What is Lorentz' Ether? Lorentz' ether

[professor]

Lorentz' "ether"

I have recently read a paper written by H.A. Lorentz in which he repeatedly referred to an "ether"... what seems strange to me is i am not sure what this ether is, and it is only described as how it can manipulated mathmatically. It has appeared in more than one of his papers... is this the translators way of describing gravity (or some such similar force)

 

[Pengwuino]

I believe ether was the original means of propogation for light that the older physicists use to believe in (1800's). I guess they just have ruled it it's existence out based on experimental data

 

[DrChinese]

Yes, the ether is the hypothetical substance through which electromagnetic waves were supposed to propagate. This is essentially an outdated concept, in large part due to the introduction of Special Relativity by Einstein in 1905. It is possible there is an ether, but there is no experimental evidence for it and there is no theoretical support for it at this time.

 

[Jonny_trigonometry]

Pervect says that a lasar gyroscope can detect if it is spinning or not. GR explains this as it's ability to detect motion w/respect to absolute space-time, aka. aether.

 

[jtbell]

absolute space-time, aka. aether.

You can call a dog a horse if you like, but that doesn't make it a horse.

Likewise, you can call the spacetime of GR an aether if you like, but that doesn't make it "the" aether as understood by Lorentz, Einstein and other physicists up to 1905.

(Somebody had better move this thread to the relativity forum, by the way...)

[added: Ah, I see it's now been moved.]

 

[CarlB]

Lorentz's version of relativity predates Einstein's. An easy way to get it is to take Einstein's picture and instead of assuming that there is no preferred reference frame, instead just choose one arbitrarily.

Supposing that one of the possible reference frames happens to be the preferred one (but which one it is cannot be detected, or at least has not yet been clearly detected) is compatible with Einstein's relativity. It's generally thought that Einstein's relativity is preferable because it apparently has fewer assumptions. But work on Lorentz's relativity continues. Einstein never received a Nobel prize for relativity because the idea was not thoroughly accepted in the physics community until those who believed in ether, such as Lorentz, died off. By that time Einstein was dead too.

Lorentzian relativity is still pursued by a small number of physicists. A recent article that got a lot of press is:
http://arxiv.org/abs/astro-ph/0311576
See the references above and references to the above for more.

Carl

 

[professor]

carl thanks your were quite helpfull.. dident realize i was dealing with a whole different relativity...foolish

 

[yogi]

Einstein never rejected the concept of an aether - but it was superfluous to his explanation of MMx which he called SR. Lorentz was searching for a physical mechanism to explain MMx and contrived (actually FitzGerald did it first) the notion that physical bodies shrink in the direction of motion as they move through the aether. That aspect of Lorentz's theory is no longer believed (by most) to be correct - but the issue of the nature of the void is still an unanswered question.

 

[ahrkron]

I don't know Carl,... that article about the reinterpretation of MMx sounded a bit fishy to me; although I must say that I only looked it over rather quickly.

 

[CarlB]

I don't know Carl,... that article about the reinterpretation of MMx sounded a bit fishy to me; although I must say that I only looked it over rather quickly.

I don't think it's the best article, but it is the one that has most recently garnered the most attention. On the other hand, I think most of the work in Lorentzian relativity has been in the specialty that raises the importance of proper time, and from that replaces Minkowski space with a Euclidean space. A list of current researchers with links in that area is here:
http://www.rfjvanlinden171.freeler.nl/links.htm

Also, there is a somewhat similar branch of relativity that seems to be drifting towards an Euclidean geometry. They call it a gauge theory of gravity and it was developed by three Cambridge physicists, Lasenby, Doran and Gull, but I think is best described by Hestenes, who made popular the geometric algebra used to describe the theory. Hestenes wrote a review article and published it in Foundations of Physics. It's available here:
http://modelingnts.la.asu.edu/pdf/GTG.w.GC.FP.pdf

But my favorite comment by Hestenes on this theory of gravity (which Hestenes says is identical to GR but preferable because it is more geometric) is on pages 21-23 of this article concerning the difference between manifolds and flat spacetime:

"IX Vector Manifolds"
http://modelingnts.la.asu.edu/pdf/SpacetimeGeometry.w.GC.proc.pdf

Technically, the above gauge gravity isn't a "Lorentzian Relativity" theory because it really doesn't seem to need a preferred reference frame. But if you'll read it, I think you'll see that it's natural to include it with the others.

Of course none of these theories are included in the standard education of physicists.

Carl

 

[clj4]

I don't know Carl,... that article about the reinterpretation of MMx sounded a bit fishy to me; although I must say that I only looked it over rather quickly.

The Consoli paper suffers from several problems:

1. The authors think that rerunning MMX in a system imersed in a medium having the refraction index n>1 "might" produce non-null results

2. At the time of the paper publication the authors had not run ANY experiment

3. Now comes the punch line : the authors seem completely ignorant of the fact that the experiment they are suggesting...had already been run...several times...long ago...with NULL results. [1][2]

4. To make the matters even worse, the authors base their calculations on another paper suggesting the same idea , by Reg Cahill that is completely wrong. (BTW, mr. Cahill hasn't run the experiment either).

[1]Shamir and Fox, N. Cim. 62B no. 2 (1969), p258.
A repetition of the MMX with the optical paths in perspex (n = 1.49), and a laser-based optics sensitive to ~0.00003 fringe. They report a null result with an upper limit on Vaether of 6.64 km/s.

[2]Trimmer et al., Phys. Rev. D8, p3321 (1973); Phys. Rev. D9 p2489 (1974).
A triangle interferometer with one leg in glass. They set an upper limit on the anisotropy of 0.025 m/s. This is about one-millionth of the Earth's orbital velocity and about 1/10,000 of its rotational velocity.

 

[Hans de Vries]

The Consoli paper suffers from several problems:

4. To make the matters even worse, the authors base their calculations on another paper suggesting the same idea , by Reg Cahill that is completely wrong. (BTW, mr. Cahill hasn't run the experiment either).

Indeed, Consoli, and thus Cahill's erroneous theory again...

The simplest interferometer experiment, inferior even to the original
Michelson- Morley experiment from 1887, would reveal the absolute
speed with great accuracy when performed in water or any other
medium with a refractive index sufficiently different from vacuum.

This paper is from 2003, still no experiment...Regards, Hans

 

[Hans de Vries]

I have recently read a paper written by H.A. Lorentz in which he repeatedly referred to an "ether"... what seems strange to me is i am not sure what this ether is, and it is only described as how it can manipulated mathmatically. It has appeared in more than one of his papers... is this the translators way of describing gravity (or some such similar force)

What killed this "aether", was that it was assumed to be something like air
in which electromagnetic radiation propagates like sound propagates in air.
Like normal wind there should then be an "aether wind",

No such wind was ever found, not in 1887 with the first experiments and
not today with the latest incredible accurate inferometers which would be
able to measure such wind-speeds with micrometer/second accuracy.

It has since long found out however, in quantum mechanics, that not only
electromagnetic radiation propagates, but everything does so, that is
electrons propagate, protons, molecules, everything propagates, including
me and you.

Therefor we cannot detect any such wind since we are part of that in
which we propagate.

The physical laws that describe the propagation are all very much alike.
They contain the Laplacian which describes, in technical terms, a socalled
"deconvolution with the lightcone" This means for instance that nothing
can move faster than light.

Also, all these propagation laws are socalled "Lorentz Invariant". This
is a real understatement: The Lorentz transformations describe the
effects of Special Relativity while the Propagation Laws produce the
effects of Special Relativity.Regards, Hans