Since so many people are referring to Mark Barton's answer, I’m going to have to deal with some of the problems in it before moving on.
There is a huge issue of the sociology of scientific knowledge that we have to address to answer this question.
First off, I know him through many conversations in which, any time I dared to question consensus it resulted in his immediate, vicious ad hominem attack and this occurred repeatedly, on quora. Since he represents consensus however, his behavior has never been punished and will never be punished. I however, have been punished for responding in kind. This is only relevant because it’s crucial to understand the impacts of socially dominant viewpoints on the way we learn and pass along information.
So let’s deal with one of his first direct and easily refuted disagreements with history:
…and there’s no new physical effect to cancel it. And it should be highly plausible that there wouldn’t be because it’s beyond obvious that there isn’t a relativity principle for rotation.
So let’s go right to On the Electrodynamics of Moving Bodies. (The special relativity paper end of section 4):
It is at once apparent that this result still holds good if the clock moves from A to B in any polygonal line, and also when the points A and B coincide.
If we assume that the result proved for a polygonal line is also valid for a continuously curved line, we arrive at this result: If one of two synchronous clocks at A is moved in a closed curve with constant velocity until it returns to A, the journey lasting *t* seconds, then by the clock which has remained at rest the travelled clock on its arrival at A will be 1/2 tv^2 / c^2 second slow. Thence we conclude that a balance-clock at the equator must go more slowly, by a very small amount, than a precisely similar clock situated at one of the poles under otherwise identical conditions.
(Emphasis mine)
So why did he get it so blatantly and obviously wrong? Where did his idea come from? He got it from being taught consensus and believing that is the path to truth instead of understanding consensus is polluted by fashion, popularity, and primate games. He is just repeating the most common excuse used, even though the slightest critical examination shows it to be horrifically inane.
Let’s reiterate with an easy example: For instance, if we use a thought experiment, we can demonstrate the problem easily. If some ancient intergalactic space-faring species set up a round-the-galaxy Sagnac experiment in which a ship has both the emitters and the interference point on board, we could board the ship as it passed and look at the experiment and find that it has a non-null result. The line the ship is following is so close to straight from our tiny perspective that it’s not distinguishable from curved. According to all our various Sagnac experiments, however we know that the quote from Einstein above is correct. Even around a circular path there is an effect.
Here’s the kicker: What is detected is always the very classical and aether-based result. (contrary to constancy) We do not get an effect based upon radians per second which would make the thought experiment above as undetectable as the curvature. This would demonstrate a difference between rotation and straight line motion. Instead the readings we always get are straight-forward classical edge speeds. We will get a large difference in arrival times demonstrating a preferred frame.
Unfortunately, this ability to determine the absolute speed of that space-ship I just mentioned, points out that the experiment is unequivocal proof of preferred frame mechanics being true and constancy being false. The Sagnac experiment was created for the purpose of proving that light speed constancy is a faulty concept and it did so. Understanding how little of relativity this changes is the problem most people have. They do not understand that all the effects of relativity can occur within preferred frame mechanics. That’s the theory of Lorentz that Einstein based everything on in the first place. (they want to hang on to the faulty idea of constancy that Einstein later abandoned)
One more word on social mechanics that pollute science. People who use consensus as truth have no personal arrogance. They, in fact, have far too little confidence in their own ability to understand reality alone. They cannot stand boldly against any group they respect. They do however, gain supreme arrogant and angry confidence on behalf of their chosen group. Their self worth becomes tied to the group instead of their personal self doubt they fail to vanquish. This is why humble people will attack you based upon what they think the group believes. This is why people riot when their team loses.
So now let’s contrast Sagnac and Michelson and answer your question:
You’re asking how Special relativity calls into question the validity of the experiment and why it does not with Sagnac. We’re going to have to pick at the language a little to clarify what we’re talking about.
The experiment was for the purpose of detecting the solar system’s motion through the aether with respect to the center of the galaxy. This is a highly presumptuous set of expectations that Michelson had. He was assuming aether had no local currents and that it was centered on the galactic center. This is far too presumptuous, but it’s a starting place.
So the theoretically null result is what invalidated his methodology, not Lorentz’s aether theory or its child, Special Relativity, but what do you mean by special relativity invalidating it? I’m going to, fairly safely, assume you mean that the principle of constancy found in relativity means that no absolute motion can be detected in a light based experiment.
Furthermore, there is this odd insistence by relativity teachers that the principle of constancy somehow doesn’t apply to rotation which is an obviously absurd assertion. Therefore the difference between the two is that one fires a beam in a straight line and the other “follows a polygon such a A and B coincide.”
You are missing the pre-programmed axiom (taught by consensus) that others presume without question:
“Rotation is fundamentally and utterly different from straight line travel” and if we see that the Sagnac experiment gives a completely classical effect, the correlate to this thought is that “the slightest non inertial component perfectly annihilates relativistic effects.”
Now all of them will admit the first statement but will immediately deny the second even though they are very obviously inseparable when we consider the results of all Sagnac experiments. This is not a differentiation that Einstein gave us but is passed along by cultural and oral tradition. (this is why we MUST talk a lot about culture in this answer)
By later in his career, just before general relativity, Einstein actually understood these conflicts but people were already starting to ignore him and the scandle around both his use of his wife’s mathematics and the obvious (nearing plagiaristic) use of David Hilbert’s work in General relativity left some mud on Einstein’s reputation that wasn’t forgotten till around the 1970s.
In 1912 Einstein was publicly “accused” of giving up on the principle of relativity (by Max Abraham) because he was so blatantly disregarding the idea of constancy in his development of general relativity:
"This is, in my opinion, not the limit of validity of the principle of relativity, but is that of the constancy of the velocity of light, and thus of our current theory of relativity." - Albert Einstein, Annalen der Physik 38, 1912
So the problem is that the consensus narrative brought forward is a poor understanding of the capability of the theory and its precursor. It’s a failure to understand the necessity of preferred frame mechanics. It’s a failure to understand a crucial differentiation.
This is something he tried to explain later:
“According to the general theory of relativity space without ether is unthinkable; for in such space there not only would be no propagation of light, but also no possibility of existence for standards of space and time (measuring-rods and clocks), nor therefore any space-time intervals in the physical sense.” - Albert Einstein, 1920, university of Leiden
The principle of relativity and the constancy of light only seem inseparable to those NOT educated in history! (they are separable)
This is the problem you are encountering and the problem I’ve been working for years to solve. The constancy of light is completely faulty and Einstein admitted it. The principle of relativity can exist in a preferred frame environment when you understand the kinematics that Lorentz designed.
Our understanding of the “principle of relativity” can be interpreted that reality itself is relative, or alternatively our perception and current methods of testing of it is. We haven’t yet pierced an illusion we are (or were) quite sure exists. This idea is actually covered analogously by a quote that pertains to a related problem in QM:
“The conception of the objective reality of the elementary particles has thus evaporated not into the cloud of some obscure new reality concept, but into the transparent clarity of a mathematics that represents no longer the behavior of the particle but rather our knowledge of this behavior.” - Werner Heisenberg
Lorentz created an aether theory in which constancy was an illusion created by the very real mechanical effects of time dilation and length contraction caused by motion through the aether. It’s an entirely mechanical theory (counter to consensus relativity) and the confusion left over today in our narrative is because people cannot differentiate between the illusory part and the real part of the theory. (because of ignorance of history) By the time of general relativity, Einstein had backed up to this precursor point of view but he did so quietly, because nobody trumpets their mistakes.
Minkowski, unfortunately, codified constancy as a real effect and therefore gave us the idea of a reality to relative simultaneity which is also a mathematical illusion in relativistic aether. The Minkowski convention deepens the illusion by adding another layer of obfuscation.
By simply using Lorentz’s original conception which also becomes Einstein’s later concept of constancy and relativity, there is never the slightest hint of any of the paradoxes or other problems commonly seen in modern explanations of relativity. Yet there is still time dilation, length contraction and most all the other effects of relativity. The paradoxes come from irrational conceptions modern sources believe they understand but do not. They think they have solved the paradoxes but have not.
They are all generated by a faulty understanding that has become a cultural norm and therefore consensus.
If you’d like to understand the genesis of relativity you can read my older blog posts with diagrams here:
…and if you’d like to track down the history of aether theory and how it extends into modern science, read my pre-print here:
[1804.01846] History of the NeoClassical Interpretation of Quantum and Relativistic Physics
Creation time: Jul 17, 2018 11:23 AM PDT
The Michelson-Morley was non-null. It didn’t miss anything; the people looking at it did.
Let’s quickly address this before people’s heads explode. Null is technically 5% or less of expectation as a standard, and people remember Michelson’s quote of “1/40th” without knowing he (our first American Nobel laureate) went to his grave still believing the aether was detected.
So what about that 1/40th? That comes from his expectation of the aether behaving as a grid-like solid and therefore the wind being perfectly from an east-west direction that changes directions from day to night. These specific ideas are what produce his 1/40th assessment by looking at the experiment from this very particular skew.
If one is agnostic of all these expectations, however, and simply looks at the experiment with the expectation of a dual sine-wave of readings that will indicate a direction with the peaks and troughs representing the full magnitude of the reading, then the reading itself when we compare readings is ~7%.
Comparing readings, however, is asinine since it’s a second order effect and is non-linear. Therefore when we compare speeds of the aether wind we find that the original michelson-morley detected ~8-12 km/sec which is just 1/3rd of the expectation. However, the expectation itself was nonsense.
Dayton Miller went on to replicate the experiment tens of thousands of times in different places at different times with different people and ingenious “double-blinding” procedures and won a prize from the AAAS for successfully proving the aether which directly blocked Einstein’s Nobel consideration for relativity.
Now addressing the “no-preferred frames” issue of Hafele-Keating
Let’s first point out that you are referring to the 1971 flying of atomic clocks in east and west directions that is reported in a variety of unreliable ways. In some cases it is said to be consistent with special relativity and at other times it is said to be consistent with the Sagnac effect. (different depending on east west direction)
It cannot be both!!! (unless we reduce SR to Lorentzian preferred frame relativistic aether)
Furthermore there was an around-the-world-sagnac-experiment in which signals were sent around GPS satellites which confirmed a preferred propagation direction which, of course, falsifies special relativity (without falsifying the mathematics) but since so few people understand constancy who defend relativity, it’s a difficult nut to crack when talking to them.
Around-the-World Relativistic Sagnac Experiment.
The point of misunderstanding failure lies in ignorance of the difference between Lorentzian relativistic aether and special relativity which are mathematically equivalent.
In Lorentz’s metaphysics constancy is an optical illusion and in Einstein’s metaphysics it’s a new aspect of reality’s extra dimension of time. (same math!)
I’ve spoken with hundreds of people who believe themselves to be knowledgable about relativity who do not understand how and why a one-way speed of light test is required to establish the primacy of Einstein’s metaphysics over Lorentz’s. (that there is no experimental reason to prefer Einstein’s interpretation over Lorentz’s)
If they slightly grasp this, then they do not understand how the idea of relative simultaneity is like a religious get-out-of-jail-free card when it comes to the one-way speed of light. Like religions which excuse magical beliefs, the system of belief around relative simultaneity makes all evidence against Einstein and Minkowski metaphysics be another effect of their system of confabulation.
It is not, however, the rational and mechanical aether that is eliminated by Occam’s razor. Any human capable of thought outside the hive can see that since Lorentz’s theory is mathematically equivalent, it is the addition of infinite new 3D realities to every instant of time and time traveling waves that have nothing waving and a disjointed set of realities is the system of absurd beliefs that falls to Occam’s razor.
How mentally unstable do you have to be to believe a simple medium is more complex than that giant ball of magical beliefs?
Not a single solitary paradox we see in relativity ever occurs when we simply use the same math and Lorentz’s metaphysics and wow is my patience on this worn thin…
If I have to talk to one more computer-brained person who talks about the math of relativity and cannot grasp a conversation about the application of math or uses the word “metaphysics” as a pejorative MY head is going to explode!
Creation time: Aug 06, 2018 10:01 AM PDT
There is no experimental basis to prefer the constancy postulate over prior interpretations of the Michelson-Morley.
What people never tell you is that the Lorentz factor -and subsequently the Lorentz transform- created by Hendrik Lorentz, is just a group of equations describing the Michelson Morley experiencing a perspective illusion. To differentiate between Lorentz-Poincare relativistic aether and Einstein-Minkowski spacetime, you need a successful one-way speed of light test, and that has NEVER been accomplished.
So again, you must understand there is no experimental basis to replace the rational mechanical reasoning of Lorentz with Einstein's “after-the-fact” absurd irrational idea of constancy. Same math… Two completely different ways to link the math to reality. It is crucial to remember that the math’s creator was describing something in particular and the math was stripped of the link to what it described.
That’s what math is… a representation of mechanical behaviors. Math doesn’t just exist on its own without reason for application and representative links to reality.
This truth is lost modern on numerologists (“pure mathematicians”) who have somehow gained legitimacy for their potent new brand of mysticism that infected science.
Math is a tool. It does things. We created it to mirror reality’s behaviors but the mirror image is not the actual thing reflected. It’s magical thinking when you start losing track of these abstraction layers, and WOW have we lost track over the past century. That’s why you keep hearing so much about all the magical weirdness of reality instead of hearing about all the factually workable deterministic mechanics that are available as an alternative. There IS a rational view of the math, and the math DOESN’T say one specific thing on its own.
“There is a difference between a shaky or out-of-focus photograph and a snapshot of clouds and fog banks.” -Schroedinger
We CHOOSE to believe in the magical nonsense.
“But why then had Bohm not told me of this ‘pilot wave’?... Why did von Neumann not consider it? More extraordinarily, why did people go on producing “impossibility” proofs, after 1952, and as recently as 1978?... Why is the pilot wave picture ignored in textbooks? Should it not be taught, not as the only way, but as an antidote to the prevailing complacency? To show us that vagueness, subjectivity, and indeterminism, are not forced on us by experimental facts, but by deliberate theoretical choice?” - J. S. Bell. (1987), p. 160.
So, to answer the question more directly, I’ll give a short version of the blog posts I’ll give below that have nice diagrams and simple explanations to compare/contrast the two versions of Lorentz and Einstein.
If the earth is travelling through the aether, then light should - theoretically - have to travel in a medium that we are moving through. We know we are moving, via a few different observations, so if we are moving through some fluid then the waves in that fluid should have to “swim upstream” when they go into the wind and get sped up by a tailwind in the other direction.
Now, we know this is partially based on perspective like the “wind” you experience in your car window on a perfectly calm day, but the basic principle still holds since all mechanical waves are just behaviors of a medium that have to do with its properties of elasticity, rigidity, etc. So a wave usually travels the same speed in all directions according to the stationary frame of its medium.
The Michelson Morley makes light race itself back and forth “crossways” to the wind as well as up and down the wind. Obviously the path you have to travel swimming up and back in a river is diferent from the one you have to travel across and back, right?
So this should apply to light and we should be able to use math to determine how fast we are going since the two paths for light should be different if there is a wind.
Michelson detected so little wind that everyone decided it was perfectly zero and that is the narrative passed down to us. It wasn’t factually zero, but detected roughly 1/3 of the expected speed. Nobody other than Dayton Miller actually faithfully replicated these white light experiments and he got the same 8–12km/sec readings as was found in the Michelson experiment. This was along with the same expected way that the data should behave in a specific pattern and did so in all these experiments.(understanding the importance of some of these details require intimate understanding of interferometry)
So, in summary, if we assume our planet is definitively moving, and the Michelson detected perfectly zero wind, and we decide the medium isn’t dragged along with our planet, subject to currents, and then we assume that an aether wouldn’t have shortening effect on matter like described by Lorentz….
Then we have to assume light is a wave (a behavior of a medium) that has no medium and shortcuts through reality in a way that makes it infinite from it’s own frame but perfectly one particular arbitrary speed in every other and therefore the universe is made up of infinite versions of 3D reality in every 4D moment of time and things exist between these realities as shortened versions of themselves and a whole host of other twisted logic, paradoxes etc.
When we could just accept an aether plays a simple perspective trick on us… AND PRESERVE THE EXACT SAME MATH. Have zero paradoxes, additional useful information, mechanical explanations for seemingly magical effects etc, etc, etc.
[Can you tell I’m a little annoyed with having to repeat this same obvious story for the ten billionth time in the past decade? But, oh, no, I’m just a crackpot for believing the rational deterministic picture that can be painted with the exact same math. *rolling eyes so hard they get stuck*]
Don’t buy into the pretty picture of a mystical reality and the nice feels you get for thinking magically. Don’t listen to ancient numerologists or the new ones putting together absurd patterns with their schizophrenic methods.
The mystical, magical BS we are begin fed is a CHOICE. And it starts with constancy, something Einstein himself abandoned within a few years after special relativity!
"This is, in my opinion, not the limit of validity of the principle of relativity, but is that of the constancy of the velocity of light, and thus of our current theory of relativity." - Einstein "Relativität und Gravitation. Erwiderung auf eine Bemerkung von M. Abraham", Annalen der Physik 38, 1912
If you’d like a little more in-depth understanding of how Lorentz came up with the riddle that accidentally destroyed science and ended the age of reason, please read more below:
The laymen’s terms simple explanation: Relativity Demystified
A peer reviewed paper on the history and future of aether theory: History of the NeoClassical Interpretation of Quantum and Relativistic Physics
Creation time: Nov 02, 2018 08:23 AM PDT
Yes. He won a prestigious prize from the AAAS who thoroughly examined nearly 20 years of many different types and sets of data. The Newcomb Cleveland prize was for the discovery of the aether wind specifically and directly blocked Einstein’s consideration for a relativity Nobel.
Only Michelson and Miller used white light interferometry which avoids a host of issues with the experiment caused by monochromatic light.
Such as one effect called “lock in” that would fully annihilate the data. Therefore there have been no replications other than Michelson and Miller.
Then when directed to Dayton Miller - Wikipedia, the one “refutation” (Roberts) is not from a peer reviewed journal but is a self-publish which should not be allowed but because of cyber-squatting, it has not been allowed to be removed even though it is directly against guidelines.
Shankland was living in Miller’s shadow as his successor to the chair position at Case and used his criticism of Miller’s work to ingratiate himself with Einstein and that relationship was rewarded as the only real fame he achieved… via being in my opinion, just a sycophant.
His arguments about temperature were directly dealt with and falsified by Miller’s experiments.
Needless to say, however, the stakes seem high and Shankland’s lifeline was gulped up by all those who wanted to see the theory move forward. Thus Shankland’s fame was ensured via providing an entire community with an excuse for their confirmation bias.
"My opinion about Miller's experiments is the following. ... Should the positive result be confirmed, then the special theory of relativity and with it the general theory of relativity, in its current form, would be invalid. Experimentum summus judex. Only the equivalence of inertia and gravitation would remain, however, they would have to lead to a significantly different theory." — Albert Einstein, in a letter to Edwin E. Slosson, July 1925
"I believe that I have really found the relationship between gravitation and electricity, assuming that the Miller experiments are based on a fundamental error. Otherwise, the whole relativity theory collapses like a house of cards." — Albert Einstein, in a letter to Robert Millikan, June 1921 (in Clark 1971, p.328)
More on this here: Shiva Meucci's answer to Why didn't Albert Einstein win a Nobel Prize for his work on Special/General Relativity? Was he at least nominated for the Nobel for this?
Roberts’s analysis (the self publish) however, relies upon the fact that most people do not understand Fourier analysis at its core or how it can be used improperly.
He took a small subset and then treated it like wave data.
A fourier analysis presumes the mechanical interaction of waves known as interference. It attempts to “undo” the combination of multiple unknown waves.
A simplification is necessary here: If the combined “signal” is at zero at one point but then at other locations there appears to be regular highs and lows that create the pattern of a wave such that the zero’d location appears to be a missing peak or trough, the method assumes there is another peak or trough of equal and opposite sign or phase. Truthfully it may not be a single other wave upon final examination but multiple other waves of various frequencies converging at that point to cause the cancellation.
Regardless, the point is to understand that there is a mechanical interaction between waves that the algorithm is attempting to figure out and reverse engineer. Peaks add, troughs subtract, and various frequencies put together have weird combinations of this effect.
The data being examined, however, is not wave data. There is no consistent back and forth between peak and trough in the data and no mechanism to cause interference.
The data is, however, wave-like. (hold on for discussion on Fourier analysis)
The data is reading points around a circle with some error in the estimation and some specific unidirectional walk in the data… IE you’re estimating readings from a clock and the hands are actually going too fast or too slow. (The walk, and bear with a weak analogy at that point)
Said another way, imagine you were told to read from a watch-like dial that was so scratched you could barely see where the needle was and you needed to give a very precise reading estimate over and over and over for a specific timing to see if the watch was drifting around randomly or actually had some sort of timing.
Instead of going all the way to twelve, however, it counts backwards after 6.
The only real way to know if the clock is right with a fairly small sample size is to increase the number of samples by doing thousands of estimation cycles to get a mean error level.
The data you are producing, if plotted and the watch is actually at least cycling, looks like a wave but it is not a wave.
Lining up all the thousands of readings you’ve taken on the perfect watch’s timing will give you a good average of the data that will at least establish if the cycling is real or not.
The data you produce however, will have random error spikes upward and downward for the truth because of the estimation process.
If the data is treated as actual waves, then the errors may be treated as wave components especially at only 12 “samples” per cycle. (samples here is a keyword related to wave analysis unlike the uses found elsewhere in this article which are more general)
This “false” wave recognition caused by the error will amplified the more the real signal is close to the size of the error. (IE the clock goes from 0 to .06 and back and you might accidentally give an estimation +/- .02)
Therefore the errors themselves will look like waves adding to and subtracting from the data but it’s purely random, not a wave continuing beyond a single “sample” point as might be assumed by the Fourier analysis. Multiple errors will randomly line up to look like waves however.
This will remove some signal because it looks boosted by the noise. Any “noise removed from the data will not simply be removed from the “top and bottom” but from the “center” as well because of the presumed effect of the waves present.
This is what Roberts did.
On the other hand, if one simply averages all the readings along a cycle of timing from outside the system (the other clock) and there are lots and lots of samples, then a completely random set of data (if the blurry clock is random) will just average out to basically nothing with small variations that give no discernible pattern.
This is how Miller treated the data and (somewhat) how Michelson treated it. (with possibly a tiny method error mentioned below)
One final point about the “cycle” of data.
Any data which is not a random plot and instead shows a dual cycle of readings is 100% positive for an aether wind and only a random plot give the 100% negative for the existence of an aether wind. It’s a binary decision of the existence or non-existence of the aether.
The original Michelson experiment with only a few days reading, when combined showed a clear dual sine wave of readings exactly as required of a wind, not a random plot.
The tens of thousands of experiments by Dayton Miller performed in different circumstances by different experimenters (some of which were blind to certain events of the experiment to avoid expectation bias) at different elevations and different locations with different devices made of different materials…
All gave the same result as the original Michelson… a dual wave of readings per rotation with a reading equating to approximately 8–12km/sec.
“Wait a second! Michelson said 1/40th, I can google that anywhere!!!”
And he expected the wind from a specific direction instead of from the northwest where it showed in his data. Also, because it is a second order effect, there is a non-linear relationship between the reading on the device and the actual speed of the wind. Finally he expected it to change from day to night (be exactly east/west) and may have combined the data one half turn in opposition depending on time of day. Miller certainly made this mistake of expectation once later and had to retract it.
This second order effect size, however, is why Miller’s tens of thousands of replications were so important. To show that such a small reading was not happenstance of a small sample size but could be seen over massive sets of data as well.
The important part here however is not the speed found, or the direction, it is the consistency of the data in showing a pattern that indicates a consistent unidirectional wind.
Miller consistently found that pattern with the max and min pointing in a particular direction on the earth that changed slightly but only perfectly in time with the seasons. Incidentally that change was also a slight magnitude change that correlated with the apsis points of earths orbit.
Yes, the readings were not just consistent, they matched variations in astronomical observations including even the sidereal day and according to one Nobel laureate data analysis expert, Maurice Allais also found indications that the data indicated not just what I’ve listed but possibly other astronomical phenomena such as a black hole in a particular direction.
Final summary:
All the perfect matching with astronomical data and consistency makes the aether wind irrefutable not just because of the speed or direction, but the type of result which is specifically a binary question.
“Is there a wind yes or no?”, is determined by ANY non null reading, which equates to any consistent directional wind that shows a double cycle of readings. Especially if it consistently points he same direction, (though it’s not required)
Below is a comparison between Michelson’s (not Miler’s which is far better) original data plotted against what one would expect of an aether wind:
Final Implications:
This does not invalidate the core concepts of relativity that include time dilation, length contraction and the illusion of light speed constancy in two-way experiments. (but not in one-way)
Lorentz created that math not just in the presence of a theoretical relativistic aether, but specifically to describe that aether’s impact on experiments.
…and it is unaltered mathematically in special relativity, though the implications massively change downstream. This is the one thing almost no modern scientist understands and very few older scientists did.
“Einstein starts from the hypothesis that the laws will look the same to all observers in uniform motion. This permits a very concise and elegant formulation of the theory, as often happens when one big assumption can be made to cover several less big ones... But in my opinion there is also something to be said for taking students along the road made by FitzGerald, Larmor, Lorentz and Poincaré. The longer road sometimes gives more familiarity with the country. “— J. Bell
We didn’t follow Bell’s advice and now history is lost along with the understanding of our most crucial theories.
History of the NeoClassical Interpretation of Quantum and Relativistic Physics
====
Edit Jan, 2021: It seems I originally omitted one fact that is crucial but mildly confusing to the overall picture. It is crucial to understand that Lorentz’s relativistic version of aether upon which Einstein’s relativity is based, also expects a perfectly null experimental outcome, if carried out in a vacuum.
However, these experiments by Miller and Michelson were carried out in a gaseous medium. (air) At the time of FitzGerald’s involvement, who inspired Lorentz’s work, Fitzgerald was aware of a partial aether drag effect that Fresnel predicted and the Fizeau experiment verified exactly in the amount Fresnel predicted. Therefore, a very small positive effect would be expected in gaseous medium by Fitzgerald but not necessarily others. It is possible that only FitzGerald would have known about and expected the very small positive effect those experiments did detect since he is the direct connection to the older understanding of aether that was granted by MacCullagh and was actively being explored by Kelvin at the time.
The simplification of expecting purely null is true and valid for experiments in a vacuum. Even in an aether environment, an experiment in which there is no gas or liquid to create a partial aether drag, the experimental results should be null.
So there is a combination of small effects, simplifications, and serendipity involved here that makes the entire story of experimental history more complex. The end result, however, is the important fact that gas is also needed for a small non-null detection like occurred with Michelson and Miller. …and though too dense of a medium can also nullify the result, I’ll skip further digression.
Creation time: Mar 13, 2019 12:27 AM PDT
Unfortunately hardly anyone knows their history in physics…
The question is “which aether?”
-
Aether that is some weird gridlike solid or gel with no flow? Yes
-
Aether that is like a fluid that flows all over the place like the ocean? Maybe. Never really tested in orbit so massively entrained bubble contained by the earth’s magnetic field for instance, would be a problem.
-
Relativistic aether that Lorentz created the Lorentz factor to describe? Yes and No.
The relativistic aether that is described by the Lorentz transformation would detect no wind whatsoever in a vacuum… ever.
However, if the light had to travel through a medium like air then the index of refraction would determine an amount by which the light was dragged along and a very small effect would occur in Lorentz’s relativistic aether.
Therefore the Michelson Morley and Miller’s subsequent open air experiments are crucial one-way light speed test that… guess what… WERE NOT NULL!
They detected a speed that was one-third the expectation (~8–12 km/sec) in a pattern of readings expected (not a random walk or plot) but it’s a second order effect so the speed is not linearly related to the effect on the device.
Those tens of thousands of successful experiments for which Dayton Miller received an award from the AAAS for discovering the aether wind, represent the divider between Lorentz-Poincare relativity (Lorentz Kinematics combined with Poincare electromagnetism) and Einstein’s relativity. The theories are NOT “indistinguishable” as is widely reported. That is reported by people who do not understand the faintest thing about aether or its firm place in history as the causal system that underlies all modern physics.
“Space without aether is unthinkable” - Einstein, 1920
Einstein knew relativistic aether was a necessity for any of modern physics to work but the pressure of Minkowski’s untimely death and Minkowski’s students and friends (such as Hilbert) social pressure for Einstein’s negative comments, “Since the mathematicians have invaded the theory of relativity I do not understand it myself any more.” led to him continuing to support Minkowski’s spacetime that codifies constancy which Einstien repeatedly said was wrong. (it left him genuinely conflicted and it shows)
Volume 4: The Swiss Years: Writings 1912-1914 (English translation supplement): “On the other hand I am of the view that the principle of the constancy of the velocity of light can be maintained only insofar as one restricts oneself to spatio-temporal regions of constant gravitational potential”.
Volume 4: The Swiss Years: Writings 1912-1914 (English translation supplement): “I arrived at the result that the velocity of light is not to be regarded as independent of the gravitational potential. Thus the principle of the constancy of the velocity of light is incompatible with the equivalence hypothesis”.
Volume 4: The Swiss Years: Writings 1912-1914 (English translation supplement): “the writer of these lines is of the opinion that the theory of relativity is still in need of generalization, in the sense that the principle of the constancy of the velocity of light is to be abandoned”.
Volume 6: The Berlin Years: Writings, 1914-1917 (English translation supplement): “In the second place our result shows that, according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity and to which we have already frequently referred, cannot claim any unlimited validity”.
Volume 7: The Berlin Years: Writings, 1918-1921 (English translation supplement): “Second, this consequence shows that the law of the constancy of the speed of light no longer holds, according to the general theory of relativity, in spaces that have gravitational fields. As a simple geometric consideration shows, the curvature of light rays occurs only in spaces where the speed of light is spatially variable”.
History of the NeoClassical Interpretation of Quantum and Relativistic Physics
So Einstein agrees there’s an aether. The one principle that was against aether is false according to him.
Finally there’s tens of thousands of experiments done by one famous scientist, Miller that prove over gargantuan averages that an effect shows a specific direction and variation according to celestial phenomena across different devices in different places with different experimenters. (it’s utterly and completely irrefutable)
The only “refutation” was falsified directly by Miller and was posed by his successor trying to get out from under Miller’s shadow by cuddling up with Einstein. It worked. Shankland’s name is only remembered for his association with Einstein and for making claims against Miller.
Be aware that the “Roberts” analysis on the Miller wikipedia page is a self-publish that’s been taken down once for being against the rules but it being cybersquatted. Roberts’ analysis is completely biased trash and gross misapplication of Fourier analysis.
“Yet NEVER has Miller’s and Michelson’s positive results been duplicated” I hear minds religiously supportive of orthodoxy chanting to themselves for comfort.
This is because not only have those experiments been duplicated in a medium to allow for aether drag, but they use monochomatic (or worse laser light) to perform the experiment. Michelson and Miller went through 2–3 hours of setup time with sodium light, just to eliminate the problems of monochromatic light.
Specifically there’s something called “lock-in” known in sagnac devices where any phase difference below 1/2 a wavelength is utterly annihilated instantly and at all times. This is why the used white light and went through all those setup hours instead of just using the sodium light for the experiment.
Michelson’s results detected a wind, he just didn’t expect the right direction. He expected the effect of aether type 1 above and that screwed up what he reported about the data but the data is still available and it shows the characteristic double sine wave of readings one would expect of an aether wind and it’s of a magnitude of ~8 km/sec for anyone who actually does the doggone math themselves! (I have)
Bonus points on experimenter error!!
There’s this thing with “sound lasers” that transmit ultrasonic sound. They actually alter the medium in a way that causes a phase transition and Kerr-like in the medium itself.
Self-phase modulation - Wikipedia
Sound from ultrasound - Wikipedia
Obviously a laser would do the same thing to aether…
Unfortunately since lock-in is part of the problems to overcome in weapons guidance systems, most of the internet has been scrubbed of this information post 911.
Just as unfortunately, the information about the kerr effect in sound projection devices has also become harder to find because that technology is now being weaponized as part of crowd control.
Whenever you get closer to the real truth in physics every little part of it has been classified without any intention to hide the larger picture. Just a consequence of real physics advancements is that they are applicable to weapons. Ergo secrecy and bureaucracy accidentally hides the truth.
No conspiracy needed. Just compartmentalization. Just emergence.
You say: “What does this mean for physics if what you’re saying is right?”
Not nearly as much as some think and way more than others think.
Most relativistic considerations are still correct. Most calculations remain completely unchanged. Constancy is just an illusion caused by particular physical mechanisms of length contraction and time dilation which occur when a physical object moves through aether.
There are no apparent paradoxes however, because time contraction and length dilation are also present in equal amounts with the normal expectation. There’s no relative simultaneity because that’s part of the constancy illusion.
There’s no factual extant 4th dimension, there’s only the use of the 4th dimension as a handy notation method of measuring differences in changes that are mediated by electromagnetic forces. Time is a perception of change not a physical dimension.
Furthermore the pilot wave theory makes more sense in this context.
Basically new explorations are available for fundamental revolution within the constraints of known experimental knowledge… just like we all know we need.
Creation time: Apr 24, 2019 03:03 AM PDT
Michelson never accepted the “no aether” interpretation of relativity popular today. (which descends from interpretations of Minkowski’s joining of conjoining space and time into space-time)
There’s a wide difference between saying that there is no necessity to assume an aether and directly stating there certainly is not an aether! (Einstein did subscribe to the former and not to the latter.)
Michelson, the first American Nobel Laureate, continued to conduct various attempts to detect preferred frame physics (the aether) for the remainder of his life, and some of his subsequent attempts were believed to have done so by various people. However, what is little remembered is that Einstein still believed there was some sort of aether, lecturing on he necessity in 1920 (15 years after Special Relativity)
I have not yet run across indications that Michelson specifically supported the Lorentz-Poincare relativistic aether, but as late as 1925 he published positive results of the Michelson-Gale experiment in which he stated this:
“The expression for the difference in path between two interfering pencils, one of which travels in a clockwise, and the other in a counterclockwise direction, may be deduced on the hypothesis of a fixed ether as follows:” - A A Michelson, THE EFFECT OF THE EARTH’S ROTATION ON THE VELOCITY OF LIGHT
It was Morley’s colleague Dayton Miller, who then repeated the Michelson experiments tens of thousands of times and was awarded the Newcomb-Cleveland prize from the AAAS for unequivocally proving the existence of the aether.
"My opinion about Miller's experiments is the following. ... Should the positive result be confirmed, then the special theory of relativity and with it the general theory of relativity, in its current form, would be invalid. Experimentum summus judex. Only the equivalence of inertia and gravitation would remain, however, they would have to lead to a significantly different theory." — Albert Einstein, in a letter to Edwin E. Slosson, July 1925
(if you investigate Miller’s work, please be aware his successor in an academic position befriended Einstein and attempted to get out from under Miller’s shadow by declaring his work defunct, whereas Miller was the only experimentalist to actually follow Michelson's methods of using white light which is now known to be absolutely crucial to any experiment of this kind)
Though I cannot say for certain, because I have not yet personally looked into the writings of Morley, I believe it is safe to assume he too believed the aether long after relativity was made so fashionable in the press.
The idea that there is no scientific controversy over whether or not there is an aether is an artifact of the “telephone-game” problem in the teaching of history. Repeated simplifications have subsequently lost all subtlety in the teaching of the history of theoretical physics and the consensus is only occurring via ignorance of historical scientific data.
It cannot be stressed enough, that just like there are equivalent opinions (not differentiated by experiment) about quantum mechanics which are called alternative interpretations, the Lorentz-Poincare aether interpretation of special relativity is an equivalent interpretation that is not currently differentiated via experiment!
Creation time: Nov 09, 2019 08:42 PM PST
Tens of thousands of replications of the Michelson-Morley experiment were performed by a colleague of theirs: Dayton Miller. (under various conditions, with various devices, at different times, by different assistants with blinding procedures in place)
All of them collectively matched the Michelson. They were NOT NULL just like the original 1887 Michelson WAS NOT NULL and they all showed the characteristic double sine wave of readings that is precisely what would only be expected if there was an aether wind. (experiment error would be random)
He won a prestigious prize from the AAAS in 1925 for unequivocally proving the aether wind. Bet you’ve never heard about that…
Below is the actual plot of the data from the original 1887 Michelson-Morley superimposed over the expectation of what the readings would look like if there was an aether wind.
The data produced by Miller however, was always showing this same pattern with such improved accuracy (over the only-three-days-worth of readings above by Michelson) that the changes from the earth’s perihelion (proximity of earth to sun) and even sidereal day were exposed in the voluminous data as mild shaping of the pattern along with changes to the wind direction it indicated. (position of peaks wrt cardinal directions) He even had to make a special brass interferometer to avoid arguments that the earth’s magnetic field was the cause of the effect.
The only argument against his work for most of the 20th century was presented by his successor to a prestigious academic position. (dumping on your predecessor is a time-honored tradition in rising through the ranks of basically anything) That argument was the claim that it was a temperature effect, so, of course, Miller set up heaters and showed how it’s a categorically different sort of alteration to the data for an interferometer.
[I’ll leave explanation of the self-published (against wiki rules) “Fourier analysis” Roberts paper being cyber-squatted on the Miller wikipedia page for a different article]
The issue is that most people don’t understand the barest mechanics of interferometers - no less their optical physics and real-world set-up necessities - nearly well enough to understand the situation of the experiments. They cannot grasp how incontrovertible the evidence is because the “gap between lecture and lab” is too great and modern technology abstracts the process way too much behind computers and automated assumptions.
Add to this a couple strange variables…
The misunderstandings leading to the reporting around these events are manifold and complex:
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People think other experiments (besides Dayton Miller’s) replicated the original Michelson, but they didn’t!
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Lorentz contraction (and all the other components of the transform we still use) came directly from aether theory and describe a null Michelson in an aether environment. Lorentz’s aether effects are real and present above. (so you should be wondering why it’s not null …and asking if I’m contradicting myself)
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Partial aether drag, as proposed by Fresnel and proven by Fizeau, is the real situation for aether’s interaction with matter in motion.
Let’s start with the fact that NO EXPERIMENT other than Miller’s experiments actually replicated the 1887 Michelson:
The original Michelson experiment used white light in open air (gaseous medium) and took many hours to set up each time because the procedure required for the experiment to first use a sodium lamp to find the central (double) fringe that indicates that the distance between the mirrors for both directions is precisely the same.
Monochromatic light (like a laser) allows the path lengths to be unequal and still show a fringe pattern while white light does not. This use of monochromatic light in other pseudo-replications allows for at least two or three effects that eliminating the small phase differences that make the experiment actually work!
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When a monochromatic light like a laser is allowed to pass back in forth in a situation like an interferometer, there’s a phenomena called “lock in” that obliterates phase changes less than significant portion of the wavelength. (RLGs and iFOGs have to use multi-frequency light or “dithering”)
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Furthermore when different parts of the beam get superimposed because of unequal path lengths, some averaging of effects can occur to eliminate phase differences.
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Elimination of a gaseous medium (pulling a vacuum) that the light passes through does not allow for “aether drag” to occur, therefore Lorentz contraction (a purely aether-mechanics effect) eliminates any “signal” perfectly. (thus giving perfect null on pseudo-replications)
So now let’s recap and explain:
Lorentz modeled an illusion that the aether creates as it changes light and matter. It gives an illusion of “light speed constancy” but it is only an illusion in aether theory he describes mathematically via the Lorentz transform unlike Minkowski spacetime INTERPRETATION associated with relativity.
The Lorentz transform is a mathematical description of how aether in motion affects light and objects. …ignoring effects like aether drag described by Fresnel.
Fresnel gave us the coefficient of aether drag which is now basically the velocity addition formula in relativity.
These two effects together (“drag” and contraction) are the only rational explanation for vast, intricate, reliable and predictive non-null dataset Miller left us in the context of all other experimental data available, but it does require that we believe Lorentz-Poincare aether over Minkowski spacetime.
Note:
This is somewhat compatible with the ideas of localized areas of aether mentioned in the paper above. However in modern aether theory (Neoclassical interpretation) we have to suppose that matter is more of an effect with the aether being more of the cause, but I’m simply explaining something furrther down the line: why drag works in an opposite fashion than expected when considering galaxy rotation rates. It is a complex part of the larger emerging modern aether picture.
All holes are closed and mathematically equivalent except one difference:
When we find that the the Michelson experiment and the Miller replications are small but non-null, this constitutes the crucial one-way speed of light tests that require us to favor relativistic aether over spacetime when considering the two mathematically equal alternatives.
This explanation requires that we accept that light speed constancy is not real but basically a sort of optical illusion and therefore conjoining space and time into spacetime (as per Minkowski convention) is completely baseless and leads to some improper expectations.
As a bonus all the appearances of paradoxes in relativity are instantly solved by the conventionally ignored inversion calculation of reality: Time contraction and length dilation, thus granting additional available information.
Nothing about relativity is nonsensical, counter-intuitive, or even apparently paradoxical if you simply downgrade light speed constancy from being an aspect of reality to being an optical illusion.
Even light’s waving behavior makes mechanical sense again.
Finally the last piece of the puzzle:
Modern Preference of Minkowksi spacetime over the mathematically equivalent Lorentz-Poincare aether is NOT EMPIRICAL SCIENCE.
The only experiment that can differentiate the two theories is a One-way speed of light experiment which is widely held to have never been done. It is WIDELY ACCEPTED that the preference we have today is utterly and only based on some hand-waving nonsense about occam’s razor and not empiricism.
That nonsense is the claim that the infinite additional copies of the universe which is granted by conjoining space with time and the reification of time itself into something pseudophysical, is somehow more “simple” than aether. It’s shameful mental gymnastics.
That feat of mental acrobatics is only matched by their insistence that you should believe the full metaphysics and thereby ignore the evidence of one-way experiments that contradict it. Let me explain that last sentence. The reason why no one-way speed of light experiment is accepted is because, if you believe in relative simultaneity, (Minkowski Metaphysics) then any one-way experiment’s apparently falsifying data must be ignored as a clock synchrony error. (infinite “relative” possible copies/versions of the universe are necessary when explaining relative simultaneity) Since clocks can never be synchronized except by relative means and there is no singular clock synchronization that is universal, then there will be times that your results of experiments will appear to show light’s one-way speed to be anisotropic. Ergo if you first believe everything is relative (no aether) and there are no preferred frames of any kind, then Minkowski’s interpretation of relativity cannot be falsified. (Via ruling out the only data that can falsify it.)
Keep your eye on the ball here: One More Time
If you believe their metaphysics are true, (relative simultaneity) then according to their metaphysics, data which proves their metaphysics false, must be ignored.
It just so happens that the Miller data, produced because of aether drag, constitutes a one-way speed of light experiment… It was not the last set of falsifying data to be ignored!
Finally, the point of one-way experiments is to prove that light speed is anisotropic and that there is preferred frame to the universe, thus invalidating the reality of constancy and the Minkowksi spacetime interpretation of it. THIS IS ACCEPTED carte blanche by GENERAL RELATIVITY.
Please think about that level of mental contortionism for a moment. Please just stop and appreciate it for a good ten seconds.
So, final recap:
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Lorentz-Poincare aether is mathematically equivalent to relativity with only one experiment that can differentiate them. It’s been done repeatedly but denied.
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The interpretation of the meaning of the math is different between the interpretations, however, in on specific way: that constancy is considered an illusion instead of the truth in a relativistic aether theory and the universe therefore has a preferred frame.
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Our current beliefs are fashionable metaphysics, and the empirical science which unequivocally dictates to prefer relativistic aether is being ignored in favor of long-standing fashionable metaphysics.
Would you like to know how we got to this crazy place? Then read this history paper: History of the NeoClassical Interpretation of Quantum and Relativistic Physics (PDF)
"My opinion about Miller's experiments is the following. ... Should the positive result be confirmed, then the special theory of relativity and with it the general theory of relativity, in its current form, would be invalid. Experimentum summus judex. Only the equivalence of inertia and gravitation would remain, however, they would have to lead to a significantly different theory." — Albert Einstein, in a letter to Edwin E. Slosson, July 1925
Would you like to understand more about the difference between Lorentz’s relativistic aether interpretation and the Minkowski interpretation of relativity we have today?
Then read through this simple and easy explanation in three blog posts:
|| BONUS CONTENT ||
For those who want to understand a little more about the weird pressures between scientists of the time that led to this debacle and how the issue of constancy in SR versus its elimination in GR never made it to the future fully formed, I highly recommend this excerpt from Historian Galina Weinstein’s excellent work:
https://arxiv.org/ftp/arxiv/pape...
Abraham started his attack by saying, "Already a year ago, A. Einstein has given up the essential postulate of the constancy of the speed of light by accepting the effect of the gravitational potential on the speed of light, in his earlier theory;[36] in a recently published work (February 1912)[37] the requirement of the invariance of the equations of motion under Lorentz's transformations also falls, and this gives the death blow to the theory of relativity. Those who repeatedly went after the sirens songs of this theory should be warned that they might be pleased to note that even its author himself is now convinced by its inconsistency".[38]
Abraham's final criticism was of Einstein's March 20 paper.[39] Abraham did not like Einstein's way of arriving at his results, even after the March correction. He did not like Einstein's use of the "Equivalence Hypothesis", and the correspondence between reference systems. It appeared to Abraham as a fluctuating basis, because Einstein did not yet adopt the Space-Time formalism of relativity (that is, he did not formulate his theory on the basis of Minkowski's space-time formalism). [40]
On July 4, 1912, Einstein replied to Abraham and explained to him that the theory of relativity is correct to the extent to which its two underlying principles are accepted.[41] "As it stands now", asks Einstein in his reply to Abraham, "what is the limit of the two principles" of the theory of relativity? Einstein thinks that the principle of the constancy of the velocity of light can be maintained only insofar as one restricts oneself to spatio-temporal regions of constant gravitational potential. "This is, in my opinion, not the limit of validity of the principle of relativity, but is that of the constancy of the velocity of light, and thus of our current theory of relativity".[42]
Einstein explained to Abraham, "This situation, in my opinion, by no means implies the failure of the principle of relativity, just as the discovery and correct interpretation of Brownian motion did not lead to the consideration of Thermodynamics and Hydrodynamics as heresies". The present theory of relativity would always retain its significance as the simplest theory for the important limiting case of spatio-temporal events in a constant gravitational potential.[43]
1 Einstein, Albert, "Uber den Einfluβ der Schwerkraft auf die Ausbreitung des Lichtes", Annalen der Physik 35, 1911, pp. 898-908; The Collected Papers of Albert Einstein. Vol. 3: The Swiss Years: Writings, 1909–1911 (CPAE 3), Klein, Martin J., Kox, A.J., Renn, Jürgen, and Schulmann, Robert (eds.), Princeton: Princeton University Press, 1993, Doc 23), p. 906.
2 Einstein, Albert (1912b), "Lichtgeschwindigkeit und Statik des Gravitationsfeldes", Annalen der Physik 38, 1912, pp. 355-369 (The Collected Papers of Albert Einstein Vol. 4: The Swiss Years: Writings, 1912–1914 (CPAE 4), Klein, Martin J., Kox, A.J., Renn, Jürgen, and Schulmann, Robert (eds.), Princeton: Princeton University Press, 1995, Doc. 3), p. 360.
4 Abraham, Max (1912a) "Zur Theorie der Gravitation", Physikalische Zeitschrift 13, 1912, pp. 1-4, "Berichtigung", p. 176; English translation, "On the New theory of Gravitation" and "Correction", in Renn (ed), 2007, pp. 331-339.
24 Einstein, Albert (1912c), "Zur Theorie des statischen Gravitationsfeldes", Annalen der Physik 38, 1912, pp. 443-458 (CPAE, Vol 4, Doc. 4).
36 Einstein, 1911.
37 Einstein, 1912b.
38 Abraham, 1912b, p. 1056.
39 Einstein, 1912c, p. 456.
40 Abraham, 1912b, p. 1058.
41 Einstein, Albert (1912e), "Relativität und Gravitation. Erwiderung auf eine Bemerkung von M. Abraham", Annalen der Physik 38, 1912, pp. 1059-1064 (CPAE, Vol. 4, Doc 8), pp. 1061-1062.
42 Einstein, 1912e, p. 1062.
43 Einstein, 1912e, p. 1063.
Creation time: Feb 14, 2020 07:36 AM PST
Wow, I’m pretty blown away that all the other answers are wrong.
The answer is complicated, so first let’s correct the assumptions of your question and put them in context.
First, it should be understood that in highly coherent monochromatic light, (single frequency) one can split a beam and then upon recombining them, aligning the same original peak or trough with its original partner isn’t necessary to create an interference pattern. They can be drastically misaligned and therefore it’s possible to get an interference pattern in a monochromatic light based interferometer experiment even when the distance between the arms is drastically different. No particular alignment is needed in highly coherent monochromatic light to create an interference or “fringe” pattern since it will simply alternate between the fringes of the Moiré pattern produced. This situation however, is highly undesirable for this experiment for complex reasons I will not attempt to explain in detail here. Suffice it to say it pollutes the results of the intended experiment and Michelson made sure to avoid that situation with a great deal of extra work.
Furthermore, beyond the ability for the lengths of the sides of the interferometer to be unequal, there is a little known effect (outside optics engineering) in monochromatic light called “lock-in” which causes any minor shifting of fringes to be ablated or nullified. Eliminating this effect in lasers is a required aspect of modern laser gyroscope designs where they must introduce multiple frequencies or noise to the signal to overcome the effect. (the reason why Michelson used white light when monochromatic light was easier to use)
So, starting all the way back with Michelson, he knew to avoid monochromatic light as an invalid way of performing this experiment. (incidentally, all classroom versions and replications of the Michelson-Morley experiment other than by Dayton Miller ignore these problems, use monochromatic light, and are therefore utterly invalid experiments)
So with pure monochromatic light, one can have a functionally unlimited amount of Fringe shifting caused by the shift of the phases between the beams and radically different path lengths on the interferometer without any problems in the fringe pattern. It will look apparently perfect, while hiding deep design issues.
Therefore Michelson used white light! So, what ingenious method did he use for perfect alignment?
So, with white light, you are almost correct in thinking that too much of a shift becomes a serious problem, but not as quickly as you thought. After a few wavelengths of yellow light, the different frequencies begin to spread away from one another. Notice the difference demonstrated below.
The slow spreading you see is what happens in the alignment of different frequencies. You can find more visualizations of that spreading process of multiple frequencies in Shiva Meucci's answer to Could a hologram from the holographic principle bend spacetime?
So what Michelson did is he used sodium light for alignment. It has a characteristic double fringe pattern (also known as sodium “d lines”) it creates in these experiments that is easier to find by eye when adjusting the interferometer. The process could sometimes take hours to complete even after Dayton Miller refined the process in later years.
Here is an example of the sodium double fringe:
And you can find more info on experiments using the periodic wash out of the double fringes to their advantage here: Experiment of The Month
We can find this process of alignment detailed in the original Michelson 1887 publication. Just remember that Michelson went through a lot of trouble to make sure not to fall prey to the problems of Monochromatic light which is now used in all supposed “replications” of the experiment. (IE they are all invalid)
That’s a little piece of easily verified history that is always absent from your history books. Unfortunately it is not just white light that is crucial, but also light travelling in a gaseous medium that is critical to the non-null experiments of Dayton Miller that won him the 1925 Newcomb Cleveland prize for proving the existence of aether, but that’s a controversial digression for another time.
Excerpt from On the Relative Motion of the Earth and the Luminiferous Ether (the original 1887 Michelson-Morley)
The paths being now approximately equal, the two images of the source of light or of some well-defined object placed in front of the condensing lens, were made to coincide, the telescope was now adjusted for distinct vision of the expected interference bands, and sodium light was substituted for white light, when the interference bands appeared. These were now made as clear as possible by adjusting the mirror e/, then white light was restored, the screw altering the length of path was very slowly moved (one turn of a screw of one hundred threads to the inch altering the path nearly 1000 wavelengths) till the colored interference fringes reappeared in white light. These were now given a convenient width and position, and the apparatus was ready for observation.
Creation time: Aug 27, 2020 06:10 PM PDT
That depends on the version of the experiment!
Great question!
In every version of the Michelson Morley, other than the original or those done by Dayton Miller, the lengths WERE different!
Both Michelson and Miller used a complex set up procedure using the double fringe of sodium light to find the perfect center and then used white light in the experiment. White light will no longer even have fringes if you look any significant number of fringe widths left or right.
Monochromatic light, however, will overlay with itself at most any different point (misaligned) so long as peaks and toughs align and give fringes any distance from the center fringe which is indistinguishable from the others.
So, the questions one must ask is, “Why didn’t Michelson just use the sodium light? You still find the center. Why switch? Why all the extra effort?
So, what happens with monochromatic light, is an overlaying of different light. The point of the experiment was to split the light apart and bring it back together with itself. If the lengths of the legs are different by even a very small amount then one beam of light is not being overlayed with it’s original wave it was split from, but instead it is overlaid with a wave from ahead or behind.
In modern times we might mention entanglement considerations, but why was Michelson putting in the effort to avoid this situation? Let’s back up and ask why it even matters.
The first thing you need to understand is that when you look at a single fringe, though it represents a single wavelength, it is actually the average of many (billions?) waves per second colliding with the surface.
The wavelength being produced by whatever source, however, both has fluctuations and does not produce a pure single frequency, but instead creates multiple extremely similar frequencies that split apart from each other given distance.
If there is a difference in the leg arms and therefore an overlaying of one beam of light with a different area of its partner, there is a sort of averaging happening in place that will tend to average out some of the signal.
There are other considerations very difficult to relay without visualizations but suffice it to say that having a definite center that ensured equal lengths is very important to the experiment’s success and avoiding numerous “averaging” situations that might destroy a signal.
Well aren’t those problems still solved by sodium light? Why go back to white light?
There is a phenomena discovered by Christiaan Huygens which still today is often called an “Odd sympathy” because it’s still poorly understood. It was originally about the tendency for clocks to begin to align their phases. It also, occurs in light, however, and is called “phase-locking” or “lock-in.”
Lasers are especially subject to this effect. What occurs is that any misalignment of the phase of two beams of light of similar frequency that are below half a wavelength misaligned will quickly be pulled together into alignment. In ring laser gyroscopes and other applications they must use dithering or multi-frequency approaches to overcome the problem.
This means monochromatic light will always give a perfect null on a Michelson interferometer if the signal is below half a wavelength. It will zero out the signal. (especially with lasers)
…and this is why the original Michelson and tens of thousands of experiments by Miller gave a positive result that was periodic in nature as expected but other experiments with monochromatic light do not.
There’s also a consideration of the index of refraction in air and Fresnel’s “partial ether drag” that gives a signal under Lorentz’s interpretation which will give null in a vacuum.
IE: They are not replicating the actual experiment in modern times. Only Miller did that and he got a very clear and irrefutable non null that matched Michelson’s unexpectedly small signal.
Creation time: Jan 27, 2018 05:26 PM PST