Talk:Variable speed of light/Archive 1

Archive 1

Removals of 15 December 2004

I removed some parts of the article, which I am copying here to explain my reasoning.

"Quantum physics (e.g., Feynman diagram) allows c to vary to any value within the limits of the uncertainty principle."

This needs to be explained or, at the least, a reference should be given. What formulation of the uncertainty principle is involved and how does that prove that c might vary?

"$\alpha ={\frac {e^{2}}{\hbar c}}$ in cgs units where e is the charge of a proton"

What do cgs units have to do with this formula?

Are you serious about that question?? cgs units have everything to do with the expression of $\alpha \$ when expressed as

$\alpha ={\frac {e^{2}}{\hbar c}}$

if you were in SI (or simply any general system of units that does not constrain $4\pi \epsilon _{0}=1\$, then the expression for the fine-structure constant is

$\alpha ={\frac {e^{2}}{\hbar c4\pi \epsilon _{0}}}$

That's the real expression for alpha, in terms of other physical quantities. r b-j 02:20, 21 Dec 2004 (UTC)

I see what you mean. You are talking about cgs units with the statcoulomb. I did not make the connection of cgs with esu (electrostatic units); probably because I'm used to using either SI units or Planck units. -- Jitse Niesen 16:50, 21 Dec 2004 (UTC)

cool. but if you're SI, then $\alpha ={\frac {e^{2}}{\hbar c}}$ is not accurate. it's not even dimensionless in SI. r b-j 18:54, 21 Dec 2004 (UTC)

"Dr Vladimir Dzuba has claimed [1] that it's meaningless to say if the speed of light is changing because it has units (it has been said that to get to the root of the changing constants problem, one has to look at unitless physical quantities - see above). But the physical quantity that determines the speed of light might be viewable as a unitless factor by the following reasoning. In the special theory of relativity, a space-time distance d is measured by pythagorean theorem, $d^{2}=x^{2}+y^{2}+z^{2}+(c*i*t)^{2}$ where x, y, and z are the first 3 dimensions of space-time and $c*i*t$ is the fourth dimension where $i={\sqrt {-1}}$

It's not just Dzuba that claims it. He references the Duff, et al "Trialogue" article. We must ask "How would we ever measure it if c changed, keeping all other constants the same?" and I have yet to see a persuasive answer to that. If $\alpha \$ changes, we would know it from measurement, but we could not ascribe the change to c, it could be due to the Elementary charge or Planck's constant. r b-j 02:20, 21 Dec 2004 (UTC)

Therefore a meter = $c*i*seconds$

$c*i$ is the conversion factor from seconds to meters. Time as a physical quantity is different from distance only by i. c is the correction factor to the historical error of thinking time and distance are different physical quantities. Meters could be defined as $seconds*i$ so that time and distance have the same units. To say that the speed of light is changing would then be to say that the relationship between the i dimension of space-time is changing relative to the other 3 dimensions."

If this is the opinion of whoever wrote it, it should be removed under the Wikipedia:No original research policy, otherwise references should be provided. Myself, I am not sure of the relevance of whether c is unitless or not: even if c is just a conversion factor, Dzuba's argument hold (compare with the conversion factor between feet and meters).

From the POV of humans with rods and clocks (or whatever measuring devices), c is not unitless because it is not dimensionless. In terms of Planck units, c is just the dimensionless 1, but before the meter was redefined, we measured c against existing standards of length and time. r b-j 02:20, 21 Dec 2004 (UTC)

I agree with everything that r b-j says. -- Jitse Niesen 16:50, 21 Dec 2004 (UTC)

"Humans need ideas to be valid (and distributable) in space and time in order for those ideas to fulfill the human need to survive and reproduce in space and time. In order for physics to make predictions about observations made by other people, first and foremost physics must be valid across space and time. Any "constants" that were found to be changing in space or time were either quickly eliminated from use or restated in an equation that would be valid in a larger range of space and time. Why publish a theory that can't be used in a distant time and place? The generalizations in physics we developed here on Earth appear to be valid in other galaxies at distant times, but it may not be just a coincidence. Galileo had a constant to predict gravitational observations on the surface of Earth, but we don't consider it a natural fundamental constant anymore because Newton made discoveries that enabled us to use a new constant G and equations to calculate gravity at any distance from a mass (not just the surface). Einstein's revelations showed that Newton's theory was not perfect and provided a new theory that enabled us to predict Mercury's orbit, and thereby extending Galileo's original observations to an even greater range of observation. Relativity equations could be said to be using a new constant, $G*2/c^{2}$ (from Schwarzschild radius), in the same way Newton's equations used a new constant to modify Galileo's $9.8m/s^{s}$ acceleration constant. As another example, some astronomers may have once thought the distance to stars was some fundamental constant of nature, but Hubble showed it changes with time. As a third example, c has already been found to be different in different situations and new equations and constants of quantum physics are used to modify the old c in some situations. None of these examples show a fundamental constant changing with time, but they do show the introduction, replacement, and modification-by-equation of previously-held constants because we insist that our fundamental constants be constant or we stop believing in their sanctity. In the same way, if c is found to be changing, then we will introduce a new constant, replace it, or modify it with a new equation, but we may never view c as changing with time just as we do not view Galileo's $9.8m/s^{s}$ as changing.

[ some stuff deleted by Scott due to article reaching limits and me agreeing that it needed deletion]

To Scott Roberts: I am sorry that I removed so much of your article, but I really think that the parts that I deleted do not belong on Wikipedia. -- Jitse Niesen 12:54, 15 Dec 2004 (UTC)

I agree with your comments with one tangential exception. Galileo didn't know "9.80000" wasn't valid on the entire surface, but neither did Newton know that his constant fails for mercury. I'll try to find references for the unitless c.

---

Although I agree with the comments as stated above, I now see there were other changes that were not mentioned that deleted and modified my statements that said light could travel faster or slower within the bounds of quantum mechanics. The following is my reference and argument that my previous statements were more accurate than the changes and that the faster-than-light wikipedia entry is in error.

Photons are commonly drawn at angles other than 45 degrees in Feynman diagrams. But photons are moving at speed c only at 45 degrees in those diagrams. To quote Feynman "...there is also an amplitude for light to go faster (or slower) than the conventional speed of light. You Found out in the last lecture that light doesn't go only in straight lines; now, you find out that it doesn't go only at the speed of light! It may surprise you that there is an amplitude for a photon to go at speeds faster or slower than the conventional speed, c." -- Chapter 3, page 89 of Richard Feynman's book "QED". I believe this is the fundamental basis of all the experiments that make individual photons go faster or slower than c. The new light-slowing experiments are not merely the old observation that photons "slow down" through a non-vacuum medium. That old observation is just multiple photons being absorbed and emitted in the molecules of the medium. The new experiments involve single photons, so that the slowing and speeding up of photons is real. To see how the uncertainty principle is involved to allow light to travel any speed, plug E=hf into the uncertainty principle's (E1-E2)(T1-T2) > h/(4pi) to get h(f1-f2)(T1-T2) > h/4pi where (f1-f2) is the precision of the frequency of the photon being studied and (T1-T2) is time interval. But f in quantum mechanics calculations is an exact number used in the summation of amplitudes, so c has to vary in order to allow f to remain a constant: use wavelength=fc to substitute (f1-f2)=(c1/w-c2/w). Rearranging, we get (c1-c2) > w/(T1-T2)/4pi where w is the fixed wavelength (frequency) of the photon being studied. So by the uncertainty principle, c can take on any value in the range (c1-c2) when you're analyzing intervals of time so small that they are subject to the uncertainty principle. Outside of the uncertainty principle (larger ranges of time), the individual amplitudes of quantum mechanics add up to produce a constant c. - Scott

I now understand that you were saying that individual photons can move slightly faster or slower than c = 299... m/s. However, I still don't see why "this is the fundamental basis of all the experiments that make individual photons go faster or slower than c." For definiteness, which experiment are you talking about? I think there is no experiment showing photons going faster than c, only experiments where photons slow down because of interaction with other matter. Furthermore, I'm uncomfortable with your use of the uncertainty principle: you say first that the frequency is not determined precisely and then that it is an exact number, so that c must change. My conclusion is quite the opposite: if you can use (E1-E2)(T1-T2) > h/(4pi), which is not totally clear to me, it follows that both the frequency f and the wavelength w can vary, but c is still a constant, like h and pi. -- Jitse Niesen 16:50, 21 Dec 2004 (UTC)

Photons are NOT localizable. They don't even have a noncovariant Newton-Wigner localization. What feynman was refering to is really the propagator. But the propagator does NOT really describe a photon created at a given spacetime point and annihilated at another. That's just a misinterpretation of quantum field theory. Phys 12:13, 4 Jan 2005 (UTC)

all this dispute seems to have done some good. i think the article has notable neutrality now, continuous modifications like the simple non-obstructive refrazing I have contributed seem to do the trick. so long as all the views are represented without hurting the concepts too badly, we can all get along in the intellectual realms here. . .

Surprisingly informative article, i like the theory that time slows, alltho it doesn't really confirm to my current uhm.. kosmology. i wonder if t slows, would there be circumstances where it slows slower, possibly circumstances that delay other generations(like nucleair reactions or lightemission), if so would you find exagerated entropy behind such a 'screen' (possibly like a bottleneck in a tidal area). If we can find such exagerated overly dense cosmic events i would assume t indeed slows. The 'speed' with what it slows appears very minor still, a wild guess would be 2 seconds in a billion years, larger values would probably somehow show in the fossil or geological record. Anyhow a slowing time is only a result of the big bang theory, and in that sense probably is moot as a cosmic value, when we interprete everything we can observe as local, wich imho makes more sense. In that situation i would hope t speeds and slows.uh? it's usually f that varies then? ah yes u have that.80.57.67.243 (talk) 17:13, 27 November 2008 (UTC)

candidate for deletion??

i won't do anything about it, but this is still in discussion in the research (or speculative) end of physics. i don't think there is enough consensus among physicists to make this topic "encyclopediac". personally i do not think that variation in any dimensionful physical "constant" is meaningful because we do not measure dimensionful quantities without measuring them against like-dimensioned quantities. we would not know the difference unless some dimensionless constant has changed. if alpha changes, fine, but to ascribe that to c changing is speculative. maybe it should be deleted. r b-j 19:12, 21 Dec 2004 (UTC)

okay, now i am restating my original suggestion here that this wiki article is too much in the speculative end (perhaps someone's original research?) to be considered suitable for wikipedia. if it isn't deleted, it should be edited to show that this is about a speculative concept that a lot of physicists will have disagreement with. this is the kinda stuff Duff was complaining about: a New York Times article saying that the speed of light is slowing down when what really is the case is that some interpretations of some evidence is that $\alpha \$ has maybe increased slightlty over 2 billion years. r b-j 02:35, 27 Dec 2004 (UTC)

By the above reasoning all references to string theory should be deleted from the wikipedia. Duff seems to be in the minority of physicists or at least cosmologists who think it's theoretically impossible for c to change. Otherwise, respectable journals wouldn't be publishing so many peer-reviewed papers on variable c models. Duff has not done the research on fundamental units and constants as shown in the 1st paper in the external links (Sep 2004 paper). Duff's last paper on the subject (July 2004) included objections from 3 others that he had to respond before they published his work, indicating that his view is outside the norm. People have a big interest in if the speed of light is changing, so as long as there are no factual errors in the article, i think it should stay. I tried to counter every argument r-b-j made while he ignored my questions. I have references in the article to support what is said where i expected r-b-j to object, even resorting to quoting for protection. The orginal research aspects i had in the article have been gone for sometime. I should point out that if the latest research is correct, alpha itself would no longer be dimensionless but have units of 1/time. Would that make it no longer a fundamental constant worthy of study? - Scott

one should go further to mention that so long as it is clearly stated that this theory is still disputed or has not yet gained widespread acceptence, there is no harm in displaying information about it. true, it can be disputed quite thuroughly, but it certainly hasn't been (and for that matter probably can't be)actually proven wrong. Information should be avaliable to whoever wants it written by whoever writes it. . . so long as both parties are aware of the situation. from this standpoint, what I suggest is simply that it be noted when an artical covers a controversial or disputable topic, but definately should not become a candidate for deleation unless it is plain derranged, though this could become controversial further as some would claim that this theory is thuroughly derrainged. so. . . if you think so, make a note to let people know that it's not to be considered fact. . . but don'd deleat it for christ's sake!

i previously said that i wouldn't do anything about it, but i am now changing that position. after posting about this to sci.physics.research where not one response (there were much fewer responses than i would have liked) took the position that "Duff's wrong and a variance of the speed of light could actually be measured", after a few other email conversations with Duff and physicists that are regulars to s.p.r, after waiting for Scott to post the theory he espouses to s.p.r for it to be tested by some real physicists (which, unless he is "zawy", has not been done at all), i came to the conclusion that because this theory decidedly has dubious physical merit, wiki readers should be alerted to that. so i put the "POV" tab at the head of the article. r b-j 21:32, 3 Feb 2005 (UTC)

The only vsl theory which has some relevance (IMHO), is creationist CDK theory, see e.g. [2]. From a scientific POV this very, very crackpot-style. At first sight you want to doublecheck, that you're not on Landover Baptist Church, but it has measureable attention.

OTOH, remodeling this article to cover that theory seems rather drastic, too.

Pjacobi 22:27, 2005 Feb 3 (UTC)

thanx for your input. as far as i'm concerned, you're preaching to the choir, but we'll see who's listening in. r b-j 01:43, 5 Feb 2005 (UTC)

I don't agree with Pjacobi that the creationist theory is the "only vsl theory which has some relevance". There do seem more serious theories, for instance that of Joao Magueijo (Imperial College London) which got some interest in the non-scholarly press. While it is definitely not mainstream, it was not rejected out-of-hand in conversations of theoretical physicists that I overheard, as the creationist theory would presumably be. Furthermore, one can build valid theories around a varying c even if it cannot be measured. Therefore I think "variable speed of light" is a valid subject for Wikipedia. However, I don't like the current article at all, even to the point that I am wondering whether it may be preferable to have no article at all instead of the current one. -- Jitse Niesen 12:31, 7 Feb 2005 (UTC)

Thanks for the name dropping. Indeed this gets enough scholarly hits [3] to be relevant and the main article getting 151 citations should not be taken lightly, even if 90% may have been dismissals.

But still no idea, how to proceed with this article.

Pjacobi 12:56, 2005 Feb 7 (UTC)

WikiPedia has lots of articles on things that are currently happening, so wouldn't it make sense just to add some tag to the effect that research is ongoing and try to be as thurough as possible about it? (I don't know anything about it... heh, just thought I'd make the suggestion. ;).

it's been a while since i had been ranting about this, but while i will not do anything to delete the article (hell there are people who believe that the Worldwide Jewish Conspiracy crashed the planes into the World Trade Center, why not talk about that?) i still will not concede scientific legitimacy to the concept of varying c. we do not measure nor perceive dimensionful quantities (we always measure or perceive them relative to a like dimensioned standard of some sort) and saying that any one of these dimensionful physical constants have changed, in and of itself, is, as Duff says, "operationally meaningless". r b-j 04:31, 27 July 2005 (UTC)

Well , i apreciate the pov tag, ofcourse it is controversial, yet as even a photon is a mere mathematical construct described as a constant, why not treat it as one (experimentally), perhaps when you slow light you are just making some new and inefficient kind of lamp,always.(thats similar to, c can't change because you can't measure it.)80.57.67.243 (talk) 17:37, 27 November 2008 (UTC)

Untitled

I removed

the gravitational constant would change: $G=3*m*c^{2}$ (excess radius, Feynman, vol 2, ch 42)

I do not have that reference, but there is the formula Excess Radius = GM/(3c^2), may be something in connection to that was meant?--Patrick 09:51, Dec 14, 2004 (UTC)

A changing C is meaningful

Contrary to the last post, i think a change in the speed of light could be a real thing and it would not necessarily cancel itself out. The most recent article about the Oklo reactors indicates alpha is changing which could very well mean c is changing (if electron charge and h have not changed). If only c and alpha have changed, then it is just an accident of the limits of our equipment and efforts that an alpha change was detected before the possible c change. Dirac himself was immensely interested in possible changes in the unitful G and Feynman himself discussed the issue and said it was not resolved (as of 1961). It is possible to simultaneously change c, G, h, and coulombs so that the known and useful unitless constants (i.e., nature itself) do not change. This situation is described in detail in planck units#Planck units and the invariant scaling of nature. On the surface the planck article makes it appear a change in c by itself is meaningless, but the article requires that all the unitless constants remain the same. In rhetoric and logic, this is known as begging the question or a "circular argument". The argument for the proposition contains the proposition itself. The article "proves" that we would not notice a change in c, but the first sentence makes a requirement (that all dimensionless physical quantities remain the same) that by definition means we would not notice the change. A change in c (without making any other requirements of other constants) would possiblly change G, h, and many dimensionless physical quantities and we would definitely be interested in the change. Likewise, if any dimensionless physical quantity changes, we are likely to see changes in other dimensionless physical quantities and c, G, and/or h. Physical constants with dimensions seem to be "put down" by some authors as not having as much meaning as the dimensionless physical quantities. But all measured constants of nature have meaning and are not just circular logic or historical accidents. We could define dimensions of "alphas", "proton ratios", and others to come up with values for c, G, and h that are without units or dimensions (plank units are not dimensionless, they are still expressed in units of planck length, time, mass, etc). Only for man-made reasons did we come up with the ideas of length, time, mass, etc and gave them units before stumbling upon "alpha units" and "proton ratios". The idea of "length" is just as arbitrary as the idea of "alphas". Our definitions and constants are arbitrary, but they important and valid because they are consistent.b - Scott aka 24.214.99.108

i wish you would register a handle with wiki and sign your "posts" on these talk pages so i can have some idea that i am making the same response to the same (or different) persons. however, do as you want. in the meantime, i'll address you as "24.214.99.108". is that okay? i made a response to you at the Talk:Natural_units, and am repeating some of it here.

But since there is an official standard for which constants are dimensionless, a variation in c has to be renormalized. If there's discussion about renormalizing it that can be considered notable, it should be included. If there isn't, it's a sign that physicists don't take it seriously enough to bother. 198.228.228.145 (talk) 13:49, 14 May 2013 (UTC) Collin237

i would not call it a circular argument. in some way it is a tautology or vacuous truth. but being so does not make it false; quite the contrary. it is saying essentially that when physicists (as well as the rest of us) measure any physical quantity, they measure it against some other like dimensioned quantity. in that, they are measuring a dimensionless number similar to when we commonly measure a length by use of a ruler and counting tick marks on it. so the vacuous truth is if $c\$ somehow changes but all dimensionless constants remain the same, and all we can ultimately measure are dimensionless values, then we can't tell if $c\$ changed and that "change" is meaningless in our existence. a better way to put it is that if $\alpha ={\frac {e^{2}}{\hbar c4\pi \epsilon _{0}}}\$ changes (which is something we can measure), we do not know if that change was due to a change in $c\$.

BTW, i do not consider it to be particularly bad to make a point by use of tautology. in my opinion, the weak anthropic principle is a tautology. saying it tells us nothing new, really, but it does help me think about a persistant question often posed by the intelligent design folks.

i dunno if the "ideas of length, time, mass, etc." are merely man-made, but clearly the definitions of the meter, second, and kilogram are. before the meter was redefined to it's present form, we had a definition of meter and second that did not depend on the speed of light. we made many different measurements of it and got different answers, mostly due to experimental error. in the sixties, when people became more and more confident about their measurement the meter was redefined because a good atomic clock was easier to reproduce than platinum bars with precise scratch marks on them. but now think about this, with this redefinition, the meter is the distance light travels in 1/299792458th second. that defines the speed of light to be 299792458 m./s . if $c\$ changes, it is still 299792458 m/s. you can think of it similarly if you measured everything in Planck units no matter what $c\$ is, it is still 1 in Planck units (and same for $G\$ and $\hbar \$).

now, i don't know why an atom's size is approximately $10^{25}l_{P}\$, but it is, or why biological cells are about $10^{5}\$ bigger than an atom, but they are, or why we are about $10^{5}\$ bigger than the cells, but we are and if any of those dimensionless ratios changed, life would be different. but if none of those ratios changed, nor any other ratio of like dimensioned physical quantity, we would still be about as big as $10^{35}l_{P}\$, our clocks would tick about once every $10^{44}t_{P}\$, and, by definition, we would always perceive the speed of light to be $c={\frac {1l_{P}}{1t_{P}}}\$ which is the same as how we do now, no matter how some "god-like" manipulator changes it.

now if some dimensionless value like $\alpha \$ changed, that's different. we would perceive the difference. but to attribute that change to a change in $c\$, that case is not defensible. you could argue that the change in $\alpha \$ is due to a change in the speed of light, and i could argue it's a change in Planck's constant or the elementary charge and there is no way to support one over the other.

please take a look at the Duff et.al. paper mentioned in the Planck units page. Michael Duff is a heavyweight, too. if you were watching Nova tonight, you would have seen him interviewed by Brian Greene. r b-j 06:43, 22 Dec 2004 (UTC)

As can be seen by your link to tautology, circular reasoning is used to make a tautology. Your argument only shows that dimensionless physical constants are important and that they must change if nature is to change. If c changes as determined by the time it takes eclipses on Jupitor's satellite Io to appear here on Earth, then it is a real change in nature and some dimensionless physical constants will also change. When we are discussing a change in c, i do not see why we must insist dimensionless physical constants are not changing. When you discussed the possibility of a alpha changing, did you require c, G, h, and electric charge to remain constant? No, you didn't. If you did, wouldn't your same reasoning show that a change in alpha in the presence of non-changing c, h, and electric charge require other dimensionless physical constants to change to such an extent that we would not know the difference? Or maybe it would show the equation for apha is in error. Either way, it seems the argument can be used both ways.

Since meters are defined as the distance traveled in c*seconds, c is a dimensionless physical quantity. c is basically seconds divided by seconds. It is nature's conversion factor between space and time. If c were suddenly c/2, then the fabric of space-time changes. Our old meter sticks would no longer agree with our definition of a meter. We would get less energy out of nuclear reactions via E=mc^2 .... Less energy is what the Oklo reactors are showing when they show alpha appears to have increased.

Michael Duff is a string theorist and string theory has not yet made it into physics because it can not be tested. Paul Davies is no less of a figure and he's arguing for a changing c. the paper you wanted me to read appears to show the debate about the importance of constants such as c, G, and h continues. The paper argues that c, G, and h are merely conversion factors between length, time, mass, etc. but this is not the same as saying that if any of them changes then it's meaningless. If nature's relationship between length and mass or between time and length changes, then i think it's of great importance. - - Scott aka 24.214.99.108

Circular reasoning is not the same as tautology nor is "circular reasoning ... used to make a tautology". A point argued with circular reasoning may or may not be true and the circular argument will not shed any light on its truth or fallacy. A tautology is true by definition, but it doesn't really say much. But at least it's true, albeit a vacuous truth. It's like saying 5x + 4y = 22 and 10x + 8y = 8(11 - y) - 10x . It's true, but it doesn't tell you much about x and y (because the equations are not linearly independent). It's like saying 5 = 5 or x = x. The problem with taking issue with a tautology is that, if it really is a tautology, then to dispute it, you're wrong. It's a lot like a truism. I realize that the problem with using a tautology in argument is to make an implication that is says more than it does. I am aware of this fallacy and I believe that I am steering clear of it, perhaps there is our dispute, I dunno. Tautologies really are simple truths and that why it's beyond me why anyone would dare to try to refute one. Perhaps deny that it's a tautology or refute some broader extension of a tautology (maybe that's what you're doing, I dunno), but if the tautology is accepted as such, it's only a loser to deny its content. It's like denying that 5 = 5.

Now Scott, I'm aware of the Oklo thing, lot'sa online references about it. Would http://www.ldolphin.org/recentlight.html be a good one? Now, I ask you, did you really read the Duff paper? It's the last third of: http://xxx.lanl.gov/pdf/physics/0110060 . It seems to me that you are not addressing the main point that he (and I) are making, as if it isn't there. It's like you haven't read it or let it soak in, but I will not make that assumption. Now I will say this, saying "string theory has not yet made it into physics" is ludicrous. Let's let the physicists say what is (or is not) physics. String theory is new and there is debate as to whether or not it is falsifiable (and if it is ever shown to be not falsifiable, it certainly will and should move from physics to philosophy, in my opinion) but just because it hasn't been tested yet, doesn't leave it out of the discipline of physics. How many years elapsed between Einstein's presentation of special relativity and the first experiments (mu meson decay?) supporting it? Was SR non-physics in the meantime? I think most physicists considered it to be an elegant and plausible explanation of some curious observation (the negative result of the Michaelson-Morley experiment) that was not yet confirmed. How is that substantively different from the state of string theory today? I hope you haven't used any bias you may have had regarding string theory as a reason not to read the point Duff is making. I think he does a better job of it than me.

So, to avoid misunderstanding, I'm gonna try to pick this apart, so we know precisely where we don't agree. The word "meaningful" is used by me if is or could be perceptible. If something or some change is not perceptible, it is not meaningful in my semantic. The distance from Vermont (where I live) to the Himalayas is meaningfully large to me but might not be if I were as big as a planet or perhaps if I lived for 10,000 years. The mass of a mountain is meaningfully large to me but might not be if, again, I were as big as a planet. The speed of propagation (light, E&M, gravity, any other ostensibly "instantaneous" action) seems fast to me given the scale that I sense distance and time. How I sense meaning in distance and time and mass has to do with how the matter and tissues and organs of me are constructed. It has to do with the fact that there are maybe about 10¹⁴ cells in my body, that each cell is about 10⁵ times bigger than the atoms that they are made of and that these atoms are about 10²⁵ larger than the natural unit of length. It is a matter of science (that we don't completely understand yet) that our particular beings are about 10³⁵ bigger than the natural unit of length and we perceive scale in that same order of magnitude. If some God changes any of those dimensionless ratios significantly, life would be meaningfully different. For whatever reason, atoms need to be 10²⁵ bigger than the natural unit of length and cells and the molecules therein need a minimum number of atoms so that they can function the way they do, and beings like us need a minimum number of cells to do what we do. A protozoa will not perceive reality like we do and a protozoa cannot exist at the scale of an atom and an atom cannot exist at the scale of $l_{P}={\sqrt {\frac {\hbar G}{c^{3}}}}$. You can go through a similar song and dance regarding how we perceive time relative to $t_{P}={\sqrt {\frac {\hbar G}{c^{5}}}}$.

The same is true regarding instruments we make to extend our range and accuracy of measurement of length and time and mass. The ratio of the wavelength of cesium radiation in an atomic clock to $l_{P}\$ is some dimensionless number. And the ratio of the period of one cycle of this radiation to $t_{P}\$ is the same dimensionless number.

Now if somehow, conceptually, $l_{P}\$ increased, if these dimensionless ratios remained the same, we and our meter sticks (and the wavelength of that cesium radiation) would get larger by the same factor. A similar argument could be made regarding $t_{P}\$ and our measurement of time. The meter and the second remain the same dimensionless multiples of $l_{P}\$ and $t_{P}\$ or some dimensionless quantities have changed, which is not the premise. Light (or other EM or gravity) will always travel one $l_{P}\$ during the time elapsed by one $t_{P}\$ and it's simply a matter of applying (invariant) scaling to say that this light will continue to travel 299792458 meters in the time elapsed by one second. If not, then some dimensionless quantity, which we can measure has changed.

It's sorta like the natural units define the tick marks on a sorta membrane (not to be confused with branes in string theory) of which all of reality exists. Stretch it in the time dimension and all times, including $t_{P}\$ change by the same factor but not relative to each other. Stretch it in the length dimension and all lengths, including $l_{P}\$ change by the same factor but not relative to each other. Same for mass and $m_{P}\$. If not and some dimensionless quantity has changed and that change is measureable, perceptible, and meaningful. The quantities $G,\hbar ,c\$ are simply diagonal slopes on this membrane and a change in any of these, such as c, would simply be a stretch in one dimension over another. Still, nothing meaningfully changed unless there is a change in times relative to $t_{P}\$ or lengths relative to $l_{P}\$, etc. All $G,\hbar ,c\$ tell us is where these tick marks are relative to the units we have created to measure $G,\hbar ,c\$ with.

Now the result of Oklo is that $\alpha ={\frac {e^{2}}{\hbar c4\pi \epsilon _{0}}}\$ may have changed in the last couple of billion years. That, if true, is a meaningful change. It could be interpreted as a measurement of the speed of light, where $c\$ is measured against another like-dimensioned quantity: ${\frac {e^{2}}{\hbar \epsilon _{0}}}\$. So the standard of measurement against which $c\$ is measured is ${\frac {e^{2}}{\hbar \epsilon _{0}}}\$ and $c\$ apparently has changed relative to that standard according to Oklo. Why interpret that as $c\$ changing? Why not something in the standard that $c\$ is measured against? Since, in my world of natural units (I can choose my units to be whatever I want and I choose them to normalize $G,\hbar ,c\$ and $4\pi \epsilon _{0}\$). Then that result of Oklo would be the result of the elementary charge, measured in natural units of charge, being different long ago than it is now. It's just as plausible (more so for my money) than a change in c which is just stretching that membrane. r b-j 06:17, 23 Dec 2004 (UTC)

We're going to have to agree to disagree. Yes, I did read all three papers, and came across plenty of statements that support my position. For example, Duff says "Indeed, papers on time-varying c are currently in vogue as an alternative to inflation. I believe that these ideas, while not necessarily wrong, are frequently presented in a misleading way and that the time-variation in the physical laws is best described in terms of time-varying dimensionless ratios, rather than dimensionful constants." My position is supported when he says "I believe", "not necessarily wrong", and "papers on time-varying c are currently in vogue". He also states some consider c to be unitless and that particle theorists do not even use length or time units but view everything in terms of mass. Duff is trying to get people to disregard dimensionful constants when working in string theory, but he also said c can be stated in terms without dimensions. He does not address what happens if c changes without a change in G.

Again you demonstrated that a "change in c" is meaningless if there is no dimensionless factor that has changed. I agree. You said allowing them to change is not part of my premise, but neither is forcing them to stay the same. In order for them to stay the same G, h, and/or e would have to change by some remarkable coincidence(s) to precise value(s) that allowed the dimensionaless physical constants to remain the same. In discussing a changing value of c, you have added the requirement that no dimensionless constants change. I do not need to go further to make my point, but i'll state that even what's considered a dimensionless constant is a man-made historical convention. Even Duff agrees that many now consider c dimensionless.

Then, looking at it the other way, you demonstrated that if a dimensionless constant changes, it is meaningful if constants with dimensions are allowed to change. Why is allowing dimensioned constants to change part of your premise? So again i ask, why isn't what's good for the goose, good for the gander? If you are allowed to change my dimensioned constants to prove your point, why can't I change your dimensionless constants? Try changing alpha without changing h, c, or e. Express alpha in planck units if you need to. You would have to conclude that the equation for alpha needs adjustment. Then i could do the same to keep alpha the same if c changes. Either way, the changes in nature are real. So now i see i can prove my case even under your requirements: if you want alpha to stay the same, then i can claim the equation changed which is why c was allowed to change by itself. Now supposed alpha and only alpha changed in the same way. Then it's the same darned thing! Divide c or multiply alpha by the same factor. To claim one perspective is better than the other is just semantics. To claim a change in c by any other method (allowing dimensioned or dimensionless constants to change) is also just as real as a change in alpha that allows dimensioned or dimensionless constants to change, provided you do not insist the formulas for planck units are a message from God, as explained below.

By insisting planck units will always = 1, you are forcing the G, h, and e to change in response to a change in c. This forces the dimensionless constants to remain the same which is why you are having a hard time abandoning your position: you think planck units=1 is a fact of nature. No, it's a human definition. In discussing a change in c, i do not think we should force G and h to change in order to keep plank units = 1. If c changes with time and G, h, and e do not change precisely as is required to allow plank units to remain = 1, then the formulas for the plank units have to be modified to include a new constant (as was done before since planck's paper was a modification to an 1870 paper to incorprate h) or to make them a function of time so that they can remain equal to one. This could be our point of reconcilliation. A change in c is a fundamental change to our concepts and therefore to the equations we have invented. You are insisting that God change c, G, h, and e at the same time and in a precise way in order to keep your man-made planck units = 1.

The above should show that "length" or "mass" is no more meaningful from God's point of view than "alpha units" or "proton ratios".

- Scott

be careful about what you ascribe to what i say (or "insist on"). i do not insist on God (if i am a theist) or Nature (if i am not) changing any of the dimensionful constants. i do say that, within small factors of $4\pi \$ that physicists might debate, that the Natural units as defined by Planck (with the extension of the so-called Planck charge) are absolutely not human constructs. ( i am of the school of thought that Planck should have normalized $4\pi G\$ instead of just $G\$ and then we would have also defined the unit charge to normalize $\epsilon _{0}\$ instead of $4\pi \epsilon _{0}\$, those would be more natural, but that is another debate and that does not change the scale appreciably nor changes the invariant scaling issue a tittle. ) those are the units inherent to nature and if you want to express any physical quantity unamibuously (so you can communicate that quantity to some alien that has no idea what a meter is nor gives a rat's ass about the density of water), without respect to any particular "thing" in the unive you must express it in terms of Planck units (or, again my preference) the "rationalized" Planck units with $4\pi G\$ and $\epsilon _{0}\$ normalized.

there are numerous items Scott made that i could go down and dispute, but it's just too much work. i would rather stick to the main issue of how we would ever know if a dimensionful universal "constant" has changed without confusion about whether something in the like dimensioned standard that we measure this dimensionful universal "constant" against has been the quantity that has changed. r b-j 01:08, 24 Dec 2004 (UTC)

That's a lot of text you two have been generating. Let me try to summarize. Consider the following two events:

• α halves and c doubles; h stays constant.
• α halves and h doubles; c stays constant.

Am I correct in saying that R B-J thinks that no experiment is able to distinguish between these two events (this is his definition of not meaningful) while Scott thinks that it is possible to distinguish between these events? -- Jitse Niesen 22:16, 23 Dec 2004 (UTC)

if a single experiment (or multiple runs of the same experiment) says that $\alpha \$ is now half of what is was yesterday, i am saying that that measurement is conceivable possible (but for all i know, the universe turns into a tomato if that happens, $\alpha \$ halving is pretty damn radical) and, from that experiment alone, there is no meaning in saying that it is from $c\$ changing vs. $\hbar \$ or $\epsilon _{0}\$ or $e\$.

perhaps there are other dimensionless constants with $c\$ in them that have changed in a manner that would be consistent with $c\$ doubling. that would lend support to the speculation that $\alpha \$ was halved because $c\$ doubled. Oklo doesn't tell us that. Oklo only tells us (that maybe) alpha had changed by a small amount in 2 billion years. and that result is still debated, however i do not take that debate to mean that result is not accurate.

i have one last suggestion about this. i would suggest that instead of arguing about it here, we take it to the USENET group sci.physics.research and see what those guys say. i have had a few misconceptions corrected by them. it doesn't hurt. r b-j 01:08, 24 Dec 2004 (UTC)

Continuing

I see we're over the 32 KB limit. I misread 22 as 20, and did an algebra error, so why not delete the algebra part and all the string theory stuff? Despite Niesen doing a fine job of trying to curtly resolve this, I unfortunately agree with everything rbj said in reply, except i would add that i only need to compare my old meter sticks with light and a clock and look at eclipses on Io to see how well the change could be contributed simply to a change in c...and that if i did the measurements carefully enough, i could have detected the change before others detected the alpha change. I see the simple question i asked twice apparently cannot be answered simply. rbj wrote: "i would rather stick to the main issue of how we would ever know if a dimensionful universal "constant" has changed without confusion about whether something in the like dimensioned standard that we measure this dimensionful universal "constant" against has been the quantity that has changed." my reply: we would need to check the constant in at least 2 different ways (Io, atomic clocks, and alpha) to resolve the confusion....there is still confusion in an alpha change because we do not know if h, c, and/or e has changed. We'll go to sci.physics.research. - Scott

and again, if the speed of light changed (and nothing else changed), then your "old" meters sticks and/or your clock would be updated in such a way that light would continue to travel 299792458 updated meters in the time elapsed by one updated second and you and i would be oblivious to the change. if you say, "no that is not true, see here it travels 299792457 meters per second." then i say that the dimensionless ratio of your meter length to the Planck length and/or the dimensionless ratio of your clock second to the Planck time, at least one of those dimensionless numbers has changed and that is the sailent, measurable difference. and i would also say that saying it is a tautology: it's pretty damn obvious and it really doesn't say much -- but it's a safe truth. i'm happy if you post this to s.p.r . recently someone else (i think it was someone else) posted a very similar question about whether c is unitless or not. i would say, it depends on how you define things. if your unit time is the second (defined the traditional way, with a cesium atomic clock) and your unit length is defined to be 1/299792458 second (with c as the reference), then c is the dimensionless number: 299792458. but then the problem with your position is that c cannot change. c is always 299792458. you cannot say that c is both dimensionless and that it is changing. well, you can say it, but that would be tangibly in error. and i think that the guys on s.p.r would back me up on that. r b-j

The current definition of a meter is based on the desire to be as close as possible to the old meter sticks. As i said before, if the speed of light changes, we have every reason to view that definition as no longer reasonable and go back to the old meter sticks. In your world, the new 8 mm nuts would only fit the old 4 mm bolts and yet you say we would be "oblivious to the change". Every manufacturer in the world would tell you to go to hades if you asked them to keep your definition of a meter. But your last point is something i can relate to. It assumes meters are just a human's way of looking at seconds that are not in the i dimension, as might be a proper view of relativity. In this case, c is just a conversion factor for human units and nothing to do with nature. It means our old meter sticks would never need correcting because the actual length of meter sticks change if c changes and they change in such a way that we do not notice it. A changing c would merely mean we've change the definition. So maybe a real changing c would have to mean relativity is in error. But how are we to know if this view of relativity is the correct one? How do we know that space is just a different way of measuring time and that therefore the relationship (ratio) between space and time (via relativity) cannot change? With a good quote from an authority, i could finally write an intro for the article that you would agree with: that a changing c is meaningless if we are to keep our view of relativity. But if i now agree with you on c, it does not mean i agree that dimensional constant changes are meaningless, and my prior questions still apply if you replace c with G or h. I am only admitting c is a particularly odd dimensionless constant that is meaningless because it is the human conversion between seconds and seconds. - scott

i think you need to test your ideas with a wider jury. some of what you just interpreted from what i said does not represent my position, but i am tired of repeating it. other of what you said sounds at least unconventional ( "So maybe a real changing c would have to mean relativity is in error. But how are we to know if this view of relativity is the correct one? "). i think that the Michaelson-Morley experiement spoke to that one. Please, Scott, let's not debate this here. let's take it to sci.physics.research . i think you should be the first to post about it because i cannot and will not try to represent your position. you need to initiate the debate. again, my position about this is that it is currently at the speculative end of physics, not orthodoxy at at. i thought that wiki or any encylcopedia is a source of info on mostly "mature" subjects that have settled a bit. not speculative, unsettled, and widely debatable topics. that's a wiki policy issue that should probably go to the talk pages of wiki policy pages. r b-j 17:13, 24 Dec 2004 (UTC)

I haven't had much luck getting good responses from s.p.r. Your description for a unitless constant c requires changing the definition of meters as c changes. If you stick with the old meter sticks as the definition, then the unitless c can change. I'll place more weight on meter sticks than on definitions. - scott

i dunno when i'm gonna tire of this. i still wish you would take this to a venue or persons much more expert in physics that i am (i am an electrical engineer, but i am still pretty confident of the physics that i have learned). however, Scott, i wonder if you realize the internal contraction in your assertion. to repeat, if on one hand, you define the unit length as 1/299792458 second, then c is the dimensionless number: 299792458 (or 299792458 sec/sec which is a ratio of like dimensioned quantities and therefore dimensionless). on the other hand, if you use the previous definition for your unit length as the distance between two scratch marks on a bar of platinum (a pretty stable meter stick), then your unit length is not the same dimension as time. it is length and defined completely independent of c or any notion of time. and then you can measure c independently and, each time you measure it, if you're really good at it you will get the result 299792458 m/s (not dimensionless), and because of experimental error, with a small +/- error that would likely be different for each experiment. perhaps, conceptually, there will be a trend that shows this value of c is slowly decreasing in time. i think that is the case you are making. but that is not a dimensionless value. you are measuring c against your pre-existing definition of a meter and second and all you know is that this ratio of c against a meter/second appears to change. there are two (actually three) possible ways for that to change. maybe your meter stick got a little longer. maybe your clock ticks a little faster. those could just as well be the source of your apparent downward trend in c.

but the thing is that none of the properties of your meter stick nor of your clock go into the fundamental equations describing physics. but c, h-bar, and G (and epsilon_0) do. and if all of reality is described or measured in terms of the Planck units, those constants go away (they become 1). but those equations are still there, doing their thing. then the physical reality that builds subatomic particles and atoms and molecules and crystal lattices and DNA and proteins and biological structures (cells) as well as stars and all things still happens. it's just that we are now looking at them in terms of the scaling standard of Planck units. but in this case, there is no c to change, no G to change, etc. c is just the unit speed and will always remain so. that is the salient concept of Natural units. in terms of these Natural units c cannot change any more than 1 can change.

so you say, "hey, we're not using Natural units, we're using meters". i say (again and again) your meter stick is a dimensionless quantity multiplied by the natural unit of length. if that dimensionless quantity changes, then something really change. maybe more atoms went into it to make your meter longer. maybe some were taken away. we would call that an experimental standard problem (which is why they redefined it in 1983 anyway). perhaps the number of atoms stayed constant (that's a good meter stick) but the size of atoms relative to the Planck length has changed. THAT DIMENSIONLESS QUANTITY IS THE SALIENT MEASURE. (or, perhaps the one that relates your clock tick to the Planck time.) to say that it is c that is changing here is, from the POV of an experimental physicist, mistaken. r b-j 03:20, 25 Dec 2004 (UTC)

I am also EE. Einstein was using scratch marks on a bar when he said time and space are equivalent with a conversion factor of c, implying c is dimensionless, based on scratch marks. Planck units were based on tick marks, not the 1983 definition of a meter. To claim the Planck length has to be defined by the new definition of a meter is circular logic and artificial because the new definition of a meter is based on the Planck length equation which was really based on tick marks. Relativity was an elucidation of the theory behind the Planck length equation L=cT but it too was derived and based on tick marks.

If you redefine meters while my c goes to 1/2 c in order to keep your c constant, then those things moving with a velocity relative to us, you will say, are now going twice as many of the new meters per second. And in both of our systems of meter measurement, the v/c ratio in relativistic equations will change for all objects moving relative to us. You would say v increased, but i would say c decreased, and in both views we would see the same real changes. Something moving at 0.6 c before the change would, in your view, now be moving at 1.2 c if there were no real changes.

I tried to make relativistic energy for rest and moving masses to remain the same before and after a change in c, while letting mass and velocity take on any values. What happens is that the the ratio of v/c has to stay be the same, which means velocities can only be measured relative to c, and that a change in c is not possible if both relativity and conservation of energy hold through a change in c.

well, i can say nothing that was not said before. one of us is missing something very fundamental, not just about the nature of measurement and physical experiment, but really about what is real. even though different physicists have different points-of-view on this, i think they all agree that dimensionless quantities are the only ones we really can perceive or measure. dimensionful physical quantities are always measured or perceived against a given standard of like dimension. for this reason Veneziano agrees with Duff "that all that matters are pure numbers." even though they disagree about other stuff. you are wrong when you say that the speed of light is a pure number if it ismeasured (as opposed to defined) by use of previously existing rods and clocks. the speed of light is not a pure number, it has dimension length/time. you are wrong that a hypothetical change in the speed of light in and of itself is anything that any of us beings (or atomic clocks) would notice as anything different. the universe does not set the speed of light. it simply is what it is, as paraphrased of Wilczek (he was talking about G, but the point is the same).

you should really post to sci.physics.research . it is a moderated newsgroup, but they will post anything that is really about physics. there are some real heavyweights there that can speak to your issue. i do not know exactly what they will say, but i doubt anyone there will tell you that a change in a dimensionful physical constant in and of itself is meaningful. we always measure these dimensionful quantities against another like dimensioned quantity and the result of the experiment (or our perception) is the ratio of these two quantities. always. r b-j 05:30, 26 Dec 2004 (UTC)

Since my relativity equations showed a change in c is absurrded, i'm less convinced of my position, but i need to rederive the the basic SR equations with a changing in c in an integral.

I believe it is probably simpler to detect if a real change has occured in a dimensionless number, but i don't know if c is dimensionless or not. Also, i think the measurement of a dimensionless constant almost always has to be carried out with instruments that measure dimensionful quantities, but the combination of those quantities based on theoretical equations is what determines the measurement of the dimensionless constant. Taking three different types of measurements concerning c and using theory to judge if c was the only thing that changed (and thereby proving c should be considered dimensionless) is doing the same thing. The first method includes the theory in the measurements, while the seconds applies the theory after the measurments are reported. This idea was touched upon in the first paper (which regards c as fundamental). - Scott

rbj what you miss is that it is not about the example of 2:1 changes, it is about sth that would be very fundamental (or perhaps only local still) plancK lengths for example, minimal potential, would change at the same rate as t or c, even entropy would then predict pK changes.It makes me wonder if pK is not just the maximum resolution of our thought. If something changes c it changes an aspect of pK we surely have no resolution for.80.57.67.243 (talk) 18:17, 27 November 2008 (UTC)

C is just a human construct

We have to keep in mind that scientists who assigned dimensions to certain quantities to make them incompatible (Length, Time , Mass etc.) were not Gods and did not change the laws of physics by making such assignments.

There is no evidence whatsoever from modern physics that shows that dimensional quantities really exist. We certainly don't need them. C is just a conversion factor that arises because we have chosen to measure Length and Time in incompatible units. Variable C theories do exist but they can be mapped to theories in with only dimensionless parameters.

See here:

http://arxiv.org/abs/hep-th/0208093

the creator of this article is aware of the Duff paper and has, indeed, put a link to it at the bottom. it's just that he doesn't really get it and is relying on the fact that other physicists have "rebutted" Duff as his justification for this latest version of cold fusion. i have tired of engaging him and am waiting for the sci.physics.research newsgroup to be reactivated (the moderators have not posted anything new for more than 5 days). r b-j 01:49, 4 Jan 2005 (UTC)

Rbj, I see the link now. I agree that sci.physics.research is a better place to discuss these issues. B.t.w. in the 18-th century people didn't know that heat and energy were the same thing. So, one could have argued that Joules and Calories should be given different dimensions and that the conversion factor is not dimensionless. Now what about a theory in which that conversion factor is space-time dependent? :)

Count Iblis 13:24, 4 Jan 2005 (UTC)

External link number 4 describes in detail how Duff was wrong and how the above comments are not relevant. Just as values were arbitrarily chosen for length, time, etc, so too were the concepts of length and time arbitrarily chosen as meaningful rather than "alpha units" and "proton ratios". God did not declare alpha to have special meaning in his heart any more than length or time. alpha comes out unitless only because we arbitrarily chose Length, Time, etc to have special meaning. I too tired of showing how each and every point RBJ made was wrong while he would not address hardly any of the counterpoints i made. I supplied a variety of references while he can only refer to Duff. In my continuing effort to dispell the bunk being posted here in the discussion area, i would like to address the point made above about the simple dimensioned conversion factor between Joules and calories. First of all, it's not a dimensioned constant, it's a dimensionless conversion factor that has units. Energy has only one dimension which is simply a (scalar) quantity that does not change with time in a closed system. There is a difference between units and dimensions, although the literature on the subject confuses the two. Yes, today's physicists can write a unitless conversion factor between space and time, namely i*c (although RBJ objects with that...as a partial reference, see Hawkin's "A Brief History of Time" in the index for "imaginary time". For more detail see the book he coauthored with Roger Penrose). But it is not a dimensionless conversion factor since space-time has 4 dimensions (hence vector quantities are needed for space and the "i" dimension is needed to specify time). If that conversion factor changes, then a big change to our ideas about physics is required. Likewise, if the conversion factor between joules and calories were observed to change, we would need to change some of our physics ideas. We currently believe Joules and Calories to be in the same dimension (i.e. energy) but measured in different units. If their relationship were observed to change, then it might require a different dimension. - Scott