regarding the article: Varying Lightspeed, Special Relativity & Maxwell’s Equations
Most of the letters we get are questions, respectful criticisms or outright praise. However there are some which are mocking and snide. The letters from Dr. Mark Kluge are the latter. He has been dogging the Setterfield work for some time on various public forums, and as he is aware of our policy of printing material from our emails on our website and responding, we are taking the liberty of including here his email to us on the subject of this article as well as Barry Setterfield's response to him.
The Kluge email:
I have just read the new article from the BS web page entitled "Varying Lightspeed, Special Relativity & Maxwell’s Equations". It has me rolling on the floor laughing.
BS says "the demands of Relativity are still fulfilled if, at any instant, the individual values of e and m are isotropic throughout the cosmos". That is totally incorrect. Firstly, the word "isotropic" is inappropriate here. That word means "[i]dentical in all directions; invariant with respect to direction" (The American Heritage Dictionary of the English Language at http://www.bartleby.com/61/70/I0257000.html). That is the ordinary scientific usage of the word as well. Isotropic does not mean "having the same value throughout space." The word BS should be using is "homogeneous", not "isotropic".
More importantly, however, BS' statement is just simply false. The principles of (special) relativity require that properties of the vacuum be homogeneous over all points of space-time, not just all points of space at an instant of time. Indeed, the latter is not even defined in the space-time of special relativity, since simultaneity of events separated by space-like intervals is coordinate-system dependent.
It may well be that some extension of special relativity is not incompatible with space-time varying speed of light. It may even be that in some space-time where there is varying c, the gradient of c is a time-like vector, so that 3-surfaces of constant c are space like and that a time-coordinate may be defined along the normal to such surfaces. However, when one transforms to coordinate systems moving with respect to that special system one will inevitably find spatial dependence of c if there is temporal c-dependence in even one coordinate system.
Bs then misuses the invariance of x1^2 - c^2*t1^2 = x2^2 - c^2*t2^2 = G. BS mistakenly claims that "the distance is required to remain intact", but BS is referring to the x distances. Unfortunately it is the quantity G, the so-called "proper distance" that remains invariant, not the distances x1 and x2 themselves. Indeed, the phenomenon of length contraction (the famous Lorentz Contraction) requires those lengths to vary with coordinate system.
BS obviously doesn't know what the Schwartzschild Metric is. He mistakenly states "[t]he same is true for the Schwartzschild metric which requires the invariance of the expression x^2 + y^2 + z^2 – c^2t^2". (I have edited the equation's superscripts--MDK) That is not the Schwartzschild Metric. It is just the Lorentz Metric in 3 + 1 dimensions. You can look up the Schwartzschild metric in any text on general relativity. I don't want to bother typing it out here on my text-only mail client. In any case anyone interested can easily verify that the Schwartzschild metric isn't what BS claims it to be.
I hope that Mr. & Mrs. BS learn a little bit of physics from this e-mail, or at least from somewhere. BS' August 2006 remarks are really pretty laughably pathetic.
M. D. Kluge
LORENTZIAN AND EINSTEINIAN RELATIVITY
Professor Mark Kluge has criticized my posting about Relativity and claims that I do not understand what is happening in Relativity theory. I will answer his specific points in just a moment, but some introductory remarks are in order about Relativity so that my comments will be seen in their correct context.
Einstein produced his version of Special Relativity in 1905, just one year after H.A. Lorentz produced a similar, but by no means identical theory . We are all aware that Einstein has had most of the attention ever since. Nevertheless, over time, the Lorentz approach has been updated so that today there is a viable alternative. Indeed, there are over 40 physicists and astronomers who currently support Lorentz rather than Einstein . Hereafter we will distinguish the two theories as LR for Lorentz Relativity, and SR for Einstein’s Special Relativity.
Those who unconditionally support Einstein will immediately point out that SR has passed eleven independent experiments confirming many of its features and predictions. They will also point out that General Relativity (GR), which is a theory of gravity, has similarly passed a number of tests and was based on SR. They will then affirm that, in view of these successes, SR is confirmed and that the speed of light must be constant.
However, there is an inconsistency here, because the competing claims of the Lorentzian approach have not been considered. These claims of LR are equally well supported, but they have several important differences, one of them being that there is no universal speed limit such as SR claims for lightspeed. SR claims that one point of reference, such as someone on a moving spacecraft somewhere out in the cosmos at position A, is indistinguishable from another frame of reference elsewhere in the cosmos at point B, even though they have a velocity relative to each other. The only thing the observers have in common is the fixed speed of light. The mathematical transformations that are done by the observer at A to work out what is happening at B will have their counterpart by the observer at B trying to work out what is happening at A. In other words, the relationships are reciprocal in SR as all frames of reference are equivalent, there being no preferred frame. This is one of the two very general postulates of SR, the other being the fixed speed of light.
But the Lorentz approach is different: it states that there is indeed a preferred frame of reference, so that the mathematical transformations only need apply one way, namely to the moving body, not reciprocally to the preferred frame at rest. It is important to note that General Relativity (GR) is built on SR using only these one-way mathematical transformations relative to the local gravitational field, the center-of-mass reference frame . Since this is the basically same as the Lorentzian approach, then GR is just as consistent with LR as it is with SR .
Which form of relativity is correct? SR requires all frames of reference to be equal, that is to say there is no preferred frame of reference. Is there a simple way of testing whether or not there is a preferred frame of reference? Well, yes, there is! It comes from astronomy and it is called the microwave background radiation, which is the evidence that space was expanded out initially. The velocity of our Solar System, the rotation velocity of our Galaxy and the direction and velocity of movement of our Galaxy through space have all been registered in reference to the microwave background. In other words the background radiation provides an absolute frame of reference on a universal scale.
On this matter, Harwit states: “Current observations indicate that the universe is bathed by an isotropic bath of microwave radiation. It is interesting that the presence of such a radiation field should allow us to determine an absolute rest frame on the basis of local measurement.” He then goes on to salvage what is left for SR by saying, “Such a frame would in no way violate the validity of special relativity which, as stated earlier, does not distinguish between different inertial frames. Rather the establishment of an absolute rest frame would emphasize the fact that special relativity is really only meant to deal with small-scale phenomena and that phenomena on larger scales allow us to determine a preferred frame of reference in which cosmic processes look isotropic.”. So an absolute frame of reference does exist, and has been experimentally proven. In other words, both observers A and B could determine their individual absolute velocities relative to the microwave background radiation. Since this goes against one of the basic postulates of SR, then if SR is valid at all, it can only be valid on a small scale. The alternative is that the Lorentzian approach may be correct since it actually requires a preferred frame to exist.
There is a further difference between SR and LR. Einstein proposed that the mathematical transformations that had to be performed applied to time, space, and mass. By contrast, LR says that such transformations only apply to clocks, meter sticks and momentum. There is an important distinction. For example, SR requires time itself to be affected by velocity or gravitational potential. By contrast, in LR nothing ever happens to time itself, just to certain types of clock attempting to keep time. In a somewhat similar way, an increase in temperature may lengthen the pendulum of some clocks and affect their time-keeping, but not the actual time itself. LR thus accepts that other types of clock exist for measuring time that may be unaffected by speed or potential. By contrast SR requires that time itself is actually affected by velocity or potential, and the same applies to mass and length. As a consequence of the fact that time itself is not affected by velocity or potential, LR recognizes that a universal time exists that is applicable to all frames of reference. In addition LR holds to the concept of an actual instant of “now” that applies throughout the cosmos.
Is there any experimental evidence to help us determine one way or the other as far as clocks are concerned? Let us look at the Global Positioning System of satellites that allow us to accurately pinpoint our position anywhere on earth. Suppose we let each atomic clock tick at their design rates in accord with whatever velocity and gravitational potential they experienced in orbit. One of the designers of the system writes: “Now suppose we tried to Einstein-synchronize the system of clocks. Satellite and ground clocks would tick at different rates. And if we tried to work in any local, instantaneously co-moving inertial frame, the corrections needed to synchronize with each orbiting clock would be unique to that observer’s frame and different from moment to moment because both clocks are accelerating. The practical difficulties of operating the system would be virtually insurmountable.” . This is what Einstein’s approach requires. However, what we have in actual practice is a situation where “all atomic clocks aboard satellites with a variety of orbital planes, and all atomic clocks all over the rotating Earth, are all synchronized with one another, and remain synchronized, despite being in many different inertial frames. This appears to be a practical realization of Lorentz’s universal time.”.Those who advocate the Einsteinian position point out that the clocks had to be adjusted in their tick rate to achieve this. But the whole point is that such a universal synchronization is possible on the Lorentz approach by a variety of mechanisms whereas it is not possible on the Einsteinian approach. It seems, therefore, that LR is again more in line with actual experimental evidence than the SR position.
The GPS experiment therefore shows that the LR approach is more likely to be correct and that nothing happens to time itself, but only to atomic clocks attempting to keep time. This allows a simple resolution of the so-called twins paradox as outlined in an article in Apeiron, Vol. 10:1 for 1st January, 2003, p.69-86. More importantly, however, this Lorentz synchronization of the GPS indicates that absolute time must exist. Therefore, there is no slowing of actual time as one’s speed increases, only of the rate of ticking of atomic clocks. For that reason, the speed of light will be a constant in atomic time, so SR will hold only in the atomic frame of reference. The speed of light measured by other clocks is therefore free to behave in accord with other physical properties of the vacuum. This, too, is at least in agreement with experiment [7, 8], even though those experimental results have been criticized as being out of step with SR. If the data disagree with theory, a choice has to be made. In this case, it seems that these results tend to support LR as being a more correct description of reality than SR.
The SR position also requires that mass increases as velocity increases. It is certainly true that this is the observed behavior of particles in accelerators since the particles have not reached, let alone exceeded, the speed of light. But it has been pointed out that a similar situation existed for propeller driven aircraft in level flight trying to exceed the speed of sound. The air molecules cannot be driven faster than sound no matter how fast the propellers spin, so the aircraft itself cannot go any faster. However, if there was a force propagating faster than the speed of sound, or a continuous acceleration, such as in a jet engine capable of exceeding that limit, then higher velocities are potentially achievable. There is some, currently contentious, evidence that the speed of gravity may in fact be significantly faster than light [9, 10]. If this is ultimately proven to be correct, it would establish that LR is again a better description of reality than SR.
The final issue that needs to be discussed is length contraction with increasing velocity that is maintained by SR. Professor Mark Kluge made much of this point in his response to my initial posting. He spent some time outlining the SR position on this issue, and he did it well. Incredibly for a theory that is so widely accepted, it seems that length contraction has never been seen directly in any experiment, but has only been inferred. The actual situation is outlined in Apeiron, Vol. 10, No. 4, October 2003, pp. 152-158 in an article entitled “Lorentz Contraction”.
In order to understand the concepts involved, it can be stated that an important feature of SR is that time will appear to be de-synchronized in any other frame of reference that has motion relative to the observer’s own frame [see for example Apeiron 10:1 (2003), pp.69ff.]. Specifically, let us allow a rod with clocks along it to be moving past an observer who also has a clock. Let the nearest clock in the moving frame of reference (that is, on the rod) be synchronized with the clock of an observer at rest. Under these conditions SR states that receding clocks in the moving frame will be experiencing time in the observer’s past, while those approaching the observer will be experiencing time in the observer’s future. A snapshot of the rod taken by the observer will not show the length of the rod all at one instant of what we might call “rod-time”. Rather, the observer will see one end at a different moment of “rod-time” than the other end. We now let the rod’s leading end be labeled D, and the rod’s trailing end be labeled E. As a result of this clock de-synchronization, the observer will see end D at a given rod-time, and will see E as some later rod-time. Thus, end E will always be seen as it was at a later moment in time than for end D. But because E is moving the same way as D, a later moment will bring end E closer to where D had been a little earlier. In other words, the rod will always appear contracted in length because the leading edge is seen at an earlier time than the trailing edge. This will apply whether the rod is approaching or receding from the observer.
As a result of these and similar examples, the Apeiron article states: “…the clear implication of our considerations here is that length contraction is not a physical shortening, but is merely an observational consequence of time desynchronization. In SR, physical bodies do not actually change dimensions.” [Ibid]. Since LR has no time de-synchronization, this means that that LR has no length contraction, nor is there any contraction of physical length or length standards either [Ibid]. But this development brings into question the whole reason for the theory of relativity in the first place. The whole idea of length-contraction and the necessity for relativity in one form or another arose because of the Michelson-Morley experiment. In this experiment, each half of a split light beam travels along one of two equally long but perpendicular arms of a special optical device, and then bounces off mirrors back to an observer. The optical device was an interferometer which, when the combined light waves of the split beams are out of step, will produce interference fringes.
As it turned out, no significant fringe shifts were observed, even when the device was rotated to other positions. Fringe-shifts had been expected because it was thought that the vacuum was a light-carrying medium or aether, and that light moving through the aether would take longer in one direction than another as it moved against the aether “current”, rather like a canoe on a river. Observation showed that the round-trip times for light going in any direction were the same. This was explained in SR by the length contraction of the arms of the interferometer in the direction of travel. This was meant to make the interferometer arms shorter by just the amount needed to compensate for what was expected to be a longer travel time through the moving aether. Now that there is another, perfectly logical, explanation for what seemed at first sight to be length-contraction in SR, this requires SR to reconsider its position on the lack of fringe-shifts, which obviously have some other explanation.
The explanation in LR is different because there is no proposed length contraction in the first place. The absence of the fringes can very logically mean that the earth apparently has no motion relative to the aether. However, this is not a problem for LR in the context of a Zero Point Energy. The ZPE is now known to be the light carrying medium rather than the old aether, and that makes all the difference. The local gravitational field of the earth can be shown to be an augmentation of the ZPE in our vicinity brought about by the presence of oscillating point charges . This local field of the (augmented) ZPE has no motion with respect to the earth’s center of mass since it originates with the presence of the earth’s mass [12-16]. Thus, the Michelson-Morely experiment will show no fringe shifts. Note however, the Earth does rotate with respect to its own gravitational field and this DOES produce fringe-shifts, known as the Sagnac effect, that were first seen in 1913 when a rotating platform was used for the experiment. It was replicated in the Michelson-Gale experiment of 1925 using the earth’s own rotation. Thus experimental agreement with LR theory has been maintained and the ZPE approach thereby reinforced.
So lengths do not actually change in LR and, indeed, not even in SR when the situation is studied closely. Professor Mark Kluge claimed my interpretation of the equations was incorrect, because he thought lengths DID change. Instead, his remarks are now suspect. To begin with, his comments are incorrect when applied to LR principles which allow a variable lightspeed, the changing rate of ticking of atomic clocks without affecting time itself, and constant lengths. They also will be incorrect as far as SR is concerned if the above analysis is accepted. The comments in my earlier posting were designed to short-circuit a lengthy explanation of why these lengths should be constant even in SR. But granted that they are unchanged in LR, it necessarily follows that my formulations were correct for that form of relativity. In addition, if the quoted analysis for constant lengths in SR is accepted, then my use of those equations is correct for SR as well, and the changing speed of light in that scenario becomes an option that should be examined.
As far as the Schwarzschild metric is concerned, I gladly acknowledge my lapse from precision in the name of the equation that I was dealing with. Thank you for that.
Barry Setterfield, 29th August 2006.
. H.A. Lorentz, “Lectures on Theoretical Physics”, Vol. III, pp.208-211, Macmillan &
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The Second response from Dr. Kluge follows. Parts of his very long email have been deleted because they were either redundant or because he was asking questions about van Flandern’s work which is best to ask van Flandern himself and not Mr. Setterfield.
I thank the Setterfields for their interesting, albeit non-responsive response to my e-mail on the compatibility between BS' theory of time-varying speed of light and Special Relativity. Although that response fails to address the substantive problems I posed it does allow us to put to rest some smaller issues.
Our apologies. We’ll try again, below.
Firstly, the Setterfields refer to me as "Professor Kluge", but that is inaccurate. Although I have an earned Ph.D. in physics I am not a proressor at any college or university.
Our apologies again. From some communication in the past or something you wrote on one of the forums, we were under the impression that you were.
Secondly the Setterfields characterize some other responses they have received as "of outright praise" while mine is mischaracterized as "mocking and snide". Nothing could be further from the truth. My remarks were instructive, and while they were in no way laudatory I did not come here to praise, but to burry Setterfield.
We think your letters speak for themselves. The constant reference to Barry as “BS” must seem funny to you. Yes, those are his initials, but if you would like to use simply his initials, please use BJS, for his name is Barry John Setterfield. Thank you.
Thirdly, I did enjoy listening to the online video of BS' short talk at the 2006 Seattle Creation Conference. Unfortunately the poor quality of the video made it unworthy watching,. View graphs were illegible.) But as I listened without watching I did find BS to be an engaging speaker, and can now see how laypersons might find his presentation of his ideas attractive.
The quality is not something under our control. And it is great that the material is finally at the level that lay people CAN understand. So much of many science presentations ignore the lay folk. What we also appreciate is the consistent positive responses we get from professional scientists as well.
(Parenthetically, since it is not really on the main topic of this letter, I only heard one really totally off-the-wall statement in BS' talk. BS claimed, seemingly hesitantly, that the reason for some astronomers' initial skepticism of the interpretation of observed galactic red shifts as recession velocities stemmed from the fact that red shift is a pure, dimensionless number, while velocities are not. I've never heard of anyone having made such an objection. If BS has a reference to one, please send it. The objection, had it been made, would have been frivolous. Although speed of recession, v, is indeed not a dimensionless number, v/c manifestly is,. Even in the 1920s physicists and astronomers understood that something like a light Doppler shift was real and that light from receding objects would be shifted towards long wavelengths by an amount which was a function of v/c. There could have been disagreement about the form of that function, or someone could have disputed the claim for other reasons, but not for dimensional reasons.)
The response to this below. There is evidently a bit of historical science you did not study or simply have not been made aware of.
Now, back to the substance. I am happy to see that BS now agrees with me on one minor point-that he misused the term "Schwarzschild metric" I also acknowledge that I did err in spelling it the "Schwartzschild Metric."
Thank you for this one point in which you were correct.
I was surprised and disappointed that BS failed even to respond to another of his misusages, that of "isotropic". I will repeat my previous remarks here. I hope that, in the spirit of negotiation wherein the parties agree on the easy issues early, that BS will be able to agree that he did misuse the term "isotropic".
He did not, as you will see below.
BS says "the demands of Relativity are still fulfilled if, at any instant, the individual values of e and m are isotropic throughout the cosmos".
…Now to the larger substance of BS' response. It is a puzzling response. I fail to see its point. In the article from his web page here. BS purported to demonstrate (or at least outline a demonstration) that his theory was compatible with Special Relativity.
It is compatible if the lengths remain constant and atomic time is used.
…So did BS mean to demonstrate that his theory is compatible with Lorentzian Relativity? If so, then why did he not say so? And why did he use and cite an equation from A. P.French's book, x'2 - c2t'2 = x2 - c2t2 = G. That equation is necessary and appropriate in working with ordinary (Einsteinian) Special Relativity, but doesn't even hold in the competitor theory, Lorentzian Relativity.
If x is a constant and ct is a constant, the whole thing remains a constant. Is this puzzling?
Does BS intend to demonstrate that his theory is compatible with SR?
Yes, when lengths remain constant and atomic time is used.
Does he intend to demonstrate that his theory is compatible with LR? Or perhaps both?
Yes, both, when lengths remain constant (again).
BS has written "with changing ZPE, the formulations of Relativity are valid if atomic time, t, is used for any measurements" does he mean to say that Einsteinian Special Relativity is valid in BS' varying light-speed theory, provided that atomic time is used rather than dynamical time?
Or does he mean that within BS' theory of varying light-speed that Lorentzian Relativity is valid, provided that atomic time is used?
Yes, because Lorentzian Relativity acknowledges that some clocks (atomic) will be affected while others are not.
By the way, what exactly is Lorentzian Relativity?
Please check your physics texts. One suggestion: Open Questions in Relativistic Physics; Franco Selleri, editor; Apeiron, 1998.
But now Tom van Flandern (With BS' apparent approbation) seems to be saying that there is no Lorentz Transformation in his version of what he calls Lorentzian Relativity. He explains the apparent constancy of the speed of light in all inertial frames (as measured by terrestrial observers, at least) as due to aether dragging in the earth's gravitational field.. Whatever may be said about gravitational aether drag it is certainly not Lorentz's theory! Whatever he or others thought about the aether.
This was dealt with in our initial response to you, above, in the part of the discussion dealing with the Michelson-Morely experiment, the Zero Point Energy and the gravitational field. Please note, as well, that van Flandern is not alone in his opinions. At least forty other physicists and astronomers agree with him. Furthermore, a list of 5 other physicists who had recently worked on this issue was given in references  to  in the first response above. As an additional note, it might be mentioned that the ZPE approach, which resolves the issue of the Michelson-Morely results, also in effect removes the necessity for these theories of relativity in the first place.
Van Flandern's comparison of Einstein's SR and van Flandern's LR is puzzling.
Please raise your questions about van Flandern’s work with him. His work has appeared in refereed journals and so it clearly has been understood by at least some others.
A SECOND REPLY TO KLUGE.
Mark Kluge claims my response is ‘puzzling’. Let me put it simply. Einstein stated that no preferred frame of reference exists whereby one may measure an absolute velocity. In fact, one does exist, it’s the microwave background radiation, and the velocity of our galaxy through space has been measured in relation to it. Therefore Einstein was wrong. This should not be puzzling, except to those who believe Einstein’s theory was absolutely correct. By contrast, Lorentzian relativity acknowledges that a preferred frame of reference exists, so that approach holds the possibility of agreeing with the data.
Einstein said that time itself is affected by velocity and gravitational fields, so that no universal time base exists whereby all clocks can be synchronized. In fact, the GPS clocks are all synchronized with each other, despite their varying velocities in orbit, as well as with earth clocks, which are at a different potential in the earth’s gravitational field. These GPS clocks have all been Lorentz synchronized with each other and with the earth clocks. This shows that something is wrong with Einstein’s concepts, and that it is possible for absolute time to exist. Consequently, Einstein’s concept of space-time may also be in doubt and so may not be good to use in a discussion on varying lightspeed. This should not be puzzling, unless you hold to the complete correctness of Einstein.
Einstein required the speed of light to be a constant and to be a maximum speed for all particles. Tachyons exist which travel faster than light, and the speed of gravity has been inferred as being very significantly faster than lightspeed. Einstein’s concepts are thereby not in accord with the data, whereas the Lorentzian approach allows it. This should not be puzzling, but a clear signal that the theory accepted by majority opinion may be flawed.
Then there is length contraction, which Einstein’s work required to exist. My reply and the references given show that length contraction does not exist in practice, and no experiment has ever proven it to exist. Einstein is again shown to be flawed. This should not be puzzling, but rather be a warning light that we have a scientific anomaly, where the theory currently accepted by the majority disagrees with the actual data.
At the same time, it is this latter data that destroys Kluge’s basis for criticism of the equations I used. He claimed that the use of these equations was wrong because lengths were held constant. By contrast, Special Relativity (SR) required lengths to vary with circumstances, which destroyed the logic of the argument. But, the evidence indicates that lengths do not change, either in SR or in the Lorentzian version. Therefore, the use of those equations employing constant lengths as part of the solution to the problem is correct. With constant lengths, the final outcome is a constant term, even though the speed of light varies. That term is constant with varying lightspeed, c, because atomic time, t, runs at a rate inversely proportional to c. Therefore (c2t2) is an unchanging quantity, which, coupled with unchanging lengths, gives a result which is constant, in agreement with expectations. That, too, should not be puzzling.
The matter of the redshift was also raised in the context of the presentation at the Seattle Creation Conference. There, it was pointed out that Hubble and others were cautious about claiming that the redshift was necessarily due to velocity, even though the Doppler effect on light was well-known. All they had to go on was the measurement of a difference in wavelength divided by a laboratory wavelength. Such measurements of wavelength divided by wavelength gave a dimensionless number. To get a velocity, that data had to be multiplied by the speed of light, c. The relevant articles by Hubble are as follows: E.P. Hubble, Proceedings of the National Academy of Sciences, 15 (1929), p.168. Also, E.P. Hubble, “The Realm of the Nebulae,” p. 121, Yale University Press, 1936. In addition, the French astronomer Paul Couderc wrote in 1960, “It is always permissible to describe the red shift by expressing the speed which would correspond to it if the ordinary Doppler-Fizeau effect be assumed, and at the same time to reserve the opinion that the matter is really a more complex phenomenon. The speed thus given is therefore symbolic…” [“The Wider Universe,” p.92, Hutchinson & Co. (Publishers) Ltd., 1960]. A fuller discussion can be found in the Journal of Theoretics paper “The Redshift and the Zero Point Energy”, 29th December 2003, by Setterfield and Dzimano.
Finally, Mark Kluge again raises the matter of the use of the word isotropic, and claims that I should use the word homogeneous instead. The word “Isotropic” means identical in all directions. Agreed. “Homogeneous” means having the same value everywhere. Agreed. I was talking about the electrical and magnetic properties of the vacuum at any instant being “isotropic and having the same value throughout space” in other words, “isotropic and homogeneous”. I fail to see what the fuss is all about. It seems that Mark Kluge is grasping at anything that he can find to “Burry” Setterfield, as he puts it.
Barry Setterfield, 1st September, 2006.
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Note from a physicist who emailed regarding this exchange and the preceding article:
You could mention that the velocity of light always changes when light travels from vacuum into air, from air to water, from water to glass and so on.
Therefore the speed of light will vary if permeability, permittivity or both change.
It used to be assumed that empty space was a pure vacuum and if that were true then c would never get any higher anywhere than 186,000 mps. Now we know that empty space has very real properties of inertia and elasticity and behaves like an actual medium like air, glass, water, etc.