Does Ether Exist? 19th Century Evidence

[jtbell]

Yes, I was responding to Buckethead, and to Nickelodeon a few posts earlier, who made a similar comment about Einstein and the MMX.

 

[Born2bwire]

There's someone who is doing just that, see http://www.youtube.com/watch?v=7T0d7o8X2-E&feature=related"
If there is an aether it would appear it is moving downwards.

That is a poor demonstration as he has not attempted to discuss various experimental error. The simplest explanation would be that objects in his test setup are slightly loose and being dislocated by gravity.

 

[sophiecentaur]

There's someone who is doing just that, see http://www.youtube.com/watch?v=7T0d7o8X2-E&feature=related"
If there is an aether it would appear it is moving downwards.

When you say "downwards" are you referring to "towards the centre of the Earth"? Are you suggesting that it is a gravitational effect (local) or that we (Earth) happened to be moving through the Aether in that direction. But his diurnal effect was only slight, was it not? According to your idea and ignoring the gravitational effect, we should be moving 'upwards' at a time 12 hours different. I appreciate that this would only apply exactly whilst near the Equator, but my point still stands.

So it has to be a gravitational effect (?).
Sagging equipment could explain this. (One of those old-age problems),

 

[cragar]

I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .

 

[Born2bwire]

I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .

One of the possible consequences to an aether model is the aether wind. If there is some medium that permeates space that is propagating light, then the Earth will have a relative velocity with this medium. The velocity of the light will thus be different depending upon how the path of the light moves related to the source and receiver's relative velocity to the medium. However, the experiments (which were repeated at different directions, different times of the year and by many many different research groups) showed that the expected shifts due to the aether windwere not existent.

And to reiterate, aether wind was just one of several aspects of the aether model that have been challenged by experimental results.

 

[sophiecentaur]

I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .

One of the 'explanations' of the MM experiment results was the Lorenz Contraction - that's all. Yes, you can measure a contraction but the fuller appreciation of SR and the other relativistic effects can't be had if that's all that you consider.

My problem with the whole business of wanting an Aether is that everyone's 'personal' bit of Aether must be behaving differently - even when they're going past, close to each other, at different rates. Hanging onto conventional ideas can very often interfere with your appreciation of new ones. There are so many examples of this - the two slits experiment is another of them.

 

[Nickelodeon]

That youtube video shows some extremely sloppy science. He sees a result that he doesn't understand: does he check to see if there is any mundane explanation - like some mirror wiggling? No, he immediately decides that this is a Major Discovery.

Things have moved on since that video was made and he has gone to considerable lengths to minimise any mechanical errors. Apart from that, there are fringe shifts when the apparatus is static in a vertical plane over a 24 hour period but not so in a horizontal plane. Could you give an explanation for why you think that should be?

 

[Nickelodeon]

When you say "downwards" are you referring to "towards the centre of the Earth"? Are you suggesting that it is a gravitational effect (local) or that we (Earth) happened to be moving through the Aether in that direction. But his diurnal effect was only slight, was it not? According to your idea and ignoring the gravitational effect, we should be moving 'upwards' at a time 12 hours different. I appreciate that this would only apply exactly whilst near the Equator, but my point still stands.

So it has to be a gravitational effect (?).
Sagging equipment could explain this. (One of those old-age problems),

Whatever it is, and one should perhaps not use the word aether any more, it is more likely to be accelerating towards the centre of the Earth and causing the gravity effect.
As I mentioned before, Martin Grusenick has tried to minimise any mechanical errors but the fringe shifts are quite apparent when the equipment is static in a vertical plane compared to a horizontal plane.

 

[Nickelodeon]

The Michelson-Morely experiment was conducted in 1887, that's [EDIT: sorry, I can't do arithmetic] [STRIKE]8[/STRIKE] 18 years before Einstein published his paper on SR, let alone GR, which came another 10 years after that! Your claim is blatantly wrong, and I don't understand how you could even post it. As far as I know, Einstein was only dimly aware of the results of this experiment in 1905, but it didn't matter because he saw no theoretical need for the luminiferous aether. The whole point of Special Relativity was that by rethinking certain ideas about mechanics (motion, space, and time) it was possible to show that the laws of electrodynamics were NOT inconsistent with the principle that the laws of physics should be the same for all inertial observers. (This perceived inconsistency was the only reason that others had for introducing the concept of the aether in the first place).

I'm trying to find where I read the article that prompted my previous post but in the meantime here is a link to an article written by Einstein in 1920 where he states "More careful reflection teaches us, however, that the special theory of relativity does not compel us to deny ether" . http://www.tu-harburg.de/rzt/rzt/it/Ether.html" .

 

[Dale]

No, but as I said back in https://www.physicsforums.com/showpost.php?p=2611230&postcount=27" it does compel us "to redefine the word 'aether' in such a way as to remove from it most of the properties usually associated with the term". The only kind of aether which is consistent with SR is a kind of aether that has properties which are consistent with there being no aether.

 

[Vanadium 50]

Things have moved on since that video was made and he has gone to considerable lengths to minimise any mechanical errors. Apart from that, there are fringe shifts when the apparatus is static in a vertical plane over a 24 hour period but not so in a horizontal plane. Could you give an explanation for why you think that should be?

Can you follow the PF Rules and give us a published reference for this? Otherwise we are chasing ghosts.

 

[ZapperZ]

I'm trying to find where I read the article that prompted my previous post but in the meantime here is a link to an article written by Einstein in 1920 where he states "More careful reflection teaches us, however, that the special theory of relativity does not compel us to deny ether" . http://www.tu-harburg.de/rzt/rzt/it/Ether.html" .

We never do physics and accept something as valid based on quotes. Einstein also made many other "blunders" (would you also like quotes for those?). You need to supply valid peer-reviewed publications.

Zz.

 

[Vanadium 50]

Furthermore, as DaleSpam pointed out, the properties of the "modern aether" are totally different from the 19th century aether. Remember my rabbit and giraffe analogy?

 

[DavidSullivan]

I would say so. As Dalespam already stated, aether is a specific theory originating in the 19th century. The luminous aether has been more or less conclusively disproven via experimental results The aether drag was not the only consequence that would be predicted by the aether model and so even the Mickelson-Morley experiment was not enough to completely debunk the aether model (nor was it by far the only experiment of its type). As time progressed, it was continually shot down by further experimentation and required more and more complicated explanations to account for these results. In the end, the theory was not viable.

To label things as an (a)ether today is still going to carry with it the connotations and inherent properties of the original luminous aether of the 19th century theory. I think it would be far more appropriate to choose a different wording or to avoid comparisons with the aether altogether. To me, it sounds like somebody comparing an astronomical theory with geocentrism, germ theory with miasma theory.

Agreed - I'm not trying to infer any relationship between the aether of old and space-time beyond t-s seeming to act as a "medium" of sorts.

-David

 

[Nickelodeon]

Can you follow the PF Rules and give us a published reference for this? Otherwise we are chasing ghosts.

I have several emails from him between 11th Nov 09 and 21st Jan 10 in which he describes, and with detailed photographs, the general progress he is making and his attempts to minimise any artifacts caused by temperature differentials, etc.. Obviously not peer reviewed in the formal sense and I don't think reviewing a published account will be of much use. It would need independent research to verify his findings under controlled conditions. Although he has some external finance he is funding it mainly by himself and with whatever bits and pieces organisations give him.

However, it would be still be good to hear your opinion as to possible causes for the fringe shifts, assuming they exist and aren't ghosts.

 

[Nickelodeon]

We never do physics and accept something as valid based on quotes. Einstein also made many other "blunders" (would you also like quotes for those?). You need to supply valid peer-reviewed publications.

Zz.

I only provided that particular 1920 address to illustrate that Einstein still had the 'ether' very much in his thought processes. I was just defending myself against Cepheid (post 47)

 

[cepheid]

I only provided that particular 1920 address to illustrate that Einstein still had the 'ether' very much in his thought processes. I was just defending myself against Cepheid (post 47)

Yeah, but ZapperZ's criticism still applies. Furthermore you took a quote out of its context. There may have been more information there that would indicate just what kind of "more careful reflection" Einstein was referring to, and what kind of ether SR does not preclude, according to him. EDIT: either way, I strongly suspect that what DaleSpam and others have been trying to point out (about the luminferous aether as it was originally conceived being obsolete) still applies.

 

[Nickelodeon]

Yeah, but ZapperZ's criticism still applies. Furthermore you took a quote out of its context. There may have been more information there that would indicate just what kind of "more careful reflection" Einstein was referring to, and what kind of ether SR does not preclude, according to him. EDIT: either way, I strongly suspect that what DaleSpam and others have been trying to point out (about the luminferous aether as it was originally conceived being obsolete) still applies.

Is anyone reading the article? The quote is not key to my argument but the title is ..

"Ether and the Theory of Relativity
Albert Einstein, an address delivered on May 5th, 1920, in the University of Leyden.

The original version is available in the Collected Papers of Albert Einstein. "


and, strange as it would seem, I would wholeheartedly agree with you that the luminiferous ether as it was originally conceived is obsolete.

 

[bjacoby]

Please identify one experiment that that is inconsistent with ether not existing. If a concept is not needed for calculations of the outcome of any physical experiment then how is that scientifically different from it not existing?

I am sorry bjacoby, but there is no evidence supporting your position. The only way to scientifically assert that there is an aether is to redefine the word "aether" in such a way as to remove from it most of the properties usually associated with the term. Sure, you can do that if the word "aether" is important to you for some reason, but it would not have anything to do with what most people mean when they use the word.

So, DaleSpam, are you saying that empty space has no properties? There is PLENTY of evidence to support the assertion that such a statement is false! And of course Einstein was referring to the necessity of having an aether for HIS calculations. That does not mean he meant that might not be needed for ANY calculations. Even Einstein was smart enough to know he wasn't God and therefore did not have knowledge of ANY and ALL calculations that one might perform.

The old argument used to be that light was a wave and therefore REQUIRED an aether to propagate. OF course now we know that this is not true. One might assert that radio waves are "waves" (hence the name! :) although there are those who assert that they are photons as well. Thus there are certain difficulties here. But logically one must assert that in physics in any phenomenon where there are waves propagated there must be media for them to propagate in. To deny that is to deny logic and create a religious dogma. Which is what it seems you are trying to do.

 

[bjacoby]

I still don’t see how the michelson morley experiment shows that the ether doesn't exist .
I thought it showed length contraction , and this led Hendrik Lorentz to formulate Lorentz transformation. I Don’t see how this had anything to do with the ether .

What MM showed was NOT that the aether does not exist (as is widely touted throughout physics) but rather that he found no "aether-drift". What fell was Newtonian mechanics of light and the idea that somehow the Earth was plowing through the aether and such plowing could be detected.

Clearly the people saying that 19th century (Newtonian) aether theory has crashed and burned are correct. However, one cannot logically dismiss the general concept of an aether so long as space has properties and one cannot explain how waves can propagate without any medium. The fact that the speed of light measures the same in all reference frames is particularly troubling to a mechanical concept of the Aether as it was viewed in the 19th century. But then now we know that light is not a wave so the problem isn't so great.

 

[bjacoby]

We never do physics and accept something as valid based on quotes. Einstein also made many other "blunders" (would you also like quotes for those?). You need to supply valid peer-reviewed publications.

Zz.

You are spouting nonsense! Are you saying that to discuss what might be in a given scientist's mind is of no relevance? Are you saying that historical facts are of no relevance to understanding the thinking in a given historical period? Are you saying only peer-reviewed papers contain truth and all others are false? Sorry you are spouting nonsense of no significance to science or the discussion here.

Einstein's views on the aether and aether theory of the age ARE relevant to this discussion. No, they certainly don't "prove" that an aether does or does not exist. And I doubt very much that any "peer-reviewed" paper will do that either at this time. And I would hardly characterize Einstein's various opinions as "blunders". To do that one would have to be God and therefore know the "correct" theory for everything. The best we can say is that Einstein had some ideas that proved to not be accepted according to what we know at present.

So let's discuss Einstein's view of the Aether in 1920:

In a speech (May 5, 1920) at the University of Leiden Holland , he stated:

"There are weighty arguments to be adduced in favor of the aether hypothesis. To deny the aether is ultimately to assume that physical space has no physical qualities whatever. The fundamental facts of mechanics do not harmonize with this view...According to the General Theory of Relativity, space is endowed with physical qualities; in this sense, therefore, there exists an aether. According to the General Theory of Relativity space without aether is unthinkable."

Obviously, Einstein HAD considered the problem of "empty space having properties" and his view in 1920 pretty much agrees with mine today.

Thus if one would wish to define a "modern" aether, one would surmise that the aether is that which gives empty space it's properties! What that means exactly is a MUCH bigger problem!

 

[Dale]

So, DaleSpam, are you saying that empty space has no properties?

I certainly never said that. Empty space has geometrical properties (e.g. distance, curvature), not material properties (e.g. density, velocity).

But logically one must assert that in physics in any phenomenon where there are waves propagated there must be media for them to propagate in.

This is demonstrably wrong. The wave equation is
\left(\frac{\partial^2}{\partial x^2}+\frac{\partial^2}{\partial y^2}+\frac{\partial^2}{\partial z^2}-\frac{1}{c^2}\frac{\partial^2}{\partial t^2}\right)A=0
This logically requires time, space, speed, and A (e.g. in the case of an electromagnetic A is the electric field). Nothing else is logically required by the mere existence of a wave. Most familiar examples of waves do have a medium, but it is certainly not logically implied by the wave equation.

To deny that is to deny logic and create a religious dogma. Which is what it seems you are trying to do.

This type of comment seems to be the last refuge of all crackpots.

 

[ZapperZ]

You are spouting nonsense! Are you saying that to discuss what might be in a given scientist's mind is of no relevance? Are you saying that historical facts are of no relevance to understanding the thinking in a given historical period? Are you saying only peer-reviewed papers contain truth and all others are false? Sorry you are spouting nonsense of no significance to science or the discussion here.

It is relevant ONLY if that is the context! If this is a historical discussion on what Einstein was thinking at that time, then yes. If this is a question on the validity of the ether, then NO! Nothing in physics is validated or invalidated just because of some quote. Cite me an example to falsify that!

And if this is such a discussion about the historical context of the ether, then it belongs in a different forum than the physics subforums!

Zz.

 

[Phrak]

I only provided that particular 1920 address to illustrate that Einstein still had the 'ether' very much in his thought processes. I was just defending myself against Cepheid (post 47)

Actually, he didn't. The 'ether' is the so called luminiferous ether. Einstein was proposing an ether of his own. This was no more and no less than the properties of empty spacetime.

Perhaps he simply asked "what is waving?" An obvious question. The answer cannot be 'nothing' and still be physics. Should there be something in the properties of spacetime that would sustain something such as eletromagnetic waves? If this should not be natural behavior of empty spacetime, then what else should sustain it?

Maybe it's just Photons--stuff, superimposed upon spacetime. This is a very un-unified state of afairs. How is stuff unified with spacetime? Einstein talks about wood and marble.

 

[ervinn]

If we assume Ether exists the strange think is lot of unknown could be explained by the Ether.
If we knew what Ether is, we could explain Dark Matter. It is not really a matter out there it is the Ether property.

Also Ether could explain Quantum Theory. We would be not surprised that in the smaller scale things are different than in bugger scale. The same way we are not surprised that a stone reach the ground faster than a leaves, the air is there. In Quantum Physic we would say the Ether is there.

With Ether we could explain why the speed of light is as it is. As we can explain why the speed of sounds is as it is. In the speed of sounds depends on the molecular movement...
Why we can not know the reason why the speed of light is what it is?

With Ether we could explain and understand the Relativity Theory. One of the Ether property could be that when greater mass is present all activities slows down. The same why when an object travels in higher (close to the light) speed, all activities slows down with the light emissions as well.

With Ether we do not need time to exists. In that case time is not exists in the physical world. Time is only invented by our mind to measure duration physical activities.

Physical activities taken place, but Ether influences them somehow. Physical activity slower when close to high mass, and slower when an object travel fast inside the Ether.

To find out the properties of the Ether and understand them, may help to join the different theories out there and come up with a Standard Unified Theory.

 

[Neandethal00]

During the 19th century, it was proposed that light travels through vacuum in the presence of a pseudo medium known as ether. But does it really exist? Is there any evidence whether it exists or not?

The ether conceived in the 19th century probably does not exist. But empty space is most likely a medium. A medium that does not interact with anything we know of yet, not even light. This medium is more evasive than neutrino, which has a mass. Experiments using light to prove or disprove existence of this medium will always fail. Only things that interact with space medium are fields, electric/magnetic/gravitational fields. Inverse square laws are an indication.

 

[DaveC426913]

The ether conceived in the 19th century probably does not exist. But empty space is most likely a medium. A medium that does not interact with anything we know of yet, not even light. This medium is more evasive than neutrino, which has a mass. Experiments using light to prove or disprove existence of this medium will always fail. Only things that interact with space medium are fields, electric/magnetic/gravitational fields. Inverse square laws are an indication.

Unless you can provide citations for this, you are asserting it as a personal theory, which is forbidden.

 

[Dale]

If we assume Ether exists the strange think is lot of unknown could be explained by the Ether.

I disagree. I think that the aether has less explanatory power than Einstein's postulates. With Einstein's postulates time dilation of EM, weak, and strong interactions is explained, and it easily generalizes to gravity. With aether the time dilation of EM can be explained, but weak and strong interactions have to be added as ad hoc assumptions, and gravity is not an obvious generalization to me.