Sounds off base to me, but I'd welcome an informed critique.
If you look at his references, you will see the experiments cited are either unpublished (performed by others) or very old (an 1887 Michelson Morley citation if you can believe it). More recent experiments which disagree with his conclusion are completely ignored.
And that is the good part of the paper, as much of the rest is devoted to slamming the physics establishment for wasting the past 100 years.
Cahill also mentions Dayton Miller. Compare this to the Usenet FAQ on the subject:
The Michelson-Morley experiment was repeated with greater accuracy in the years that followed. In 1925 Dayton Miller announced that he had detected a change in velocity of the speed of light and was even awarded prizes for the discovery, but a 1950s appraisal of his work indicated that the most likely origin of his results lay with diurnal and seasonal variations in the temperature of his equipment.
Modern instruments could easily detect any ether drift if it existed. The Earth moves around the sun at a speed of about 30 km/s, so if velocities added vectorially as Newtonian mechanics requires, the last 5 digits in the value of the speed of light now used in the SI definition of the metre would be meaningless. Today, high energy physicists at CERN in Geneva and Fermilab in Chicago routinely accelerate particles to within a whisper of the speed of light. Any dependence of the speed of light on reference frames would have shown up long ago, unless it is very slight indeed.
Cahill claims that the Michelson-Morley data (by his analysis) indicates a non-zero velocity with respect to a preferred reference frame. According to Tom Roberts (in sci.physics.relativity) Cahill did not properly take into account the experimental uncertainties in the M-M data, which can be extracted from the data themselves. Taking the actual uncertainties into account, Cahill's analysis actually is statistically consistent with a velocity of anywhere between zero and several thousand km/sec in any direction.
I'm very interested...
Reg Cahill is a senior member of the Faculty of Science and Engineering at an Australian university (http://www.flinders.edu.au" [Broken]), is the chairman of the Courses and Curricula committee for the School of Chemistry, Physics, and Earth Sciences in that faculty, but seems to be operating in the realm of fringe science...
Is this good or bad?
Check out the http://www.scieng.flinders.edu.au/cpes/people/cahill_r/processphysics.html [Broken] page. Remember, this is not a run-of-the-mill crackpot site, this is a serious academic web site at an accredited University.
He is a pottery magician.
This work looks professional and Reginald T. Cahill has referenced some interesting work on Dalton Miller and Roland De Witte (recently deceased), which I fully agree with - namely a sidereal variation in the speed of light.
However, the rest of his work is quite advanced and I can't say whether it's good or bad, without spending more time on it.
...and a search through the archives reveals all.
It's certainly an easy label to apply, but don't you think he's not your run-of-the-mill crackpot? Do you think you might be applying that label a little hastily in this case?
How does he measure up on the crackpot index?
What makes you agree with those but not these:
1. "Tests of Relativity Using a Cryogenic Optical Resonator", C. Braxmaier et al., PRL v.88, p.010401 (2002).
2. "Tests of Lorentz Invariance using a Microwave Resonator", P. Wolf et al., PRL v.90, p.060403 (2003).
3. "New Limit on Signals of Lorentz Violation in Electrodynamics", J.A. Lipa et al., v.90, p.060403 (2003).
4. Muller et al., PRL v.91, p.020401 (2003).
...And it is run by Cahill himself.
Face it, Cahill is trying to tell us that one of the most fundamental concepts of relativity is wrong without himself performing a single experiment to support the charge; and he ignores or rejects all modern published experiments (i.e. in the last 50+ years) which contradict him.
There is no peer acceptance of this work and I don't expect any in the near future for obvious reasons.
It is possible to for Lorentz Symmetry to be upheld 100%, even when the one-way speed of light is only constant relative to a preferred reference fame.
The above experiments seem to imply that Lorentz Violation is a test of the constancy of the speed of light, which it is not. However, there link is strong to the two-way speed of light measurements, but not for the one-way.
Yet, when the SAME type of experiments (Dalton Miller and Roland De Witte) showed hints of such violation, how come you didn't question why it would show up IF what you said is true? I didn't ask why you buy or don't buy the experiments I listed. I asked why you believe in one set, but NOT the other, especially when the latter are testing the SAME thing, with BETTER and more accurate measurements? If you wish to throw out the latter as being "two-way speed of light measurements" and not show any lorentz invariant, then you should also not buy into the experiments that you prefer to believe in.
I remember seeing a discussion on your idea somewhere (may have even been here on PF, a year or more ago) where you described a relatively simple experiment that would (in your view) settle this matter (for you) in a straight-forward way.
IIRC, it wouldn't involve a lot of expensive equipment; with accurate clocks and good lasers being now available at quite reasonable prices, less than a mortgage on an average family home (and maybe not much more than the cost of new Toyota sedan).
It sounded like an interesting experiment, in its own right, so perhaps with the right kind of marketing, and wrapping it up in a nice package, you might be able to find a way to get it done?
Seems to me that spending lots of time discussing how many teeth a horse has is inferior to going out and actually counting them!
And what do people make of these periodic pendulum effects?
The experiment didn't appear to reveal the anomalous effect of the eclipse on the Pendulum as reported in other eclipse events - but as they pointed out - it may be because of the geometric relationship involved in this particular eclipse. What does the principle of mutual interaction say about the periodic effects?
Are you referring to the principle of mutual interation of self creation cosmology?
The experiment needs to be replicated under stricter conditions. In particular it needs to be in a high vacuum isolated from any other field effects and vibrations. It is an interesting concept as it is claiming a higher order Foucault's pendulum effect.
As far as the PMI is concerned the interesting question is to see whether any confirmed results are correlated with the Earth's motion relative to the surface of last scattering of the CMB. They mention a possible correlation with the direction of the centre of the galaxy.
May I ask WHERE exactly do you propose to find such conditions?
Zz - In a carefully constructed laboratory experiment?
How do you propose to achieve isolation from "other field effects" such as gravity, and how high of a vacuum would suffice?
Come on! The significant word is "other"!
The pendulum has to be in a gravitational field to be a pendulum!
However local fluctuations in the gravitational field have to be guarded against, i.e. no nearby observers; therefore observations would have to be remote.
I would put the pendulum in a vacuum dewar jar, which internally would be cooled to be isothermal to a high degree and possibly near absolute zero.
The vacuum need not be too high, just sufficient that any Brownian motion type perturbation could not possibly influence the result.
The whole apparatus would be made of all non-magnetic materials and cleansed from any contamination by ferrous particles. Furthermore it could be placed, if necessary, in a Faraday cage and earthed to remove any electrostatic forces.
The whole apparatus might be mounted on a bedrock-anchored platform, which was stable to a sufficient degree, or floating in a mercury bath to absorb vibration.
The experiment will also need to be repeated at different longitudes.
I will leave any other details up to the experimenters. But it is important that all spurious noise in the signal is eliminated before periodic pendulum effects can be accepted as a real phenomenon.
Nevertheless, There are these three separate experiments, which were set up to detect a total eclipse effect and recorded a null result, and yet all recorded some periodic pendulum anomaly that might be correlated with matter distribution in the universe. It is worth pursuing the matter further.
The experiment involving pendulums necessarily involves gravity - I think Garth has in mind the elimination of all other fields. Oops - Just noticed Garth already posted his answer while I was typing the first sentence.
Interestingly, Einstein's original paper of 1905 (The most widely known and least cited paper) does not mention the Michelson Morely expt. Einstein sometimes used the constancy of light as a starting point simply because was, to him, "the thing we knew most about". (The Meaning of Relativity AE).
Later in life, AE always spoke of the MM experiment as fundamental to his thoughts. When AE was asked if the MM expt. was fundamental to his original construction of Relativity, AE replied he wasn't certain at that time if he'd heard of it!!!
That is something Einstein's biographers have had difficulty with - i suspect that he felt the beauty of the symmetry would be destroyed if it were based soley or primarily upon explaining a particular experiment. SR had greater applicability than disproving light anisotropy and confirming MMx - for example, SR works whether or not there is an ether - it works even though the two arms of the interferometer are of unequal length, and it appears to work for one way isotrophy (MMx only confimed over and back isotrophy - the second postulate of SR went way beyond what is required to explain Mmx) In summary, the theory was much more important than the experiment.
Recall, Einstein had worked on the theory since he was 16 years old - he had began to suspect time as the culpret - and he reached that conclusion before Lorentz's publication. So over and back isotrophy as confirmed by MMx would be of interest, but would not add anything to the path he was already on - I guess what I am saying, Einstien would not be surprised at any experimental result that was consistent with what he already determined theoretically.
Cahill hasn't ignored or rejected the results of any modern published experiment including those listed here by Zz; neither has he contradicted any of them. What he has reported (which you guys have failed to notice much less even begin to refute) is that all published (valid) experimental data (both the modern and the not-so-modern) are consistent with one particular locally preferred frame (first identified by Miller) with anisotropies that are proportional to (n-1) where n is the refractive index of the interferometric medium. Virtually all of the modern experiments, including those listed here by Zz, were performed in a high-vacuum where n=1.
Separate names with a comma.