Smolin, Woit, the failure of string theory, and how string theory responds

Professor Lee Smolin has been attacked by various string theorists (particularly Aaron Bergmann and Lubos Motl), but now Professor Clifford Johnson has seemingly joined in with Aaron and Lubos in a post where he claims that pointing out the failure of string theory in books is unsatisfactory because it puts “their rather distorted views on the issues into the public domain in a manner that serves only to muddle”.

This seems to be a slightly unfair attack to me.  Clifford is certainly trying hardest of all the string theorists to be reasonable, but he has stated that he has not read the books critical of string theory, which means that his claim that the books contain ‘distorted views’ which ‘muddle’ the issues, is really unfounded upon fact (like the claims of string theory).

Dr Peter Woit has a nice set of notes summarising some problems with string theory here.  These are far more sketchy than his book and don’t explain the Standard Model and its history like his book, but the notes do summarise a few of the many problems in string theory.  String theorists, if they even acknowledge the existence of critics at all (Witten has written a letter to Nature saying that he doesn’t, instead he suggests that string theorists should ignore objections while continuing to make or to stand by misleading claims that string theory ‘predicts’ gravity, such as Witten’s own claim of that in the April 1996 issue of Physics Today), dismiss any problem with string theory as a ‘storm in a teacup’, refuse to read the books of critics, misrepresent what the critics are saying, so the arguments don’t address the deep problems.

For instance, Clifford wrote in a particularly upsetting comment:

“For example, a great deal of time was spent by me arguing with Peter Woit that his oft-made public claim that string theory has been shown to be wrong is not a correct claim. I asked him again and again to tell us what the research result is that shows this. He has not, and seems unable to do so. I don’t consider that to be informed criticism, but a very very strong and unfair overstatement of what the current state of on-going research is.”

Peter Woit explains on page 177 of Not Even Wrong (which, admittedly, Clifford is unaware of since he has not read the book!) that using the measured weak SU(2) and electromagnetic U(1) forces, supersymmetry predicts the SU(3) force incorrectly high by 10-15%, when the experimental data is accurate to a standard deviation of about 3%. So that’s failure #1.

Moreover, Peter Woit also explains on page 179 that supersymmetry makes another false prediction: it predicts a massive amount of dark energy in the vacuum and an immense cosmological constant, totally contradicted by astronomy and too high by a factor of 10^55 or 10^113 depending on whether the string theory is minimally supersymmetric or a supersymmetric grand unified theory, respectively.

Either way, Dr Woit explains: ‘This is almost surely the worst prediction ever made by a physical theory that anyone has taken seriously.’ So that’s failure #2.

This is not a problem with the standard model of particle physics: comparing string theory to the standard model is false.  A student who answers one of the questions on a paper and gets it wrong, derives no excuse from pointing to another who achieved 99%, despite happening to get the same single question wrong. Any assessment by comparison needs to take account of successes, not just errors. In one case the single error marks complete failure, while in the other it’s trivial.

It’s still a a string error, whether the standard model makes it as well, or not as the case may be. String theorists have a different definition of the standard model for this argument, more like a speculative theory than an empirical model of particle physics.  The standard model isn’t claimed to be the final theory. String is. The standard model is extremely well based on empirical observations and makes checked predictions. String doesn’t.

That’s why Smolin and Woit are more favourable to the standard model. String theory if of any use should sort out any problems with the standard model. This is why the errors of string theory are so alarming. It is supposed to theoretically sort things out, unlike the standard model, which is an empirically based model, not a claimed final theory of unification.

Asymptotia

 

More Scenes From the Storm in a Teacup, VII

by Clifford, at 2:18 am, March 13th, 2007 in science, science in the media, string theory

“You can catch up on some of the earlier Scenes by looking at the posts listed at the end of this one. Through the course of doing those posts I’ve tried hard to summarize my views on the debate about the views of Smolin and Woit – especially hard to emphasize how the central point of their debate that is worth some actual discussion actually has nothing to do string theory at all. Basically, the whole business of singling out string theory as some sort of great evil is rather silly. If the debate is about anything (and it largely isn’t) it is about the process of doing scientific research (in any field), and the structure of academic careers in general. For the former matter, Smolin and Woit seem to have become frustrated with the standard channels through which detailed scientific debates are carried out and resolved, resorting to writing popular level books that put their rather distorted views on the issues into the public domain in a manner that serves only to muddle.  …” 

Everything that happens involves particle physics, so it determines the nature of everything, and is just a few types of fundamental particles and four basic fundamental forces, or three at high energy, where electro-weak unification occurs.

It’s better to have debates and disputes over scientific matters that can potentially be resolved, than have arguments over interminable political opinions which can’t be resolved factually, even in principle. I don’t agree that a lack of debate (until new experimental data arrives) is the best option. The issue is that experiments may resolve the electroweak symmetry breaking mechanism, but they won’t necessarily change the facts in the string theory debate one bit. Penrose explains the problem here on pp. 1020-1 of Road to Reality (UK ed.):

34.4 Can a wrong theory be experimentally refuted? … One might have thought that there is no real danger here, because if the direction is wrong then the experiment would disprove it, so that some new direction would be forced upon us. This is the traditional picture of how science progresses. … We see that it is not so easy to dislodge a popular theoretical idea through the traditional scientific method of crucial experimentation, even if that idea happened actually to be wrong. The huge expense of high-energy experiments, also, makes it considerably harder to test a theory than it might have been otherwise. There are many other theoretical proposals, in particle physics, where predicted particles have mass-energies that are far too high for any serious possibility of refutation.’

I’ve written a very brief review of Lee Smolin’s book on Amazon.co.uk, which for brevity concentrates on reviewing the science of the book that I can review objectively (I ignore discussions of academic problems).  Here is a copy of it:

Professor Lee Smolin is one of the founders of the Perimeter Institute in Canada. He worked on string theory in the 1980s and switched to loop quantum gravity when string theory failed.

Before reading this book, I read Dr Peter Woit’s book about the failure of string theory, Not Even Wrong, read his blog, and watched Smolin’s lectures (available streamed online from the Perimeter Institute website), Introduction to Quantum Qravity, which explain the loop quantum gravity theory very clearly.

Smolin concentrates on the subject from the perspective of understanding gravity, although he helped develop a twisted braid representation of the standard model particles. Loop quantum gravity is built on firmer ground that string theory, and tackles the dynamics behind general relativity.

This is quite different from the approach of string theory, which completely ignores the dynamics of quantum gravity. I should qualify this by saying that although the stringy 11-dimensional supergravity, which is the bulk of the mainstream string theory, M-theory (in M-theory 10 dimensional superstring is the brane or membrane on the bulk, like an N-1 dimensional surface on an N-dimensional material), does contain a spin-2 mode which (if real) corresponds to a graviton, that’s not a complete theory of gravitation.

In particular, in reproducing general relativity, string theory suggests a large negative cosmological constant, while the current observation-based cosmological model has a small positive cosmological constant.

In addition to failing there, string theory also fails to produce any of the observable particles of the standard model of physics. This is because of the nature of string theory, which is constructed from a world sheet (a 1-dimensional string when moved gains a time dimension, becoming a 1,1 “worldsheet”) to which 8 additional dimensions are added to satisfy the conformal symmetry of particle physics, assuming that there is supersymmetric unification of standard model forces (which requires the assumption that every fermion in the universe has a bosonic super partner, which nobody has ever observed in an experiment). If supersymmetry is ignored, then you have to add to the worldsheet three times as many dimensions for conformal symmetry, giving 26 dimensional bosonic string theory. That theory traditionally had problems in explaining fermions, although Tony Smith (now censored off arXiv by the mainstream) has recently come up with some ideas to get around that.

The failure of string theory is due to the 10 dimensions of supersymmetric superstring theory from the worldsheet and conformal symmetry requirements. Clearly, we don’t see that many dimensions, so string theorists rise to the challenge by a trick first performed with Kaluza’s 5-dimensional theory back in the 1920s. Klein argued that extra spatial dimension can be compactified by being curled up into a small size. Historically, the smallest size assumed in physics has been the Planck length (which comes purely from dimensional analysis by combining physical constants, not from an experimentally validated theory or from observation).

With 10 dimensional superstring, the dimensions must be reduced on a macroscopic scale to 3 spatial dimensions plus 1 time dimension, so 6 spatial dimensions need compactification. The method to do this is the Calabi-Yau manifold. But this cause a massive problem in string theory, called the landscape. String theory claims that particles are vibrating strings, which becomes very problematic when 6 dimensions are compactified, because the vibration modes possible for a string then depend critically on the size and shape parameters of those 6 compactified dimensions. The possibilities are vast, maybe infinite.

It turns out that there are at least 10^500 ways of producing standard model or vacuum ground state from such strings containing Calabi-Yau manifolds. Nobody can tell if any of those solutions is the real standard model of particle physics. For comparison, the age of the universe is something like 10^17 seconds. Hence, if you had a massive computer trying to compute all the solutions to string theory from the moment of the big bang to now, it would have to work at a speed of 10^483 solutions per second to solve the problem (a practically impossible speed, even if such timescales are available). A few string theorists hope to find a way to statistically tackle this problem in a non-rigorous way (without checking every single solution) before the end of the universe, but most have given up and try to explain particle physics by the anthropic principle, whereby it is assumed that there is one universe for each of the 10^500 solutions to string theory, and we see the one standard model which has parameters which are able to result in humans.

More radical string theorists proclaim that if you fiddle around with the field theories underlying general relativity and the standard model, you can create a landscape of unobserved imaginary universes from those theories, similar to string theory. Therefore, they claim, the problems in string theory are similar to those in general relativity and the standard model. However, this analogy is flawed because those checked theories are built up on the basis of observations of particle symmetries, electrodynamics, energy conservation and gravitation, and they also produce checkable predictions. In short, there is no problem due to the imaginary landscape in those theories, whereas there is a real problem caused by the landscape in string theory, because it prevents a reproduction (post-diction) of existing physics, let alone predictions.

Smolin suggests that the failure of string theory to explain general relativity and the standard model of particle physics means that it may be helpful if physicist get off the string theory bandwaggon and start investigating other ideas. Woit makes the same point and gives the technical reasons.

The problem is that string theory has over the past two decades become a cult topic supported by endless marketing hype, magazine articles, books, even sci fi films. Extra dimensions are popular, and the heroes of string theory have gotten used to being praised despite having not the slightest shred of evidence for their subject. Recently, they have been claiming that string theory mathematics is valuable for tackling some technical problems in nuclear physics, or may be validated by the discovery of vast cosmic strings in space. But even the mathematics of Ptolemy’s earth centred universe epicycles had uses elsewhere, so this defense of string theory is disingenious. It’s not clear that string theory maths solves any nuclear physics problems that can’t be solved by other methods. Even if it does, that’s irrelevant for the issue of whether people should be hyping string as being the best theory around.

Smolin’s alternative is loop quantum gravity. The advantage of this is that it builds up Einstein’s field equation less a metric (so it is background independent) from a simple summing of interaction graphs for the nodes of a Penrose spin network in the 3 spatial dimensions plus time dimension we observe. This sum is equivalent to taking a Feynman path integral, which is a basic method of doing quantum field theory. The result of this is general relativity without a metric. It is not a complete theory yet, and is the very opposite of string theory in many ways.

While string theory requires unobservables like extra dimensions and superpartners, loop quantum gravity works in observable spacetime using quantum field theory to produce a quantum gravity consistent with general relativity. Ockham’s razor, the principle of economy in science, should tell you that loop quantum gravity is tackling real physics in a simple way, whereas string theory is superfluous (at least until there is some evidence for it).

Obviously there is more progress to be made in loop quantum gravity, which needs to become a full Yang-Mills quantum theory if gravity is indeed a force like the other standard model forces. However, maybe the relationship between gravity and the other long-range force, electromagnetism, will turn out to be different to what is expected.

For instance, loop quantum gravity needs to address the problem that of whether gravity is a renormalizable quantum field theory like the standard model Yang-Mills theories. This will depend on the way in which gravitational charge, ie mass, is attached to or associated with standard model charges by way of some sort of “Higgs field”. The large hadron collider is due to investigate this soon. Renormalization involves using a corrected “bare charge” value for electric charge and nuclear charges which is higher than that observed. The justification is that very close to a particle, vacuum pair production occurs in the strong field strength, the pairs polarize and shield the bare core charge to the observed value seen at long distances and low energies. For gravity, renormalization poses the problem of how gravitational charge can be shielded? Clearly, masses don’t polarize in a gravitational field (they all move the same way, unlike electrons and positrons in an electric field) so the mass-giving “Higgs field” effect is not directly capable of renormalization, but is capable of indirect renormalization if the Higgs field is being associated with particles by another field like the electric field, which is renormalized.

These are just aspects which appeal to me. One of the most fun parts of the book is where Smolin explains the reason behind “Doubly Special Relativity”.

Peter Woit’s recent book Not Even Wrong has a far deeper explanation of the standard model and the development of quantum field theory, the proponents and critics of string theory, and gives the case for a deeper understanding of the standard model in observed spacetime dimensions using tools like the well established mathematical modelling methods of representation theory.

Both books should really be read to understand the overall problem and possibilities for progress by alternative ideas despite the failure of string theory.

Update: in the comments on Asymptotia, Peter Woit has made some quick remarks from a web cafe in Pisa, Italy.  Instead of arguing about the substance of his remarks, Aaron Bergmann and Jacques Distler are repeatedly attacking one nonsense sentence he typed where he wrote a contradiction that a cosmological constant can correspond to flat spacetime, whereas the cosmological constant implies a small curvature.  Unable to defend string theory against the substance of the charge that it is false, they are now attacking this one sentence as a straw man.  It’s completely unethical.  The fact that a string theorist will refusing to read the carefully written and proof-read books and then choose instead to endlessly attack a spurious comment on a weblog, just show the level to which their professionalism has sunk.  Jacques Distler does point out correctly that in flat spacetime the vacuum energy does not produce a cosmological constant.  Instead of splitting attacking critics of completely failed theories, he should perhaps admit the theory has no claim to be science.

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8 thoughts on “Smolin, Woit, the failure of string theory, and how string theory responds

  1. copy of a comment to

    http://riofriospacetime.blogspot.com/2007/03/t-minus-3-days-conference-opening.html

    I just looked up the blog post mentioned in the previous comment and the comments are shut down, preventing any response.

    Tony Smith kindly quoted a little bit I wrote saying something like “the total gravitational potential energy of the universe is on the order E = MMG/R = MMG/(ct), which when equated to E=Mc^2 gives Louise’s equation”

    However, this was then dismissed by another comment from somebody else, who did not go back and check my comment on the other blog. The point is, I also have a lot more justification, such as the reason why you need to equate the gravitational energy with the rest mass energy.

    Consider a star. If you had a star of uniform density and radius R, and it collapsed, the energy release from gravitational potential energy being turned into explosive (kinetic and radiation) energy is E = (3/5)(M^2)G/R. The 3/5 factor from the integration which produces this result is not applicable to the universe where the density rises with apparent distance because of spacetime (you are looking to earlier, more compressed and dense, epochs of the big bang when you look to larger distances). It’s more sensible to just remember that the gravitational potential energy of mass m located at distance R from mass M is simply E = mMG/R so for gravitational potential energy of the universe is similar, if R is defined as the effective distance the majority of the mass would be moving if the universe collapsed.

    This idea of gravitational potential energy shouldn’t bee controversial: in supernovae explosions much energy comes from such an implosion, which turns gravitational potential energy into explosive energy!

    Generally, to overcome gravitational collapse, you need to have an explosive outward force.

    The universe was only able to expand in the first place because the explosive outward force, provided by kinetic and radiation energy, which counteracted the gravitational force.

    Initially, the entire energy of the radiation was present as various forms of radiation. Hence, to prevent the early universe from being contracted into a singularity by gravity, we have the condition that E = Mc^2 = (M^2)G/R = (M^2)G/(ct) which gives GM = tc^3.

    ****************

    My earlier comment:

    Two ways to get GM = tc^3:

    (1)

    Consider why the big bang was able to happen, instead of the mass being locked by gravity into a black hole singularity and unable to expand!

    This question is traditionally answered (Prof. Susskind used this in an interview about his book) by the fact the universe simply had enough outward explosive or expansive force to counter the gravitational pull which would otherwise produce a black hole.

    In order to make this explanation work, the outward acting explosive energy of the big bang, E = Mc^2, had to either be equal to, or exceed, the energy of the inward acting gravitational force which was resisting expansion.

    This energy is the gravitational potential energy E = MMG/R = (M^2)G/(ct).

    Hence the explosive energy of the big bang’s nuclear reactions, fusion, etc., E = Mc^2 had to be equal or greater than E = (M^2)G/(ct):

    Mc^2 ~ (M^2)G/(ct)

    Hence

    MG ~ tc^3.

    That’s the first way, and perhaps the easiest to understand.

    (2)

    Simply equate the rest mass energy of m with its gravitational potential energy mMG/R with respect to large mass of universe M located at an average distance of R = ct from m.

    Hence E = mc^2 = mMG/(ct)

    Cancelling and collecting terms,

    GM = tc^3

    So Louise’s formula is derivable.

    The rationale for equating rest mass energy to gravitational potential energy in the derivation is Einstein’s principle of equivalence between inertial and gravitational mass in general relativity (GR), when combined with special relativity (SR)equivalence of mass and energy!

    (1) GR equivalence principle: inertial mass = gravitational mass.

    (2) SR equivalence principle: mass has an energy equivalent.

    (3) Combining (1) and (2):

    inertial mass-energy = gravitational mass-energy

    (4) The inertial mass-energy is E=mc^2 which is the energy you get from complete annihilation of matter into energy.

    The gravitational mass-energy is is gravitational potential energy a body has within the universe. Hence the gravitational mass-energy is the gravitational potential energy which would be released if the universe were to collapse. This is E = mMG/R with respect to large mass of universe M located at an average distance of R = ct from m.

    ****************

    What’s interesting is that the mainstream doesn’t want to discuss science when it comes to alternatives, as Tony Smith makes clear in his discussion of censorship.

    They use ad hominem attacks, which is a lazy approach whereby no careful science or disciplined checks are involved. The mainstream however objects if ad hominem attacks are used against it’s leaders. For example, Dr Ed Witten – M-theory creator – was misleading when he claimed:

    ‘String theory has the remarkable property of predicting gravity.’ – Dr Edward Witten, M-theory originator, Physics Today, April 1996.

    Dr Peter Woit remarks that the prediction is just a prediction of an unobservable spin-2 graviton and not a prediction of anything to do with gravity that is either already experimentally verified or checkable in the future:

    ‘There is not even a serious proposal for what the dynamics of the fundamental ‘M-theory’ is supposed to be or any reason at all to believe that its dynamics would produce a vacuum state with the desired properties. The sole argument generally given to justify this picture of the world is that perturbative string theories have a massless spin two mode and thus could provide an explanation of gravity, if one ever managed to find an underlying theory for which perturbative string theory is the perturbative expansion.’ – Quantum Field Theory and Representation Theory: A Sketch (2002), http://arxiv.org/abs/hep-th/0206135

    If you call mainstream M-theory hypers ‘liars’, ‘charlatans’, ‘crackpots’, etc., you find that you are then accused of being a ‘science hater’. So they don’t like criticism.

    To give credit where due, Dr Ed Witten published a letter in Nature, Nature, Vol 444, 16 November 2006, stating:

    ‘The critics feel passionately that they are right, and that their viewpoints have been unfairly neglected by the establishment. … They bring into the public arena technical claims that few can properly evaluate. … Responding to this kind of criticism can be very difficult. It is hard to answer unfair charges of élitism without sounding élitist to non-experts. A direct response may just add fuel to controversies.’

    So Dr Ed Witten at least doesn’t encourage attacks on critics, he just prefers to ignore them. Maybe this is worse for critics with alternative ideas, however, where the choice is controversy or being ignored altogether.

    But the mainstream as a whole does go far out of its way to use ad hominem attacks on alternatives, hence Lubos Motl’s attacks, and many others.

  2. One new idea which occurs to me: the two types of derivation in the above comment could be combined to prove one or the other. If you can take the first type of derivation as experimentally sound, for example, then that would allow you to theoretically derive Einstein’s equivalence principle between inertial and gravitational mass.

  3. HOW STRING THEORISTS AVOID THE IMPERFECTIONS OF EINSTEIN

    http://motls.blogspot.com/2007/03/einstein-may-have-started-rot.html Motl: “Einstein may have started the rot”…what string theory is doing is nothing else than continuing in Einstein’s program of theoretical physics, while AVOIDING ALL OF HIS KNOWN IMPERFECTIONS.”

    Divine Albert taught that the speed of light varied with the gravitational potential but did not vary with the relative speed of the light source and the observer, and in Chapter 22 in his “Relativity” explained why this combination of variability and invariability was not an idiocy. Motl and his brothers string theorists agree that the combination is not an idiocy and conclude that Einstein did not start the rot (someone else, perhaps the late Bryan Wallace http://www.ekkehard-friebe.de/wallace.htm , must have started it). On the other hand, brothers string theorists suspect that Divine Albert’s combination of variability and invariability, although not an idiocy, is still an imperfection. So they always avoid it by looking for sand, sticking their heads and exposing other parts of their bodies.

    Pentcho Valev
    pvalev@yahoo.com

  4. “Divine Albert taught that the speed of light varied with the gravitational potential but did not vary with the relative speed of the light source and the observer…” – Pentcho Valev

    Pentcho, you’re wrong in claiming that Einstein taught people that the speed of light varies with the gravitational potential. He actually taught that the velocity of light varies with the gravitational potential.

    The speed remains constant; the velocity varies because the direction changes and velocity is a vector, a statement of speed and direction not just speed.

    Here are a couple of quotations collected by Dr Thomas Love of California State University which demonstrate this:

    ‘… [special relativity requires] the law of the constancy of the velocity of light. But … the general theory of relativity cannot retain this law. On the contrary, we arrived at the result according to this latter theory, the velocity of light must always depend on the coordinates when a gravitational field is present.’ – Albert Einstein, Relativity, The Special and General Theory, Henry Holt and Co., 1920, p111.

    ‘… the principle of the constancy of the velocity of light in vacuo must be modified, since we easily recognise that the path of a ray of light … must in general be curvilinear…’ – Albert Einstein, The Principle of Relativity, Dover, 1923, p114.

    All the results of special relativity, the Lorentz transformation, mass-energy equivalence, etc., come from a physical picture of electromagnetism. FitzGerald came up with the contraction in 1889, well before Lorentz, and 16 years before Einstein’s first publication. It’s undoubtedly a gauge boson exchange radiation effect. Energy is exchanged between charges in Yang-Mills QFT, and any type of gravitational dynamics is likely to have some relationship to the other forces of the standard model of particle physics, so will probably also involve exchange radiation causing the force.

    Move in a radiation sea, and the pressure changes introduce a deformation to your fields, contracting their extent in the direction of motion. Since the fields are physically being maintained by exchange radiation endlessly travelling along field’s “lines of force”, any motion affects the gauge boson radiation, so at high velocities the field behaves and responds relatively slowly, which is the time-dilation effect. E=mc^2 comes just in the way Lorentz said it did, many years before Einstein’s SR. Lorentz noticed that J.J. Thomson had shown from electromagnetic theory that the mass of any charged body (ie, a fermion) is inversely proportional to its radius and so the contraction in the direction of motion causes an increase in the mass of a moving charge. This increase in mass is correlated to the increase in energy a moving fermion has! Hence expanding the Lorentz equation for the mass of the moving body by the binomial expansion, you get E=mc^2.

    Now for the addition of velocities equation in SR: this is particularly simple in a mechanistic derivation.

    You measure velocity as distance/time. When you are moving, say trying to chase after a light ray using your high speed rocket, you will find that the light ray always appears to be moving away from you at 300,000 km/s, regardless how fast you are going relative to the light ray! The reason is that your measuring system for velocity has been distorted by your own contraction in the direction of motion, and time dilation. The faster you are going, the effect of you moving at nearly the speed the ray of light is going is cancelled out by the contraction of your measuring system for distances in the direction of motion etc.

    This is a simplified version of what happens in the Michelson-Morley experiment:

    ‘The Michelson-Morley experiment has thus failed to detect our motion through the aether, because the effect looked for – the delay of one of the light waves – is exactly compensated by an automatic contraction of the matter forming the apparatus…. The great stumbing-block for a philosophy which denies absolute space is the experimental detection of absolute rotation.’ – Professor A.S. Eddington (who confirmed Einstein’s general theory of relativity in 1919), Space Time and Gravitation: An Outline of the General Relativity Theory, Cambridge University Press, Cambridge, 1921, pp. 20, 152.

    Einstein’s system is based on what the observer will see in the observable framework and the observer’s measuring instruments. Einstein does not explain how the relativity mathematics works in terms of causal mechanisms for what is producing length contraction or time-dilation or apparent impossibilities of observing light going at any speed other than c in vacuo, due to the length contraction and time dilation of the observer, it’s just a mathematical system.

    You can prove the pythagorean identity in numerous ways, by analogy, and you can’t insist that one way is “right” and another is wrong. It really is a waste of time trying to say Einstein was a nutter because his derivation of the FitzGerald-Lorentz equations is mathematically abstract and isn’t tied to physical causes and mechanisms. The reason is that there is popular sympathy of the religious kind with the people who claim that the universe is mathematical, mysterious, and lacks any kind of Rube-Goldberg mechanism for each of the mathematical tricks.

    That’s why I’m kinda worried about Woit and Smolin. They’re both kinda crazy, although much more sane than the stringers. Woit writes on p55 of the British edition of Not Even Wrong:

    “The SU(2) transformation properties of a particle have become known as the particle’s spin. This term comes from the idea that one could think of the particle as a spinning particle, spinning on some axis and thus carrying some angular momentum. This idea is inherently inconsistent for a lot of reasons. While the spin is a quantised version of the angular momentum, there is no well-defined axis of rotation or speed of rotation. Spin is an inherently quantum mechanical notion, one that fits precisely with the representation theory of the symmetry group SU(2), but has no consistent interpretation in terms of classical physics.”

    There’s a well defined axis of rotation implied by the Pauli exclusion principle, which makes adjacent fermions in atoms have opposite spins. Of course the individual directions can’t be seen, because the electrons are moving chaotically due to the 3+ body Poincare chaos effect. This applies to classical physics (or rather, it should do, although normally classical physics is taught in a way restricted to just two body interactions by definition and automatically by definition excludes multibody chaotic situations). I just think Woit lost the plot on this one, the speed of rotation from the known spin angular momentum of the electron, of (1/2)h-bar, does does a spin speed plus it imposes constraints on the physical nature of a fermion.

    What Woit means by “inherently quantum mechanical notion” is probably something like “beyond any hope or possibility of being understood in causal or mechanistic terms”. Dr Thomas Love however points out that wavefunction collapse doesn’t really occur when you measure something: that’s just a mathematical lie created by switching between time-independent and time-dependent versions of the Schroedinger equation when you make a measurement and affect the system by making that measurement (there’s a world of difference between a measurement affecting what you are measuring, and a measurement making something change from a metaphysical indeterminancy state to an absolute, definite state). To me, the spin of a particle physically cannot be indeterminate until it is measured, because in iron atoms the magnetism doesn’t occur due to orbital motions of electrons, but due to electron spin alignments. So the fact we have magnets proves that spin is a real feature; you don’t need to measure spin to see evidence of it, just measure magnetism.

    The mathematical obfuscation of special relativity for physical mechanisms was not really “rot” because at least special relativity gives the correct answers for situations where accelerations are absent (admittedly, that’s a big limitation since accelerations are needed to start and stop all forms of motion, not to mention gravitation!). The rot in physics really started with Bohr and Heisenberg’s Copenhagen Interpretation which Einstein, Polansky and Rosen fought as best they could.

    Bryan Wallace simply wasn’t putting forward useful ideas to get around the difficulties. Like many others, he could see that a lot of the religious Einstein worship (based on people loving what they can’t understand physically, and linking relativity to the occult, instead of treating it as a mathematical system based on assumptions which allow it to work for its restricted scope of non-accelerating situations) wasn’t a good thing.

    In particular, Wallace analysed NASA interplanetary radar data and discredit the principle of relativity directly. It’s pretty obvious that light speed is absolute in an absolute (imaginary) frame of reference: the reason why the speed of light when measured in vacuum seems to be always 300,000 km/s is due to the contraction or time dilation effects affecting the measuring instrument when that is in motion, chasing after the light or whatever.

    The cosmic background radiation shows a preferred absolute direction.

    R. A. Muller showed from the +/-0.003 K redshift and blueshift in the 2.7 K microwave background (the variation forms a cosine relationship to our absolute direction) that the Milky Way is going at 600 km/s towards Andromeda, publishing this is his Scientific American article:

    Muller, R. A., “The cosmic background radiation and the new aether drift”, Scientific American, vol. 238, May 1978, p. 64-74

    Abstract

    U-2 observations have revealed anisotropy in the 3 K blackbody radiation which bathes the universe. The radiation is a few millidegrees hotter in the direction of Leo, and cooler in the direction of Aquarius. The spread around the mean describes a cosine curve. Such observations have far reaching implications for both the history of the early universe and in predictions of its future development. Based on the measurements of anisotropy, the entire Milky Way is calculated to move through the intergalactic medium at approximately 600 kms. It is noted that in a frame of reference moving with the original plasma emitted by the big bang, the blackbody radiation would have a temperature of 4500 K.

    Nobody cared about that, even though it went into the Scientific American! The general reaction was: “So if you assume the cosmic background radiation field is an absolute frame of reference, you can derive absolute motion. So what?”

    The idea that the public in general gives a damn about special relativity is wrong. In any case, Einstein says that general relativity – which is background independent and thus compatible with any metric, not just Lorentz invariance – is the correct theory, not special or “restricted” relativity:

    ‘The special theory of relativity … does not extend to non-uniform motion … The laws of physics must be of such a nature that they apply to systems of reference in any kind of motion. Along this road we arrive at an extension of the postulate of relativity… The general laws of nature are to be expressed by equations which hold good for all systems of co-ordinates, that is, are co-variant with respect to any substitutions whatever (generally co-variant). …’

    – Albert Einstein, ‘The Foundation of the General Theory of Relativity’, Annalen der Physik, v49, 1916.

    No newspaper published this on the front page in 1916 with a headline like “Einstein says special relativity is bunk in general!”, because relativity only got into the newspapers in 1919 when general relativity was verified by deflection of starlight.

    What you find is that few people know what general relativity is about beyond the mathematical structure. If you treat these things as purely mathematical systems, then physical facts are all too easily dismissed as philosophical speculations. This is the problem. Einstein never presented either special or general relativity as a physical theory with causal mechanisms because he was too far into Mach’s philosophy that only stuff the observer measures is real. He did make a mess of things when he stated:

    ‘According to the general theory of relativity space without ether is unthinkable.’

    – Albert Einstein, Sidelights on Relativity, Dover, New York, 1952, p23.

    Problem was, Einstein did not have the data required about the various force fields (the standard model of particle physics) when he was trying to solve the problems, and that was only developed (after a lot of experimentation with particle physics) in the 1970s.

    Theories must be based on experimental facts. Once you start trying to build a theory which unifies speculative spin-2 gravitons with speculative Planck scale unification, by means of adding speculative extra dimensions, supersymmetric partners, an increase of tunable standard model parameters from 19 to 125 or more, etc., you’re no longer doing physics. That’s where mainstream physics is today, without even mentioning the cosmology crisis with evolving dark energy, etc.

    I’m writing up a textbook presenting the facts, but the more I learn about the current crisis and the way that even people like Drs Woit and Smolin actually think about physics, the clearer it becomes that even if string theory sinks, physics is not the scientific subject I thought it to be when a kid. Instead, physics is all about prejudices of one form or another, and closed-mindedness. It’s too much about elite power politics, not little concerned with facts. That’s not new of course, things are always difficult.

  5. Nige wrote: “Pentcho, you’re wrong in claiming that Einstein taught people that the speed of light varies with the gravitational potential. He actually taught that the velocity of light varies with the gravitational potential. The speed remains constant; the velocity varies because the direction changes and velocity is a vector, a statement of speed and direction not just speed.”

    http://www.pitt.edu/~jdnorton/papers/OntologyOUP_TimesNR.pdf “What Can We Learn about the Ontology of Space and Time from the Theory of Relativity?”, John D. Norton: “…ALREADY IN 1907, A MERE TWO YEARS AFTER THE COMPLETION OF THE SPECIAL THEORY, [einstein] HAD CONCLUDED THAT THE SPEED OF LIGHT IS VARIABLE IN THE PRESENCE OF A GRAVITATIONAL FIELD; indeed, he concluded, the variable speed of light can be used as a gravitational potential.”

    http://www.logosjournal.com/issue_4.3/smolin.htm Lee Smolin: “… SPECIAL RELATIVITY WAS THE RESULT OF 10 YEARS OF INTELLECTUAL STRUGGLE, YET EINSTEIN HAD CONVINCED HIMSELF IT WAS WRONG WITHIN TWO YEARS OF PUBLISHING IT.”

    http://www.physlink.com/Education/AskExperts/ae13.cfm “So, IT IS ABSOLUTELY TRUE THAT THE SPEED OF LIGHT IS NOT CONSTANT in a gravitational field [which, by the equivalence principle, applies as well to accelerating (non-inertial) frames of reference]. If this were not so, there would be no bending of light by the gravitational field of stars….Indeed, this is exactly how Einstein did the calculation in: “On the Influence of Gravitation on the Propagation of Light,” Annalen der Physik, 35, 1911. which predated the full formal development of general relativity by about four years. This paper is widely available in English. You can find a copy beginning on page 99 of the Dover book “The Principle of Relativity.” You will find in section 3 of that paper, Einstein”s derivation of the (variable) speed of light in a gravitational potential, eqn (3). The result is, c’ = c0 ( 1 + V / c2 ) where V is the gravitational potential relative to the point where the speed of light c0 is measured.”

    http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html “Einstein went on to discover a more general theory of relativity which explained gravity in terms of curved spacetime, and he talked about THE SPEED OF LIGHT CHANGING in this new theory. In the 1920 book “Relativity: the special and general theory” he wrote: . . . according to the general theory of relativity, the law of the constancy of the velocity of light in vacuo, which constitutes one of the two fundamental assumptions in the special theory of relativity [. . .] cannot claim any unlimited validity. A curvature of rays of light can only take place when the velocity of propagation of light varies with position. Since Einstein talks of velocity (a vector quantity: speed with direction) rather than speed alone, it is not clear that he meant the speed will change, but the reference to special relativity suggests that he did mean so.”

    Pentcho Valev
    pvalev@yahoo.com

  6. NC’s note in response to above comment: Pentcho, I’ve modified this comment by editing out some of the superfluous material in the quotes which make them unreadably off-topic and irrelevant. I’ve explained to you that the effect of gravity in general relativity is change the direction of light, which means changing the velocity, not the speed. If your car is going 100 miles per hour and changes direction without changing speed, its velocity changes.

    Your quotation of John D. Norton indicates he doesn’t understand the distinction between vectors like velocity and scalars like speed, because he is completely wrong. Your quotation of Lee Smolin is interesting polemics. The quote you give from http://www.physlink.com/Education/AskExperts/ae13.cfm is completely inaccurate physics: Einstein’s 1911 paper is wrong. Your quotation from http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html just shows how that site is confused about Einstein’s general relativity, first claiming to be quoting Einstein saying the speed of light depends on gravity, then giving a quotation where Einstein clearly and correctly states that the velocity (not speed) depends on gravity.

    Consider now a black hole. Light can’t escape from it (the Hawking radiation mechanism has light produced just beyond the event horizon due to pair production, with one charge in the pairs of charges created falling into the black hole). Is this because light which is moving in the outward radial direction in a black hole is slowed down and can’t escape?

    What happens here is crucial. R. V. Pound and G. A. Rebka Jr. in 1959 proved that light is redshifted by gravity, as predicted by general relativity by sending gamma rays upwards in a 22.5 metres high tower and measuring the shift in gamma ray energy using the extremely sensitive Mößbauer effect, see http://en.wikipedia.org/wiki/Pound-Rebka_experiment

    So you send gamma rays or light upwards against gravity, and it loses energy. It is not deflected by gravity in this case, because the light is travelling parallel to (i.e., along) radial gravitational field lines. The question is whether gravitationally redshifted light is slowed down, and blueshifted light speeded up. In the longitudinal Doppler effect with sound in air, this doesn’t happen because the whistle sound from a receding train travels at the same speed towards you that it would in the air regardless of the train’s recession speed. The physics of the Doppler shift is that the wavelengths of the sound are stretched at the boundary from the whistle cavity containing air moving with the train, to the surrounding air.

    The light wave has its oscillations perpendicular to the direction that light propagates. The Doppler effect doesn’t occur with light with the mechanism that occurs in sound waves. Whereas the sound wave speed is independent of the speed of the sound emitter, that may not be the case for light waves.

    In particular, we know that light loses energy and is redshifted when it travels away from a heavy mass. The question is physically how that redshift occurs. General relativity is a mathematical model, not a physical mechanism. So it doesn’t say what happens.

    In special relativity, it’s taken as impossible to measure any effect of motion on the velocity of light in a vacuum (obviously, light travels at slower speed in dense glass or water because of the interactions of the electromagnetic fields in light with those of the electrons and nuclei in the glass or water). The reason is that to measure velocity of light, you are measuring the ratio of distance to time, and both distance and time are subject to local modifications in the measuring instrument. Material contracts in the direction of motion, clocks slow down. This is why the Michelson-Morley experiment failed to measure absolute velocity of light. However, you can measure absolute velocity in the cosmic background radiation, as proved by R.A. Muller, ‘The cosmic background radiation and the new aether drift’, Scientific American, vol. 238, May 1978, p. 64-74: ‘U-2 observations have revealed anisotropy in the 3 K blackbody radiation which bathes the universe. The radiation is a few millidegrees hotter in the direction of Leo, and cooler in the direction of Aquarius. The spread around the mean describes a cosine curve. Such observations have far reaching implications for both the history of the early universe and in predictions of its future development. Based on the measurements of anisotropy, the entire Milky Way is calculated to move through the intergalactic medium at approximately 600 kms.’

    Notice that this +/- ~3 mK anistropy in the CBR is millions of times bigger than the tiny anistropy accepted as evidence for inflation by crackpots and cranks in the mainstream, who ignore the far bigger and more important anistropy and its consequences completely in their discussions of it. So there is a frame of absolute motion in the cosmic background radiation if you take physics seriously and want to try to find it, instead of hyping failures as if it is some kind of proof that topics you don’t want to discuss (for sociological physics tea party reasons), don’t exist.

    Anyway, the question to focus on is what happens when a ray of light travelling radially outward from a mass is redshifted by gravity. Is it slowed down? Is redshift associated with slowing of light speed, and blueshift associated with speeding up?

    In view of the failure of Maxwell’s aether to explain light properly (see my recent posts on this blog for example), the best way to firmly establish facts is to do experiments. The amount of redshift of light is normally too small to be measured as a velocity change. However, one exception is the cosmic background radiation, which is the most redshifted light there is. It is redshifted from an emission temperature of 3000 K at 300,000 years after the big bang to 2.7 K today. Hence, redshift has reduced the energy carried by cosmic background radiation photon by a factor of 1,100 or so, and if there is a velocity reduction with redshift then the velocity of the cosmic background radiation would be down from 300,000 km/s to about 270 km/s, a difference which should be easy to measure.

    All you need is a long tube with a detector at one end and a shutter (possibly based on a high speed revolving metal disc with a hole in it) at the other end. The shutter could let a brief burst of cosmic background radiation to enter, and the delay time in reaching the detector would inducate the speed. Problem sorted! However, the experiment would be tricky. The tube would probably need to be big, and placed in space to avoid interference. There might be problems designing a suitable shutter to let the cosmic background radiation enter at one end of the tube in brief pulses that can be timed. One option is to have a normal light bulb outside the tube, so that a burst of visual light enters at the same time as the cosmic background radiation, and is detected by a detector at the detection end of the instrument, beside the microwave background radiation sensor. The comparison of the delay times for the light from the non-receding bulb, with the highly redshifted cosmic background radiation, would confirm if redshift is accompanied by a speed change.

    It is possible that all light redshifts are accompanied by a corresponding speed decrease. General relativity is known to be incomplete for many reasons (see recent posts on this blog) so it doesn’t give the mechanism for what is occurring.

  7. I will just add to Pentcho Valev that most of the crackpot claims that relativity has varying velocity of light seem to derive from people who haven’t read the papers properly thinking that v is velocity, whereas in many papers Einstein uses it for frequency as well.

    Hence Einstein’s equation for frequency shift of light due to gravity looks like a velocity change to people who get easily confused. E = hf is Planck’s energy-frequency equivalence for quanta, but that is often written E = hv, with v being frequency. In electromagnetism things easily become confusing for beginners because E is electric field strength (volts/metre) and quite often has to be used for energy (Joules). Since energy is a scalar while E is a vector, the E of electric field strength can be written in bold print, and E for energy just in italics.

    Even in elementary school the units can play havoc, with the unit of time being the second, s, and s also being used for distance, ostensibly to avoid confusion with the derivative symbol d. So ds means the differential element of s. It would be confusing to write dd for the differential element of d, because it would look like d^2 longhand. Obviously this is vital for a spacetime metric, where you don’t want to use x, y, z, or r which have other definitions, but generally it is better to use say r for distance if it is radial distance, or x, y, z, instead of using s, which causes a lot of confusion because in dimensional analysis you then have time represented by s, while when not using dimensional analysis distance is represented by s. Feynman said that all the energy units which exist are proof that physicists are as irrational as anybody. But it’s not just energy units which maximise the moronic confusion …

  8. “Instead of splitting attacking critics of completely failed theories, he should perhaps admit the theory has no claim to be science.”

    Very embarrassing. This final sentence in the post is presumably missing the word “hairs”, which would fit nicely between the words splitting and attacking. Alternatively, perhaps the word splitting should be removed. I’ll fix it when I’ve time.

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