• [deleted]

An Open Question to FQXi's Steve Carlip

http://math.ucr.edu/home/baez/physics/Relativity/SpeedOfLight/speed_of_light.html

Steve Carlip: "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. This interpretation is perfectly valid and makes good physical sense, but a more modern interpretation is that the speed of light is constant in general relativity. (...) Finally, we come to the conclusion that the speed of light is not only observed to be constant; in the light of well tested theories of physics, it does not even make any sense to say that it varies."

http://arxiv.org/pdf/gr-qc/9909014v1.pdf

Steve Carlip: "It is well known that the deflection of light is twice that predicted by Newtonian theory; in this sense, at least, light falls with twice the acceleration of ordinary "slow" matter."

Steve Carlip,

The top of a tower of height h emits light with frequency f, speed c and wavelength L (as measured by the emitter). An observer on the ground measures the frequency to be f'=f(1+gh/c^2), the speed of light to be c' and the wavelength to be L'. Please answer the following questions: c'=? L'=?

Thank you in advance,

Pentcho Valev pvalev@yahoo.com

Good morning Sophie Hebden

Thanks for an excellent presentation of some the points finding attention of mainstream physicists. In PicoPhysics - we have less items of worry about. For example invariance of speed of light is a simple Corollary to Unary law 'Space contains energy'.

May I invite you to review my essay at http://fqxi.org/community/forum/topic/1326

I look forward to your comments and evaluation of the essay.

Vijay Gupta

16 days later
  • [deleted]

Inconstant speed of light in the Perimeter Institute:

http://www.perimeterinstitute.ca/newsletter/2012/spring/files/assets/seo/page12.html

"Laurent Freidel and Lee Smolin, both faculty members at the Perimeter Institute, have been collaborating with Giovanni Amelino-Camelia at Sapienza University of Rome in Italy and Jerzy Kowalski-Glikman at the University of Wroclaw in Poland. The quartet has been investigating the effects of a curvature of momentum space. What they discovered is shocking: the curvature of momentum space would indeed distort the conservation laws. Special relativity would say that any two photons, regardless of their energies, would travel at exactly the speed of light. In a curved momentum space, though, that's no longer true: high-energy photons would move differently than low-energy ones."

Of course, this only concerns the Perimeter Institute. Ordinary Einsteinians should know that the speed of light is constant and that's it. The practice of singing hymns is called hymnody:

http://www.haverford.edu/physics/songs/divine.htm

DIVINE EINSTEIN: No-one's as dee-vine as Albert Einstein not Maxwell, Curie, or Bo-o-ohr!

http://www.youtube.com/watch?v=5PkLLXhONvQ

We all believe in relativity, relativity, relativity. Yes we all believe in relativity, relativity, relativity. Everything is relative, even simultaneity, and soon Einstein's become a de facto physics deity. 'cos we all believe in relativity, relativity, relativity. We all believe in relativity, relativity, relativity. Yes we all believe in relativity, relativity, relativity.

Pentcho Valev pvalev@yahoo.com

  • [deleted]

Doppler effect threatens relativity:

http://moodle.davidson.edu/moodle2/pluginfile.php/15877/mod_resource/content/1/Intro120-Week-13.pdf

"When the observer is moving, the sound waves emitted from the source are undisturbed, the wavelength does not change as observed from the moving observer he/she just comes across more/less wavefronts per time (...) when moving towards/away from the source and consequently sees a change in frequency."

If in the above quotation the word "sound" is replaced with "light", the text will be fatal for relativity - the speed of light, as measured by the observer, will turn out to vary with the speed of the observer. Relativity can only be saved if additional changes in the text are made:

When the observer is moving, the LIGHT waves emitted from the source are DISTURBED, the wavelength DOES CHANGE as observed from the moving observer SO THAT he/she just comes across more/less wavefronts per time (...) when moving towards/away from the source and consequently sees a change in frequency.

Do the additional changes in the text have any justification? Is it reasonable to believe that the motion of the observer DOES CHANGE the wavelength of the light wave but DOES NOT CHANGE the wavelength of any other wave? How can this variation of the wavelength of light with the speed of the observer be explained in physical terms? Why no such explanation can be found in the relativistic literature?

Pentcho Valev pvalev@yahoo.com

    • [deleted]

    Doppler effect really threatens relativity:

    Question: The observer is moving away from the light source with a speed Vo. In time t, the number of waves observed by him is (c-Vo)t/lambda, where lambda is the wavelength. What is the speed of the light waves as measured by the observer?

    Answer: The speed of the light waves as measured by the observer is c-Vo, in violation of special relativity.

    http://www.cmmp.ucl.ac.uk/~ahh/teaching/1B24n/lect19.pdf

    Tony Harker, University College London: "The Doppler Effect: Moving sources and receivers. The phenomena which occur when a source of sound is in motion are well known. The example which is usually cited is the change in pitch of the engine of a moving vehicle as it approaches. In our treatment we shall not specify the type of wave motion involved, and our results will be applicable to sound or to light. (...) Now suppose that the observer is moving with a velocity Vo away from the source. (...) If the observer moves with a speed Vo away from the source (...), then in a time t the number of waves which reach the observer are those in a distance (c-Vo)t, so the number of waves observed is (c-Vo)t/lambda, giving an observed frequency f'=f(1-Vo/c) when the observer is moving away from the source at a speed Vo."

    Pentcho Valev pvalev@yahoo.com

    • [deleted]

    This is a fun thread. OK, when do we quit goofing around and begin work on a superluminal drive model? OK, I'll go first.

    A patch of space-time, which can contain a spaceship, is just a particle in a superluminal space-time. The speed of light in this superluminal space-time is c' >> c.

    Question: can we describe the kind of field that we have to generate around our spaceship so that we can maneuver in superluminal space?

    Any takers?

    • [deleted]

    Doppler effect is fatal for relativity: the speed of the light waves, as measured by the observer, varies with the speed of the observer:

    http://www.phys.uconn.edu/~gibson/Notes/Section6_3/Sec6_3.htm

    Professor George N. Gibson, University of Connecticut: "Now imagine that you are returning to shore, and so you are traveling in the same direction as the waves. In this case, the waves may still overtake you, but AT A MUCH SLOWER RATE - you will bob up and down more slowly. In fact, if you travel with exactly the same speed as the waves, you will not bob up and down at all. The same thing is true for sound waves, or ANY OTHER WAVES."

    Pentcho Valev pvalev@yahoo.com

    • [deleted]

    Variable speed of light in a gravitational field:

    http://physics.aps.org/story/v16/st1

    "Imagine a pulse of light emitted downward from the top of a cliff just as a diver jumps. By the time the light reaches the ground, the diver will have gained speed and will regard a detector stationed on the ground as moving upward. According to the diver, the light source was stationary when it emitted the pulse, but the detector is racing upwards toward the light pulse at the moment of detection. So the detector should see the light's frequency increased by the Doppler effect."

    As judged from the frame of the diver, at the moment of detection the detector is racing upwards with a speed v. So what is the relative speed of the light pulse and the detector at the moment of detection, ACCORDING TO THE DIVER? Both antirelativists and (clever) relativists claim that, ACCORDING TO THE DIVER, the relative speed is:

    c' = c v

    Pentcho Valev pvalev@yahoo.com

    • [deleted]

    Einstein's nightmare: The speed of light relative to an observer varies if that observer moves towards or away from the light source:

    http://www.aip.org/history/einstein/essay-einstein-relativity.htm

    John Stachel: "But here he ran into the most blatant-seeming contradiction, which I mentioned earlier when first discussing the two principles. As noted then, the Maxwell-Lorentz equations imply that there exists (at least) one inertial frame in which the speed of light is a constant regardless of the motion of the light source. Einstein's version of the relativity principle (minus the ether) requires that, if this is true for one inertial frame, it must be true for all inertial frames. But this seems to be nonsense. How can it happen that the speed of light relative to an observer cannot be increased or decreased if that observer moves towards or away from a light beam? Einstein states that he wrestled with this problem over a lengthy period of time, to the point of despair. We have no details of this struggle, unfortunately. Finally, after a day spent wrestling once more with the problem in the company of his friend and patent office colleague Michele Besso, the only person thanked in the 1905 SRT paper, there came a moment of crucial insight. In all of his struggles with the emission theory as well as with Lorentz's theory, he had been assuming that the ordinary Newtonian law of addition of velocities was unproblematic. It is this law of addition of velocities that allows one to "prove" that, if the velocity of light is constant with respect to one inertial frame, it cannot be constant with respect to any other inertial frame moving with respect to the first. It suddenly dawned on Einstein that this "obvious" law was based on certain assumptions about the nature of time..."

    Time did obey Einstein's orders - it started to flow differently for the moving observer so that the speed of light relative to him could gloriously remain constant. Unfortunately Einstein forgot to tell the wavelength to vary with the speed of the observer so as to neutralize the frequency shift. The danger is obvious - bad people may remember the formula:

    (frequency) = (speed of light)/(wavelength)

    and come to the conclusion: "The frequency varies as the observer moves towards or away from the light source but the motion of the observer obviously cannot alter the wavelength of any wave - it remains unchanged. Then the formula tells us that the frequency shift can only be caused by a shift in the speed of light. In other words, the Doppler effect amounts to an experimental confirmation of the variation of the speed of light with the speed of the observer. No we don't believe in relativity, relativity, relativity anymore!"

    Pentcho Valev pvalev@yahoo.com

      • [deleted]

      The Pound-Rebka experiment confirmed the Newtonian tenet that, as light falls in a gravitational well, its speed increases exactly as the speed of any falling particle does:

      http://www.einstein-online.info/spotlights/redshift_white_dwarfs

      Albert Einstein Institute: "One of the three classical tests for general relativity is the gravitational redshift of light or other forms of electromagnetic radiation. However, in contrast to the other two tests - the gravitational deflection of light and the relativistic perihelion shift -, you do not need general relativity to derive the correct prediction for the gravitational redshift. A combination of Newtonian gravity, a particle theory of light, and the weak equivalence principle (gravitating mass equals inertial mass) suffices. (...) The gravitational redshift was first measured on earth in 1960-65 by Pound, Rebka, and Snider at Harvard University..."

      Is this compatibility between the Pound-Rebka experiment and Newton's emission theory of light dangerous for Einstein's theory? Many Einsteinians don't know the answer to that question and teach, just in case, that the speed of light does not increase at all:

      http://www.amazon.com/Why-Does-mc2-Should-Care/dp/0306817586

      Why Does E=mc2?: (And Why Should We Care?), Brian Cox, Jeff Forshaw, p. 236: "If the light falls in strict accord with the principle of equivalence, then, as it falls, its energy should increase by exactly the same fraction that it increases for any other thing we could imagine dropping. We need to know what happens to the light as it gains energy. In other words, what can Pound and Rebka expect to see at the bottom of their laboratory when the dropped light arrives? There is only one way for the light to increase its energy. We know that it cannot speed up, because it is already traveling at the universal speed limit, but it can increase its frequency."

      Pentcho Valev pvalev@yahoo.com

      • [deleted]

      The gravitational redshift can be explained in terms of shift in the speed of photons, as is suggested in one of the quotations in my previous post. Accordingly, the redshifted light Radek Wojtak refers to is one having a speed lower than c. However if he had said that in his paper, neither Nature nor any other mainstream journal would have published the paper:

      http://www.wired.com/wiredscience/2011/09/galaxies-einstein-relativity/

      "The researchers, led by Radek Wojtak of the Niels Bohr Institute at the University of Copenhagen, set out to test a classic prediction of general relativity: that light will lose energy as it is escaping a gravitational field. The stronger the field, the greater the energy loss suffered by the light. As a result, photons emitted from the center of a galaxy cluster - a massive object containing thousands of galaxies - should lose more energy than photons coming from the edge of the cluster because gravity is strongest in the center. (...) The effect is known as gravitational redshifting."

      Ironically, Einstein's general relativity, just like Newton's emission theory of light, predicts that, as light is escaping a gravitational field, it will lose SPEED (as judged from the frame of the observer):

      http://www.speed-light.info/speed_of_light_variable.htm

      "In the presence of gravity the speed of light becomes relative. To see the steps how Einstein theorized that the measured speed of light in a gravitational field is actually not a constant but rather a variable depending upon the reference frame of the observer: 'On the Influence of Gravitation on the Propagation of Light', Annalen der Physik, 35, 1911. Einstein wrote this paper in 1911 in German. It predated the full formal development of general relativity by about four years. You can find an English translation of this paper in the Dover book 'The Principle of Relativity' beginning on page 99; 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+phi/c^2) where phi is the gravitational potential relative to the point where the speed of light co is measured. Simply put: Light appears to travel slower in stronger gravitational fields (near bigger mass). You can find a more sophisticated derivation later by Einstein (1955) from the full theory of general relativity in the weak field approximation: (...) For the 1955 results but not in coordinates see page 93, eqn (6.28): c(r)=[1+2phi(r)/c^2]c. Namely the 1955 approximation shows a variation in km/sec twice as much as first predicted in 1911."

      Pentcho Valev pvalev@yahoo.com

      9 days later
      • [deleted]

      Einstein and the emission theory of light:

      http://www.pitt.edu/~jdnorton/papers/companion.pdf

      John Norton: "Einstein could not see how to formulate a fully relativistic electrodynamics merely using his new device of field transformations. So he considered the possibility of modifying Maxwells electrodynamics in order to bring it into accord with an emission theory of light, such as Newton had originally conceived. There was some inevitability in these attempts, as long as he held to classical (Galilean) kinematics. Imagine that some emitter sends out a light beam at c. According to this kinematics, an observer who moves past at v in the opposite direction, will see the emitter moving at v and the light emitted at c+v."

      And the frequency the observer will see is f'=(c+v)/L, where L is the wavelength:

      http://www.hep.man.ac.uk/u/roger/PHYS10302/lecture18.pdf

      Roger Barlow, Professor of Particle Physics: "Moving Observer. Now suppose the source is fixed but the observer is moving towards the source, with speed v. In time t, ct/(lambda) waves pass a fixed point. A moving point adds another vt/(lambda). So f'=(c+v)/(lambda)."

      Einsteinians,

      Is f', the frequency the observer sees, compatible with c'=c+v, the variable speed of light predicted by Newton's emission theory of light?

      Einsteinians ready to answer the question:

      http://game2gether.de/wordpress/wp-content/uploads/2012/01/wall1-1280x1024-1024x819.jpg

      Pentcho Valev pvalev@yahoo.com

      • [deleted]

      Now watching Supermassive Black Holes on channel 170.

      There is a direct linear correlation between the velocity of the most distant stars orbtibing any given galaxy and the size of the black holes of that given galaxy. This per the show I am now watching.

      Can someone confirm that this same linear relationship exists with the velocity of the outer electron field surrounding atoms of small nucleus (i.e. carbon) and those of larger atoms (i.e. gold). My guess is that we find the same linear relationship. I have no idea how to find it, but its probably there. Get government funding!

      Can someone please answer my balloon inquiry? Where does the Space come from?

      (that is if CIG Theory is wrong) Please.

      (I'm scared of Black Holes - won't sleep well tonight)

      Doug

      a month later
      • [deleted]

      Walther Ritz no longer an unperson?

      It is not too dangerous to criticize Einstein's relativity and even extract career and money from the criticism - some high-ranking Einsteinians are experts in this. Yet as soon as one starts questioning the original falsehood - Einstein's 1905 light postulate - one automatically becomes an unperson:

      George Orwell: "Withers, however, was already an unperson. He did not exist : he had never existed."

      Walther (or Walter) Ritz is undoubtedly an unperson and yet:

      "The Thomas Jefferson Center for the Study of Core Texts and Ideas presents a lecture by Alberto A. Martínez, Associate Professor of History at The University of Texas at Austin entitled "Einstein, Relativity, and Myths" (...) Martínez will discuss how Einstein's relativity paper of 1905 changed physics and how it also led to misinterpretations and myths."

      The problem is that Alberto Martinez, like many high-ranking Einsteinians, is a Ritzian deep in his heart:

      Alberto Martinez: "Does the speed of light depend on the speed of its source? Before formulating his theory of special relativity, Albert Einstein spent a few years trying to formulate a theory in which the speed of light depends on its source, just like all material projectiles. Likewise, Walter Ritz outlined such a theory, where none of the peculiar effects of Einstein's relativity would hold. By 1913 most physicists abandoned such efforts, accepting the postulate of the constancy of the speed of light. Yet five decades later all the evidence that had been said to prove that the speed of light is independent of its source had been found to be defective."

      Alberto Martinez: "In sum, Einstein rejected the emission hypothesis prior to 1905 not because of any direct empirical evidence against it, but because it seemed to involve too many theoretical and mathematical complications. By contrast, Ritz was impressed by the lack of empirical evidence against the emission hypothesis, and he was not deterred by the mathematical difficulties it involved. It seemed to Ritz far more reasonable to assume, in the interest of the "economy" of scientific concepts, that the speed of light depends on the speed of its source, like any other projectile, rather than to assume or believe, with Einstein, that its speed is independent of the motion of its source even though it is not a wave in a medium; that nothing can go faster than light; that the length and mass of any body varies with its velocity; that there exist no rigid bodies; that duration and simultaneity are relative concepts; that the basic parallelogram law for the addition of velocities is not exactly valid; and so forth. Ritz commented that "it is a curious thing, worthy of remark, that only a few years ago one would have thought it sufficient to refute a theory to show that it entails even one or another of these consequences...."

      Pentcho Valev

      • [deleted]

      Initially the observer is stationary in the beach water but then starts walking out into the ocean with a speed v. Relative to him, the frequency of the ocean waves shifts from f=c/L to f'=(c+v)/L and their speed shifts from c to c'=c+v.

      Initially the observer is stationary with respect to the sound source but then starts moving towards the source with a speed v. Relative to him, the frequency of the sound waves shifts from f=c/L to f'=(c+v)/L and their speed shifts from c to c'=c+v.

      Initially the observer is stationary with respect to the light source but then starts moving towards the source with a speed v. Relative to him, the frequency of the light waves shifts from f=c/L to f'=(c+v)/L and their speed shifts from c to c'=....? Einsteinians?

      Einsteinians: Help! Help! Divine Einstein! Yes we all believe in relativity, relativity, relativity! Who's asking?

      Pentcho Valev

        • [deleted]

        For all waves (light waves included), when the observer starts moving towards the wave source with a speed v, the speed of the waves relative to him shifts from c to c'=c+v:

        http://www.takoi.edu.hk/~phy/0304_S6_webpage/Doppler%20effec1[1].2.htm

        "Approaching observer with stationary source. The wavelength observed by the observer remains unchanged. (lambda)=c/f. Apparent speed of the wave relatively to the observer: c'=c+Vo. Apparent frequency observed by the observer: f'=c'/(lambda)=[(c+Vo)/c]f."

        The awful formula c'=c+v provokes two reactions among Einsteinians:

        Ordinary Einsteinians' reaction.

        High-ranking Einsteinians' reaction.

        Pentcho Valev

        8 days later
        • [deleted]

        "Where are the "Einsteinians?" So as we celebrate the 100th anniversary of Einstein's great discoveries, the question arises: How many professional physicists are Einsteinians?"

        Smolin asked this question in 2005. At that time the Einsteinians were still quite many but almost all of them have left the sinking ship since then:

        "It is still not clear who is right, says John Norton, a philosopher based at the University of Pittsburgh, Pennsylvania. Norton is hesitant to express it, but his instinct - and the consensus in physics - seems to be that space and time exist on their own. The trouble with this idea, though, is that it doesn't sit well with relativity, which describes space-time as a malleable fabric whose geometry can be changed by the gravity of stars, planets and matter."

        "Many physicists argue that time is an illusion. Lee Smolin begs to differ. (...) Smolin wishes to hold on to the reality of time. But to do so, he must overcome a major hurdle: General and special relativity seem to imply the opposite. In the classical Newtonian view, physics operated according to the ticking of an invisible universal clock. But Einstein threw out that master clock when, in his theory of special relativity, he argued that no two events are truly simultaneous unless they are causally related. If simultaneity - the notion of "now" - is relative, the universal clock must be a fiction, and time itself a proxy for the movement and change of objects in the universe. Time is literally written out of the equation. Although he has spent much of his career exploring the facets of a "timeless" universe, Smolin has become convinced that this is "deeply wrong," he says."

        Pentcho Valev

          • [deleted]

          Antirelativists will have to solve a fundamental epistemological problem: How to disprove a theory that nobody defends. The solution, if any, is by no means trivial. It may turn out that the immortality of Einstein's relativity is due to its ghostliness - no matter how hard you strike, you cannot cause injury.

          Pentcho Valev

          • [deleted]

          "University of Adelaide applied mathematicians have extended Einstein's theory of special relativity to work beyond the speed of light. (...) "Our approach is a natural and logical extension of the Einstein Theory of Special Relativity, and produces anticipated formulae without the need for imaginary numbers or complicated physics." The research has been published in the prestigious Proceedings of the Royal Society A in a paper, 'Einstein's special relativity beyond the speed of light'. Their formulas extend special relativity to a situation where the relative velocity can be infinite, and can be used to describe motion at speeds faster than light."

          "A natural and logical extension of the Einstein Theory of Special Relativity" means that a valid deductive chain exists between Einstein's 1905 postulates and the new formulas. This is obviously not the case.

          In fact, Einstein's relativity stopped being deductive shortly after 1905. Rather, arbitrary manipulation of the equations until the desired predictions are obtained became the main method. The introduction and withdrawal of the cosmological constant and the long and painful adaptation of the theory to the Mercury's perihelion anomaly are typical examples.

          Pentcho Valev

            • [deleted]

            If deduction had not been abandoned, Einstein's relativity would have been refuted by the following simple argument:

            PREMISE: "If we accept the principle of equivalence, we must also accept that light falls in a gravitational field with the same acceleration as material bodies."

            CONCLUSION: In gravitation-free space, the speed of light (as measured by the receiver) varies with the speed of the receiver.

            VALIDITY OF THE ARGUMENT: The emitter (E) and the receiver (R) are at rest: E at the earth surface, R at a distance h above E. In accordance with the PREMISE, the receiver measures the speed of light to be c'=c(1-gh/c^2). This scenario is equivalent to one in which E and R are fixed in an elevator accelerating, in gravitation-free space, with constant acceleration g in the direction E->R. So when the light signal reaches R, R has acquired speed v=gh/c. Accordingly, the receiver in the elevator measures the speed of light to be c'=c(1-gh/c^2)=c-v.

            Pentcho Valev