GR support for a preferred frame 2
Neil Bates
to current expansion, but in principle it could have been) then consider
what happens inside a box "actually moving" through space: since internal
test bodies follow great circle routes (geodesics) on the hypersphere, they
will oscillate back and forth inside the container as it travels around the
hypersphere at a rate proportional in part to "velocity" relative to the
geometric construct itself. (Consider that their individual geodesics
can't stay parallel; they must intersect like longitude circles on the
earth.)
This is simply unavoidable, and means that once you have rules about
"following" this or that path on a curved surface, then it becomes a
standard for referencing motion on that surface. Well, relative to what? I
would suppose, the average motion of matter, but this issue really isn't
adequately clarified, and not adequately presented in discussion and
textbooks. (Sure, Taylor and Wheeler show ships coming together while
traveling the surface of the earth in _Spacetime Physics_, but don't really
apply that to the implications for standard of motion in the universe.)
--
Fine minds make fine distinctions.
Androcles
"Neil Bates" <neil_...@caloricmail.com> wrote in message
news:13acqgm...@corp.supernews.com...
: For example, if space is hyperspherical (which maybe it isn't due
The fine distinction a fine mind makes is that the natural Universe
doesn't give a flying hyperfuck about hypercrackpot theories,
including fine hyperspheres with an "if" in front of them.
Hayek
Sure, if the Earth can do frame dragging, then the universe can create a
frame, and it does at some eleven magnitudes better, just like it
influences clocks. Many people do not realize that if a clock is slowed
down a few billionths by the Earths gravitation, that the other billion
parts of slowing are done by the masses in the universe. A clock is an
inertiameter.
The pages on inertia and Machæ„€ principle from gravitation, by Misner,
Thorne and Wheeler :
http://www.xs4all.nl/~notime/inert/gravp543.html
Uwe Hayek.
Uwe Hayek.
Tom Roberts
> [...]
Yes, GR does indeed have many manifolds in which there is a "preferred
frame" that is "preferred" due to some symmetry of the manifold. You
merely give one example.
Note, however, that this is not the usual meaning of "preferred frame"
in physics. Historically that phrase has meant a frame in which the laws
of physics are somehow special. GR has no "support" whatsoever for this
kind of "preferred frame".
Tom Roberts
Ben Rudiak-Gould
> Yes, GR does indeed have many manifolds in which there is a "preferred
> frame" that is "preferred" due to some symmetry of the manifold. You
> merely give one example.
Another example (as you know but the OP might not) is all versions of the
FLRW geometry that's used to model our universe, even when space is flat or
hyperbolic rather than (hyper)spherical. The "preferred frame" is observable
as the state of motion with respect to which the CMBR is isotropic.
Historically it was known as rest with respect to the fixed stars. It's also
called the Hubble flow.
-- Ben
Neil Bates
"Androcles" <Engi...@hogwarts.physics> wrote in message
news:O3upi.19972$2U6....@fe1.news.blueyonder.co.uk...
up. It's part of GR and not a crackpot theory, IMHO. If you really think
it's cracked, tell us why, but don't blame me for inventing it.
Neil Bates
"Ben Rudiak-Gould" <br276d...@cam.ac.uk> wrote in message
news:f862cu$eh2$1...@gemini.csx.cam.ac.uk...
Yes, I've heard of the frame where the cosmic MW background is isotropic.
But that is about observing something entering from outside. BTW, what
determines whether a particle would end up in that frame or not? By
contrast, in my example, the internal physics are actually different.
Neil Bates
"Tom Roberts" <tjrobe...@sbcglobal.net> wrote in message
news:Izvpi.10666$eY....@newssvr13.news.prodigy.net...
But the environment inside the moving box really is a special frame, because
objects experience a tidal field with no internal sources, or specific
external ones (it's not like passing by a planet....) because this is an
effect from the overall density of the universe. (In particular, it isn't
what can be simulated by acceleration or rotation in an inertial space.)
Note, this goes beyond physics, because it means we can define "motion" on a
featureless geometric body once we have rules like the following of a
geodesic. That is counterintuitive given there not being "marks" on the
hypersphere to reference relative motion.
Ben Rudiak-Gould
> Yes, I've heard of the frame where the cosmic MW background is isotropic.
> But that is about observing something entering from outside. BTW, what
> determines whether a particle would end up in that frame or not? By
> contrast, in my example, the internal physics are actually different.
In principle you can detect the Hubble flow from spacetime curvature alone,
as in your thought experiment. You'd have to measure over an enormous volume
of space because of local inhomogeneity and because the overall curvature is
so small. I don't know of a nice simple experiment like the one you described.
I don't understand your question (what determines...).
-- Ben
Shubee
You asked, "relative to what?" Obviously everything becomes relative
to the absolute and physically distinguished frame of the geometry. As
to the essence of your observations, I see no need to complicate the
physics by presupposing a dynamical law that connects an energy-
momentum tensor with the geometry.
http://arxiv.org/abs/gr-qc/0304038
http://www.everythingimportant.org/viewtopic.php?t=79
http://arxiv.org/abs/gr-qc/0503070
http://cornell.mirror.aps.org/abstract/PRD/v8/i6/p1662_1
http://physics.ucr.edu/Active/Abs/abstract-13-NOV-97.html
http://prola.aps.org/abstract/PRA/v63/i4/e044104
http://www.iop.org/EJ/abstract/0143-0807/23/3/306
http://arxiv.org/abs/astro-ph/0606559
http://www.everythingimportant.org/viewtopic.php?t=605
http://www.everythingimportant.org/relativity/simultaneity.htm
Shubee
Dono
>
> http://www.everythingimportant.org/relativity/simultaneity.htm
>
> Shubee
Shobo, you have an ELEMENTARY arithmetic ERROR in the "derivation" of
your "absolute simultaneity transforms"
You must have been carrying it for years, since your original
"discovery". Even a 6-th grader can see it.
So, you:
x'=gamma*(x-vt)
t'=t/gamma
are .....BOGUS.
Thanks for the laughs. :-)
Tom Roberts
> x'=gamma*(x-vt)
> t'=t/gamma
I assume gamma = 1/sqrt(1-v^2), and c=1.
Then that is the Tanghileri transform, which has been discussed here
quite often (though not recently). It is experimentally
indistinguishable from SR. The only difference from SR is how coordinate
clocks are synchronized. One can interpret it as having an "ether" frame
which is completely unobservable (similar to LET).
Tom Roberts
Shubee
More generally, the transform can be interpreted as either being
physical indistinguishable from SR or a very natural choice of clock
synchronization for a Minkowski spacetime with an absolute frame of
reference.
Shubee
Dono
Tom,
Did you make the effort to read Shitbert's "derivation"? It contains a
very basic arithmetic error. Take the time to read it, ok?
Dono
Except that yoour "derivation" is based on a basic arithmetic error.
If you did your aritmetic right, you would get .....the standard
Lorentz transform.
Thanks for the laughs, Shitbert :-)
Dono
You mean, the TANGHERLINI transform, right ? :-)
http://www.springerlink.com/content/qp20860n41445152/
Yes, I know of it and this is not what Shobo's "derivation" should
have produced if he were to calculate things correctly. Check out his
paper but please don't tell him what the error is, I like his papers
so much more with errors in them. Especially when Shitbert writes
stuff like this:
[quote] Einstein's second greatest scientific blunder, which he never
repudiated, was his fallacy of no absolute time order for all events
in the universe and that we may not conceptualize time being divided
into an absolute past, present and future.[/quote]
Eric Gisse
[...]
Thus providing further evidence that Shooby thinks special relativity
is the Lorentz transform and nothing else.
I'm still waiting for his promised derivation of energy and momentum,
but he doesn't like to talk to me anymore. Too many questions and
arguments he can't handle. :(
Martin Hogbin
You might find this book interesting.
Mach's principle: From Newton's Bucket to Quantum Gravity
edited by Julian Barbour and Herbert Pfister
Einstein Studies, Volume 6
Birkhauser
--
Martin Hogbin
Androcles
:
: "Androcles" <Engi...@hogwarts.physics> wrote in message
To understand why it's hypercracked, look at the guy who invented it
and what he based it on.
Fine minds do not claim 1/2(16+4) = 16, the other half is 4.
http://www.androcles01.pwp.blueyonder.co.uk/Smart/Smart.htm
mathematician
I found an interesting old posting of Matt McIrvin from the year 1992
where he discussed about SR subject Re: A "preferred reference
frame".
I put a copy below. Please take a look for commnets.
Hannu
----COPY BELOW------
Path: sparky!uunet!usc!sdd.hp.com!caen!kuhub.cc.ukans.edu!
husc-news.harvard.edu!husc8!mcirvin
Newsgroups: sci.physics
Subject: Re: A "preferred reference frame"
Message-ID: <mcirvin.713900948@husc8>
From: mcir...@husc8.harvard.edu (Mcirvin)
Date: 15 Aug 92 17:49:08 GMT
References: <80...@dirac.physics.purdue.edu>
Nntp-Posting-Host: husc8.harvard.edu
Lines: 44
hin...@maxwell.physics.purdue.edu (Jason W. Hinson) writes:
>The following is a science fictional excursion discussing the possiblity
>of space-time having a preferred frame of reference without violating
>relativity. My request is that someone tell me how we know that it cannot
>be true.
[description of a physics in which, to paraphrase a bit, instantaneous
communication can occur, but only along a preferred set of spacelike
surfaces]
We do not know that this cannot be true. Your statement that there
would
be no problem with causality is correct, since spacelike
communication-->
causality violation depends on the ability to change the spacelike
surface (or in SR, the inertial frame) in which the communication is
instantaneous, and this proposal explicitly removes the possibility.
It does "violate relativity" in the sense that it denies one of the
basic postulates, namely that *all* the laws of physics are the same
in all inertial frames. It doesn't completely tear it apart, though;
it just turns it into a theory of some special subset of physics,
including all physics currently known. It doesn't violate causality.
Rather than just say that the "ether" has the property that c is the
same in all frames, I'd say that the "ether" is only an ether for
these extra, instantaneous interactions, and has no relevance to
anything else.
This is, as others and I have pointed out before, a nice self-
consistent
way to put faster-than-light travel into science fiction. It isn't
at odds with any data and doesn't introduce the possibility of time
travel into the past. All one needs to assume is some nonlocal
phenomenon which disobeys relativity in this way.
The other side of the coin is that there is absolutely no evidence for
any such thing, and no need to introduce it other than that it might
be nice to have. Relativistic covariance has turned out to be an
extraordinarily successful framework in which to construct a model
of physics, and to most of us, at least, there seems to be no reason
to abandon it. But nothing currently known from experiment rules out
extra physics of the sort you describe.
--
Matt McIrvin, Cambridge, Massachusetts, USA
Ben Rudiak-Gould
> But the environment inside the moving box really is a special frame [...]
It's a debate over words. I tend to agree with you that the Hubble flow
deserves to be called "special" or "preferred". Tom Roberts' point is that
general relativity, as a theory, doesn't prefer any frame. Of course, the
canonical theory /with/ a preferred frame is a theory with a luminiferous
aether, but that has always struck me as historical revisionism; those
theories don't have a preferred frame, they just have a substance that fills
all of space and, like any other substance, has a state of motion. Galilean
invariance isn't explicitly broken in these theories, it's spontaneously
broken (though that's just another kind of historical revisionism).
-- Ben
Shubee
You must be right in your own mind since you voted for yourself 35
times. What an idiot!
Dono
Shitbert,
Can you find your elementary arithmetic error in your "discovery"?
I'll give you a hint, if you take the error out you obtain....the
Lorentz transforms !
Thanks for the laughs, Shitbert!
Shubee
You are truly demented to vote for yourself 54 times. No one is stupid
enough to agree with you. Why not try to live your life with self-
respect and honestly? How long have you been living as a shit-throwing
chimpanzee? Anyone with any intelligence at all can plainly see my
competence in math.
Shubee
http://www.everythingimportant.org/relativity/special.pdf
Dono
Shitbert, Shitbert
Found your basic arithmetic error yet? How long have you had the
"derivation"? Years? Five minutes into looking at it and there it
is. :-)
Dono
You'll never see it. Come on, the guy cant even see the simple
arithmetic mistake in the "derivation" of his "absolute simulatneity"
transform. Had he not cheated, he would have gotten ...the stock
Lorentz transforms!
And this perpetual blunderer and cheat has the audacity to write about
the Einstein "blunders". Look at the new link he's listed but please
DO NOT correct his mistake, we need him dumb , he's much funnier this
way:
http://www.everythingimportant.org/relativity/simultaneity.htm
This psycho is so desperate for attention that he would post
litterally any shot in order to get it. So, he's getting plenty of it,
but not the way he expected it :-)
Eric Gisse
> On Jul 25, 12:51 am, Eric Gisse <jowr...@gmail.com> wrote:
>
> > On Jul 24, 10:11 pm, Dono <sa...@comcast.net> wrote:
> > [...]
>
> > Thus providing further evidence that Shooby thinks special relativity
> > is the Lorentz transform and nothing else.
>
> > I'm still waiting for his promised derivation of energy and momentum,
> > but he doesn't like to talk to me anymore. Too many questions and
> > arguments he can't handle. :(
>
> You'll never see it. Come on, the guy cant even see the simple
> arithmetic mistake in the "derivation" of his "absolute simulatneity"
> transform. Had he not cheated, he would have gotten ...the stock
> Lorentz transforms!
>
> And this perpetual blunderer and cheat has the audacity to write about
> the Einstein "blunders". Look at the new link he's listed but please
> DO NOT correct his mistake, we need him dumb , he's much funnier this
> way:
>
> http://www.everythingimportant.org/relativity/simultaneity.htm
You say mistake as if there was only one. His little argument about
black holes is especially amusing since not only does he not know what
he is doing, he has no idea how to solve the field equations to get
the Schwarzschild solution.
>
> This psycho is so desperate for attention that he would post
> litterally any shot in order to get it. So, he's getting plenty of it,
> but not the way he expected it :-)
Though seeing posts get scored up/down a huge amount of times
irritates me, hearing cranks whine about it amuses me even more. This
is the only medium they have, and they know it.
Tom Roberts
> But the environment inside the moving box really is a special frame, because
> objects experience a tidal field with no internal sources, or specific
> external ones (it's not like passing by a planet....) because this is an
> effect from the overall density of the universe.
Sure. That specific frame reflects a symmetry of the manifold.
But still, it is not "special" in the usual sense of the laws of physics
being different in that frame. In my office things fall down; in the
international space station things do not fall at all (to a casual
observer); yet the laws of physics are the same in both places.
Different physical situations yield different results.
> Note, this goes beyond physics, because it means we can define "motion" on a
> featureless geometric body once we have rules like the following of a
> geodesic. That is counterintuitive given there not being "marks" on the
> hypersphere to reference relative motion.
Hmmmm. If there are no "features" on a geometric body, then one cannot
tell whether one is moving on its surface or not -- think of an infinite
plane or the surface of a perfect sphere. If there are features (e.g.
mountains and lakes) then one can. For manifolds of GR with certain
symmetries, one can determine if one is moving relative to the frame
that expresses the symmetry -- just as one can tell if one is moving
AWAY from either that sphere or plane. There's nothing new or
"counterintuitive" about this.
Tom Roberts
Tom Roberts
>
> You mean, the TANGHERLINI transform, right ? :-)
Yes.
Tom Roberts
Neil Bates
> Neil Bates wrote:
>> But the environment inside the moving box really is a special frame,
>> because objects experience a tidal field with no internal sources, or
>> specific external ones (it's not like passing by a planet....) because
>> this is an effect from the overall density of the universe.
>
> Sure. That specific frame reflects a symmetry of the manifold.
>
> But still, it is not "special" in the usual sense of the laws of physics
> being different in that frame. In my office things fall down; in the
> international space station things do not fall at all (to a casual
> observer); yet the laws of physics are the same in both places. Different
> physical situations yield different results.
Well, it is special in a sense, because small test particles spontaneously
fall towards and away from the center of the box even though there is no
mass density *within the box* (well, I assume we can keep other matter out
of the box as it moves, and still maintain sufficiently geodesic motion for
the test particles.) But yes, OTOH, particles falling to the center of the
earth do that also, so the inside of the box is a sort of tidal field. The
important thing to me is not whether the box environment should be called
"special", but the very fact we can tell how fast we are "moving through the
universe" - IOW, the preferred frame for velocity, not "special" in any
sense beyond that. See the interesting comments by Ben Rudiak-Gould on this
issue.
>
>> Note, this goes beyond physics, because it means we can define "motion"
>> on a featureless geometric body once we have rules like the following of
>> a geodesic. That is counterintuitive given there not being "marks" on the
>> hypersphere to reference relative motion.
>
> Hmmmm. If there are no "features" on a geometric body, then one cannot
> tell whether one is moving on its surface or not -- think of an infinite
> plane or the surface of a perfect sphere. If there are features (e.g.
> mountains and lakes) then one can. For manifolds of GR with certain
> symmetries, one can determine if one is moving relative to the frame that
> expresses the symmetry -- just as one can tell if one is moving AWAY from
> either that sphere or plane. There's nothing new or "counterintuitive"
> about this.
No, because we can indeed tell that we are moving on the featureless surface
in this case, that's the whole point of my illustration. (This post has two
points, the first is about motion in a real physical universe - even if ours
isn't curved that particular way. The second point is about motion "on a
mathematical sphere", where oddly we can also tell "how fast we are moving"!
We can tell how fast we are moving by the rate of acceleration of the test
bodies inside the box. We aren't moving relative to the frame except to
imagine that something of the surface is absolute as a holder of rest, since
we aren't moving farther or closer to anything (uniform curvature
everywhere, and we stay inside the manifold.) This *is* odd and
counterintuitive, since a "mathematical entity" like a sphere isn't suppose
to be thought of the way we'd consider a steel ball, that we know how fast
we are sliding along because there's a "real surface" to be moving past
constituent particles of. I think it shows something about "time" being
special as a concept.
(Fun commenter fact: I'm in hits #1, 2, 3 and 4 from Google search for
"quantum measurement paradox"! Check it out, I may be on to something ...
Hit #1: http://www.lepp.cornell.edu/spr/2000-11/msg0029236.html)
Neil Bates
Thanks for some insights, but: the Hubbled flow is supposed to be the
tendency to expansion, am I right, which is not the point here. The
convergence of geodesics of the test particles happens even if the
hypersphere stays the same size. Indeed, if it grows or shrinks, that makes
things messier for showing "absolute velocity." My question goes further, by
pointing out that the same effect applies to purely mathematical entities,
and not just material spaces - which is really weird: see my reply today to
Tom Roberts.