stevo247 Posted April 10, 2008 Posted April 10, 2008 For some reason, I had been under the mistaken impression that the Michelson-Morley experiment had determined that the general concept of an ether was no longer viable and warranted no further consideration what-so-ever. I’ve recently found out though, that the Michelson-Morley experiment had only determined that a specific form of the ether-concept could not be true. Namely, that the ether was a stationary matter that the earth passed through. I was surprised to learn that Einstein, in 1920, continued to comment on the ether after the Michelson-Morley experiment. “It may be added that the whole change in the conception of the ether which the special theory of relativity brought about, consisted in taking away from the ether its last mechanical quality, namely, its immobility.” “The ether of the general theory of relativity is a medium which is itself devoid of all mechanical and kinematical qualities, but helps to determine mechanical (and electromagnetic) events.” http://www.mountainman.com.au/aether_0.html Since the concept of an ether is not inconsistent with SR and GR, I was wondering if any research had been done, from the accepted school of SR and GR, on the nature of a possible ether? Please remember, that I know almost nothing about SR and GR.
jedaisoul Posted April 10, 2008 Posted April 10, 2008 “The ether of the general theory of relativity is a medium which is itself devoid of all mechanical and kinematical qualities, but helps to determine mechanical (and electromagnetic) events.” Since the concept of an ether is not inconsistent with SR and GR, I was wondering if any research had been done, from the accepted school of SR and GR, on the nature of a possible ether? If the "ether" of the general theory has no mechanical nor kinematic qualities, how would one set out to research it? It's an abstract framework that does not interact with reality, but defines how real things interact. The key word is abstract. It's just an idea, not a thing, but it is needed by GR to explain reality. If that sounds silly, bear in mind that the whole of relativity is based on the idea of frames of reference and how they affect reality. Frames of reference do not actually exist. They are abstract ideas that exist only in our minds. Yet in SR and GR they have properties. That's the trouble with letting mathematicians loose in physics. They blur the distinction between reality and concepts of it.
swansont Posted April 10, 2008 Posted April 10, 2008 One issue here is that the aether was defined in a certain way, and falsified, but there is a continual parade of concepts using the same term. Space has properties, or to be more specific, the vacuum has properties. And yes, it gets investigated — the Casimir force measurements jump immediately to mind. http://en.wikipedia.org/wiki/Casimir_effect
jedaisoul Posted April 10, 2008 Posted April 10, 2008 One issue here is that the aether was defined in a certain way, and falsified, but there is a continual parade of concepts using the same term. Agreed. Space has properties, or to be more specific, the vacuum has properties. And yes, it gets investigated — the Casimir force measurements jump immediately to mind. Shouldn't that be the field has properties? Einstein said: "Thus, according to the general theory of relativity, gravitation occupies an exceptional position... since the ten functions representing the gravitational field at the same time define the metrical properties of the space measured". A. Einstein, "The Foundation of the General Theory of Relativity", Annalen der Physic, 49, 1916. Also (when discussing the electromagnetic field) he said: "The field thus becomes an irreducible element of physical description, irreducible in the same sense as the concept of matter in the theory of Newton". A. Einstein, Appendix 5, "Relativity and the Problem of Space" from the 15th edition (in 1952) of "Relativity the Special and the General Theory".
swansont Posted April 10, 2008 Posted April 10, 2008 Shouldn't that be the field has properties? Einstein said: "Thus, according to the general theory of relativity, gravitation occupies an exceptional position... since the ten functions representing the gravitational field at the same time define the metrical properties of the space measured". A. Einstein, "The Foundation of the General Theory of Relativity", Annalen der Physic, 49, 1916. Also (when discussing the electromagnetic field) he said: "The field thus becomes an irreducible element of physical description, irreducible in the same sense as the concept of matter in the theory of Newton". A. Einstein, Appendix 5, "Relativity and the Problem of Space" from the 15th edition (in 1952) of "Relativity the Special and the General Theory". Properties exist in the absence of a gravitational field, though, e.g. permittivity and permeability
Graviphoton Posted May 2, 2008 Posted May 2, 2008 For some reason, I had been under the mistaken impression that the Michelson-Morley experiment had determined that the general concept of an ether was no longer viable and warranted no further consideration what-so-ever. I’ve recently found out though, that the Michelson-Morley experiment had only determined that a specific form of the ether-concept could not be true. Namely, that the ether was a stationary matter that the earth passed through. I was surprised to learn that Einstein, in 1920, continued to comment on the ether after the Michelson-Morley experiment. “It may be added that the whole change in the conception of the ether which the special theory of relativity brought about, consisted in taking away from the ether its last mechanical quality, namely, its immobility.” “The ether of the general theory of relativity is a medium which is itself devoid of all mechanical and kinematical qualities, but helps to determine mechanical (and electromagnetic) events.” http://www.mountainman.com.au/aether_0.html Since the concept of an ether is not inconsistent with SR and GR, I was wondering if any research had been done, from the accepted school of SR and GR, on the nature of a possible ether? Please remember, that I know almost nothing about SR and GR. Einstein was heavily influenced by his mathematical insights, and this gave him great understanding into the world of particle behaviour - this too must bring with it the forces that 'carry' these specific particles… This included a particular medium for all matter called the Aether. What is 'Aether Theory' all about? Einstein wrote a paper on what was called, 'The Investigation of the State of Aether in Magnetic Fields'. I find it a most interesting paper. I believe it was originally devised contemporaneously for [one] of his uncles. Also known as 'Ether' from the Greek Word (aio'np), which basically means 'upper' or a.k.a. 'pure fresh air,' - it was believed to be an all-spacetime filling field. They refer its effects as a 'transmissional medium'. The Aether hypothesis has come in numerous forms, through the multiple interpretations throughout history. The orthodox Aether Interpretation is that it is a physical force/medium that permeates every corner of spacetime thus indicating an influence on all materialistic bodies contained within all spacetime. Another result of Aether presents properties that give rise to the electric, magnetic and gravitational potentials, and also determines the propagating velocity of their effects. It get's even more complex: it states that the propagating effects throughout all of the universe, are determined by the physical field of the Aether - which acts in a manor analogous to sound waves, such as the wave properties of a photon. Any developing propagation and potential effects within spacetime due to their velocities are viewed as having real effects. Thus, fundamental interactions depend on this Aether Force, in intrical ways. The rippling or ''propagation'' of the Force of Aether also presents time directionality, reflected in the 'Radiative Arrow’ - found in quantum evolution. Though, the effect in velocities predicted by Aether indicates the possibility in the answering of matter formations, and the age discrepancies that haunt our observations of galactic formations. This is as elementary as i can express it: Aether is a physically-interactive force field which acts as a mediator throughout all universal bodies - even between them in the vast Intergalactic Cosmological Medium - and like all 'mediums', if it exists, as i believe it does, must have fundamental attributes consisting of a pressure, a tension, a mass density and temperature. Aether, as controversial as it has become to be known in the academic world, has played, as i believe, one of the biggest roles in the developing theories of the equally controversial quantum mechanics. And this is why: During the 19th century, the most elementary fundamental forces where known as electrical, magnetical and 'luminous' phenomena. By unifying these fundamental characteristics, brought with it new modes of theories... integrating the fields of force into a single network. The Preferred Model of Aether Theory Thus, the attention during the 19th century was focused on the fundamental interaction of electromagnetic phenomena. It was in fact assumed for a while by the majority of the physicists of that era that 'ponderable' matter, consistent of having what is called 'rest value,' and 'inertia', was inexorably differential, that was 'somehow' meshed, or, enveloped through the permeating, all-space and all-time Aether. Now, some strange conclusions can be made here. If the above is correct, this interpretation states that an object must literally 'plow' through the Aether. If it 'plows' through the Aether, it then must also drag the ''fabric'' of Aether along its trajectory. If the hypothetical object does not move the distribution of pressure exerted by the strange Aether, means that it is equally proportional in all directions! A function coined by scientists as (isotropic). It has also come to be more widely known as the 'Rest Frame of The Aether.' Thought indicated that the measure of matter in motion through this Aether Field was highly important. One way to measure such an effect would be found in the momentum of the Earth, which was considered to be suffice in magnitude, that its speed was determinable. Thus a physicist called Albert Michelson in 1881 set out to find the tail whip of the Aether wind as earth ploughed through it. The Test of Matter in Motion Through The Aether Michelson solved the question to this, through experimental tests, that, unfortunately resulted in 'the Big Goose Egg,' - 'absolute nada'. Again, it was repeated in 1887, this time counterparted with physicist Edward Morley, and their experiment became to be known as the 'Michelson-Morley Experiment.' However, even this revived experiment proved fruitless! It basically meant at the time, that the positive results predicted by the ‘Preferred Model,’ were not conclusive with the predicted results. So How Should Matter in Aether Be Viewed? Well, science informs us that any medium would itself react to any movement of a physical ''meshed'' object, the postulate of a static Aether is also assumed to be flawed. However, ways around this can be evaluated. The 'classic way' to describe the following, is that, whenever you swirl your hand in water, and if the medium has any viscosity, it will experience a 'dragging effect', thus can be now imagined to cause a circular motion - a bit like the way a Black Hole itself drags space and time with it... However, as the time variables increase, so does the relative speed and drag between the body and the medium. This results the overall magnitude to be equally dependant on the 'value of viscosity', which relentlessly leads to many variants of the Aether theory and the momentum of matter through it. These lead to 'Coefficient Theories,' and principles for how all Bradyonic matter should interact with the Luxen particle of light. The progressive evolution in Aether theories has paradoxically made our search rather difficult, as they open 'too many doors', making any initial theory almost invalid to make any self-assured predictions. Quantum Mechanics and Aether Theory Quantum Mechanics, as you will undoubtedly know, is used to interpret the function of matter at the fundamental level. We see this as all arising from the vacuum, like the spontaneous bubbling of electrons and antielectrons out of the Dirac Sea whenever there is enough energy present. Remember, the Dirac Sea is packed full with negative particles. Matter must come out of the vacuum, and create two distinct forms of longer-lived spacetime distortional fluctuations; a particle and its antipartner. This was called by physicist J. A Wheeler as ''quantum foam.'' These fluctuations arise out of a spatial coordinate - this size is 1.616 x 30^-33, which is the smallest known 'box' of space. The fluctuations also arise out of the smallest time possible, called the ‘Planck Time,' which is 5.391 x 10^-44 seconds. It is here, in this infinitesimal unit of space that releases an enormous amount of virtual energy in the quickest time possible! On this small level, space and time literally forces these spontaneous rapid releases of quantum bubbles of energy/gas that breaks into a particle and its antiparticle. Thus, Quantum Theory might itself be indicating an equivalence with 'zero-point energy field,' that may be the shadow of a ''particulate Aether''. There are simply some aspects about the Aether field that we simply ‘just need’. There are many more theories about the Aether though which are very controversial such as The Einstein-Aether Theories… And all this originally stemmed from physicist Thomas Young’s experiment of a photons quantum wave. I don't think the Aether field will be solved any time soon – however, the Aether field is now gaining more and more interest, as I have been informed by a Ph.D… The reason why is because some scientists believe that dark energy might be linked to the Aether… And because we know so very little about dark energy, this has got the scientists very excited.
stevo247 Posted May 3, 2008 Author Posted May 3, 2008 Graviphoton, Thanks for your comprehensive response. It was very helpful and much appreciated.
Obelix Posted May 9, 2008 Posted May 9, 2008 I’ve recently found out though, that the Michelson-Morley experiment had only determined that a specific form of the ether-concept could not be true. Namely, that the ether was a stationary matter that the earth passed through. This, however, must be combined with the fact that the other possibility - Earth and planets dragging the Ether along with them - has been excluded by astronomical observations (by Huygens, if my memory serves me right). By the context of his speech, it appears that Einstein says the following two things: 1) Special Relativity does not disprove the existence of an Ether. That was always known: Ether is just simply NO LONGER NECESSARY in the formulation of Electromagnetism, according to SR. 2) In General Relativity, spacetime interacts with matter. And it is this concept of spacetime that Einstein names "Ether" in his 1920 text.
Zephir Posted May 9, 2008 Posted May 9, 2008 ...what is 'Aether Theory' all about? I think, you may be interested about Aether Wave Theory. Do you know, the first article of Albert Einstein in sixteens was dedicated to Aether Theory? ...Ether is just simply NO LONGER NECESSARY in the formulation of Electromagnetism, according to SR.. It may still be necessary for ab-initio explanation of constant speed of light, strings, brane structure of vacuum and fundamental particles, the postulates of GR and QM and so on. Most of human knowledge remains based on ad-hoced postulates without further reasoning.
Farsight Posted May 10, 2008 Posted May 10, 2008 Steve, if you haven't already, you should read Einstein's Leyden Address of 1920. See: http://www.zionism-israel.com/Albert_Einstein/Albert_Einstein_Ether_Relativity.htm "Recapitulating, we may say that according to the general theory of relativity space is endowed with physical qualities; in this sense, therefore, there exists an ether. 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... " The thing to note is that this ether doesn't fill space, nor is it a "field". It is space. And like swanson was saying, it has properties: One issue here is that the aether was defined in a certain way, and falsified, but there is a continual parade of concepts using the same term. Space has properties, or to be more specific, the vacuum has properties. And yes, it gets investigated — the Casimir force measurements jump immediately to mind... Unfortunately "ether" is something of a dirty word. Almost taboo. There's been a great deal of research in this area, but it has tended to suffer sneering dismissal or even censorship and suppression from what you'd describe as the "accepted school", who are not in line with Einstein. But things are now changing. See Focus magazine issue 183 http://www.focusmag.co.uk/viewIssue.asp?id=879 for an article called "The science of nothing" involving research into the vacuum. It talks about aether quite freely. Sorry, I can't find the full text online, this is just a stub: Victorian scientists used the mysterious 'luminiferous aether' to explain how light is propagated through empty space. But now the idea is making a resurgence and could transform medical treatments.
swansont Posted May 10, 2008 Posted May 10, 2008 Unfortunately "ether" is something of a dirty word. Almost taboo. There's been a great deal of research in this area, but it has tended to suffer sneering dismissal or even censorship and suppression from what you'd describe as the "accepted school", who are not in line with Einstein. What you call sneering dismissal and censorship is what I think most scientists would call lacking rigor and failure to provide testable predictions. IOW, it's dismissed because it's not science. You'd probably get the same reaction from a biologist if you asked him or her to dissect a piece of granite. This, however, must be combined with the fact that the other possibility - Earth and planets dragging the Ether along with them - has been excluded by astronomical observations (by Huygens, if my memory serves me right). By the context of his speech, it appears that Einstein says the following two things: 1) Special Relativity does not disprove the existence of an Ether. That was always known: Ether is just simply NO LONGER NECESSARY in the formulation of Electromagnetism, according to SR. 2) In General Relativity, spacetime interacts with matter. And it is this concept of spacetime that Einstein names "Ether" in his 1920 text. I think it goes a little beyond that. Not only is the ether not necessary, it can't have the properties originally ascribed to it: the medium through which light travels, and the rest frame of the universe. The first part is unnecessary, but the second part can't actually exist. So whatever properties space has, it will only cause confusion to call it "aether," and yet that's exactly what has happened. I don't think it's correct to say that matter interacts with spacetime in GR. It's a classical theory which says that spacetime has a geometry that need not be flat. It's not a force, per se, because objects following a geodesic are obeying Newton's laws where no force is present. It may still be necessary for ab-initio explanation of constant speed of light, strings, brane structure of vacuum and fundamental particles, the postulates of GR and QM and so on. Most of human knowledge remains based on ad-hoced postulates without further reasoning. Science is about investigating how nature behaves, and not necessarily why it behaves this way. The postulates of relativity were not ad hoc.
Obelix Posted May 10, 2008 Posted May 10, 2008 I don't think it's correct to say that matter interacts with spacetime in GR. It's a classical theory which says that spacetime has a geometry that need not be flat. It's not a force, per se, because objects following a geodesic are obeying Newton's laws where no force is present. Matter DOES interact with Spacetime in General Relativity, according to Einstein's Field Equations: [math]R_{\alpha\beta}-\frac{1}{2}g_{\alpha\beta}R=-\kappa T_{\alpha\beta}[/math] Matter/Energy defines the geometry of Spacetime, and is itself defined, in turn, as a geometrical feature of the latter. This is what is meant by "interraction: Not the classical interraction by mutual exertion of "forces".
Farsight Posted May 11, 2008 Posted May 11, 2008 Well said Obelix. Steve, here's another quote from Einstein's Leyden Address: “Mach’s idea finds its full development in the ether of the general theory of relativity. According to this theory the metrical qualities of the continuum of space-time differ in the environment of different points of space-time, and are partly conditioned by the matter existing outside of the territory under consideration. This space-time variability of the reciprocal relations of the standards of space and time, or, perhaps, the recognition of the fact that ‘empty space’ in its physical relation is neither homogeneous nor isotropic....” Swanson, that's Einstein talking about the ether of General Relativity. Your "piece of granite" jibe was uncalled for.
swansont Posted May 11, 2008 Posted May 11, 2008 Swanson, that's Einstein talking about the ether of General Relativity. Your "piece of granite" jibe was uncalled for. As opposed to your appeal to conspiracy that prompted it?
Obelix Posted May 14, 2008 Posted May 14, 2008 In his 1920 paper Einstein wrote that "light cannot propagate without an Ether". He also wrote that "no standards of length and/or time can be given without an Ether", and that "the fact that matter interracts with space means that there is an Ether". However that Ether was not the one assumed by Physicists of 19th. century. The latter was a "quasi - solid" medium such that light propagated in the form of a MECHANICAL VIBRATION along it. It had to be ("quasi - ") SOLID(!) as well, since light displays properties of a TRANSVERSE wave (polarization). All that was in accordance with the spirit of the 19th century Physics. During that time period Mechanics was the only complete (and very successful) branch, whence there was a tendency to interprete everything in terms thereof. Electromagnetic waves were interpreted as a mechanical vibration... The "Ether" Einstein had in his mind in 1920 was something different altogether: It was the FIELD: Gravitational, electromagnetic, etc. It is quite clear that without some kind of "Ether" (electromagnetic field in this case) light cannot possibly propagate. It is clear that, according to General Relativity, without another form of "Ether" (gravitational field and a metric tensor thereof) nothing can be defined as regards length, time, etc. Einstein explained that light, geometry, etc. cannot propagate through, or be properties of an "empty space". In other words, what was thought of as "vaccuum" was nothing of the kind: It was "something" - something DYNAMICAL too, interracting with matter. It also clear that General Relativity identifies field with spacetime, since gravitation is a property of the latter's geometry. Moreover, Einstein had in mind to identify ALL fields (= all forms of "Ether") with spacetime and spacetime geometry via his planned "Unified Field Theory", which, however, was not achieved. In another paper of 1950, Einstein drops the term "Ether" and adopts openly the term "Field". In 1920 "Ether" was still in use, however in 1950 that had changed. More details can be found in in pp. 235 - 246, and pp. 414 - 418 of: "A stubbornly persistent illusion", ed.: Running Press, forwarded by Stephen Hawking.
Graviphoton Posted May 14, 2008 Posted May 14, 2008 Well thar's because we need a quantum aether. This aether has planck scales as coordinates, and from the very small regions from which energy bubbles from, turns out to spontaneously appear. But one answer is that they ''pop'' into existence from a quantum aether. Recently, there was some speculation as to whether dark energy might have something to do with this stuff we call quantum aether.
Farsight Posted May 14, 2008 Posted May 14, 2008 Obelix: in his last paper, Einstein admitted that perhaps the concept of field was inadequate. The fields go, and you're left with a Unified Theory rather than a Unified Field Theory. It's all in the geometry.
Copernicus_Meme Posted December 28, 2008 Posted December 28, 2008 I was surprised to learn that Einstein, in 1920, continued to comment on the ether after the Michelson-Morley experiment. Well, Einstein's mention of it had to do with the metric field of GR, there was no preferred state attached to it. Hence, it is concistent at least as far as one of his basic contributions goes, ie no essential difference between a resting and moving frame of reference, therefor he wasn't really precluding a reference frame relative to the aether as so. As general bit of relevant curiosa, in his own words; By and by I despaired of the possibility of discovering the true laws by means of constructive efforts based on known facts. The longer and the more despairingly I tried, the more I came to the conviction that only the discovery of a universal formal principle would lead us to assured results. The example I saw before me was thermodynamics. The general principle there was given in the theorem: the laws of nature are such that it is impossible to constructa perpetuum mobile (of the first or second kind). How, then, could such a universal principle be found? After ten years of reflection such a principle resulted from a paradox upon which I had already hit at age sixteen: If I pursue a beam of light with the velocity c (velocity of light in a vacuum), I should observe such a beam of light as a spatially oscillatory electromagnetic field at rest. However, there seems to be no such thing, whether on the basis of experience or according to Maxwell's equations. From the very beginning it appeared to me intuitively clear that, judged from the standpoint of such an observer, everything would have to happen according to the same laws as for an observer who, relative to the earth, was at rest. For how, otherwise, should the first observer know, i.e., be able to determine, that he is in a state of fast uniform motion? One sees that in this paradox the germ of the special relativity theory is already contained. Einstein, Autobiographical Notes, “Albert Einstein: Philosopher-Scientist”, Volume One, p. 53, Open Court Classics
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