Einstein Objecting to using Observables

Einstein's unhappiness with quantum mechanics was already clear in 1926, within a year of the theory being formulated.

Heisenberg told this story:

In the spring of 1926, I was invited to address this distinguished body [University of Berlin] on the new quantum mechanics, ...

[Einstein said] "What you have told us sounds extremely strange. You assume the existence of electrons inside the atom, and you are probably quite right to do so. But you refuse to consider their orbits, even though we can observe electron tracks in a cloud chamber. I should very much like to hear more about your reasons for making such strange assumptions."

“We cannot observe electron orbits inside the atom," I must have replied, "but the radiation which an atom emits during discharges enables us to deduce the frequencies and corresponding amplitudes of its electrons. After all, even in the older physics wave numbers and amplitudes could be considered substitutes for electron orbits. Now, since a good theory must be based on directly observable magnitudes, I thought it more fitting to restrict myself to these, treating them, as it were, as representatives of the electron orbits."

"But you don't seriously believe," Einstein protested, "that none but observable magnitudes must go into a physical theory?"

[Heisenberg] "Isn't that precisely what you have done with relativity?" I asked in some surprise. "After all, you did stress the fact that it is impermissible to speak of absolute time, simply because absolute time cannot be observed; that only clock readings, be it in the moving reference system or the system at rest, are relevant to the determination of time."

"Possibly I did use this kind of reasoning," Einstein admitted, "but it is nonsense all the same. Perhaps I could put it more diplomatically by saying that it may be heuristically useful to keep in mind what one has actually observed. But on principle, it is quite wrong to try founding a theory on observable magnitudes alone. In reality the very opposite happens. It is the theory which decides what we can observe.

Einstein is credited with abolishing the aether, absolute space, absolute time, etc., but maybe that is not how he thought about it at all. He went on to try to develop unified field theories that were completely detached from observation.

Can Gravity be Renormalized?

A big achievement of XX century Physics was renormalizing quantum electrodynamics (QED), by Feynman and others. That showed how infinities could be canceled out, so the theory can make predictions in all energy ranges.

QED is a gauge theory on the circle group. Then 'tHooft showed renormalization applied to gauge theories over other groups. Since the known particles were classified by group representations of other groups, that opened the way to the Standard Model. They just had to use the groups already linked to the the particles, and apply gauge theory renormalization.

Gauge theory was the only known renormalizable theory, so there was no choice.

Not everyone agrees that renormalizability is so important. The later invention of effective field theory seemed to bypass renormalization. String theory also provides another approach.

Attempts to quantize gravity have failed because general relativity is not renormalizable. This led people to say string theory is the only game in town, except for maybe loop quantum gravity. Neither approach has produced a quantum gravity theory.

I did not know that general relativity could be easily modified to a theory that is renormalizable.

Luca Buoninfante posts a new paper:

An important theoretical achievement of the last century was the realization that strict renormalizability can be a powerful criterion to select Lagrangians in the framework of perturbative quantum field theory. The Standard Model Lagrangian (without gravity) is strictly renormalizable from a perturbative point of view. On the other hand, the inclusion of gravity seems not to respect this criterion, since general relativity is perturbatively non-renormalizable. The aim of this work is to provide concrete evidence that strict renormalizability is still a valid criterion even when applied to gravity. First, we show that adding quadratic curvature terms to the Einstein-Hilbert action gives rise to a strictly renormalizable theory known as quadratic gravity. Second, we argue that this unique theory represents the most conservative approach to quantum gravity and, at the same time, is highly predictive, as it can explain new physics beyond general relativity already in the sub-Planckian regime.

The simplest way to define a physics theory is to specify the Lagrangian. If you do that for the Standard Model, you can fit it on a t-shirt.

General relativity is the theory derived from the scalar curvature R being the Lagrangian. Or subtract a constant, for general relativity with a cosmological constant. This paper says that you just have to add a quadratic term in the curvature, such as R² or other contractions of the squared Riemann tensor, and you get a renormalizable theory. News to me. This model is sometimes called Starobinsky inflation, and used to explain the early universe.

We do not have any way to test quantum gravity, so the best argument for this approach is that renormalizability has been such a crucially important criterion in the past. It is how we got the Standard Model.

Adding a quadratic term is a bit like Einstein adding the cosmological constant to general relativity. It could not be measured at the time, and was intended to improve the global properties of the theory. It was only measured 80 years later.

Maybe someday this quadratic gravity will be seen as the natural way to modify general relativity to handle extreme conditions.

Everybody always says that quantum mechanics and gravity are incompatible. There is no experiment that shows a problem, so there is only a theoretical incompatibility that might only apply at the center of a black hole or in the first nanosecond of the big bang.

Now I question this. As this paper explains, just add a couple of quadratic terms to the gravity Lagrangian, and there is no problem renormalizing quantum field theory predictions. The only problem is that we do not have experimental data to determine the coefficients of those extra terms. Presumably they are small enough not to affect the known celestial mechanics and cosmology.

So we have a perfectly good quantum gravity theory, with a couple of undetermined coefficients. Those coefficients are too small to affect any of our observations. Viewed that way, it is incorrect to say that there is any incompatibility between gravity and quantum theories.

A few years ago, you could have said that general relativity was incompatible with the concept of a quantum zero point energy. Now the cosmological constant is accepted, and that is believed to be the energy. Maybe we just need to add one or two more cosmological constants, and quantum gravity will cease to be a theoretical issue.

The Aether is not a Rest Frame

Physicist Sean M. Carroll says, in his latest AMA that quantum field theory has no aether because the whole point of the aether is to have a rest frame for measuring motion:

Marson chady or chatty says 50:03 when I was in high school we were told that the 19th century scientists were looking for a medium which they called 50:08 ether in which light waves would propagate eventually the theory of electromagnetism established that there 50:14 was no such medium yet I can't help but think that the original view was Vindicated by Quantum field Theory isn't 50:20 the electron field of quantum field Theory the equivalent of ether uh no it 50:25 is not the equivalent of E I have answered this question or talked about it in various times but it's been a while so let's address it again um the 50:34 fields of quantum field Theory are just the quantum versions of the fields of classical field Theory so if you think 50:41 that classical electromagnetism which is a classical field Theory uh doesn't need 50:47 ether then you don't you think that Quantum Fields don't need ether either the point is that ether was supposed to 50:53 be like you say A medium in which waves propag at whereas in contrast field 50:59 Theory uh classical or Quantum takes the fields as the fundamental independent 51:05 entities uh the waving electron field or the waving electromagnetic field or the 51:10 waving higs field or whatever none of these are waves in something other than themselves okay so that's the 51:17 ontological difference and there's also a practical difference the whole point of The Ether in 19th century physics was 51:24 to allow for there to be a rest frame with respect to which you can measure your motion uh as opposed to the naive 51:31 reading of Maxwell's equations which say there is no uh Universal rest frame so 19th century physicists went to Great 51:37 Lengths to sort of bend over backwards and figure out how you could reconcile the existence of a rest frame determined 51:44 by The Ether with the fact that you couldn't observe it in any way in Maxwell's equations and that's how they 51:49 invented things like Lorent Transformations even before relativity came on the scene but in Quantum field 51:55 Theory there's no rest frame there's no rest frame everything is perfectly relativistically invariant so the whole 52:01 point of the ether is completely missing in Quantum field Theory so I don't think that's an especially useful way of 52:07 thinking about things

No, I don't think that anyone thought that was the point of aether. For my sources, see the essays on aether in the Encyclopedia Britannica by Maxwell (9th ed, 1878) and Larmor (11th ed, 1911). See also Einstein's views on the aether. None of these say that the aether gives a rest frame.

Maxwell wrote:

The hypothesis of an aether has been maintained by different speculators for very different reasons. To those who maintained the existence of a plenum as a philosophical principle, nature's abhorrence of a vacuum was a sufficient reason for imagining an all-surrounding aether, even though every other argument should be against it. ...

But besides these high metaphysical necessities for a medium, there were more mundane uses to be fulfilled by aethers. Aethers were invented for the planets to swim in, ...

The only aether which has survived is that which was invented by Huygens to explain the propagation of light. The evidence for the existence of the luminiferous aether has accumulated as additional phenomena of light and other radiations have been discovered; ...

Whatever difficulties we may have in forming a consistent idea of the constitution of the aether, there can be no doubt that the interplanetary and interstellar spaces are not empty, but are occupied by a material substance or body, which is certainly the largest, and probably the most uniform body of which we have any knowledge.

In quantum field theory, the vacuum is not empty, and could be regarded as a medium for the propagation of light, and for electrons and everything else.

The story is often told that Einstein invented relativity in order to disprove the aether, show that there can be no rest frame. This story is false, as Einstein did not invent relativity, and what he said about the aether was essentially the same as what Lorentz wrote ten years earlier. The theory of relativity does not say whether there can be a rest frame.

I wonder why people keep telling this silly story. My guess is that people like to believe that the aether was some sort of superstitious belief of lesser men, and that rejecting it was a great intellectual accomplishment, along with rejecting God, the monarchy, and geocentrism.

Carroll is also asked to speculate about the development of general relativity:

nichel Kramer says if Einstein had 2:00:51 not veloped general relativity when he did how soon would it have been developed well we don't know um I don't 2:00:57 think it would have taken that long like it wouldn't have taken 50 or 100 years we already had all the tools right we 2:01:03 had riemanian geometry we had special relativity it's possible for example 2:01:08 that minkowski or minkovsky to be a little bit more correct would have developed it Herman minkovski of course 2:01:14 um was the first to promote the idea of thinking about relativity in terms of SpaceTime and he was a mathematician he 2:01:21 had actually taught Einstein uh so it was 1907 2 years after Einstein's special relativity papers that minkovsky 2:01:27 first said we should think about it in terms of SpaceTime um Einstein eventually settled on general relativity 2:01:33 in 1915 but minkovski passed away in 1909 so he didn't really get a chance to 2:01:39 follow up on his Insight that we should think about things in terms of SpaceTime maybe he would have come up with it but 2:01:45 you know it's an interesting fact about the progress of physics that the progress of physics on theoretical 2:01:51 physics is usually led by physicists not by mathematicians with overwhelming um 2:01:57 probability not that it's impossible to imagine mathematicians doing it but when we think back to how general relativity 2:02:04 came about and there were you know real mathematical issues there and a lot of important steps were taken by 2:02:11 mathematicians benovsky is one David Hilbert of course is another but still it was a physicist it was Albert 2:02:16 Einstein who actually put it together because that physics insight about 2:02:22 the principle of equivalence and how gravity works and things like that that's the bread and butter of physicists not mathematicians the 2:02:29 question is was there any other physicist who would have thought the same way as Einstein there were certainly physicists who had the same 2:02:36 mathematical chops that Einstein did but the physical Insight that he had was unmatched since Galileo basically uh and 2:02:43 has still been unmatched since so it might have taken a while but the tools were there so I don't think it would have taken too 2:02:49 long

I agree that physicists are better at physical insight than mathematicians, but his examples are distorted.

Poincare, Minkowski, Grossmann, and Hilbert were all primarily mathematicians, and they were the chief originators of relativity theory, after Lorentz. Poincare published the first relativistic theory of gravity. Poincare and Minkowski both died before general relativity. Einstein's first general relativity version was a joint work with Grossmann, and his second was a joint work with Hilbert. Einstein also worked with mathematicians Levi-Civita and Ricci.

Carroll says that Minkowski's 1907 spacetime was two years after Einstein, but it is doubtful that Einstein's work was any influence at all. Minkowski's spacetime was based on Poincare's spacetime.

The Aether was not a Fringe Theory

An anonymous Wikipedia comment:

I'm perplexed that the other commenters identify ether theory as a fringe theory. I suppose, by their definition, Newtonian mechanics is also a "fringe theory" simply because it is outdated, and yet nobody is out to debunk Newtonian mechanics (in fact we teach it in schools). "Debunking" ether theory and obscuring its pedagogical utility is clearly an emotional pursuit for these people. It's hard to understand where this religious mentality about ether theory comes from, except in the context of a century of propaganda, as you pointed out. The attitude is clearly political and inappropriate (yet all too common) on Wikipedia.

I agree. If you think that aether theory was somehow wrong or unscientific, then read J.C. Maxwell's 1878 article in the Encyclopedia Britannica. He did not know that the aether had to be invariant under Lorentz transformations, but his essay holds up pretty well.

Here is what Lorentz's famous 1895 relativity paper said. After dismissing some aether theories:

It is not my intention to enter into such speculations more closely, or to express assumptions about the nature of the aether. I only wish to keep myself as free as possible from preconceived opinions about that substance, and I won't, for example, attribute to it the properties of ordinary liquids and gases. If it is the case, that a representation of the phenomena would succeed best under the condition of absolute permeability, then one should admit of such an assumption for the time being, and leave it to the subsequent research, to give us a deeper understanding. ​That we cannot speak about an absolute rest of the aether, is self-evident; this expression would not even make sense. When I say for the sake of brevity, that the aether would be at rest, then this only means that one part of this medium does not move against the other one and that all perceptible motions are relative motions of the celestial bodies in relation to the aether.

Einstein said essentially the same thing in 1905:

The introduction of a “luminiferous ether” will prove to be superfluous inasmuch as the view here to be developed will not require an “absolutely stationary space” provided with special properties, nor assign a velocity-vector to a point of the empty space in which electromagnetic processes take place.

Poincare wrote in a popular 1902 book that the aether is a convenient hypothesis what will someday be thrown aside as useless.

The lesson from relativity was not that the aether was wrong, or unscientific, or nonexistent, or exemplary of 19th century thinking.

The lesson was that theories based on motion against the aether were disproved.

The aether is sometimes defined as whatever transmits electromagnetism. If it is Lorentz invariant, then it poses no problem for relativity.

The existence of a preferred frame poses no problem either. The cosmic microwave radiation can be used to define what a rest frame is, so there is nothing wrong with that concept.

There was a time, maybe a century ago, when one could make fun of ancient scientists for lacking the imagination to understand that a vacuum might be empty space. But a vacuum is not really empty in today's theories either.

Reality and substantiality of the luminiferous ether

Science Friday has a segment making of wrong theories in the history of science, and last Friday the target was the aether. They mock this 1884 Lord Kelvin essay:

This thing we call the luminiferous ether. That is the only substance we are confident of in dynamics. One thing we are sure of, and that is the reality and substantiality of the luminiferous ether. ...

I move through this “luminiferous ether” as if it were nothing. ... What can this luminiferous ether be? It is something that the planets move through with the greatest ease. It permeates our air; it is nearly in the same condition, so far as our means of judging are concerned, in our air and in the inter-planetary space. The air disturbs it but little; you may reduce air by air-pumps to the hundred thousandth of its density, and you make little effect in the transmission of light through it. The luminiferous ether is an elastic solid, for which the nearest analogy I can give you is this jelly which you see, 5 and the nearest analogy to the waves of light is the motion, which you can imagine, of this elastic jelly, with a ball of wood floating in the middle of it. ...

What we know of the luminiferous ether is that it has the rigidity of a solid and gradually yields. Whether or not it is brittle and cracks we cannot yet tell, but I believe the discoveries in electricity and the motions of comets and the marvellous spurts of light from them, tend to show cracks in the luminiferous ether — show a correspondence between the electric flash and the aurora borealis and cracks in the luminiferous ether. Do not take this as an assertion, it is hardly more than a vague scientific dream: but you may regard the existence of the luminiferous ether as a reality of science; that is, we have an all-pervading medium, an elastic solid, with a great degree of rigidity — an rigidity so prodigious in proportion to its density that the vibrations of light in it have the frequencies I have mentioned, with the wave-lengths I have mentioned. The fundamental question as to whether or not luminiferous ether has gravity has not been answered. We have no knowledge that the luminiferous ether is attracted by gravity; it is sometimes called imponderable because some people vainly imagine that it has no weight; I call it matter with the same kind of rigidity that this elastic jelly has.

Okay, some of this stuff about cracks and jelly seem ridiculous today, but most of it is mostly correct. The discovery of dark energy could be said to be an answer to his question about "whether or not luminiferous ether has gravity".

Special relativity taught nothing about whether the aether exists. It only taught that any such aether must be Lorentz invariant. As the program conceded at the end, modern quantum field theory does have the concept of a pervasive medium like the aether, as that is how the Higgs field is explained.

The program explained about the Michelson-Morley experiment, and how it failed to detect aether motion. While it was decisive in the discovery and acceptance of special relativity, Einstein seemed to have only vague third-hand knowledge of it.

Yes, it is a historical fact that the MM experiment was crucial for special relativity, but not for Einstein's thinking. Einstein's famous paper was to give an exposition of Lorentz's theory, but it did not bother to explain Lorentz's MM-based reasoning.

Einstein was not the aether slayer

A anonymous commenter repeats the belief that credits Einstein for abolishing the aether:

Once Einstein's relativity theory of popularized by Minkowski, many papers were written, and references to Einstein (and Lorentz) were abundant. For example, in 1910, Wilhelm Wein proposed Lorentz and Einstein jointly for the Nobel prize for relativity. Einstein was famous among physicists as the originator of special relativity and the "ether slayer" long before he became a popular celebrity. Poincare's paper was nearly forgotten (Pauli had to be prompted by Klein to mention it in a footnote in his 1921 encyclopedia article) until the 1950's when historians of science started to notice it.

The notion of Einstein as an "ether slayer" (or aether slayer, in the old-fashioned spelling) is a widespread misconception. To show how wrong this is, I repost a 2011 article that quotes what Lorentz, Einstein, and Poincare actually said about the aether.

There are many claims [in the Relativity priority dispute article on Wikipedia] that Lorentz and Poincare clung to a stationary aether, while Einstein abolished it. It is much more accurate to say that Lorentz and Einstein had the same beliefs about the aether, and Poincare abolished it.

Lorentz's 1895 paper says, after a discussion of previous aether theories:

It is not my intention to enter into such speculations more closely, or to express assumptions about the nature of the aether. I only wish to keep me as free as possible from preconceived opinions about that substance, and I won't, for example, attribute to it the properties of ordinary liquids and gases. ...

That we cannot speak about an absolute rest of the aether, is self-evident; this expression would not even make sense. When I say for the sake of brevity, that the aether would be at rest, then this only means that one part of this medium does not move against the other one and that all perceptible motions are relative motions of the celestial bodies in relation to the aether.

Einstein's 1905 paper only says this about the aether:

The introduction of a “luminiferous ether” will prove to be superfluous inasmuch as the view here to be developed will not require an “absolutely stationary space” provided with special properties, nor assign a velocity-vector to a point of the empty space in which electromagnetic processes take place.

So Lorentz said that he was not expressing assumptions about the aether, and Einstein said that the introduction of aether was superfluous to his presentation. Lorentz said that the absolute rest of the aether makes no sense, and Einstein said that absolutely stationary space was not required.

In the three years after 1905, there is no record of Lorentz or Einstein expressing any disagreement about the aether, or of anyone else finding any such difference. Their theory was called Lorentz-Einstein theory. After 1908, the Poincare-Minkowski spacetime approach became popular, and the Lorentz-Einstein theory was obsolete.

Poincare wrote:

Whether the ether exists or not matters little - let us leave that to the metaphysicians; what is essential for us is, that everything happens as if it existed, and that this hypothesis is found to be suitable for the explanation of phenomena. ... while some day, no doubt, the ether will be thrown aside as useless. [1889]

There is no absolute space, and we only conceive of relative motion; and yet in most cases mechanical facts are enunciated as if there is an absolute space to which they can be referred. 2. There is no absolute time. When we say that two periods are equal, the statement has no meaning, and can only acquire a meaning by a convention. [1901]

It is very strange that anyone would attach such great importance to the aether, when it played no part in Poincare's theory.

See also this 2012 post where I discuss some confusing Einstein writings about the aether in 1907 and 1909.

Not to reveal to us the real nature of things

Much of the confusion over the interpretation of quantum mechanics concerns whether the mathematical wave functions reveal to us the true (ontic) nature of electrons and photons.

Henri Poincare explained it in his famous 1902 book:

The object of mathematical theories is not to reveal to us the real nature of things; that would be an unreasonable claim. Their only object is to co-ordinate the physical laws with which physical experiment makes us acquainted, the enunciation of which, without the aid of mathematics, we should be unable to effect. Whether the ether exists or not matters little — let us leave that to the metaphysicians; what is essential for us is, that everything happens as if it existed, and that this hypothesis is found to be suitable for the explanation of phenomena. After all, have we any other reason for believing in the existence of material objects? That, too, is only a convenient hypothesis; only, it will never cease to be so, while some day, no doubt, the ether will be thrown aside as useless. [Science and Hypothesis, chap. 12, 1st paragraph]

Yes, I could not say it better today. The object of mathematical theories is to make sense of quantified experiments, not to be a perfect description of the real nature of electrons.

The aether is a convenient hypothesis, because our best theories assume a pervasive and uniform quantum field. Even in a vacuum, it has energy, Lorentz symmetries, gauge fields, and virtual particles. Quantum electrodynamics is all about perturbations to that quantum vacuum. In the early XXc the aether was cast aside as useless but it keeps coming back under different names.

It is foolish to think that the true nature of the electron is its wave function. That is just a mathematical device for predicting observables. Attempts to clarify the nature of electrons with hidden variables, as by Bell and his followers, are even more foolish.

Bouncing oil droplets reveal slippery truth

Ross Anderson writes:

I am a heretic. There, I've said it. My heresy? I don't believe that quantum computers can ever work.

I've been a cryptographer for over 20 years and for all that time we've been told that sooner or later someone would build a quantum computer that would factor large numbers easily, making our current systems useless.

However, despite enormous amounts of money spent by research councils and government agencies, the things are stuck at three qubits. Factoring 15 is easy; 35 seems too hard. A Canadian company has started selling computers they claim are quantum; scientists from Google and NASA said they couldn't observe any quantum speed-up.

Recently, the UK government decided to take £200m from the science budget and devote it to found a string of new "quantum hubs". That might be a bad sign; ministerial blessing is often the last rites for a failing idea.

So will one more heave get us there, or is it all a waste of time?

Not only that, he has co-authored Maxwell's fluid model of magnetism. He claims that physics went bad about 150 years ago, and some ideas that were abandoned then are really right.

Scott Aaronson says that it is extremely safe to say that he is wrong, but is not able to pinpoint the error. Aaronson trashed some related work in 2013.

I sometimes get comments saying that mainstream physics has been wrong for a century or more. I don't know how to evaluation such claims. Science is never that completely wrong.

Anderson's theory seems to be some sort of hidden variable theory. I am persuaded that XX century quantum theory and experiments have ruled these out. So I do not see how he can be right.

Anderson is one of the world's experts on cryptographic security for banking and related industries. My guess is that he is frequently asked whether banks should use quantum cryptography, or worry about attacks from quantum computing. He surely comes to the conclusion, as do I, that both subjects are almost completely irrelevant to banking. Then he must be frustrated by bankers who doubt him because so many big-shots are over-hyping the quantum stuff.

I think that he is right that quantum computers will never work, and that failures so far give good reason for skepticism. I differ from him in that I doubt that there is anything fundamentally wrong with quantum mechanics.

Nonempty vacuum is not crazy

Physicist Lawrence Krauss writes:

Throughout my career I’ve been surprised. Perhaps the most amazing surprise to me was actually one that I ultimately proposed but it defied everything I'd thought before. And that is this amazing result that empty space has energy.

It is so weird to think that you can get rid of all the particles and all the radiation in space and it still weighs something. It seems crazy. And when I was a graduate student, we were all certain that the energy of empty space was zero. And ultimately we were dragged - in fact, I was dragged, kicking and screaming by the observations - to propose this incredibly crazy idea that empty space has energy.

In fact, it’s been observed to have energy. In fact, the people who observed it won the Nobel Prize last year. And I think for me that has changed everything about my understanding of the universe. Both its past, its present, and its future. And I think it’s a wonderful example of how scientists are willing to throw out ideas like yesterday’s newspaper.

This opinion is odd. The Wikipedia article on Zero-point energy says that the concept is a century old, and has been essential to our understanding of quantum mechanics. In the 19th century, it was called the aether. People were skeptical about it being cosmologically observable, and I agree with giving a Nobel Prize for the 1998 astronomy work, but it was not so contrary to conventional wisdom. It was not a crazy idea.

I agree with his point about throwing out failed ideas, but that means throwing out many-worlds interpretation, string theory, Bohm nonlocal mechanics, supersymmetry, black hole firewalls, proton decay, massless neutrinos, etc.

Update: Sabine Hossenfelder posts examples of papers before 1998 suggesting an accelerating cosmological expansion.

Poincare disbelieved in the aether

Henri Poincaré's Wikipedia page says, "but contrary to Einstein he continued to use the ether-concept in his papers". This is backwards.

Here is an example of someone misreading Poincare to argue that he believed in the aether. A 2006 paper, Can science advance effectively through philosophical criticism and reflection?, by Roberto Torretti, says:

In the highly acclaimed electrodynamic theory — or ought we to say theories? — of Lorentz, the ether is completely motionless and its mechanical structure and behavior — if it has any — is of no concern at all. As Whittaker lucidly wrote: “Such an aether is simply space endowed with certain dynamical properties” (1951/53, 1:393).

That's right. Today people try to put down Lorentz's relativity by calling it Lorentz aether theory, instead of electron theory, as it used to be called. It did not depend on the aether, as noted here and here.

It is therefore no wonder that, despite Lorentz explicit warning to the contrary,50 the general public, including most philosophers and even some physicists, identified his ether with Newton’s absolute space, or at any rate assumed that it was at rest in it.51 Still, the idea that this elusive form of matter was part of the furniture of the universe had become deeply entrenched during the 19th century, and nobody seemed willing to dismiss it. Surely it is not easy for a highly respected profession to admit that one of its time-honored terms of art is a noun without a referent.52 Even Poincaré, who in 1889 had predicted that “the day will doubtless come when the ether will be rejected as useless”,53 at the Paris Congress of Physics of 1901 argued thus for believing in it:

We know where our belief in ether comes from. If we receive light from a distant star, for several years that light is no longer at the star and is not yet on the Earth. It must therefore be somewhere, sustained, so to speak, by some material support. The same idea can be expressed in a more mathematical and more abstract way. What we record are the changes suffered by material molecules; we see, for example, that our photographic film displays the consequences of phenomena staged many years earlier in the incandescent mass of the star. Now, in ordinary mechanics, the state of the system under study depends only on its state in an immediately preceding state; the system therefore satisfies differential equations. But if we did not believe in the ether, the state of the material universe would depend not only on the immediately preceding state (l’état immédiatement antérieur), but on much older states; the system would satisfy finite difference equations. To avoid this derogation of the general laws of mechanics we have invented the ether.54

[Footnote 54] Poincaré (1901b); translated by me from Poincaré (1968), pp. 180-181. I cannot repress the feeling that Poincaré the mathematician must have known (i) that if a given physical state depends on another in accordance with a system of differential equations, none of the two states can immediatelyprecede (or follow) the other one, and (ii) that time dependent vector fields can be defined on space without assuming a material support for them to sit on. I suppose (ii) is the reason why he talks of inventing the ether at the end of this tirade about believing in it.

Poincare did not argue for believing in the aether. He argued that it was a mathematical convenience. His philosophy is often called conventionalism because of opinions such as this.

This is a point that mathematicians grasp immediately, but physicists and philosophers have a lot of difficulty with. Poincare was a mathemetician. Mathematicians frequently define concepts for mathematical convenience, regardless of whether they are physically observable.

Anyone who says that Poincare believed in the aether fails to grasp that simple point.

Why solid matter is solid

The current Radiolab podcast says:

It's comforting to think that if you take an object -- a rock, let's say -- and break it down into tinier and tinier more elemental parts, that that's exactly what you end up with: smaller and smaller particles until you reach the smallest. And voila! Those are the building blocks of everything around us.

But as Jim Holt, author of Why Does the World Exist? points out... that's an old worldview that no longer jives with modern-day science. If you start slicing and sleuthing in subatomic particle land -- trying to get to the bottom of what makes matter -- you mostly find empty space. Your hand, your chair, the floor...it's all made up of mostly of nothing.

I say the old worldview is more accurate.

It is not true to say the modern-day science teaches that atoms are mostly empty space. First, there is no such thing as empty space, as modern physics teaches that it is filled with pervasive fields that used to be called the aether. Second, atoms are held together by nuclear and electromagnetic fields, and those fields fill up atoms and material objects.

Holt goes on to say that solid matter is solid because of the Pauli Exclusion Principle and the Heisenberg uncertainty principle, and not because of the electrical properties of electrons. This is only partially correct, and not a helpful explanation. For a more technical explanation, I suggest this review.

Holt's attitude seems to be that because we have mathematical descriptions of subatomic particles, matter is just ethereal math, and is not substantial. Physicists sometimes talk this way, so he is not just making it up. First, we have not reduced these atoms to pure math. Second, having mathematical approximations has nothing to do with matter being substantial.

Holt's book made the NY Times list of the 10 best books of 2012, and it was the only science book on the list. Maybe I should read his book to get his full story, as maybe he quotes prominent physicists for his goofy ideas.

Aether no more than a metaphysical construct

Steve Carlip and Philip Gibbs summarize the history of special relativity:

In 1879 it was thought that light must propagate through a medium in space just as sound propagates through the air and other substances. The two scientists Michelson and Morley set up an experiment to attempt to detect the ether, by observing relative changes in the speed of light as the Earth changed its direction of travel relative to the sun during the year. To their surprise, they failed to detect any change in the speed of light.

Fitzgerald then suggested that this might be because the experimental apparatus contracted as it passed through the ether, in such a way as to countermand the attempt to detect the change in velocity. Lorentz extended this idea to changes in the rates of clocks to ensure complete undetectability of the ether. Einstein then argued that those transformations should be understood as changes of space and time rather than of physical objects, and that the absoluteness of space and time introduced by Newton should be discarded. Just after that, the mathematician Minkowski showed that Einstein's theory of relativity could be understood in terms of a four dimensional non-euclidean geometry that considered space and time as one entity, ever after called spacetime.

This refers to Fitzgerald 1889, Lorentz 1895, Einstein 1905, and Minkowski 1908. It ignores the 1899-1905 work of Lorentz and Poincare, where they perfected the Lorentz transformations and applied them to space and time more generally than Einstein, and before Einstein.

But what if we pursued the original theory of Fitzgerald and Lorentz, who proposed that the ether is there, but is undetectable because of physical changes in the lengths of material objects and the rates of clocks, rather than changes in space and time? For such a theory to be consistent with observation, the ether would need to be completely undetectable using clocks and rulers. Everything, including the observer, would have to contract and slow down by just the right amounts. Such a theory could make exactly the same prediction in all experiments as the theory of relativity; but in that case the ether would be no more than a metaphysical construct unless there was some other way of detecting it — which nobody has found. In the view of Einstein, such a construct would be an unnecessary complication, to be best eliminated from the theory.

That is correct about Lorentz aether theory, and it is what Poincare always said. As early as 1889, he said:

Whether the ether exists or not matters little - let us leave that to the metaphysicians; what is essential for us is, that everything happens as if it existed, and that this hypothesis is found to be suitable for the explanation of phenomena. After all, have we any other reason for believing in the existence of material objects? That, too, is only a convenient hypothesis; only, it will never cease to be so, while some day, no doubt, the ether will be thrown aside as useless.

Poincare also said this in his popular 1902 book, which Einstein read with his physicist friends. They say that he was greatly fascinated by it.

Sometimes Einstein fans imply that Lorentz and Poincare had an inferior understanding of relativity because they did not realize that experiments had reduced the aether to an undetectable metaphysical construct. But that is exactly how Poincare described it. Einstein was not as clear about it, and used language similar to Lorentz.

I explain these points in my book.

Aether dominates accepted physics

Canon T3i 18.0MP Digital SLR Camera with 18-55mm IS Lens - Digital (Google Affiliate Ad)The Wikipedia article on the Relativity priority dispute says:

But they [most historians of science like Holton] argue that it was Einstein who completely eliminated the classical ether ...

Yes, most historians like Holton say that, but it is also directly contrary to what other reputable sources say. For example, a very prominent physicist says:

“Quite undeservedly, the ether has acquired a bad name. There is a myth repeated in many popular presentations and textbooks, that Albert Einstein swept it into the dustbin of history. The real story is more complicated and interesting. I argue here that the truth is more nearly the opposite: Einstein first purified, and then enthroned, the ether concept. As the 20th century has progressed, its role in fundamental physics has only expanded. At present, renamed and thinly disguised, it dominates the accepted laws of physics.” [Fantastic Realities: 49 Mind Journeys And a Trip to Stockholm, By Frank Wilczek, Betsy Devine, 2006, p.293]

Yes, Wilczek is correct. Yes, the aether is essential to modern theories of electromagnetism. The biggest physics news of the 21st century is the discovery of the Higgs boson, and that was the confirmation of a 50 year old aether theory.

It is crazy to talk of eliminating the aether as if that were some great accomplishment. Explaining the failure to detect aether velocity led to the theory of relativity, but Einstein himself said that it was a mistake to deny the aether. The aether (under various names) is essential to modern physics.

The Higgs aether

With all the publicity about the discovery of the Higgs boson, hardly anyone is explaining that it is a confirmation of modern Aether theories. Usually any mention of the aether is followed by saying that it was a quaint 19th century concept that was disproved by Einstein's relativity. But that is not true, and was not even Einstein's view.

The concept of the luminiferous aether dates back to ancient times, and refers to whatever fills outer space that allows us to see the light of the stars. It is sometimes said that the vacuum is empty space, and that no such aether is needed to explain the propagation of light. But that is not true either, as modern theories of light require a nonempty vacuum. Quantum electrodynamics is a perturbation theory of the aether.

The authoritative description of the 19th century aether is J.C. Maxwell's 1878 encyclopedia article. That concluded:

No theory of the constitution of the aether has yet been invented which will account for such a system of molecular vortices being maintained for an indefinite time without their energy being gradually dissipated into that irregular agitation of the medium which, in ordinary media, is called heat.

Whatever difficulties we may have in forming a consistent idea of the constitution of the aether, there can be no doubt that the interplanetary and interstellar spaces are not empty, but are occupied by a material substance or body, which is certainly the largest, and probably the most uniform body of which we have any knowledge.

Whether this vast homogeneous expanse of isotropic matter is fitted not only to be a medium of physical interaction between distant bodies, and to fulfil other physical functions of which, perhaps, we have as yet no conception, but also, as the authors of the Unseen Universe seem to suggest, to constitute the material organism of beings exercising functions of life and mind as high or higher than ours are at present, is a question far transcending the limits of physical speculation.

Maxwell's view was that the aether was pervasive, uniform, invisible, frictionless, and permeating matter. It is sometimes said that the aether presupposed some sort of fixed coordinate system, but Maxwell does not say that.

What I say here is the consensus view, except that not everyone uses the word "aether". Frank Wilczek, the 2004 Nobel Prize winner in physics, wrote the book, The Lightness of Being: Mass, Ether, and the Unification of Forces:

In the first part of the twentieth century, the upheavals of relativity and (especially) quantum theory shattered the foundations beneath classical physics. Existing theories of matter and light were reduced to rubble. That process of creative destruction made it possible to construct, over the second part of the twentieth century, a new and deeper theory of matter/light that removed the ancient separation. The new theory sees a world based on a multiplicity of space-filling ethers, a totality I call the Grid. The new world-model is extremely strange, but also extremely successful and accurate.

He details:

What is Space? Is it an empty stage, where the physical world of matter acts out its drama -- an equal participant, like the classical Ether, that both provides background and has a life of its own -- or the primary reality, of which matter is a secondary manifestation? Today, the third view is triumphant. Where our eyes see nothing our brains, pondering the revelations of sharply tuned experiments, discover the Grid that powers physical reality.

The Higgs boson is not just some isolated particle. It is the quantization of an aether that is pervasive, uniform, invisible, frictionless, and permeating matter. And that aether is completely essential to modern physics.

The Higgs aether gives mass to the electrons and quarks, the basic constituents of matter. All electrons are identical, and have the same mass. So the Higgs is the same everywhere. The aether is the largest and most uniform body, just as Maxwell said.

You could also say that there is an electron field in a vacuum, with fluctuations making virtual electrons. But there is no net number of electrons. The Higgs aether is different in that the Higgs field is nonzero in the vacuum.

Higgs boson discovered

The Higgs boson discovery is being announced:

On Wednesday (July 4), scientists heading two major experiments at the LHC plan to announce their most recent findings ...

The Higgs boson is the last piece of the physics Standard Model, a collection of theories that underpin all modern physics. The Higgs particle is theorized to mediate mass -- like a photon (also a boson) mediates the electromagnetic force, i.e., light -- and creates the "Higgs field" that must pervade the entire Universe, endowing matter with mass.

Dennis Overbye writes:

Known as the Higgs boson, it explains why things in the universe have mass, and is a cornerstone of modern physics despite never being seen.

Here is why we believe in the Higgs, and why it was really discovered decades ago.

Geometry symmetry is the most important concept in 20th century physics. Poincare introduced it with his 1905 geometric version of special relativity, and his search for physical laws that obey symmetries. Its crucial importance to classical mechanics was shown by Noether, and the importance to quantum mechanics by Hermann Weyl. The concept can be used to generalize electromagnetism to other fields (like strong and weak forces), as shown by Weyl, Higgs, 'tHooft, and others.

The Standard Model is based on geometric symmetries, but if there are too many of them, then all particles are massless like photons and nothing interesting happens. So there has to be a field that breaks the symmetry. All fields are quantized, so there has to be a particle also. That is what is being found at 125 GeV.

In a sense, the Higgs is like an aether that is uniform, everywhere, and invisible. You could say that mass is just a measure of resistance to passing thru the Higgs aether. This description is a little misleading because most of the proton mass comes from the binding energy of the quarks, but the quark mass is believed to be derived from the Higgs breaking the symmetry. This is all explained in my book. For a recent survey by an expert, see Wilczek, Origins of Mass.

If you have been watching PBS TV science shows, you might have been expecting LHC announcements on string theory, supersymmetry, and the multiverse. However, all of the evidence has been against those misguided concepts.

Update: Overbye adds in the July 4 NY Times:

Physicists working at CERN’s Large Hadron Collider said Wednesday that they had discovered a new subatomic particle that looks for all the world like the Higgs boson, a potential key to understanding why elementary particles have mass and indeed to the existence of diversity and life in the universe. ...

Confirmation of the Higgs boson or something very like it would constitute a rendezvous with destiny for a generation of physicists who have believed in the boson for half a century without ever seeing it. And it reaffirms a grand view of a universe ruled by simple and elegant and symmetrical laws, but in which everything interesting in it, such as ourselves, is due to flaws or breaks in that symmetry.

According to the Standard Model, which has ruled physics for 40 years now, the Higgs boson is the only visible and particular manifestation of an invisible force field, a cosmic molasses that permeates space and imbues elementary particles that would otherwise be massless with mass. Particles wading through it would gain heft.

Without this Higgs field, as it is known, or something like it, physicists say all the elementary forms of matter would zoom around at the speed of light, flowing through our hands like moonlight. There would be neither atoms nor life. ...

Although they have never been seen, Higgs-like fields play an important role in theories of the universe and in string theory. Under certain conditions, according to the strange accounting of Einsteinian physics, they can become suffused with energy that exerts an anti-gravitational force. Such fields have been proposed as the source of an enormous burst of expansion, known as inflation, early in the universe, and, possibly, as the secret of the dark energy that now seems to be speeding up the expansion of the universe.

The Higgs boson is the most unusual known particles, being spin 0 and playing a unique symmetry-breaking role. Its discovery is the most dramatic achievement of theoretical physics in history. It is part of the aether that is completely essential to modern physics. The aether is everywhere, uniform, and invisible.

The aether probably explains dark energy, but none of this has anything to do with string theory. String theory does not predict an aether, Higgs boson, or dark energy. After 30 years of work by the world's smartest physicists, it has never had a success like the Higgs. The Higgs is a confirmation of the theory that string theory was supposed to replace.

SciAm blogger John Horgan writes:

Hearing all the hoopla about the Higgs, the public might understandably assume that it represents a crucial step toward a unified theory–and perhaps at least tentative confirmation of the existence of strings, branes, hyperspaces, multiverses and all the other fantastical eidolons that Kaku, Stephen Hawking, Brian Greene and other unification enthusiasts tout in their bestsellers.

But the Higgs doesn’t take us any closer to a unified theory than climbing a tree would take me to the Moon.

That's right. The LHC spent $10B to confirm the high-energy physics of the 1970s, but all hopes for a grander theory have been a total failure.

Horgan also says:

Physicists have already produced theories –- Newtonian mechanics, quantum mechanics, general relativity, nonlinear dynamics –- that work extraordinarily well in certain domains, and there is no reason why there should be a single theory that accounts for all the forces of nature. The quest for a unified theory will come to be seen not as a branch of science, which tells us about the real world, but as a kind of mathematical theology.

I agree with that, and I go further in my FQXi essay. I say that there is no reason that this mathematical theology should even be valid for those domains like quantum mechanics. Theoretical physicists are chasing the impossible.

Dark energy is an aether

Caltech cosmologist Sean M. Carroll writes:

Probably the biggest single misconception I come across in popular discussions of dark matter and dark energy is the accusation that these concepts are a return to the discredited idea of the aether. They are not -- in fact, they are precisely the opposite.

Back in the later years of the 19th century, physicists had put together an incredibly successful synthesis of electricity and magnetism, topped by the work of James Clerk Maxwell. They had managed to show that these two apparently distinct phenomena were different manifestations of a single underlying "electromagnetism." One of Maxwell's personal triumphs was to show that this new theory implied the existence of waves traveling at the speed of light -- indeed, these waves are light, not to mention radio waves and X-rays and the rest of the electromagnetic radiation spectrum.

The puzzle was that waves were supposed to represent oscillations in some underlying substance, like water waves on an ocean. If light was an electromagnetic wave, what was "waving"? The proposed answer was the aether, sometimes called the "luminiferous aether" to distinguish it from the classical element. This idea had a direct implication: that Maxwell's description of electromagnetism would be appropriate as long as we were at rest with respect to the aether, but that its predictions (for the speed of light, for example) would change as we moved through the aether. The hunt was to find experimental evidence for this idea, but attempts came up short.  The Michelson-Morley experiment, in particular, implied that the speed of light did not change as the Earth moved through space, in apparent contradiction with the aether idea.

So the aether was a theoretical idea that never found experimental support. In 1905 Einstein pointed out how to preserve the symmetries of Maxwell's equations without referring to aether at all, in the special theory of relativity, and the idea was relegated to the trash bin of scientific history.

Aether was a concept introduced by physicists for theoretical reasons, which died because its experimental predictions were ruled out by observation. Dark matter and dark energy are the opposite: they are concepts that theoretical physicists never wanted, but which are forced on us by the observations.

I do not agree with this. The main experimental prediction of the aether was that light has wave properties, and has the same properties everywhere.

Here is what Michelson concluded in his 1881 paper, The Relative Motion of the Earth and the Luminiferous Ether:

The result of the hypothesis of a stationary ether is thus shown to be incorrect, and the necessary conclusion follows that the hypothesis is erroneous.

This conclusion directly contradicts the explanation of the phenomenon of aberration which has been hitherto generally accepted, and which presupposes that the earth moves through the ether, the latter remaining at rest.

So only a particular aether hypothesis was negated. Lorentz later showed in 1895 that this conclusion was false, and that the experiment was consistent with an aether at rest. Lorentz himself said said in 1895, "It is not my intention to ... express assumptions about the nature of the aether."

Contrary to Carroll, the aether was not necessarily thought to have a “frame of rest” in the 1800s. See Maxwell's 1878 essay for a survey of aether theories.

Dark energy is the discovery that the ubiquitous and uniform aether has positive energy and negative pressure. We do not know that the energy has a role in the transmission of light, so there may be more than one aether. But it fits right in with the aethers that Maxwell wrote about.

Explained by local deterministic processes

The 2010 Wolf Prize in Physics citation says:

The puzzling properties of entangled quantum states, first noted by Einstein, Podolsky and Rosen, who suspected that quantum mechanics is not a complete theory, were dramatically delineated by the remarkable work of John Bell. Bell showed that certain statistical correlations between properties of two physically separated particles, which were produced in an entangled quantum state, cannot be explained by any theory of local deterministic processes even if other unobserved properties (‘hidden variables') are allowed for.

None of this is correct. Entanglement was part of quantum mechanics before the 1935 EPR paper. Einstein got it from Popper's 1934 experiment. EPR was about uncertainty principle and completeness, not spin and determinism. More importantly, Bell's theorem only shows that quantum mechanics differs from certain local hidden variable theories. It says nothing about local deterministic processes.

The Wolf statement is like saying, "relativity experiments like Michelson-Morley show that light cannot be explained by any theory of space and time, even if the aether is allowed for. Well, no. Relativity explains Michelson-Morley and quantum mechanics explains spin entanglement.

Relativity does require some adjustments to your preconceptions about space and time, and quantum mechanics requires some adjustments to your preconceptions about hidden variables. If you refuse to make those adjustments, and insist on making your own assumptions, then sure, you will get some contradictions. That is what Bell and those Wolf Prize winners discovered. But they did not discover any experiments that cannot be explained by local deterministic processes.

Why There Is Something Rather Than Nothing

Lawrence Krauss's book, A Universe From Nothing: Why There Is Something Rather Than Nothing, continues to cause controversy, as noted below. Peter Woit writes:

In this morning’s developments, we have prominent skeptic Michael Shermer, in Much Ado About Nothing, making the case that the Multiverse finishes off that “God” business, using “multiverse hypotheses predicted from mathematics and physics”.

Krauss doubles down against bad reviews with his Atlantic interview:

Philosophy is a field that, unfortunately, reminds me of that old Woody Allen joke, "those that can't do, teach, and those that can't teach, teach gym." And the worst part of philosophy is the philosophy of science; the only people, as far as I can tell, that read work by philosophers of science are other philosophers of science. ... [philosophy] hasn't progressed in two thousand years. ...

Well, I read a moronic philosopher who did a review of my book in the New York Times ...

But if you can show how a set of physical mechanisms can bring about our universe, that itself is an amazing thing and it's worth celebrating. I don't ever claim to resolve that infinite regress of why-why-why-why-why; as far as I'm concerned it's turtles all the way down. The multiverse could explain it by being eternal, in the same way that God explains it by being eternal, but there's a huge difference: the multiverse is well motivated and God is just an invention of lazy minds. ...

The religious question "why is there something rather than nothing," has been around since people have been around, and now we're actually reaching a point where science is beginning to address that question. And so I figured I could use that question as a way to celebrate the revolutionary changes that we've achieved in refining our picture of the universe. ...

"the remarkable revolutions that have taken place in our understanding of the universe over the past 50 years -- revolutions that should be celebrated as the pinnacle of our intellectual experience." ...

If I'd just titled the book "A Marvelous Universe," not as many people would have been attracted to it.

So his title is flamebait, but it suckered Dawkins into endorsing the book by saying that it is the "deadliest blow to supernaturalism" since Darwin.

Krauss continues to defend himself, and attack philosophers, in a comment to Coyne's blog

I haven’t responded to the review by Albert simply because it seemed to me not worthy of response.. and nothing has changed my mind about that.

and now in a SciAm article:

Which brings me full circle to the question of nothing, and my own comments regarding the progress of philosophy in that regard. When it comes to the real operational issues that govern our understanding of physical reality, ontological definitions of classical philosophers are, in my opinion, sterile. ...

That question can be phrased as follows: How can a universe full of galaxies and stars, and planets and people, including philosophers, arise naturally from an initial condition in which none of these objects—no particles, no space, and perhaps no time—may have existed? Put more succinctly perhaps: Why is there ‘stuff’, instead of empty space? Why is there space at all?

About the only philosopher Krauss credits is Peter Singer, the wacky animal rights guru.

I attack philosophers myself on this blog, and in my book. But the NY Times reviewer, David Z. Albert, was a legitimate physicist before he turned to philosophy, and his criticisms are never directly addressed by Krauss. Albert wrote a book on the many-minds interpretation of quantum mechanics, which is pretty goofy, but not directly relevant.

The core of the problem is that modern physics has nothing to say about nothingness. There is no such thing, as far as we know. The closest we can get to empty space is the luminiferous aether, also called the quantum vacuum state. Our best quantum theories, such as quantum electrodynamics (QED), are really perturbation theories of the aether. That is, what seems like empty space to us is really a complicated set of fluctuating relativistic quantum fields.

A few decades ago, cosmologists proposed that the observable galaxies are the remnants of quantum fluctuations during the first nanosecond of the big bang. Krauss elaborations on this, and says that the whole universe might be the result of quantum fluctuations. As he tacitly admits, he is not really telling us Why There Is Something Rather Than Nothing, but rather giving a modern variant of Turtles all the way down.

All of this nonsense would be hardly worth commenting on, except that Krauss and Dawkins are two of our leading science expositors, and they are peddling nonsense. They should know better. I don't bother attacking crackpots. I started this blog when I realized that our leading academic scholars were promoting ideas about science that are entirely mistaken. The current May SciAm cover story is a wildly speculative story about combining supersymmetry and gravity into supergravity:

More profoundly, the novel methods breathe new life into a unified theory that physicists left for dead in the 1980s. The force of gravity looks like two copies of the strong subnuclear interactions working in unison.

The tipoff is that the authors keep talking about how radical and revolutionary their approach is, but cannot point to any substantive progress since the 1980s when many experts decided that it was a dead-end. The same issue has a separate article explaining why supersymmetry is dead. While there is some debate about that, supergravity is surely dead and not worthy of a SciAm cover story.

Evidence against entraining the aether

Joseph Levy of France has just posted Is the aether entrained by the motion of celestial bodies? What do the experiments tell us?. He revisits the issue of whether the Michelson–Morley experiment rules out luminiferous aether drift from the motion of the Earth.

Since the publication of Einstein’s basic article “On the electrodynamics of moving bodies” in 1905, the aether has been excluded from the area of physics, being regarded as inexistent or at least inactive. Such an attitude signified that the laws of physics could be formulated in the same way, that the aether exists or not,...

This approach appeared quite revolutionary in 1905, since it called into question the ideas developed by a number of classical physicists such as Hooke, Lavoisier, Young, Huygens, Laplace, Fresnel, and Lorentz among others.

I do not agree with this. I say that Einstein did not refute Lorentz, and what Lorentz meant by the aether was what he said in 1895:

It is not my intention to ... express assumptions about the nature of the aether.

Levy does explain how the aether concept (if not the name) is universally accepted today:

In fact, despite its properties that seem so different from ordinary matter, a number of arguments speak in favour of a substratum [9] and these arguments have multiplied in the early twentieth century with the development of quantum mechanics. It is difficult, indeed, to accept that a “vacuum”, endowed with physical properties such as permittivity and permeability may be empty. The ability of such an empty vacuum to transmit electromagnetic waves is also doubtful.

Quantum mechanics, on its part, regards the vacuum as an ocean of pairs of fluctuating virtual particles-antiparticles of very small life-time, a ppearing and disappearing spontaneously, which can be interpreted as a gushing of the aether, although the aether is not officially recognized by quantum mechanics. The interaction of the electrons and the vacuum, in particular, is regarded as the cause of the shifting of the alpha ray of the hydrogen atom spectrum, referred to as lamb shift [10]. The fluctuations of the vacuum are also assumed to expl ain the Casimir effect [11], and the Davies Fulling, Unruh, effect [12].

Einstein himself around 1916 changed his mind as regards the hypothesis of the aether. ...

A proof of the undeniable existence of the aether was given in ref [14]. Thus, the question to be answered today is not to verify its existence, but rather to specify its nature and its properties, and, in the first place, to determine if it is entrained (or not) by the translational motion of celestial bodies due to gravitation.

You will be reassured to learn that the conclusions of Lorentz and Poincare about relativity in 1900 are still good today, and evidence is against the aether drag hypothesis.

Darkness threatens mankind

AP reports:

VATICAN CITY (AP) — Pope Benedict XVI, carrying a tall, lit candle, ushered in Christianity's most joyous celebration with an Easter vigil service Saturday night, but voiced fears that mankind is groping in darkness, unable to distinguish good from evil. ...

Still, Benedict worried in his homily: "The darkness that poses a real threat to mankind, after all, is the fact that he can see and investigate tangible material things, but cannot see where the world is going or whence it comes, where our own life is going, what is good and what is evil."

This sounds like dark matter! Or maybe the undetectability of motion thru the aether.

The service began dramatically. Except for the twinkle of camera flashes, the basilica was almost pitch-black as the thousands of faithful in pews awaited Benedict's arrival through the rear entrance. ... "Today we can illuminate our cities so brightly that the stars in the sky are no longer visible," he said. "Is this not an image of the problems caused by our version of enlightenment?"

He is complaining about light pollution. He should be happy that the Arizona governor vetoed the billboard bill. The Vatican does have a long history of supporting astronomy.

Happy Easter. Whether these analogies make any sense or not.