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Aether theories which are experimentally indistinguishable from SR.

  1. Dec 29, 2004 #1

    Tom Mattson

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    From John Baez’ page on the experimental basis of Special Relativity, he says that:


    My question pertains to the remarks in blue: aether theories that are experimentally indistinguishable from SR. Where are these theories published? One member (Yogi) makes reference to the so-called Selleri (sp?) transformations, saying that they lead to the same predictions as SR, but are predicated on different premises. The problem is that no one who advocates the “alternative to SR” view ever presents the alternative in sufficient detail. So I’d like to know where Selleri’s theory can be found. I tried Googling it, but there’s nothing out there.

    Baez makes reference to “Test Theories” of SR. Might I find what I am looking for here?

  2. jcsd
  3. Dec 29, 2004 #2
    Hi Tom - Happy Holidays

    I will post some links Re Selleri - I can tell you it is basically a theory that derives from assuming the over and back velocity of light as a fact - but it rejects the notion that the one way velocity of light is true. Since you have mentioned Zhang, here is another quote from him. He has three books out - I have one on order - but have not received it yet - when I do I will be happy to discuss his experiments. Anyway, here is what he says in his teaser to his first book entitled: Special Relativity and its Experimental Foundation

    "....In the second part, variant types of experiments performed up to now are analyzed and compared to the predictions of SR. This shows that the experiments are a test of the two-way speed of light, but not the one-way speed of light"


  4. Dec 29, 2004 #3
    Tom - here is one citation - don't get the idea I totally endorse everything this guy says - I think he is wrong on his views about Sagnac and GR - but - anyway:
  5. Dec 30, 2004 #4


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    John Bell, in an essay in "Speakable and unspeakable in quantum mechanics" (this essay is the one that introduces the Bell spaceship paradox), is the only example that comes to my mind for an "ether theory that's indistinguishable from SR".

    Garth provides another reference inthis thread

    There are a lot of non-credible references on the WWW for "ether theories", of course.
  6. Jan 5, 2005 #5


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    Classical electrodynamics is an aether theory:

    J. Clerk Maxwell, A dynamical theory of the electromagnetic field, Philos. Trans. Roy. Soc. 155, pgs 459--512 (1865). Abstract: Proceedings of the Royal Society of London 13, pgs 531--536 (1864)

    "..we are obliged to admit that the undulations are those of an aethereal substance, and not of the gross matter, the presence of which merely modifies in some way the motion of the aether."

    More recently Paul Dirac published this:

    P.A.M. Dirac, A new classical theory of electrons, Proc. Roy. Soc. A, 209, 291 (1951).

    And in a follow-up letter published in Nature, he said this:

    "...It was soon found that the existence of an aether could not be fitted in with relativity, and since relativity was well established, the aether was abandoned...If one re-examines the question in light of present-day knowledge, one finds that the aether is no longer ruled out by relativity, and good reasons can now be advanced for postulating an aether...We can now see that we may very well have an aether, subject to quantum mechanics and conforming to relativity, provided we are willing to consider the prefect vacuum as an idealized state, not attainable in practice. From the experimental point of view, there does not seem to be any objection to this...Thus with the new theory of electrodynamics we are rather forced to have an aether."

    P.A.M. Dirac, Nature, 168, 906 (1951).

    What about gravity, all of the matter in the universe, and all of the energy in the universe? Substitute any (or all) of these for "ether" in the above quotation, and see for yourself how utterly misleading such statements are.

    I respectfully object to this editorial statement by PF which appears at the head of Special & General Relativity: "Space and time are relative concepts rather than absolute concepts". The Space-time of SR is a relative concept, but it is only valid in the limit as the space-time volume under scrutiny approaches zero. Clearly, it is not valid anywhere in the real world. For example, cosmological time is an absolute concept that is consistent with GR.
    Last edited: Jan 6, 2005
  7. Jan 5, 2005 #6
    Another type of aether theory that is gaining a growing number of advocates is the ether inflow theory of gravity. Persons interested may want to read some of Tom Martin's papers on the interent. Tom has proposed a number of tests that would distinquish "in flow" from GR. What is most significant about inflow theory is that it correlates the clock rate given by the LT for the influx velocity with the gravitational slowing of clocks a la GR at the same radius from the mass center.
  8. Jan 6, 2005 #7


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  9. Jan 7, 2005 #8
    The jury is out on whether special relativity passes the one-way test. Although the list of references look impressive there are serious misgivings as to whether these are as accurate as they claim to be or indeed if they even qualify for one-way tests.

    From John Baez’s post of an article by Tom Roberts in 2000 (Original by Siegmar Schleif and others, 1998).

    Response: Martin Miller suggests that this test for the anisotropy of light is misguided due to nature not synchronizing clocks according to Einstein’s way. If Martin is right then this test is invalid and cannot be used to qualify as a one-way test. See



    Note: In 1990 Krisher et al performed a one-way light experiment by using two hydrogen-maser standards separated by 21km. The light from each maser is split and one-half modulates a laser light that travels one-way along a fibre optics (fiber optics) cable, and the other sent to a local detector. The relative frequency of the local and laser light are compared, and a variation in the frequency should show up due to the ether flowing passed the rotating Earth.
    However, the experimental noise is too large to detect an ether flow - that is at rest with respect to the microwave background radiation - of the magnitude suggested by Dayton Miller, and the 5-day duration of the experiment was perhaps too short to detect the sidereal period variation. The experimental result was inconclusive.

    Response: In 1988 Gagnon, Torr, Kolen and Chang, published the results of their experiment "Guided-wave measurement of the one-way speed of light".
    Although they reported, "Our results have not yielded a measurable direction-dependent variation of the one-way speed of light. A clear null result is obtained for a hypothesis in which anisotropy of the cosmic background radiation is used to define a preferred reference frame", Harold Aspden's considers their work important, as their experimental data clearly shows an eastward motion effect. And so it is possible to sense the speed of a test device using optical speed-of-light sensing wholly confined within the enclosure housing the apparatus.
    See Harold Aspden's Lecture No IIIb - One-way speed of light.

    Other works not covered by Baez are:

    Silverthooth’s work puts a stronger case against SR.
    In 1986 E W Silvertooth claimed to have measured the 378 km/s cosmic motion using an optical sensor that measures the spacing between standing wave nodes. Although the experiment has not been confirmed, see
    See Harold Aspden's Lecture No IIIb - One-way speed of light

    And Dayton Miller's work, see http://www.orgonelab.org/miller.htm

    Clearly there is a need to carry out more one-way tests, in which clocks are not forced into synchronization by Einstein’s way.
    Last edited by a moderator: Apr 21, 2017
  10. Jan 7, 2005 #9


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    Cosmological clocks are theoretically ideal for carrying out such one-way tests, but the technology isn't advanced far enough for that quite yet.

    The speed of light is locally Lorentz invariant, and is presumed not to vary with the speed or direction of any photon emitter or photon detector whatsoever. Nevertheless, proper time is definitely not Lorentz invariant, and [tex]\frac{d\tau}{dt}[/tex] may very well be found to exhibit a dipole anisotropy when the precision of our cosmological clocks becomes good enough to detect it. If so, a locally preferred frame will be identified which corresponds to that frame in which [tex]\frac{d\tau}{dt}[/tex] is isotropic.
    Last edited: Jan 8, 2005
  11. Jan 8, 2005 #10


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  12. Jan 9, 2005 #11
    Thanks for the links. I will study this fully, but I can see things are not right from the start. From “Why the Ether is Unobservable” dated November 21, 1999:

    This opening paragraph is a bit controversial, suggesting that there is no proof of the ether, when there is real evidence to suggest that the detection of the ether is possible, the latest example being the Dewitte experiment.
    It also says that there are no ether theories with address the propagation of light that could devise an experiment to detect the ether. This is not true. A one-way experiment similar in nature to the DeWitte experiment would reveal the existence of the ether.

    Much of the comments about there being no viable ether theory that can meet the stringent conditions imposed is just not the case.

    The closest ether to the truth is:
    But his comments on the MMX are incorrect.
  13. Jan 9, 2005 #12


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    wisp, where can I get the complete details on how to reproduce the DeWitte experiment?
  14. Jan 9, 2005 #13


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    There has got to be an aether theorist willing to fork over the $10,000 or so required to do a tabletop 1-way test. Why hasn't one been done yet? Are they afraid of the answer?
    Last edited: Jan 9, 2005
  15. Jan 10, 2005 #14
    Russ - you might be right. But On the other hand there are a number of publications that claim we cannot detect one way velocity using terrestrial sources. There were however some experiments by Silvertooth - discredited of course by mainstream physics - if I am not mistaken he measured the earth velocity wrt to space as being very close to what we determine from the CBR - but I believe his experiments were performed before the CBR anisotrophy was detected. On the other hand, if his tests really showed what he claimed - why have they not been repeated? Something definitely missing in this story.

    wisp -
    Would totally concur that anyone who makes a statement that MMx refutes the existence of an ether has no knowledge of the subject matter. Einstein himself stated it had no bearing on the issue - only that it was not necessary to consider it in his derivation of the transforms
  16. Jan 10, 2005 #15
    Russ - one more point. As between SR and LR, there would be nothing proved by such a test since both predict that light is one way isotropic in the earth frame - SR because of Einsteins postulate, LR because the gravitational field is postulated to create an isotropic local ether that masks the earth's motion relative to the universe.
  17. Jan 10, 2005 #16


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    This just seems too convenient to me - assuming that reality resides in a loophole. Anyway, slowly but surely, the loopholes that aether theories can fit in are getting closed. Eventually, the "local ether" will be the entire universe. In any case, you can see why people would have trouble with this, can't you? Aether theories are predicated on the assumption of an unobserved (and possibly unobservable) flaw in a highly successful theory.
  18. Jan 10, 2005 #17


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    One way velocities are strictly a statement about coordinate systems. Coordinate systems don't have any ultimate physical significance - that's why one-way velocities don't, either.

    So basically getting hung up on the issue of one-way velocities is a dead end. It doesn't tell you anything more, or different, about what you can measure. Furhtermore, systems with non-isotropic one-way velocities are more complicated to deal with. As I've remarked in another thread, there can be some justification for changing units or coordinates to make the mathematics and the exposition of a theory simpler. In this case, changing to non-isotropic coordinates makes the math and the exposition of a theory harder, not simpler. So it's pretty much a lose-lose proposition.
  19. Jan 10, 2005 #18
    I didn’t make this statement; it was quoted by from an article by Tom Roberts in 2000 (Original by Siegmar Schleif and others, 1998) as being the reason why rigid ether was ruled out. I know Einstein claimed that the MMx had no bearing on the development of SR, but it is generally acknowledged as being the main experimental proof that supports the principle of relativity – the speed of light being constant…

    A link to the Roland DeWitte experiment (a one-way electrical pulse experiment) is


    The important points are:
    Only something that has a galactic origin can cause a sidereal period variation in the results.
    He used three sets of atomic clock standards to ensure accuracy of measurements.
    A similar experiment using a laser and two atomic clocks would produce similar findings.

    I’m reading Tom Roberts’ three articles about the ether.
    Last edited by a moderator: Apr 21, 2017
  20. Jan 10, 2005 #19


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    I'll begin to get excited about the DeWitte experiment when someone replicates it. Besides the total lack of replication, it would be important to rule out effects due to the solar day. One of the first effects that come to mind is very simple, the temperature.

    The argument that the period is the sidereal day rather than the solar day does not seem to me to be very a very strong argument, as the periods are very close, and it is unclear that the experiment is really capable of distinguishing between them.
  21. Jan 10, 2005 #20
    Wisp - I know you didn't make the statement - it was a quote - but I am surprised that Tom Roberts would endorse it.
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