Is There an Absolute Rest Frame in a 2D Universe?

[yogi]

Nereid - perhaps I am missing something in your questions. I do not see why GR cannot be correct and there still be one or more preferred frames. To my way to thinking, the conditioning of local space by matter implies a detectable, measurable spacetime attribute that is different from spacetime far removed from matter - one of those characteristics might be local light isotrophy. This impacts the generality of SR, that is, the symmetry is observable only when the matter conditioning field exists (a local condition), but it does not influence the modus operandi of time dilation in GR. While it is often said that SR is a special case of GR, there is a difference (primarily in the assumptions made to derive the equations). GR seeks and offers a physical explanation of gravity independent of the second hypothesis of SR; SR tells us how relative motion leads to different perceptions, but we get to these same results with Lorentz ether theory and other transforms based upon a preferred frame. Should it ever be demonstrated that the second hypothesis in SR is incorrect in a free-space MMx environment (e.g., the discovery of a preferred frame), it would not invalidate GR - nor would it invalidate any of the the many SR consequences that are based upon the invariance of the spacetime interval. The SR experiments neither validate nor invalidate the slippage term vx/c^2 as this factor is canceled out in the formulation of the temporal rate differences as determined by high speed particle lifetimes.

 

[Garth]

Just to throw in a little light relief how about this eprint out today?
"The Einstein Postulates: 1905-2005 A Critical Review of the Evidence"
Reginald T. Cahill (Flinders University)
http://arxiv.org/abs/physics/0412039
From the abstract

While the relativistic effects are well established experimentally it is now known that numerous experiments, beginning with the Michelson-Morley experiment of 1887, have always shown that the postulates themselves are false, namely that there is a detectable local preferred frame of reference.

Going back to the discussion above, I would argue that if there is a preferred frame in which the laws of physics take on a unique aspect (as I have argued with the Cosmological Twin Paradox) then it would affect GR rather than SR.

I do not see how a preferred frame can appear in SR as any preferred frame must be linked to the presence of matter, "to hang it on", and SR is framed in the pristine flat space-time in the absence of gravitational masses.

However it is when we move from SR to GR by considering the effect of stress-energy-momentum on space-time that a preferred frame may creep in. If it does then the GR postulate that would be challenged would be the equivalence principle as physics in the freely falling frame would no longer be locally those of SR. This would then affect the conservation of energy-momentum.

Garth

 

[Rob Woodside]

Much of the noise in this thread comes from people talking at cross purposes because they have different notions of preferred and absolute frames.

As someone said a preferred frame is a convenient frame- a frame where things look physically or mathematically simple. Physically these include the global inertial frames of Newtonian mechanics or special relativity and the local inertial frames of general relativity. Mathematically perferred frames include Schwarzschild coordinates for a spherical star and Boyer-Lindquist coordinates for rotating black holes. In fact any published metric tensor is given as coordinate functions of a preferred frame. This includes the isotropic CMB frame.

However, cosmologists have followed Newton's dictum "time is defined to make motion look simple." They infer spatial expansion with a uniform time from red shift data on distant galaxies. One could equally well say that spatial distances remain fixed but recent clocks tick more quickly than old clocks. A photon's frequency is a frozen clock rate of the emitting atom. An early distant atom has a slower clock rate than a modern earthly one. Since the frequency times the wavelength is the constant speed of light, the wavelength of the old photon is longer since the clock rate is faster when it is absorbed at earth. Apart from Newton's dictum, I can't see how to tell these two scenarios apart.

Some posters have used absolute frames interchangeably with preferred frames and this has raised the hackles on other posters. They are NOT interchangeable. The word "absolute" has special connotations from Newtonian mechanics. Newton's first law gives the constant speed straight lines needed to set up the coordinate lines of an inertial frame. Newton was well aware of Galileo' principle of relativity and he knew that two inertial frames could slide through each other at a constant speed. Not knowing of a maximum speed that would be the same in all inertial frames, he turned to religion. Since his God was omniscient and omnipresent, just one of these frames would be God's sensorium, but which one? It was obvious to him that it should be the frame of the fixed stars. This frame in which the aether was at rest defined the absolute space and time. It was called absolute because velocities were now not just relative to some inertial frame, but were absolute with respect to the rest frame of the aether. Further, when viewing in one inertial frame the rods and clocks tied to another inertial frame they would appear identical to those in the viewing frame. There was no length contraction or time dilation, space and time were immutable. It is these old connotations that raise a red flag every time the word absolute is used.

 

[ZapperZ]

Just to throw in a little light relief how about this eprint out today?
"The Einstein Postulates: 1905-2005 A Critical Review of the Evidence"
Reginald T. Cahill (Flinders University)
http://arxiv.org/abs/physics/0412039
From the abstract

I would seriously suggest (i) that you wait till this thing is actually accepted for publication and (ii) look at all the "evidence" he cited, and then look at all the evidence that *I* have listed in my Journals, and see for yourself which one is more convincing. Has he been asleep the past 10 years and missed ALL (not even ONE) of the most recent evidence before he put this up? What does that tell you about how up-to-date he is on keeping up with all the experimental evidence?

Honestly, people! We need to be a bit more discriminating on our sources here! If not, any quack who either have a website or could somehow wrangle onto ArXiv would get free publicity on here!

Zz.

 

[Nereid]

Much of the noise in this thread comes from people talking at cross purposes because they have different notions of preferred and absolute frames.

Excellent post Rob! However, I prefer, perhaps because it's convenient, to not be so absolute in saying that it's noise

I think there are different strands to our discussion here, several (all?) of which are very worthwhile.

For example, if there is a claim that the CMBR somehow allows an absolute or preferred (no one challenges the statement that it is convenient, do they?) frame, then let's see that claim in detail ... and let's ask the proposers to make clear what assumptions about the CMBR and the universe that they must make to establish their claim. OTOH, if there are folk who claim that the CMBR allows us to easily (!) identify "the cosmological co-moving frame in which the universe is isotropic and homogeneous" (thank you Garth), but that this does not lead to problems with the core postulates of GR, let's hear their case too (I think we already have, but there may still be some doubt).

OTTH (Harry Truman would turn in his grave), if there are cosmological models which use modified GR (or even modified Newtonian dynamics ) - and which are consistent with the observational data - it is interesting to learn (well, interesting to me at least) the extent to which 'preferred' and 'absolute' make sense in these models (Garth has already said quite a bit about his SCC in this regard; do we have any MOND supporters here?)

 

[Garth]

I would seriously suggest (i) that you wait till this thing is actually accepted for publication and (ii) look at all the "evidence" he cited, and then look at all the evidence that *I* have listed in my Journals, and see for yourself which one is more convincing. Has he been asleep the past 10 years and missed ALL (not even ONE) of the most recent evidence before he put this up? What does that tell you about how up-to-date he is on keeping up with all the experimental evidence?

Honestly, people! We need to be a bit more discriminating on our sources here! If not, any quack who either have a website or could somehow wrangle onto ArXiv would get free publicity on here!

Zz.

I said "Just to throw in a little light relief "

Garth!

 

[Rob Woodside]

Excellent post Rob! However, I prefer, perhaps because it's convenient, to not be so absolute in saying that it's noise

Thanks for the Kind words. There is much less noise here than at SPR.

 

[Aether]

I'm particularly interested in seeing how - in principle! - it [CMBR] could be used to create an absolute ruler and clock, oh, and an absolute set of coordinate directions (orthogonal or not) would be nice, as too would an absolute origin for the coordinate system and clock.

Please be sure to explain why the procedures you describe would yield the same results whether I'm here on Earth, somewhere in the Bootes void, orbiting M87's SMBH (just so I don't get sucked in), or somewhere in the vicinity of one of the primordial galaxies in the HUDF field (z ~=8). {Garth's cosmological paradox method is not permitted; you can't assume anything about the geometry}

To make an absolute clock one seems to need a specific cosmological model in combination with an instantaneously Lorentz invariant observable quantity like the CMB monopole, but not necessarily that one since there are other examples of such quantities and no guarantee that most supposedly Lorentz invariant quantites aren't evolving over cosmological time. I mean, without our cosmological model to tell us different, the CMB monopole would almost certainly be listed right along with all of the other fundamental physical constants. http://arxiv.org/abs/gr-qc/0211052

Given an absolute clock and a specific cosmological model, then a minimium CMB monopole temperature T_{min} can be defined for a closed universe, and this can be used to define the units for both the absolute clock T(OneBigTick) = T_{min} and the absolute ruler R(T_{min}) = OneFurPiece.

So a closed universe has a preferred frame of reference! It has so by virtue of its topology, which is finite yet unbounded.

It is interesting that a closed universe is also a condition of Garth's preferred frame. I am not sure about how to define the units of an absolute clock or an absolute ruler, in anything other than a closed universe, without being arbitrary.

Any absolute set of coordinate directions is bound to be arbitrary, unless there is something of cosmological significance about the odd alignment of the CMB multipole that nobody has told us about yet. As a group, humans are predisposed to favor a dextral orientation (e.g., right hand rule) in lots of circumstances.

The absolute origin for the clock is given by the cosmological model, and the spatial origin for the coordinate system is the center of mass of the universe.

By absolute I mean with respect to the matter and energy distribution of a closed universe.

 

[windscar]

I am amussed that you mentioned light being the absulote rest frame of the universe. I have also considered this. If your thinking about two objects in this frame of reference, I would say that both object observe them being at rest and moveing at a constant speed at the same time. Therefore, they would both see each other's time going slower relative to each other. And the actual time dilation wouldn't be able to be resovled unless you found out which object accelerated. I have read that as an object accelerates, the intervals of light you see while observeing the other object could change how you see their speed of time through difference in doppler shift's. So I guess it could depend on from which side of the sphere you observed the other object. One direction would be faster and from the other side would be slower if not equadistant from each other along the sphere. It would depend from what side they met up from each other.