sec), then the light should move past the observer at the rate of 299,971 km/sec (185,982 mi/sec); if the observer is moving in the opposite direction, the light should move past the observer at 300,029 km/sec (186,018 mi/sec). It was this difference that the Michelson-Morley experiment failed to detect.
Microsoft® Encarta® Reference Library 2002. © 1993-2001 Microsoft Corporation. All rights reserved.

The Michelson-Morley experiment failed to detect the added velocity of the observer (as worded above) because the observer was not moving relative to the source of the light, the ray of light was moving relative to the ether flow. In the above quote, they are implying the observer is moving relative to the source. It should read like this:

If a ray of light is moving through space in the direction of the ether flow at 300,000 km/sec (186,000 mi/sec), and an observer is moving in the same direction as the ether flow at 29 km/sec (18 mi/sec), then the light should move past the observer at the rate of 299,971 km/sec (185,982 mi/sec); if the observer is moving in the opposite direction of the ether flow, the light should move past the observer at 300,029 km/sec (186,018 mi/sec). It was this difference that the Michelson-Morley experiment failed to detect.

How does the Michelson-Morley experiment prove what an observer (the observer) will measure while traveling towards the source?
Is SR just another theory used to explain the null results of the Michelson-Morley experiment?

The questions are in blue, thanks for helping!

 

[wespe]

I thought the observer couldn’t measure a change since his measuring stick has also contracted?

True, the observer can't measure any change in his own mesauring stick (or better, there isn't any change according to him). But he does measure the measuring sticks in other frames shorter than his measuring stick. "his measuring stick has also contracted" is from the perspective of other frames.

Imagine you and I are holding 1 meter measuring sticks in the direction of each other. We both agree when we are at rest wrt each other. Then let us approach at a speed. I would see your meter contracted, and you would see my meter contracted. We would both think our [own] meters didn't change [it's always the other's meter that changed] and we would not agree on whose meter is shorter. But from a third person's perspective, both of our sticks might have been contracted. Everyone is correct according to oneself.

"The negative result of the Michelson-Morley experiment was explained by the assumption that the light actually traversed a shorter distance in the same time".
This is how I see it, what is your opinion?

Well, this explanation is from aether's perspective. Since we don't think aether exists anymore, it doesn't look like a good explanation now.


http://scienceworld.wolfram.com/physics/Michelson-MorleyExperiment.html
At the end of the page:"Einstein's idea of space-time contraction replaced Lorentz's interpretation "

So, Lorentz thought things contracted from aether's perspective. Now we say things (excluding oneself) contract from everyone's own perspective . Note that this also includes aether, so if you want to assume aether exists, things would contract from its perspective too. It is just that such a preferred frame cannot be distinguished from any other frame, so it was dismissed.

I think I have said above all that I can. Please let me know if something seems unclear.

edit: I see you questions in blue, maybe edited for more. I'm not ignoring them. Just wanted to make sure above points are clear first.

 

[grounded]

When I said "This is how I see it, what is your opinion?", I meant the writing below, not the writing above.

 

[grounded]

So, Lorentz thought things contracted from aether's perspective. Now we say things (excluding oneself) contract from everyone's own perspective.

Before we go on, do you agree that the Lorentz contraction was created to explain why we DID NOT measure a change in the speed of light when it traveled against the aether during the Michelson-Morley experiment?

I do know that Einstein replaced the Lorentz contraction, but wasn't it still used to explain why we DID NOT measure a change in the speed of light when it traveled against the aether?

 

[ram1024]

he's saying there is no aether.

contraction was made up to satisfy condition of relative light speed. not aether

 

[quantumdude]

Originally posted by geistkeisel
Tom, excuse me if I've asked this before, but show me Grounded's math in 19th Century physics, AND that 19th century physics is passe because it is so old.

You did ask, and I did answer. Whether or not he realizes it, he is using the Galilean velocity transformation to determine the speed of the light emitted by a moving source. And it’s not “passe because it is so old”, it is passe because it is wrong.

Tom, Grounded showed by example the necessity of including the observers relative velocity less a mistake be made in the measurement of the length of the cars (wave length of light).

No, he didn’t. All he showed is that he doesn’t understand why Galilean relativity fails.

The SR system creates a mistake in measuremment and needed to create SR to explain the error.

No, it doesn’t. SR has nothing to do with how measurements are made. SR is a theory, not an experimental procedure. It just so happens that when you do make a measurement, the theory of SR gets it right, and the theory of Galilean relativity gets it wrong.

How many times can you echo "the vast amount of experimental results" describing your collective error? The experiments that prove time dilation, contraction of matter, loss of simultaneity?

How long can you keep it up before the echo wears thin?

I’ll keep it up until stubborn knuckleheads such as yourself keep polluting our site with anti-scientific nonsense.

Tom, lifting the weight of SR will be a relief, a huge relief.

How, precisely, will abandoning an accurate theory of the physical world be any relief to me as a physicist?

They're are errors Tom, great big huge errors.

And how would you even know? You've already confessed a refusal to even learn the theory.

 

[quantumdude]

Originally posted by grounded
Tom, you say it is not "built in", but consider the following;

Can you calculate the relative velocity between a moving car and yourself by measuring the following?

Event 1: Car Accelerated (Assume instantaneous acceleration to 60 Miles Per Hour)
x₁=Location of car on x-axis at time t₁.
t₁=Time of acceleration.

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

The speed of the car relative to you is then:

v=(x₂-x₁)/(t₂-t₁).

Yes, that’s exactly right.

Can you alter the relative speed of the car while using this formula?

Sure. The car can accelerate, or I can, or we both can.

It’s not that they (edit: trains and light) behave differently, it’s that we calculate them differently.

You are half right, and half wrong here. It is true that the speed of trains and the speed of light don’t “behave differently”. But you are wrong in saying that we calculate them differently. Both the speed of trains and the speed of light are calculated according to the formula I gave. Furthermore, they both are calculated from a third party perspective using the SR velocity addition law. But for low speeds, the Galilean velocity addition law gives a good enough approximation, so that we apply it to trains for simplicity’s sake. But one should not be fooled into thinking that we can use that velocity addition law for light.

If you measure the train like we measure the light, then the speed of the train will never change.

Incorrect. If either myself or the train accelerates, then the measured (and calculated) speed will change.

If you measure the light like we measure the train, then the length of the boxcar will never change.

Not so. The length of the boxcar will be contracted. I’m sorry you don’t accept it, but it is a fact.

 

[ram1024]

you guys always talk about "the data" as if it proves the theory. yet surprisingly no one brings forth the actual data.

vast amounts of data, yet not a single bit of it brought into play. are you sure there's vast amounts of it?

 

[quantumdude]

What you have not yet understood is that the amount of change in the length of the boxcar due to your "length contraction", is equal to the change in distance between the source and the observer per second (caused by the change in relative speed), divided by the number of boxcars that now pass you in one second.

No, it isn't. The length of the boxcar is contracted according to the following formula:

L=L₀/&gamma;

That is not the simple ratio of speed to boxcars-per-second.

The reason we measure a change in length is because the distance the observer has traveled (relative to the ground or the source) is never included.

You are still confusing measurements with calculations. When you measure a length contraction, a time dilation, or a relative change in wavelength, then that's what its value is. Period. If you modifiy it with a calculation, then it is just that: a calculation, not a measurement.

The methods currently used to measure or calculate the relative speed of light were created to match Einstein’s two postulates.

Einstein stated his postulates then created the math to match it. That is why current measurements and SR calculations used to find the relative speed of light will always equal the speed of light. For example see post #14 and post #141.

I can't believe you are still preaching this. All you have to do is measure the time and place of emission and the time and place of detection. That method of mearsurement does not guarantee the SR result on simple a priori grounds.

I do not believe in length contraction or time dilation. Both are tools used to keep the speed the same in order to validate Einstein’s two postulates. If you have the time, all my ideas are described in my first post.

You are also wrong about this. Length contraction and time dilation aren't "tools used to keep the speed the same" in various inertial frames. Length contraction and time dilation are the logical consequences of that postulate. In other words, they are derived from it.

 

[quantumdude]

you guys always talk about "the data" as if it proves the theory. yet surprisingly no one brings forth the actual data.

That's a good point. The reason we don't get to talk about the data is that we are so bogged down on stupid thought experiments.

vast amounts of data, yet not a single bit of it brought into play. are you sure there's vast amounts of it?

There is. I am going to dig out a bunch of papers I have packed in a box and prepare something. It's about time we get back to the real world.

 

[ram1024]

make sure you include the data about scientists getting light to travel 100 times faster than normal calculated speeds using cold caesium chamber and group resonance beams of light.

according to einstein's "time" that speed makes the pulses received out of the other end of the chamber happen BEFORE the pulses are introduced to the entrance chamber.

the result? using light to measure instant time is a bad idea. DERIVING time from light is a better idea. using synchronicity to define time is the best idea.

looking forward to what you can come up with

 

[quantumdude]

make sure you include the data about scientists getting light to travel 100 times faster than normal calculated speeds using cold caesium chamber and group resonance beams of light.

I will indeed track down that paper. In the mean time, please do read what the actual experimenters had to say about it:

http://www.cnn.com/2000/fyi/news/08/21/speed.of.light/#3

according to einstein's "time" that speed makes the pulses received out of the other end of the chamber happen BEFORE the pulses are introduced to the entrance chamber.

That is indeed the prediction of SR. Now the question is, were the photons that came out of the chamber the same as those that went in?

the result? using light to measure instant time is a bad idea. DERIVING time from light is a better idea. using synchronicity to define time is the best idea.

You believe this because you still do not understand the necessity of SR for electrodynamics.

 

[ram1024]

does it matter that the light wasn't the same particles as what went in? not in the slightest.

think of a hose filled with water. you start forcing water into one end and water starts coming out the other side. this was water already in the hose, not water you put in, your water doesn't come out till later

but what IS accomplished is the speed of information transfer IS faster than light speed. the modality of synchronizing events "by light" is trumped by this new "speed". if something CAN be faster than light, what's to say something can't be even faster than THAT thing. which was why i was saying deriving instances of time is a good way to handle things, using known speeds of light is a good thing. but using light as a governor of when things happen in "time" is not so good, as things traveling faster than it "information" will go back in time, which is Unpossible <Ralph Wiggum>

 

[quantumdude]

does it matter that the light wasn't the same particles as what went in? not in the slightest.

Of course it matters!

Given permission by the city, I could rig up a series of streetlights to turn on--one at a time--in such a way that it appears that there is one light that is moving faster than 'c', when nothing is actually moving at that speed.

 

[ram1024]

yes, but you couldn't rig it to change the order of events as they appear according to viewing "by light" as "time" as they have done in the lab.

there's no prediction or preplanning. the photons exit the chamber about 300 times sooner than they should have using direct light beam transmission

that's called "faster than light" in any definition of the term :D

doesn't matter than it wasn't LIGHT moving faster than LIGHT. INFORMATION did.

 

[quantumdude]

doesn't matter than it wasn't LIGHT moving faster than LIGHT. INFORMATION did.

But the experimenters themselves never claimed that they could send information faster than light. How could you possibly claim to know it?

 

[ram1024]

there was an event on one side and a reaction on the other side, a reaction that happened 300 times faster than SHOULD have happened using light speed as a measure.

think binary. a bit of information "1" was sent into the tube. a bit of information "1" was received 300 times faster than it would have been using direct light transmission over the same distance.

THAT is why.

 

[quantumdude]

there was an event on one side and a reaction on the other side, a reaction that happened 300 times faster than SHOULD have happened using light speed as a measure.

think binary. a bit of information "1" was sent into the tube. a bit of information "1" was received 300 times faster than it would have been using direct light transmission over the same distance.

THAT is why.

The experimenters also reported that part of the pulse was detected at the exit before it was detected at the entrance, and yet Wang (the head scientist) specifically denies that he could use the effect to send information back in time. Furthermore, every analyst of this experiment has concluded that information was not sent faster than light. Aren't you even the least bit curious as to why? Don't you feel compelled to consult the literature on the experiment? Doesn't the first hand testimony of the people who designed the experiment and witnessed the effect carry any weight with you? Or are you satisfied with your simplistic explanation based on only a partial knowledge of what actually occurred in that lab?

 

[ram1024]

Aren't you even the least bit curious as to why?

i've already read about "why"

they're coming to the wrong conclusion trying to intercept the whole pulse,

ANYTHING coming out the other end can be taken as that "bit" of data.

align 4 tubes <arbitrary number> and transmit using all 4, by moving to another "tube" while waiting for the one you just used to complete in rotation you can transmit data AT LEAST 4 times faster than the speed of light.

with 300 tubes you could utilize the full capabilities of this speed. course the "switching" would have to be damn complex for that ;D

in any case I'm sure they adequately realize the potential of their results, but don't want to "give" any of the technology away if they can help it.

 

[quantumdude]

i've already read about "why"

Somehow, I don't think you have read the articles that appeared in the research journals.

they're coming to the wrong conclusion trying to intercept the whole pulse,

Well, you should email them right away!

Here's their Science director's webpage:

http://www.neci.nj.nec.com/homepages/chadi

ANYTHING coming out the other end can be taken as that "bit" of data.

But it is not the case that anything coming out can be seen as intelligible information.

in any case I'm sure they adequately realize the potential of their results, but don't want to "give" any of the technology away if they can help it.

What they want is to make a name for themselves, not to get patents. Scientists publish their results freely in journals such as Physical Review Letters. These scientists are no exception.

 

[wespe]

Before we go on, do you agree that the Lorentz contraction was created to explain why we DID NOT measure a change in the speed of light when it traveled against the aether during the Michelson-Morley experiment?

Yes. The contraction would cancel the effect of aether resistance.

I do know that Einstein replaced the Lorentz contraction, but wasn't it still used to explain why we DID NOT measure a change in the speed of light when it traveled against the aether?

Well, since aether was dismissed, it isn't currently used to expain anything about aether. As I wrote before, if you want to assume aether exists, you can treat it like any other frame of reference, and the length contraction explanation would appy.

However, there's another issue. Suppose you simply explain MMX result with length contraction. There is no need to abandon absolute space, and all observers could agree on how their lengths would compare. But according to SR, observers will not agree. I think that's an important point.