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The problem: How can significant fringe exist and not exist for the same experiment?

The length of a light path or a measuring rod is constant and the same for all observers.

The time for light to traverse the length of a light path or the time for light to traverse a measuring rod is constant and the same for all observers.

PREDICTIONS:Relative velocities greater than the speed of light will be discovered to be common place.

Because the pairs of light waves recombined perfectly judged from relative rest the amount of time for light to traverse each of the light paths was equal judged from relative rest. Because the time was equal for both light paths judged from relative rest and the speed of light is equal for both light paths, both light paths and both arms of the instrument were of equal length judged from relative rest.

Therefore, neither arm was contracted compared to the other judged from relative rest. Therefore, the concept of length contraction in the direction of motion and not perpendicular to the direction of motion in the moving frame judged from relative rest as hypothesized in the Theory of Special Relativity is invalid.

I was under the impression that the experiment has never shown up any difference - that no significant fringe ever showed up at all

If it's in the same frame as they are, it will be the same. If it's in some other frame, it will appear to be different (depending on its alignment).

True in one sense, but false in another - if the measuring rod is moving relative to an observer, light may appear to get from one end of it to the other end faster in one direction than the opposite direction.

They are observed all the time when looking at objects moving relative to the frame of the observer. It's only when you measure stationary things within your own frame that you measure the relative speed of light to those things as c.

The first sentence of that is correct, but the second is wrong. The light covered the same distance on both paths, but the arms of the instrument are not equal lengths. Consider a gun pointing sideways out through of the window of a car such that it is pointing at 90 degrees to the direction of travel. Now drive the car at 400mph - the same speed as the gun fires bullets.

Conclusion not valid - the arm has to contract in order to make the two light paths the same length as each other.

QuoteI was under the impression that the experiment has never shown up any difference - that no significant fringe ever showed up at allYou are absolutely right and that is my point. There was never any significant fringe observed from within the relatively moving frame of the experiment. However, fringe would have been observed from relative rest pursuant to The Theory of Special Relativity due to the following:

1. Per SR the speed of light is constant and the same for all observers.

2. Per SR observed from relative rest length in the direction of motion, including wave length, is contracted judged from relative rest.

3. Per SR the rules of physics are the same for all observers.

4. Rule of physics: when light of an equal frequency is combined no fringe is produced. Conversely, when the frequencies are not equal fringe is produced.

5. Rule of physics: for light the frequency (f) multiplied by the wavelength (w) equals the speed of light (c). – fw=c – solved for f – c/w=f

For the Michelson Morley experiment judged from relative rest:Per 1: wave length perpendicular to the direction of motion = w and wave length in the direction of motion = w*sqrt(1-v*v/c*c)Per 1, 2, 3, and 5: For light perpendicular to the direction of motion – f=c/w . For light in the direction of motion – f=c/w*sqrt(1-v*v/c*c).Per 4 and above: when v is greater than zero the frequency of light perpendicular to the direction of motion does not equal the frequency of light in the direction of motion and fringe is produced observed from relative rest.

QuoteIf it's in the same frame as they are, it will be the same. If it's in some other frame, it will appear to be different (depending on its alignment).That conclusion is verified by the facts cited in the beginning of this thread. However, according to SR the length of a measuring rod oriented in the direction of motion is contracted judged from relative rest. In what sense of the word “alignment” do you mean?

QuoteTrue in one sense, but false in another - if the measuring rod is moving relative to an observer, light may appear to get from one end of it to the other end faster in one direction than the opposite direction.Albert Einstein (1879–1955). Relativity: The Special and General Theory. 1920.http://www.bartleby.com/173/ [Links inactive - To make links active and clickable, login or click here to register]VII. The Apparent Incompatibility of the Law of Propagation of Light with the Principle of RelativityParagraph 1“By means of similar considerations based on observations of double stars, the Dutch astronomer De Sitter was also able to show that the velocity of propagation of light cannot depend on the velocity of motion of the body emitting the light. The assumption that this velocity of propagation is dependent on the direction “in space” is in itself improbable.”

QuoteThey are observed all the time when looking at objects moving relative to the frame of the observer. It's only when you measure stationary things within your own frame that you measure the relative speed of light to those things as c.Per SR “the speed of light is constant and the same for all observers”

QuoteThe first sentence of that is correct, but the second is wrong. The light covered the same distance on both paths, but the arms of the instrument are not equal lengths. Consider a gun pointing sideways out through of the window of a car such that it is pointing at 90 degrees to the direction of travel. Now drive the car at 400mph - the same speed as the gun fires bullets.Within the relatively moving frame, relative to the moving frame the instrument is at rest and the length of the arms of are equal. Also, the relatively moving frame is moving at different relative velocities compared to different rest frames. That is, it may have the relative velocity of .01c compared to one rest frame and .99c compared to another rest frame or any other relative velocity. So within the frame there is no sense of motion the motion is only observable from other frames and any consequences of that motion can only be observed from those frames per SR.

QuoteConclusion not valid - the arm has to contract in order to make the two light paths the same length as each other.Please clarify “one arm has to contract…”

I find that hard to follow, but the wave length is not contracted.

Wrong with all of those - the wavelength is the same in both directions as it is not contracted. Objects are contracted, but light is not affected.

If a measuring rod is moving past you and aligned such that it is moving along its length (with the trailing end passing through the same point which the leading end went through a moment earlier), then it will be contracted from your point of view. If the measuring rod is moving past you and aligned such that it is moving along its width (i.e. sideways), then it's width will be contracted instead of its length. At other alignments, both its length and width will be contracted.

Indeed - the light that comes off a moving torch will always be travelling at c from your point of view as the torch moves towards or away from you. My point was that when you take into account the movement of the torch, you can measure the relative speed of the torch and the light coming from it as being greater or less than c. If the relative speed of torch and light from your point of view was required to be c, the torch would be banned by the laws of physics from moving relative to you. It isn't though - light is allowed to move at speeds relative to the torch which are greater or less than c (from the point of view of an observer who is moving relative to the torch). When you measure the speed of the light, though, it will have to be exactly c (in a vacuum), and when you calculate the speed of the same light from the point of view of the torch by applying the Lorentz transformation, you will get exactly c as the result of your calculations (once you've taken into account the effect that has on length and time for the torch).

Same misunderstanding as above. The speed of light is constant for all observers - that doesn't ban you from measuring light as being faster or slower than c for objects which are moving relative to you.

I'm having difficulty working out what's moving relatively to what - your descriptions are confusing and could be worded a lot more clearly.

The first sentence of that is correct, but the second is wrong. The light covered the same distance on both paths, but the arms of the instrument are not equal lengths. Consider a gun pointing sideways out through of the window of a car such that it is pointing at 90 degrees to the direction of travel. Now drive the car at 400mph - the same speed as the gun fires bullets…

The arm which is aligned with the direction of travel of the apparatus has to contract (or be treated as if it has contracted). [From Einstein's point of view there is no actual contraction - if you're looking at things from a different frame you're merely seeing things as contracted because they are not actually contracted when viewed from within their own frame.] In the case of the MM equipment moving at 0.866c in the direction of one of the arms, that arm can from a stationary frame be measured as having contracted to half its known length. The light moving along it is not contracted though.

(Personal note: Excuse 26s: When immersed in a problem and the AH HA comes and seems so obvious that it has to be obvious to everyone – Think again. Even to me it was as clear as mud for a while. THANK YOU! I will definitely have to make a major revision to the Problem.)

When the value of one of directly proportional quantities is changed the value of the other is changed proportionally. In the environment of special relativity, the speed of light is constant and the same for all observers with no exceptions. The speed of light does not change for any observer. Therefore, for the Michelson Morley experiment the speed of light and the directly proportional length of the arm and light path in the direction of motion could not change judged by any observer to include an observer at relative rest.

The problem is the Theory of Special Relativity hypothesizes this length in the direction of motion is changed (contracted) judged by an observer at relative rest notwithstanding contradictory laws of physics.

The length of the arm does change for observers who aren't moving relative to the MM apparatus, and the time it takes for light to go through it also changes. When you watch the apparatus pass by you will see the arm shortened and the time taken to complete both trips along the arms and back being lengthened as well. The thing that doesn't change for different observers is the speed of light.

The theory of special relativity says that this length will appear to be shortened, and that fits in with what happens in the real universe. It also says that time for the apparatus will appear to be slowed down, if you're looking at a clock attached to the apparatus and displaying the time that's passing for it. When you do the maths to work out how it appears to a scientist travelling with the apparatus, you can then see that (s)he will not notice any slowing of time for it and will not notice any length contraction either, but from your vantage point that is not how it looks at all.

Per the rule of proportions when the value of d, the length of the arm/light path is decreased (contracted) for an observer at relative rest the value of v is also decreased by the same factor for that observer. However, v is the speed of light which is constant and the same for all observers and does not change, then d, the length of the arm/light path cannot change for any observer.Then, for the Michelson Morley experiment, d, the length of the arm/light path in the direction of motion does not change/contract judged by an observer at relative rest.

When the value of d is decreased, the value of v will stay the same, so it has to be t that changes instead, but d will actually increase rather than decrease, and that means that t will increase with it.

There are two lengths you need to treat as separate values. One is the length of the contracted arm and the other is the distance the light has to travel through space to get along the arm and back. At 0.866c the length of the arm is halved, but the distance the light has to travel to complete a trip from one end to the other and back is doubled.

The equipment is moving across the sheet of paper, as it must do if the arm is to be seen as shortened...

However, the length of the arm/light path and the wavelength of the light in the light path in the direction of relative motion are contracted judged by observer “B” at relative rest.

I apologize for the delay. I will get back to you as soon as I can.Thank you,Butch

at 0.866c a clock will from the point of view of a stationary observer tick at half the normal rate, and light being produced by a source in the moving apparatus will also be affected in the same manner.

it would be easier for us to judge the frequency of the light as that removes any Doppler effect complications,

Although this was designed to detect any boost in the speed of light, the addition of the speed of the source and the speed of light, it also indicates there is no lag. That is, the speed of light was not measured to be slower, which would be the case if emission source moved forward in relationship to the point in space it occupied when the light was emitted. I understand your logic, but this is the rule until proved otherwise.

The MM apparatus is moving at 0.866c and we are moving with it...

The MM apparatus is moving at 0.866c and we are stationary,...

You're making exactly the same mistake as you did last time...arm is halved in length,... the length of the perpendicular arm...

If the apparatus is contracted in its direction of travel, you're automatically working with a case where the behaviour of light has to conform to the rules of a frame in which there is no contraction.

You're attacking a position I have never held.

It affects the frequency instead, so if the source is moving towards you it will result in blue shift, whereas if it is moving away it will result in red shift. The point I've been making concerns how you should handle the speed of light when you're working things out from within any particular frame of reference....

This illustrates why an understanding of Lorentz's theory should be considered as essential before people try moving on into exploring SR. All of this should be worked out under a theory which has a preferred frame. Once you've understood all the details of how that works, then you'll understand straight away how the rules have to be applied in SR to make SR work properly.

QuoteThe MM apparatus is moving at 0.866c and we are moving with it...The velocity of the apparatus compared to the velocity of the observer is zero. The velocity of one relative to the other is zero. At the relative velocity of zero there is no relativistic effect and all else is moot.

QuoteThe MM apparatus is moving at 0.866c and we are stationary,...Here it appears that phenomena from one frame crossed into the other frame. Only that which is entirely within the relatively moving frame is a consideration.

No mistake was made. There was no mention of arm length in my last reply.However, the lengths of the arms are one half the length of the corresponding light path in all circumstances without exception. The calculation for light path lengths at the relative velocity .866c is at the end of this reply.Please share the mathematical calculations you used for your comment.

Judged from relative rest for light in the direction of motion length is contracted by the factor .5 and time is slower in the moving frame by the factor of 2. wf=c or .5d/light wave * light wave/2t=c the “light wave” term cancels .5d/2t=c .5d/2t * 2/.5= c * 2/.5 simplify d/t=4c d/light wave * light wave/t=4c or wf=4c

Judged from relative rest for light perpendicular to the direction of motion length is not contracted and time is slower in the moving frame by the factor of 2. wf=c or d/light wave * light wave/2t=c the “light wave” term cancels d/2t=c d/2t * 2= c * 2 simplify d/t=2c d/light wave * light wave/t=2c or wf=2c

QuoteIf the apparatus is contracted in its direction of travel, you're automatically working with a case where the behaviour of light has to conform to the rules of a frame in which there is no contraction.Please share the mathematical calculations for this as well.

QuoteYou're attacking a position I have never held.I never attack a person or an idea. An attack does not promote constructive discourse, is generally counter productive and can easily result in avoidable useless acrimony.

The length of the light path is .5 times the proper length (.5d)

QuoteYou're making exactly the same mistake as you did last time...arm is halved in length,... the length of the perpendicular arm...No mistake was made. There was no mention of arm length in my last reply.However, the lengths of the arms are one half the length of the corresponding light path in all circumstances without exception. The calculation for light path lengths at the relative velocity .866c is at the end of this reply.Please share the mathematical calculations you used for your comment.

QuoteQuoteIf the apparatus is contracted in its direction of travel, you're automatically working with a case where the behaviour of light has to conform to the rules of a frame in which there is no contraction.Please share the mathematical calculations for this as well.You don't seem to have got the key point about how things work, so let me try to explain it more clearly. If you are looking at a system where there is no contraction, you must be stationary in the frame of reference in which the thing you're observing is also stationary. As soon as you're moving relative to the thing you're observing, you're going to see length contraction in the thing you're observing - you and the object are stationary in different frames, so you must treat the object as if it is moving through your frame and you must consider the light to be moving at c through your frame at all times. This means that when you observe the MM apparatus moving through your frame, you will work out that light will take much longer to travel along the contracted arm than it does when going back the other way and you will also work out that for light to get from one end of the uncontracted arm to the other it will have to cover twice the distance through your frame than the length of that arm because the arm is moving through your frame.

You proved my point!!!Light traverses the arm that is in the direction of motion at half the speed that light traverses the arm that is perpendicular to the direction of motion judged from relative rest.

THE PROBLEM IS:The speed of light is constant and the same for all observers yet for this observer at relative rest LIGHT HAS TWO DIFFERENT SPEEDS and both of those speeds are different that the speed of light observed within the relatively moving frame THE THIRD SPEED OF LIGHT in this exercise!!!!

var a=0; b=0; c=0; d=0; f=0.8660254; e=-0.5; h=0.8660254; g=-0.5; y=0.8660254; z=0; zz=0; bc2=1; mms=10; d1t=-6; d1l=-124; d2t=-6; d2l=-144; d3t=-6.5; d3l=-60; d4t=-6.5; d4l=-80; function run() { z+=bc2; if(z<0){z=0; bxc2()} else{ mms+=y; mm.style.left=mms; d1t+=a; d1l+=b; dot1.style.top=d1t; dot1.style.left=d1l; d2t+=c; d2l+=d; dot2.style.top=d2t; dot2.style.left=d2l; d3t+=e; d3l+=f; dot3.style.top=d3t; dot3.style.left=d3l; d4t+=g; d4l+=h; dot4.style.top=d4t; dot4.style.left=d4l; ttec2(); zz=z-79; time.innerHTML=zz}} function ttec2() { if(z==39 && bc2==1){a=-1; c=-1} if(z==39 && bc2==-1){a=0; c=0} if(z==79 && bc2==1){a=0; b=-1; e=0; f=-1} if(z==79 && bc2==-1){a=1; b=0; e=0.5; f=-0.8660254} if(z==112){f=1} if(z==204){b=1; c=1} if(z==329 && bc2==1){c=0; d=1; g=0.5} if(z==329 && bc2==-1){c=-1; d=0; g=0.5} if(z==349 && bc2==1){b=0; d=0} if(z==349 && bc2==-1){b=-1; d=-1} if(z==578 && bc2==1){g=0; h=1} if(z==578 && bc2==-1){g=-0.5; h=-0.8660254} if(z==654 && bc2==1){f=y, h=y} if(z==654 && bc2==-1){f=-1, h=f}}

The take away, you must agree, is that the speed of light in the direction of motion is different than the speed of light perpendicular to the direction of motion judged from relative rest.

You did an impressive job of creating the animation from the mathematics.

That second animation depicts the MMX at relative velocity .866c observed from relative rest.

That second animation shows that observed from relative rest light traverses the arms at 2 different speeds.Please, before you offer further explanation, is the statement above true? Yes or No, then give your explanation, PLEASE.

When you average out the speeds for the two journeys along the horizontal arm, you then get the same speed of light along that arm and back as you do for the journey up and down the other arm. It's only the round trip that really counts because it's impossible to measure the speed of light in just one direction unless you also know which is the preferred frame (and that depends on such a thing existing).

Yes, except that it's three different speeds

Take a look at your animation again.You get the same time in the direction of motion and perpendicular to the direction of motion.However, the lengths are different, therefore, the speeds are different.

Contraction in the direction of motion causes the constant speed of light not to be constant.

The speed of light is only always constant (or giving the appearance of being constant) within the frame in which you're measuring it.

“The speed of light is CONSTANT and the same for ALL observers.” NO EXCEPTIONS!!!That is the mantra.Right?

What you're trying to do is extend its meaning to cases which it simply isn't intended to cover: i.e. those cases where you add c to (or subtract c from) the speed of other objects moving through your frame where you will then necessarily produce values that aren't c.

QuoteWhat you're trying to do is extend its meaning to cases which it simply isn't intended to cover: i.e. those cases where you add c to (or subtract c from) the speed of other objects moving through your frame where you will then necessarily produce values that aren't c.Albert Einstein (1879–1955). Relativity: The Special and General Theory. 1920.http://www.bartleby.com/173/6.html [Links inactive - To make links active and clickable, login or click here to register]Section VI. The Theorem of the Addition of Velocities Employed in Classical MechanicsThere is only one paragraph.This is what Einstein said:“We shall see later that this result, which expresses the theorem of the addition of velocities employed in classical mechanics, cannot be maintained; in other words, the law that we have just written down does not hold in reality. For the time being, however, we shall assume its correctness.”

http://www.bartleby.com/173/14.html [Links inactive - To make links active and clickable, login or click here to register]XIV. The Heuristic Value of the Theory of RelativityParagraph 1This is what Einstein said:“Experience has led to the conviction that, on the one hand, the principle of relativity holds true, and that on the other hand the velocity of transmission of light in vacuo has to be considered equal to a constant c. By uniting these two postulates we obtained the law of transformation for the rectangular co-ordinates x, y, z and the time t of the events which constitute the processes of nature. In this connection we did not obtain the Galilei transformation, but, differing from classical mechanics, the Lorentz transformation.”

http://www.bartleby.com/173/11.html [Links inactive - To make links active and clickable, login or click here to register]XI. The Lorentz TransformationParagraph 2This is what Einstein said:“In other words: Can we conceive of a relation between place and time of the individual events relative to both reference-bodies, such that every ray of light possesses the velocity of transmission c relative to the embankment and relative to the train? This question leads to a quite definite positive answer, and to a perfectly definite transformation law for the space-time magnitudes of an event when changing over from one body of reference to another.”

Do you disagree?

Perhaps you can show me, though I imagine that if you aren't getting the right numbers out of it you can't be applying it correctly either

http://www.bartleby.com/173/11.html [Links inactive - To make links active and clickable, login or click here to register]XI. The Lorentz TransformationXII. The Behaviour of Measuring-Rods and Clocks in MotionHere Einstein gives all you need to know.

A light-signal is sent along the positive x-axis, and this light-stimulus advances in accordance with the equationx = ct,i.e. with the velocity c. According to the equations of the Lorentz transformation, this simple relation between x and t involves a relation between x' and t'. In point of fact, if we substitute for x the value ct in the first and fourth equations of the Lorentz transformation, we obtain:

from which, by division, the expressionx' = ct'immediately follows. If referred to the system K', the propagation of light takes place according to this equation. We thus see that the velocity of transmission relative to the reference-body K' is also equal to c. The same result is obtained for rays of light advancing in any other direction whatsoever. Of course this is not surprising, since the equations of the Lorentz transformation were derived conformably to this point of view.

The reason I am not getting the same numbers is because I strongly disagree.

The Theory of Special Relativity only addresses length contraction of rigid bodies in the direction of motion and not the light and the consequences to light in the light paths delineated by those contracted lengths which is part and parcel of the Michelson Morley experiment.