# Einstein and the Ether

Gold Member
I'm about to purchase a book on Amazon by this title where the author describes Einstein's interest in a "new" ether, a relativistic ether that in no way compares to the clasical ether of the 19th century but an ether just the same. If all this is true, I was glad to hear about it.

With the recent data sent back from the Gravity-B probe and the confirmation of the warping of space and the Lentz-Therring effect there is no doubt now that space is indeed "warping" due to both rotational effects and gravitational effects. The massive question on my mind is why in the face of all this is there still no respect for the "fact" that there must be something that is warping? Einstein in 1905 dismissed any form of ether because SR doesn't need it and space warping was not an issue, but with GR this all changed but the dogma continues.

I fully recognize that the mathematics don't need ether as GR can be worked out just fine without it and this no doubt is the reason for it's perpetual dismissal, but certainly it is clear not to just me that if space is warping, then space must be made of something, not necessarily of matter or energy, but of something, so why is this ignored as if it were in the same league as "consciousness". In other words, something that can't be discussed. Is it because there is no place to begin? I know for a fact that ether was dismissed not only because of MMX, as Lorentz resurected it again with his length contraction formulas, but because of physical problems such as the fact that it would have to be a solid to transmit light due to the transverse nature of light waves. However, since in this day and age we consider such far out ideas as Dark Matter (which I still don't believe in) which are not Bosons, then why is is such a stretch to consider that ether could be made of some exotic material as well that acts like a solid, but has no traditional matter properties. We are dealing with light here as well, whose nature we do not fully understand (waves and/or particles anyone?) so traditional propagation physics may not necessarily apply.

I am a strong proponent of ether because it can also be used to explain the flat rotational curves of galaxies which is currently being explained by DM but incorporates nothing more than the Lentz-Thering effect. With the Gravity B results, is anyone else taking ether a little more seriously?

Related Special and General Relativity News on Phys.org
Interesting! Do you have more info on how the ether concept can be used in explaining the flat galaxy rotation curves?

Bill_K
With the recent data sent back from the Gravity-B probe and the confirmation of the warping of space and the Lentz-Therring effect there is no doubt now that space is indeed "warping" due to both rotational effects and gravitational effects.
That's Lense-Thirring. The Gravity-B probe did not measure 'warping' but it did confirm several predictions of General Relativity in the post-Newtonian approximation.
The massive question on my mind is why in the face of all this is there still no respect for the "fact" that there must be something that is warping?
General Relativity says that the gravitational field affects the metric, i.e. the distance between neighboring points. That's all, period. You're welcome to visualize this as a 'warping of something', and even imagine that extra Euclidean dimensions are required to hold the warped result, but that's not part of the theory and not supported by any evidence.
since in this day and age we consider such far out ideas as Dark Matter (which I still don't believe in) which are not Bosons, then why is is such a stretch to consider that ether could be made of some exotic material as well that acts like a solid, but has no traditional matter properties.
There's good evidence now for dark matter, that's what's different. When you base your arguments on terms like 'dogma', 'believe' and 'it's clear to me', you've left the realm of physics.
We are dealing with light here as well, whose nature we do not fully understand (waves and/or particles anyone?) so traditional propagation physics may not necessarily apply.
We fully understand the nature of light, as much as we understand anything.

bcrowell
Staff Emeritus
Gold Member
I am a strong proponent of ether because it can also be used to explain the flat rotational curves of galaxies which is currently being explained by DM but incorporates nothing more than the Lentz-Thering effect. With the Gravity B results, is anyone else taking ether a little more seriously?
This is completely muddled. Either you've misunderstood half a dozen things, or you're paraphrasing someone else inaccurately, or you're repeating something said by someone else who has misunderstood half a dozen things.

FAQ: Didn't Einstein say that general relativity was an aether theory? Is general relativity compatible with an aether?

No, Einstein didn't say that general relativity was an aether theory. Einstein wrote a 1924 paper in which he made the philosophical point that although relativity killed off the luminiferous aether as the supposed medium of electromagnetic vibrations, it still imbued the vacuum with specific physical characteristics, such as curvature and energy. The basic point of the paper is that we can't decide, purely based on philophical ideas like Mach's principle, whether the vacuum has its own properties; we actually have to go through the usual scientific cycle of theory and experiment in order to find out the answer. Internet kooks love to misinterpret and overinterpret this paper, or to misrepresent it by saying that Einstein referred to GR in general, throughout his career, as an aether theory.

A more subtle question is what kinds of aether theories can be constructed, and how they relate to (or don't relate to) general relativity. Philosophers and historians of scientists have debated whether any real aether theory ever actually existed, and what that would mean. Earman (1989) investigates earlier work by Trautman (1966), and concludes: "[A]bsolute space in the sense of a distinguished reference frame is a suspect notion, not because armchair philosophical reflections reveal that it is somehow metaphysically absurd, but because it has no unproblematic instantiations in examples that are physically interesting and that conform even approximately to historical reality." Debate on this philosophical and historical issue continues,[Rynasiewicz 2003] but one should keep in mind that this discussion is all about theories that have been falsified by observation since the Michelson-Morley experiment. Jacobson (2008) has investigated a theory in which Lorentz invariance is approximate, and is broken in the gravity sector at large Lorentz boost velocities. This theory includes phenomena like aether dust settling onto a planet and giving it an aether charge. Jacobson's model has two adjustable parameters which, if nonzero, differentiate it from general relativity, and which are constrained by astrophysical observations. It is important to note that the model is not compatible with Galilean relativity, and it predicts all the same counterintuitive phenomena as standard relativity, including, e.g., the twin paradox, length contraction, and black holes.

A. Einstein, "Über den Äther," Schweizerische naturforschende Gesellschaft 105 (1924) 85

original text - http://www.wikilivres.info/wiki/Über_den_Äther

English translation of [Einstein 1924]- http://www.oe.eclipse.co.uk/nom/aether.htm [Broken]

commentary by John Baez on [Einstein 1924] - http://web.archive.org/web/20070204022629/http://math.ucr.edu/home/baez/RelWWW/wrong.html

A. Trautman, in B. Hoffmann (editor) Perspectives in Geometry and Relativity, Bloomington, 1966, p. 413.

J. Earman, World Enough and Space-Time, Absolute versus Relational Theories of Space and Time. Cambridge, 1989, MIT.

Rynasiewicz, "Field Unification in the Maxwell-Lorentz Theory with Absolute Space," Philosophy of Science 70 (2003) 1063, available at http://philsci-archive.pitt.edu/archive/00001096/ . Rynasiewicz starts by summarizing two important earlier papers that are now difficult to obtain: Trautman 1966 and Earman 1989.

Ted Jacobson, "Einstein-aether gravity: a status report," 2008, http://arxiv.org/abs/0801.1547

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Gold Member
Interesting! Do you have more info on how the ether concept can be used in explaining the flat galaxy rotation curves?
I have found an interesting relationship between observed rotational curves of 2 randomly chosen galaxies and an "ether" that rotates with a constant angular velocity that envelopes the galaxies. The relationship indicates that the observed mass of the galaxy is sufficient to explain the flattened rotational curve without the need for DM. I wrote a paper on this complete with supporting data, but it is woefully amateurish and was laughed at by an astrophysicist to whom I submitted it for review. Made me sheepish, but after I re-write it and add more supporting data, I'll post it, then everyone can laugh at it together. The cool part about it, is that it uses only 1 constant (the angular velocity of the "ether") and if the constant is set correctly the theory can be used to calculate the observed mass from the observed rotational curve. I suspect that the constant is related strongly to the average rotational velocity of the galaxy in question, but I have not yet worked on the exact relationship in detail. If I can do this then I'll have one whopping hell of a theory since it can then be used to calculate the observed rotational curve using only the observed mass of the galaxy. It will probably and forever be an amateurish paper but if it sparks a serious discussion and ends up being thought of as having real merit by a real physicist, I'll die a happy man.

turbo
Gold Member
@OP, if you would like an interesting collection of essays by some VERY smart people, including Einstein on the nature of "empty" space, see if you can pick up a copy of "The Philosophy of Vacuum" by Saunders and Brown. It's not a very large book, but it is very expensive, so check Amazon for used copies. I paid about $40 for mine. Last edited: Gold Member General Relativity says that the gravitational field affects the metric, i.e. the distance between neighboring points. That's all, period. You're welcome to visualize this as a 'warping of something', and even imagine that extra Euclidean dimensions are required to hold the warped result, but that's not part of the theory and not supported by any evidence. The goal of science is to understand nature, and although I can agree that GR may not describe nature, but simply stops short by offering a tool with which to calculate the existance of phenomenon that is verified by observation, at some point a theory as to the the nature of "nature" must be made. GR says "something" is happening, but not exactly what. As a starting point, it is fine to say that the distance between neighboring points changes as predicted by GR, but it is necessary to say what that means in order to follow through with the goal of science. On the one hand if the distance between two objects changes, then one or more of those objects must accelerate. If the distance between those objects changes and neither accelerate, then that is something else altogether and must be atributed to a change in the empty space between them. A "warping" if you will. If space changes, it is physical. If it is physical it is made of something even if it is exotic. There's good evidence now for dark matter, that's what's different. When you base your arguments on terms like 'dogma', 'believe' and 'it's clear to me', you've left the realm of physics. I disagree. There is great evidence for the necessity of a theory to explain what is currently being attributed to DM, but there is no evidence for DM. Expensive detectors are currently in use to try and find DM, but none has succeeded. No one can agree on what DM could be made of and even the size and shape of DM globes that supposedly surrounds galaxies is created using observational data, rather than from some deeper theoretical formula which might give it more credibility. Additional "evidence" is excessive lensing from galactic clusters and microwave background issues, but none of this evidence pointes directly to dark matter particles, only to the need for a good theory. The DM theory was a reasonable place to start, but it's sad that it has now become the only theory because everyone thinks it's the correct theory. (Dogma) We fully understand the nature of light, as much as we understand anything. Well said!! We fully understand the nature of light, as much as we understand anything. Great, then can you explain why light travels at precisely c, and also why it is that it travels invariantly? GrayGhost Gold Member @OP, if you would like an interesting collection of essays by some VERY smart people, including Einstein on the nature of "empty" space, see if you can pick up a copy of "The Philosophy of Vacuum" by Saunders and Brown. It's not a very large book, but it is very expensive, so check Amazon for used copies. I paid about$40 for mine.
Thanks for the tip on this one. The current used price is $87 which means I probably have to put it off for now but I will keep it on my list. How would you rate the level of comprehensibility? Understandable at least to a degree to an educated layman? Gold Member This is completely muddled. Either you've misunderstood half a dozen things, or you're paraphrasing someone else inaccurately, or you're repeating something said by someone else who has misunderstood half a dozen things. FAQ: Didn't Einstein say that general relativity was an aether theory? Is general relativity compatible with an aether? No, Einstein didn't say that general relativity was an aether theory. Einstein wrote a 1924 paper in which he made the philosophical point that although relativity killed off the luminiferous aether as the supposed medium of electromagnetic vibrations, it still imbued the vacuum with specific physical characteristics, such as curvature and energy. The basic point of the paper is that we can't decide, purely based on philophical ideas like Mach's principle, whether the vacuum has its own properties; we actually have to go through the usual scientific cycle of theory and experiment in order to find out the answer. Internet kooks love to misinterpret and overinterpret this paper, or to misrepresent it by saying that Einstein referred to GR in general, throughout his career, as an aether theory. A more subtle question is what kinds of aether theories can be constructed, and how they relate to (or don't relate to) general relativity. Philosophers and historians of scientists have debated whether any real aether theory ever actually existed, and what that would mean. Earman (1989) investigates earlier work by Trautman (1966), and concludes: "[A]bsolute space in the sense of a distinguished reference frame is a suspect notion, not because armchair philosophical reflections reveal that it is somehow metaphysically absurd, but because it has no unproblematic instantiations in examples that are physically interesting and that conform even approximately to historical reality." Debate on this philosophical and historical issue continues,[Rynasiewicz 2003] but one should keep in mind that this discussion is all about theories that have been falsified by observation since the Michelson-Morley experiment. Jacobson (2008) has investigated a theory in which Lorentz invariance is approximate, and is broken in the gravity sector at large Lorentz boost velocities. This theory includes phenomena like aether dust settling onto a planet and giving it an aether charge. Jacobson's model has two adjustable parameters which, if nonzero, differentiate it from general relativity, and which are constrained by astrophysical observations. It is important to note that the model is not compatible with Galilean relativity, and it predicts all the same counterintuitive phenomena as standard relativity, including, e.g., the twin paradox, length contraction, and black holes. A. Einstein, "Über den Äther," Schweizerische naturforschende Gesellschaft 105 (1924) 85 original text - http://www.wikilivres.info/wiki/Über_den_Äther English translation of [Einstein 1924]- http://www.oe.eclipse.co.uk/nom/aether.htm [Broken] commentary by John Baez on [Einstein 1924] - http://web.archive.org/web/20070204022629/http://math.ucr.edu/home/baez/RelWWW/wrong.html A. Trautman, in B. Hoffmann (editor) Perspectives in Geometry and Relativity, Bloomington, 1966, p. 413. J. Earman, World Enough and Space-Time, Absolute versus Relational Theories of Space and Time. Cambridge, 1989, MIT. Rynasiewicz, "Field Unification in the Maxwell-Lorentz Theory with Absolute Space," Philosophy of Science 70 (2003) 1063, available at http://philsci-archive.pitt.edu/archive/00001096/ . Rynasiewicz starts by summarizing two important earlier papers that are now difficult to obtain: Trautman 1966 and Earman 1989. Ted Jacobson, "Einstein-aether gravity: a status report," 2008, http://arxiv.org/abs/0801.1547 Thank you for the thorough response. There is an additional Einstein quote I'd like to add: "We may still use the word ether but only to express the physical properties of space. The word ether has changed its meaning many times in the development of science. At the moment, it no longer stands for a medium build up of particles. Its story, by no means finished, is continued by the relativity theory." So although you are likely correct in saying that Einstein did not say GR was an ether theory, it is clear he had strong feelings about giving space (as you say) properties which to me says that he is endowing space with properties of a physical, possibly measurable nature. With regard to your statement: "The basic point of the paper is that we can't decide, purely based on philophical ideas like Mach's principle, whether the vacuum has its own properties; we actually have to go through the usual scientific cycle of theory and experiment in order to find out the answer." Einstein made clear we can endow space with physical properties as indicated in the quote above, and indeed this (to me) only makes sense. Take the Gravity B probe for example. We have a gyroscope pointing at a very distant star, and in the vicinity of a large massive object we find that the gyroscope rotates due to mass and also due to the rotation of the mass. Why? Well, one reason might be that the same mechanism that occurs in the nucleus of an atom, namely messenger particles such as gluons, could be acting upon the gyroscope and causing it to shift, gravitons in other words, but does the analogy really hold? gravitons hitting the gyroscope in such a way that it shifts position? I just can't see that happening. No, the answer has to be an actual shift in the surrounding space and the gyroscope is simply following it's lead. If space is shifting, what exactly is space made of that it can shift like this? The gyroscope is responding to something, what is it responding to? Your reflection on the comment "A]bsolute space in the sense of a distinguished reference frame is a suspect notion,.." is an interesting one and I suppose is the real meat of the matter. When one thinks of ether (absolute space) the first notion is to think of a distinguished reference frame and this has been historically shown to be a hard pill to swallow, but is it really possible to have a space with physical properties (possibly meaning abstract properties) that has no preferential location? I'm not saying it's not, I'm really just asking. I actually prefer to think of it as somewhat dynamic, moving with moving bodies, making itself SR friendly, while on the other hand having a degree of preferential position giving it properties that can be defined by GR (such as warping and frame dragging). "...but one should keep in mind that this discussion is all about theories that have been falsified by observation since the Michelson-Morley experiment...." One should still keep an open mind about what the result of the MMX means. Please keep in mind that Lorentz, a dear friend of Einstein, until his death refused to give up on the clasical ether theory and had lengthy discussions with Einstein about it. The Lorentz transformations are a cornerstone of physics history (and of course of SR) and the author of these equations cannot be taken lightly. His equations in fact were created to explain the MMX null result and although Einstein took them and successfully ran with them, their true intention was to explain the MMX result. (I apologize I don't have any reference for this claim but I think it might be accepted knowledge). Thanks for the additional links, I will look at them when I can. Last edited by a moderator: member 11137 For the eyes of an amateur the debate about the ether looks quite amazing: why? The MM experiment and its interpretation gave rise to the Lorentz transformations and to SR. Some years later came the GR and, as a consequence, the prediction of the Thiring Lense effect. The latter has been recently confirmed. We can now say that it is proving that the metric is deformed around the earth because of its rotation. Philosophically speaking: doesnot all this mean that the metric tensor is the modern and actual mathematical representation of what has been called the "ether"? In some way the concept stays but its representation is a mathematical tool, not a real phenomenon. I know that it makes a great difference. Concerning the DM problem: what do you think about the Tully-fisher experimental law? Do you think we really need that concept of DM? Some references seems to suggest a negative answer. Can we derive the TF law from GR? turbo Gold Member Thanks for the tip on this one. The current used price is$87 which means I probably have to put it off for now but I will keep it on my list. How would you rate the level of comprehensibility? Understandable at least to a degree to an educated layman?
Check Abe's Books, etc. You may be able to find a cheaper copy. Mine is pristine, with a perfect dust-jacket, and no, you can't buy it.

Comprehensibility is variable, based on the complexity of the concepts in the essays, and your willingness to plow in and do some extra work when necessary.

A. Einstein, "Über den Äther," Schweizerische naturforschende Gesellschaft 105 (1924) 85

original text - http://www.wikilivres.info/wiki/Über_den_Äther

English translation of [Einstein 1924]- http://www.oe.eclipse.co.uk/nom/aether.htm [Broken]
You always have interesting stuff in your posts bcrowell.

I read some of that Einstein paper. I left thinking Einstein was saying that the "old way" of thinking of spacetime with aether is wrong because spacetime is not homogeneous itself. But that using the postulate of some sort of medium is the intuitive way to think of spacetime. And, same as the point you raised, is a personal matter. And I'd add, currently independent of experiement.

"Internet kooks love to misinterpret and overinterpret this paper, or to misrepresent it by saying that Einstein referred to GR in general, throughout his career, as an aether theory."

I'm not at all suprised he didn't publish (science) his opinion on what best describes spacetime.

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A. Einstein, "Über den Äther," Schweizerische naturforschende Gesellschaft 105 (1924) 85

original text - http://www.wikilivres.info/wiki/Über_den_Äther

English translation of [Einstein 1924]- http://www.oe.eclipse.co.uk/nom/aether.htm [Broken]

[..][/url]
Thanks for that nice list of links to Einstein's answer on that question.

For clarity (as it allows comparison), here are links to two more papers in which he expressed similar thoughts as in 1924:

- Einstein's 1920 Leiden inauguration speech (official translation with link to the German original):
http://en.wikisource.org/wiki/Ether_and_the_Theory_of_Relativity

- Einstein's 1918 paper on the clock paradox (it has a short and easy to understand discussion on the ether near the end):
http://wikilivres.info/wiki/Dialog_über_Einwände_gegen_die_Relativitätstheorie
An unofficial English translation can be found here:

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[..] I actually prefer to think of [the ether] as somewhat dynamic, moving with moving bodies, making itself SR friendly, while on the other hand having a degree of preferential position giving it properties that can be defined by GR (such as warping and frame dragging). [..]
Sorry, that would be a kind of "Stokes" ether which had been disproved well before SR. SR is compatible with an immaterial Lorentz ether (of before GR) but not with a material Stokes ether. Einstein phrased it in 1920 as follows:
The ether of the general theory of relativity is transmuted conceptually into the ether of Lorentz if we substitute constants for the functions of space which describe the former, disregarding the causes which condition its state.
Concerning the wave/particle question, you may be interested to search for contributions of Arnold Neumaier on this forum, for example in this thread: