Michelson- Morley's experiment

[hunarahmad]

Hi everyone I'm a new member

Despite I'm not graduated from college of physical science, but I'm super interested in physics. this summer I tried to study relativity theory by my self with some good references, I was very happy when I get to understand the concepts of relativity and I convinced my self that the ultimate relative speed between any two objects is (C) based on the results of Michelson- Morley's experiment.

but when I investigated more carefully about this experiment I realized that the source of light emission which they used were fixed on the same Earth which the mirrors and detector were fixed on, (previously I thought that they were using a fixed star as a source of light or some thing like that) so there was no relative motion between the emitter and the detector how could fringes occur in this state?? What If we assumed that the light composed of particles, the results of this experiment could be easily explained just by Galilean transformations without using Lorentz transformation.

I searched the net and I found many other researches proves that of Michelson- Morley's demonstration has many fatal errors could not be trusted to prove any thing, e.g try this research (a pdf document).
also try this one http://www.Newtonphysics.on.ca/michelson/michelson.html

And also I found this site:
http://www.Newtonphysics.on.ca/index.html
the author of this site is a strong supporter of classical physics and he claims that time dilation, length contraction, perihelion of mercury, every thing could be explained by classical physics and even E=MC2 could be derived without using relativity concepts!

Now, at the end of this summer I'm near a bout to loss my confidence in relativity theory unless someone from this lovely forum save me.

My question is that does anyone has a strong evidence rather than Michelson- Morley's experiment to show me that C is the ultimate relative speed between any two objects even if they approach opposite direction to each other with a velocity more than 200000km/s?

And thank you

 

[genneth]

That's kind of the point. The Michelson-Morley experiment shows the lack of an absolute "aether" through which EM waves propagate. It doesn't show anything else about light. Special relativity has two postulates, the one about the speed of light being c in all frames is partially tested by this experiment.

Let's look at it this way: for the last hundred years, we've come a remarkably long way, with the help of special relativity, and some very clever people who used it to produce technology and new theories. What's more likely: relativity has such huge, gaping holes that no-one has noticed, or that you've not yet fully grasped the details?

By the way, don't trust what you read on websites. Look in things which have been reviewed by many people, and which have been used to build on: papers in peer reviewed journals, often used and highly regarded textbooks, etc. Random rantings on a website by semi-insane people are not as reliable.

 

[ZapperZ]

I am going to let this stand, for now, because there is a need to debunk this thing clearly. However, take note that, per our PF Guidelines, crackpottery, crackpot links, and this-physics-is-wrong type of arguments are not allowed on PF without VALID citation. And valid citation must include peer-reviewed papers, NOT simply someone's pet website.

If you don't understand something, ASK first. Don't make proclamations based on lack of understanding. If this thread deteriorates into another "Relativity is wrong" argument, it will be locked or completely deleted.

Zz.

 

[russ_watters]

but when I investigated more carefully about this experiment I realized that the source of light emission which they used were fixed on the same Earth which the mirrors and detector were fixed on, (previously I thought that they were using a fixed star as a source of light or some thing like that) so there was no relative motion between the emitter and the detector how could fringes occur in this state??

You completely miss the purpose of the experiment. The purpose of the experiment was to find/measure the motion of the aether past the detector and emitter.

It works similar to having fixed observers on both sides of a river. By sending a boat across the river at a known speed, you can measure the speed of the river based on the time the boat took to get across. The boat has to angle upstream to go straight across and thus travels further than if the river wasn't moving.

That is all the MM experiment was trying to measure.

My question is that does anyone has a strong evidence rather than Michelson- Morley's experiment to show me that C is the ultimate relative speed between any two objects even if they approach opposite direction to each other with a velocity more than 200000km/s?

Particle accelerators show that. GPS satellites show the time dilation that accompanies that.

And please - takea step back and a deep breath. Thousands of physicists use these theories every day and tens (hundreds?) of thousands have worked on the issues and and performed the experiments to back up the theories since they were first proposed. It is pretty arrogant to believe that with no formal education and having never performed an experiment, you know something they don't.

 

[tabchouri]

The hole relativity theory is build upon the constancy of the speed of light in vacuum.
That constancy is assumed to be true, no matter the circumstances : mouvement of the observers or emitters, presence of forces or gravity nearby ...
Until now, no experiment or observation contradicted that fact, but rather support it.
So the speed of light in vacuum is a universal constant, at least as far as our current knowledge of the universe and the laws that govern it is involved.
End of story.

-----------------------------------------------------
Correct me if I am wrong.
http://ghazi.bousselmi.googlepages.com/présentation2

 

[hunarahmad]

That's kind of the point. The Michelson-Morley experiment shows the lack of an absolute "aether" through which EM waves propagate. It doesn't show anything else about light.

Thank for your advices, it returns some confidence to me. But the above research shows that MM experiment even can not disprove the existence of absolute ether its just like someone tries to measure the speed of his car by using Doppler effect while he puts the sound source and the detector on the same car so there will be no change in frequency.

Let's look at it this way: for the last hundred years, we've come a remarkably long way, with the help of special relativity, and some very clever people who used it to produce technology and new theories. What's more likely: relativity has such huge, gaping holes that no-one has noticed, or that you've not yet fully grasped the details?

But the accuracy of a theory is not measured by the time which it has survived for e.g Newton's lows lasts for 300 years without anyone notice an error and also Aristotle's lows of motion lasts for about more than 1000 years before Newton find the errors. this dose not mean that the previous human beings were less intelligent than the current (the theory is a theory every time its liable to change)

If you don't understand something, ASK first. Don't make proclamations based on lack of understanding. If this thread deteriorates into another "Relativity is wrong" argument, it will be locked or completely deleted.

I'm so sorry I did not read the lows of this forum, so forgive me this time. I'm just wanted to seek help to return my confidence in this theory because I loved this theory and seeking for stronger evidences to increase my faith in this theory.

It works similar to having fixed observers on both sides of a river. By sending a boat across the river at a known speed, you can measure the speed of the river based on the time the boat took to get across. The boat has to angle upstream to go straight across and thus travels further than if the river wasn't moving

There is a science dealing with reflections of light on moving mirror and it states that reflection of light on moving mirrors will differ from that of fixed mirrors and they said that MM experiment were over simplified because its ignored the effect of moving mirrors, we know that in 1887 the scientists were so confident about the existence of ether even after MM experiment they tried to explain the results without rejecting the existence of ether even Lorentz him self derived his equation on length contraction to save the postulate of absolute ether as he explained by his equation that moving objects in ether contracts at direction of its motion, later Einstein removed that part of lorentz equation which describe ether, so this means that there is a fixed style of thinking dominated in brains of scientist at that time, they did not consider particle property of light and many other properties which discovered later. At last let's know that lorentz transformation born to save ether theory on bases of MM experiment.

It is pretty arrogant to believe that with no formal education and having never performed an experiment, you know something they don't

I'm very sorry if I behave arrogantly so forgive me I'm just like a child interested in some thing, so please do not reject me.

Thank for everyone replies and sorry for any misunderstanding, I believe in relativity theory I just want to increase my confidence in it by empting any question in my mind bothers me.

 

[JesseM]

Thank for your advices, it returns some confidence to me. But the above research shows that MM experiment even can not disprove the existence of absolute ether its just like someone tries to measure the speed of his car by using Doppler effect while he puts the sound source and the detector on the same car so there will be no change in frequency.

What you don't seem to understand is that waves in a medium will always travel at the same speed relative to the rest frame of the medium, not relative to the rest frame of the emitter. So if I'm in an open-topped car and I clap my hands in the middle of the car, someone at the back of the car will hear the sound before someone at the front of the car, since the car is moving forward in the air's rest frame, and sound waves from the clap travel at the same speed of sound in both directions in the air's rest frame (not the car's).

 

[russ_watters]

Thank for your advices, it returns some confidence to me. But the above research shows that MM experiment even can not disprove the existence of absolute ether its just like someone tries to measure the speed of his car by using Doppler effect while he puts the sound source and the detector on the same car so there will be no change in frequency.

The MM experiment measures time delay, not doppler shift. And as Jesse said, you can indeed measure the speed of a car via the time delay of a sound traveling from the back to the front of the car, outside the car.

 

[yogi]

The MMx experiment showed that the over and back average would always be c. It did not disprove the existence of a medium, a medium is as Einstein put it, superfluous to SR since one cannot find a meaningful reference frame in featureless space.

 

[mjsd]

The following is for your interest only (I do not otherwise endorse or rebuke it for I have not spent time studying their theories). Just to show that there exists academics from a "reputable" university (well, at least field medalist Prof. Terence Tao used to go there as an ugrad) who dismisses the MM experiment and probably Einstein's theory as a whole...

Michelson-Morley Experiments Revisted and the Cosmic Background Radiation Preferred Frame
The Michelson-Morley interferometer experiments were designed to measure the speed of the Earth through the aether. The results were always believed to have been null - no effect. This outcome formed the basis for Einstein's Special and General Relativity formalism. The new process physics shows that absolute motion, now understood to be relative to the quantum foam that is space, is observable, but only if the interferometer operates in gas mode. A re-analysis here shows that the results from the gas-mode interferometers were not null, but in fact large when re-analysed to take account of the effect of the air, or helium, in which the apparatus operated. The speed of absolute motion is comparable to that determined from the Cosmic Background Radiation anisotropy, but the direction is not revealed. So absolute motion is meaningful and measureable, thus refuting Einstein's assumption. This discovery shows that a major re-assessment of the interpretation of the Special and General Relativity formalism is called for, a task already provided by Process Physics. This new information-theoretic physics makes it clear that Michelson-Morley type experiments are detecting motion through the quantum foam, which is space. Hence we see direct evidence of quantum gravity effects, as predicted by Process Physics. (This version corrects an earlier version of this paper, at arXiv:physics/0205065.)

more at
http://www.scieng.flinders.edu.au/cpes/people/cahill_r/processphysics.html

 

[hunarahmad]

What you don't seem to understand is that waves in a medium will always travel at the same speed relative to the rest frame of the medium, not relative to the rest frame of the emitter. So if I'm in an open-topped car and I clap my hands in the middle of the car, someone at the back of the car will hear the sound before someone at the front of the car

It seems that I have failed to give a good example. You are right about that if we consider wave property of sound but light has dual property wave and particle (you can describe light as a wave to describe one phenomenon and as a particle to describe another phenomenon)

till now no body seems to understood me I wanted to draw a scheme to show my Idea but the PF guidelines did not permit image links so for the last time I will repeat if we consider particle property of light, Einstein described photoelectric effect by considering light as packets of energy and later Compton described light particles as billiard balls to describe Compton effect)
So… what is the problem if we describe light particles as a gunshots and the light source as a Gun it is very very very very easy & simple to describe the results of MM experiment by using Galilean transformation only.

Suppose that you have a gun and you are inside a moving room and you stand midway between back wall and the front wall what makes you think that the gunshots which directed toward the front wall will reaches the wall before those gunshots that directed towards the back wall ? Does the speed of gunshots differ according to direction (in relation to someone in the same room)? of course you can not use this gun to measure the speed of this room you can not even know that the room are moving because you & your system are isolated its just like MM experiment when they used a light source (a gun), fixed one the same Earth (moving room) and mirrors (walls), fixed on the same Earth then they expected that light beams (gunshots) will reach the mirrors (walls) at different speeds. how could this be?

I hope some one understand what I mean this time
Thank you.

 

[genneth]

No, we understood perfectly, it's you who's failing to understand. The point of the MM experiment was to find an absolute aether, which supports EM waves, and which is absolute -- so the Earth would be moving through it. The null results shows that no such absolute aether exists. Your example of the room and speed of sound propagation depends on the motion of the air (the medium through which the sound propagates). If the air is moving with the room, then you can't distinguish it. Otherwise, you can. However, we also know that the aether wasn't being "dragged" by the earth, as we do not observe refraction from the boundary where the aether is presumably stationary wrt to some other body. However, none of this suggests that c is a "maximum speed". Indeed, in SR, that's not one of the postulates, but one of the consequences.

mjsd: it's always possible to change the names that we give things, and arrive at a seemingly different theory. If a theory is self-consistent, and agrees with SR, then it's probably just calling something by a different name. For instance, even in SR, there has been a historical divide reflected in the names "relativistic mass" and "invariant mass".

 

[ZapperZ]

It seems that I have failed to give a good example. You are right about that if we consider wave property of sound but light has dual property wave and particle (you can describe light as a wave to describe one phenomenon and as a particle to describe another phenomenon)

No it is not. Read the FAQ in the General Physics forum. If you want use this as simply a conversation tool for the general public, then yes, such "duality" is adequate. However, if you want to talk to physicists or formulate a "theory", then such naive and superficial idea is wrong.

So… what is the problem if we describe light particles as a gunshots and the light source as a Gun it is very very very very easy & simple to describe the results of MM experiment by using Galilean transformation only.

Then would you like to show how you can make Maxwell Equations covariant under galilean transformation?

Zz.

 

[yogi]

Treating photons as particles does not validate the emission theory - specifically - the velocity of the light source is not added to the velocity of propagation - there are a number of experiments that have tested for this and they have all proved the emission theory to be incorrect.

The fact that SR explained the null result of the MMx experiment, however, did not prove the truth of SR. There are other theories that explain the results - in fact any theory that leads to Gamma will work - that is, the experiments all demand a contraction of space and a dilation of time in order to comport with the null result for over and back type measurements. SR offers the simplest solution and is preferred because of its symmetry, but you can still find many who embrace the notion of an ether along the lines originally proposed by Lorentz and Larmore, and while such theories can explain the failure to detect a medium, it will take further experiment to determine if SR needs to be modified. So far SR has weathered all assaults upon its validity

 

[yogi]

"If my theory of relativity proves to be correct, Germany will claim me as one of their own, and France will say I am a citizen of the world. If it proves to be incorrect, France will say I am a German, and Germany will say I am a Jew." Albert Einstein

 

[mjsd]

No, we understood perfectly, it's you who's failing to understand. The point of the MM experiment was to find an absolute aether, which supports EM waves, and which is absolute -- so the Earth would be moving through it. The null results shows that no such absolute aether exists. Your example of the room and speed of sound propagation depends on the motion of the air (the medium through which the sound propagates). If the air is moving with the room, then you can't distinguish it. Otherwise, you can. However, we also know that the aether wasn't being "dragged" by the earth, as we do not observe refraction from the boundary where the aether is presumably stationary wrt to some other body. However, none of this suggests that c is a "maximum speed". Indeed, in SR, that's not one of the postulates, but one of the consequences.

mjsd: it's always possible to change the names that we give things, and arrive at a seemingly different theory. If a theory is self-consistent, and agrees with SR, then it's probably just calling something by a different name. For instance, even in SR, there has been a historical divide reflected in the names "relativistic mass" and "invariant mass".

my point in citing that link was to reply to the subject of this thread
Michelson- Morley's experiment is wrong! and perhaps point out to ppl of this forum that SR and GR, in the opinion of some (even academics!), is not the true story.

again I have to admit I have not studied their theories and not sure how different/inefficient those theories are. :uhh:

 

[pmb_phy]

Hi everyone I'm a new member

Then let me take this opportunity to welcome you to the forum! Welcome! :)

..this summer I tried to study relativity theory by my self with some good references, ..

What were these sources? I noted that web page you mentioned above about a guy who believes that Newtonian mechanics can predict things like E = mc^2 etc. If you want to know if this guy is a crackpot or not then read his material. Does it seem reasonable to you? There's a ton of stuff there so it shouild take a very long time to go over it. The important thing is to look for anything he has actually published on what he claims in that web site.

I was very happy when I get to understand the concepts of relativity and I convinced my self that the ultimate relative speed between any two objects is (C) based on the results of Michelson- Morley's experiment.

Many people believe that is how the results should be interpreted. But not everyone. I recommend that you pick up a copy, or get a lend from your library, on a book called Special Relativity, by A.P. French, MIT Press (1968). Turn to page 127-128 and you can read the following

In the particular case that one of the combining velocities-say u_x’ – is equal to c and b₁ – is equal to c, giving b₂ = 1, then Eq. (5-4) yields the result u_x = c for any value of v. This then includes the result that light emitted from a source that is moving relative to the laboratory still has the speed c, no matter how fast the source is moving.
As we mentioned in Chapter 3, this result, although an essential feature of Einstein’s formulation of relativity, did not receive a convincing demonstration until much later. One crucial reason is that propagation of light through a medium (even a transparent one) involves a continual process of absorption of the incident light and its reemission as secondary radiation by the medium – and it takes only a very small thickness of matter to bring about this replacement. Thus, for example, with visible light, a thickness of about 10^-5 cm of glass or 0.1 mm of air at atmospheric pressure is enough to erase any possible memory, as it were, of the motion of the original source. This phenomenon, known as extinction (even tough it many not involve any appreciable loss of intensity in the light beam), has invalidated some of the observations (e.g. apparent motions of binary stars, already referred to in Chapter 3) that were at first believed to provide confirmation of Einstein’s second postulate – the invariance of c. We shall no describe two experiments which do not appear to be vitiated by the extinction phenomena.

The author references the physics article in the American Journal of Physics

Evidence Against Emission Theories, J.G. Fox, Am. J. Phys. 33(1), January 1965

Unfortunately this is an article I haven't read yet. Perhaps I'll read it this week since I just created a web page on the Michelson-Morely experiment. That web page is located at - http://www.geocities.com/physics_world/sr/mmx.htm

Since I just made it there may be some errors in it that I have over looked. If anyone can find any errors in it then I would be very appreciative if you can let me know what those errors are.

If anyone would like to read the Fox article I can make this available online for you to download it at your convinience. Please let me know it this is something you'd like me to do, okay?

..but when I investigated more carefully about this experiment I realized that the source of light emission which they used were fixed on the same Earth which the mirrors and detector were fixed on, ..

That was the intent of the experiment. It was to detect the motion of light through the ether. If the source is at rest in frame S and emits light in S then the speed of the light will have the value c as measured from the ether frame. If S is not the ether frame then the speed of light will be different for to-and-fro motion along the direction of the ether flow and have different values for to-and-fro motion across the ether wind. This is all shown in the web page I mentioned above.

I searched the net and I found many other researches proves that of Michelson- Morley's demonstration has many fatal errors could not be trusted to prove any thing.

In the sense stated above, I agree. But this is because the Michelson-Morely experiment was done in open air. Later experimentsm, such as the Kennedy-Thornedyke experiment was done in a hard vacuum. The result of this experiment was a null result meaning that they couldn't measure different speeds along the different arms of the interferometer.

Now, at the end of this summer I'm near a bout to loss my confidence in relativity theory unless someone from this lovely forum save me.

That is a very honorable request that we will try to help you with. If you have any questions about my comments in this post or in the web page I created yesterday then please let me know. Especially about my web page. All of my web pages I like to have reviewed by others. I usually get that from my friends but I also look at whatever others say too.

My question is that does anyone has a strong evidence rather than Michelson- Morley's experiment to show me that C is the ultimate relative speed between any two objects even if they approach opposite direction to each other with a velocity more than 200000km/s?

Michelson-Morley experiment seems to be wrong to me in that the presence of an atmosphere will cause the phenomena of extinction to override the speed of light relative to the ether. This is what French's book tells me. And I've met French several times. He's a very sharp educator in physics.

Best wishes

Pete

 

[russ_watters]

It seems that I have failed to give a good example...

Suppose that you have a gun and you are inside a moving room and you stand midway between back wall and the front wall what makes you think that the gunshots which directed toward the front wall will reaches the wall before those gunshots that directed towards the back wall ? Does the speed of gunshots differ according to direction (in relation to someone in the same room)? of course you can not use this gun to measure the speed of this room you can not even know that the room are moving because you & your system are isolated its just like MM experiment when they used a light source (a gun), fixed one the same Earth (moving room) and mirrors (walls), fixed on the same Earth then they expected that light beams (gunshots) will reach the mirrors (walls) at different speeds. how could this be?

I hope some one understand what I mean this time
Thank you.

This is getting frustrating because your previous example was more correct than this one! What you describe is the principle of relativity, but it is not what the MM experiment was trying to measure. Again, the MM experiment was trying to measure the motion of the aether past the detector and emitter. In your example now, you've sealed-off the room, so there isn't any wind to affect the motion of the bullet! Of course it won't be affected by the motion of the room. But aether theory was based on the idea that even if you seal-off the room as best you could, there is still a medium that carries light that would be in motion through the room.

If what you are saying were correct, we'd measure the speed of light differently inside and outside. We don't.

 

[hunarahmad]

Originally Posted by genneth
No, we understood perfectly, it's you who's failing to understand. The point of the MM experiment was to find an absolute aether, which supports EM waves, and which is absolute -- so the Earth would be moving through it. The null results shows that no such absolute aether exists

Did you know why I made the title of this thread states that "Michelson- Morley's experiment is wrong"?? Because if I said "can anyone give me an evidence on light speeds constancy" no doubt everyone would gave me Michelson's experiment as an evidence.

You are right about the original purpose of MM. exp. was to find an absolute aether, which supports EM waves, and which is absolute, but when the experiment failed to do its purpose there was a need to explain this negative result?? What those explanations led to?

These are some possible explanations to the null results of MM experiment (of course if we ignored technical errors):-

1) If we supposed that like composed of particles just like bullets their velocity of propagation are added to sources velocity, then its simple to explain the results using Galilean transformation.
But why nobody thought of this possibility? Because at that time (1887) the corpuscular theory of Newton were dead, as a result of young's experiments and Maxwell's equations, scientists were so confident about the wave nature of light that nobody could mention that light may be composed of particles even if someone did they make fun of him.

2) If we supposethat aether dragged with moving objects…… (Not succeeded)

3) If lengths contract in direction of motion, then we can save aether and explain null results of MM, so Lorentz transformation were born to save aether. this will lead us to conclude that if length contraction is correct we ought to believe in existence of absolute ether otherwise the null result of MM couldn't be explained.

4) Then Einstein came and kicked aether out from equations not on the bases of experimental evidence but he saw that if C is constant, Lorentz transformation will still work well even if there is no aether so he used the principle of cut and economy.

So ….
The final consequences based on MM experiment led to the conclusion that C is the absolute relative speed.
That’s why I can,t take MM experiment as a direct evidence on constant light velocity.

Originally Posted by ZapperZ
Then would you like to show how you can make Maxwell Equations covariant under Galilean transformation?

Well, scientists indeed wanted to modify Maxwell Equations to be covariant under Galilean transformation but after SR appeared they modified Galilean transformation instead and let Maxwell Equations unchanged.
However nobody know exactly changing which one is better, as you know Max blank modified some concepts of classical EM energy that enable him to explain blackbody's radiation and discovered light quanta

Originally Posted by yogi
Treating photons as particles does not validate the emission theory - specifically - the velocity of the light source is not added to the velocity of propagation - there are a number of experiments that have tested for this and they have all proved the emission theory to be incorrect

That’s exactly what I want. Those experiments which you are talking about may greatly satisfy me, if you do not mind; can you give names or links to those experiments? I will be grateful to you

Originally Posted by pmb_phy
Let me take this opportunity to welcome you to the forum! Welcome

Thank you for your kindness

If you want to know if this guy is a crackpot or not then read his material. Does it seem reasonable to you?

You are right about this guy, he behaves as like Einstein killed his father!
But however we can not say there is no even a single error in SR if it was, then why it can't explain micro-world??

binary stars, already referred to in Chapter 3) that were at first believed to provide confirmation of Einstein’s second postulate – the invariance of c.

I read this example from Einstein's book (evolution of physics) however I couldn't understand what it means.

If anyone would like to read the Fox article I can make this available online for you to download it at your convinience. Please let me know it this is something you'd like me to do, okay?

Why not?? It may be the solving key for my problem I'll be very grateful to you if you do this for me.

All of my web pages I like to have reviewed by others. I usually get that from my friends but I also look at whatever others say too.

A very very nice page, I saved many pages from it for later reading, however some links in your site led me indirectly to "strong crackpottery" sites. What worried me is their confidence on their claiming even some of them claims that there are mathematical mistakes in Einstein's derivations and they are ready to reveal these mistakes in scientific journals!

Originally Posted by russ_watters
In your example now, you've sealed-off the room, so there isn't any wind to affect the motion of the bullet

Even if the room were opened you will get the same result because the bullet and the observer in the same inertial frame.

If what you are saying were correct, we'd measure the speed of light differently inside and outside. We don't

That’s what I search about: an experiment measures velocity of the same light beam in different frames of motion not the same frame as MM experiment.

 

[ZapperZ]

Well, scientists indeed wanted to modify Maxwell Equations to be covariant under Galilean transformation but after SR appeared they modified Galilean transformation instead and let Maxwell Equations unchanged.
However nobody know exactly changing which one is better, as you know Max blank modified some concepts of classical EM energy that enable him to explain blackbody's radiation and discovered light quanta

You have said nothing here. I still want to see how you can make Maxwell Equations covariant under Galilean transformation. Till you can do that, you have shown nothing other than arguing things based on a matter of tastes.

Oh, and while you're at it, please re-read the PF Guidelines that you have agreed to.

Zz.

 

[OOO]

You have said nothing here. I still want to see how you can make Maxwell Equations covariant under Galilean transformation. Till you can do that, you have shown nothing other than arguing things based on a matter of tastes.

Oh, and while you're at it, please re-read the PF Guidelines that you have agreed to.

Zz.

Hats off to all you regular posters here ! Never say die !

 

[JesseM]

Did you know why I made the title of this thread states that "Michelson- Morley's experiment is wrong"?? Because if I said "can anyone give me an evidence on light speeds constancy" no doubt everyone would gave me Michelson's experiment as an evidence.

You are right about the original purpose of MM. exp. was to find an absolute aether, which supports EM waves, and which is absolute, but when the experiment failed to do its purpose there was a need to explain this negative result?? What those explanations led to?

Defining it in terms of ether is a little narrow though. Physicists already knew that Maxwell's equations gave very accurate-looking predictions amount electricity and magnetism, and Maxwell's laws clearly predict that electromagnetic waves always move at the same speed which is independent of the emitter. But as ZapperZ points out, Maxwell's laws are not invariant under the Galilei transformation (the fact that they predict electromagnetic waves move at the same speed in all directions is sufficient to show this, if two objects are moving at the same speed in opposite directions one Galilean frame, you can always find other frames where their speed is different). So, physicists imagined that Maxwell's laws might only work perfectly in one frame--which they imagined was the rest frame of a physical substance called "the ether" which electromagnetic waves were vibrations in, although this isn't a necessary assumption--and would have to be modified by a Galilei transform in other frames. MM showed this didn't hold up, helping lead to Einstein's realization that if all the laws of physics were Lorentz-invariant rather than Galilei invariant, then Maxwell's laws could hold in every inertial frame.

Your argument basically depends on abandoning the idea that Maxwell's laws work at all in any frame. The thing is, there was already plenty of experimental evidence in support of Maxwell's laws. Is it possible to construct an alternate theory which predicts all the same phenomena that had already been verified by the time of the Michelson-Morley experiment (along with any other phenomena predicted by Maxwell's laws or quantum electrodynamics which have been verified since then), yet predicts that the velocity of electromagnetic waves depends on the velocity of the emitter? I have my doubts. Of course one might try to test the proposition that light's velocity depended on the emitter's velocity even if one couldn't think of a theory that predicted this and was compatible with other observations, but this wasn't the point of the MM experiment, so it isn't fair to say the experiment is "wrong" just because it doesn't address the question that you're interested in.

If you're looking for experiments that do address the question of whether light's velocity is changed depending on the source velocity, have a look here for starters:

http://www.math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html#moving-source tests

But however we can not say there is no even a single error in SR if it was, then why it can't explain micro-world??

SR just says that the fundamental laws of physics, whatever they are, should all be Lorentz-invariant, it doesn't try to explain every other aspect of what these fundamental laws should be like. And the equations of quantum field theory are Lorentz-invariant, so nothing about them suggests an "error" in SR.

 

[rbj]

But the above research shows that MM experiment even can not disprove the existence of absolute ether its just like someone tries to measure the speed of his car by using Doppler effect while he puts the sound source and the detector on the same car so there will be no change in frequency.

well, that's not how it works. it's more like someone trying to measure the speed of his car through the air by measuring windspeed past his car. now maybe, if that someone in the car happens to drive his car precisely with the wind (from the weather) at every stretch and turn, his/her windspeed indicator would always say zero, because he/she is always moving along with the wind and has zero velocity relative to the wind. but if i were to get such results and i was driving my car all over the place with no consideration as to where the wind might be blowing, i might conclude that it's more reasonable to believe there simply is no air if, wherever i go and whatever my velocity is, i just never measure any windspeed.

the null result of the MM experiment shows that either:

1. we are always moving along with the aether, no matter what time of day or day of year. somehow that aether knows how to move around the Sun with our planet.

2. aether exists, but has no measurable properties. (so then what good is it? if it exists, but has no effect on anything, even light.) that would not be the aether that was postulated by physicists who thought it must be there, as a medium for E&M interaction to propagate in.

3. there is no aether there to measure properties.

that's how to reasonably look at something that has been searched for multiple times and has always evaded detection.

 

[pmb_phy]

Why not?? It may be the solving key for my problem I'll be very grateful to you if you do this for me.

Then I need to know your e-mail address. I will have to send you three e-mails because placing them all in one e-mail bounces back to me with an error that the file was rejected by the server as being to large. Someone else here sent me an e-mail with the same request. He gave me his e-mail address. I recommend you do the same thing. Send me a PM message with your e-mail address in it. I will then send three separate e-mails. Then print out all the images (which are images of the article pages and clear enough to read comfortably). Then staple them together and you have the article

A very very nice page,..

Thank you. Its most gratifying hearing that all my work pays off by helping others with physics. Thanks!

I saved many pages from it for later reading, however some links in your site led me indirectly to "strong crackpottery" sites.

I did my best to make sure that would never happen. Please post what sites these are and the web page where you found the link. If I agree with you then I will delete the reference.

What worried me is their confidence on their claiming even some of them claims that there are mathematical mistakes in Einstein's derivations and they are ready to reveal these mistakes in scientific journals!

Well Einstein did make mistakes like the rest of us. Even in his first SR paper he did something weird. While it is not literally an error it was a very hinky thing to do. This is described in http://www.geocities.com/physics_world/sr/ae_1905_error.htm. This "error" was mentioned in a book by Aurthur Miller and will also be mentioned in a new book which will be comming out which was written by a well-known relativist.

Best wishes

Pete

 

[ZapperZ]

Why don't you cut him some slack? He's not claiming that relativity is wrong. Note what his first comment was, i.e. Despite I'm not graduated from college of physical science, but I'm super interested in physics. All the posts that I've seen of his do not violate the forum rules. He may have come to some false conclusions but he is asking us to help him understand what he is doing wrong. Zz, you'd just too quick to criticize. You made it less desirable to want to post in this forum. That is meant as contructive criticism and not an insult. How well do you respond to contructive criticism? Or will you start warning me too?

Pete

And you should read the post that I asked him that originally, especially on what he claimed about galilean transformation. I believe that is a valid request when one has made such a statement (and it wasn't even a question if you care to check).

When someone makes such a claim, but refuses to clearly show either directly or via citation how such a thing can be accomplished, then one has made some unverified claim while refusing to directly respond to a request for an answer. Such a claim then becomes highly speculative!

So which part of that do you disagree?

Zz.

 

[russ_watters]

Even if the room were opened you will get the same result because the bullet and the observer in the same inertial frame.

No. The motion of bullets is most certainly affected by wind. Hunters and snipers have to account for it.

 

[hunarahmad]

Oh, and while you're at it, please re-read the PF Guidelines that you have agreed to.

Zz

.

well, I couldn't continue this discussion because I couldn't guarantee you that there will be no violation (freedom limit is too narrow here)

thank you for everyone replied.

 

[hunarahmad]

Let me add this:

Discussion is just like fighting and in fighting there is one winner but for knowledge the winners are both because both sides get more information.
When I said this idea is wrong, this means that its wrong in my point of view may be I'm wrong. For me this forum is not a peer-reviewed journal to be afraid that my claiming will be disproved if I were 100% sure that my claiming is right, then why I release it in this forum I will release it in a scientific journal.

 

[ZapperZ]

You should also ask yourself "Now why did I agree to those Guidelines if I didn't want to follow follow them in the first place? After all, I knew what I was agreeing to and the criteria that they have imposed on anyone participating here. So why did I still continue to do what I know they don't allow?"

Zz.

 

[Dale]

My question is that does anyone has a strong evidence rather than Michelson- Morley's experiment to show me that C is the ultimate relative speed between any two objects even if they approach opposite direction to each other with a velocity more than 200000km/s?

I like this site:

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

It has a list of many specific peer-reviewed experiments that have been published testing various predictions of special relativity. I would encourage you to start there, and go to your local university library for copies of any interesting manuscripts. The experimental evidence, as you can see, is overwhelming. Special Relativity is correct.

But the accuracy of a theory is not measured by the time which it has survived for e.g Newton's lows lasts for 300 years without anyone notice an error

I am always somewhat troubled by this kind of statement. Newton's laws are still correct in the sense that they accurately describe a wide variety of phenomena and they have been extensively tested and verified. Relativity did not find an "error" in Newton's laws, but instead simply identified an unknown limitation in the domain of applicability of Newton's laws. Specifically, Newton applies when v<<c and in this limit Special Relativity reduces to Newtonian mechanics.

You are undoubtedly correct that at some point there will be another theory that "surpasses" relativity, but it will do so in a similar manner. The new theory will reduce to relativity in some limit. If it did not, then the new theory would be incompatible with decades of experimental evidence. Thus, even when relativity is surpassed it will still be useful and still correctly describe a wide variety of phenomena, just as Newton's laws still do.

-Regards
Dale

 

[jostpuur]

... and even E=MC2 could be derived without using relativity concepts!

I don't bother following the links of the OP, but this claim alone at least is not wrong.

http://www.arxiv.org/abs/astro-ph/0504486 E = mc^2 Without Relativity

 

[pmb_phy]

I don't bother following the links of the OP, but this claim alone at least is not wrong.

http://www.arxiv.org/abs/astro-ph/0504486 E = mc^2 Without Relativity

Now that you mention it, it appears that my own derivation need to use relativity. I.e. ifI took the low velocity limit then it might work. That page is located at

http://www.geocities.com/physics_world/sr/mass_energy_equiv.htm

Pete

 

[jostpuur]

So hunarahmad explains, that if light consists of particles that fly around like bullets, then the Michelson-Morley experiment didn't prove that these particles would go with the same speed c in all frames.

There is no point in responding that hunarahmad would be wrong, because the Michelson-Morley experiment was intended to detect the ether in which light waves would have propagated, because even though Michelson-Morley experiment was intented to detect the ether in which light waves would have propagated, that does not contradict what hunarahmad was saying.

(Edit: If this was too messy, check out an explanation below in my second post, where I attempt to make it clearer.)

hunarahmad was quite right with his conclusion, but on the other hand it has little relevance because light does not consists of particles that fly around like bullets.

 

[pmb_phy]

So hunarahmad explains, that if light consists of particles that fly around like bullets, then the Michelson-Morley experiment didn't prove that these particles would go with the same speed c in all frames.

There is no point in responding that hunarahmad would be wrong, because the Michelson-Morley experiment was intended to detect the ether in which light waves would have propagated, because even though Michelson-Morley experiment was intented to detect the ether in which light waves would have propagated, ..

The purpose of the ether was to give it a medium/frame of reference with which it traveled at c. The method of detection of the ether was to measure the velocity of light relative to it. The interferometer was designed such that the interference pattern would change as the apparatus was rotated. Due to the lack of change in the interference pattern it was deduced that the speed of light was independant of the velocity of the aether since the null result demonstrated that the light waves have the same values in different frames of reference. In this way hunarahmad seems correct to me. Please correct me if I'm wrong though. I'm only 80% sure of that description.

hunarahmad was quite right with his conclusion, but on the other hand it has little relevance because light does not consists of particles that fly around like bullets.

In what sense do you say that? Light consists of particles that behave in a quantum manner, i.e. in some cases they behave as if they have particle properties (and at other times they have wave properties). I can see why hunarahmad would have a problem understanding the speed of light postulate given his picture of photons as bullets. I myself would have a hard time describing it. Especially when one is speaking of a single photon. However Dr. Willis Lamb wrote a paper called Anti-photon, W.E. Lamb, Appl. Phys, B 60, 77-84 (1995)

Abstract. It should be apparent from the title of this article that the author does not like the use of the term "photon", which dates from 1926. In his view, there is no such thing as a photon. Only a comedy of errors and historical accidents led to its popularity among physicists and optical scientists. I admit that the word is short and convenient. Its use is also habit forming. Similarly, one might find it convenient to speak of the "aether" or "vacuum" to stand for empty space, even if no such thing existed. There are very good substitutes for "photon", (e.g. "radiation" or "light") and for "photonics" (e.g. "optics" or "quantum optics"). Similar objections are possible to use of the word "phonon", which dates from 1932. Objects like electrons, neutrinos of finite rest mass, or helium atoms can, under suitable conditions, be considered to be particles, since their theories then have a viable non-relativistic and non-quantum limits. This paper outlines the main features of the quantum theory of radiation and indicates how they can be used to treat problems in quantum optics.

I believe I can get hold of of a few articles related to this thread. They are

Experimental Evidence for the Second Postulate of Relativity, by J.G. Fox, Am. J. Phys., 30:297, April 1962

Second Postulate of Special Relativity, by W.R. Haseltine, Am. J. Phys., 32:173, Feb. 1964

If anyone would like a copy if/when I get my copy please e-mail me and let me know.

Pete

 

[genneth]

http://relativity.livingreviews.org/Articles/lrr-2005-5/index.html

Perhaps that would be an interesting review for those concerned with these matters.