Your thoughts on idea that may kill string theory.
andyeverett
http://arxiv.org/abs/0905.3905
"We give one of the first known arguments for the origin of the three
observed gauge groups. The argument is based on modelling nature at
Planck scales as a collection of featureless strands that fluctuate in
three dimensions. This approach models vacuum as untangled strands,
particles as tangles of strands, and Planck units as crossing
switches.
Modelling vacuum as untangled strands implies the field equations of
general relativity, when applying an argument from 1995 to the
thermodynamics of strands. Modelling fermions as tangles of two or
more strands allows to define wave functions as time-averages of
strand crossings; using an argument from 1980, this allows to deduce
the Dirac equation.
When modelling fermions as tangled strands, gauge interactions appear
naturally as deformation of tangle cores. The three possible types of
observable core deformations are given by the three Reidemeister
moves. They naturally lead to a U(1), a broken and parity-violating SU
(2), and a SU(3) gauge group. The corresponding Lagrangians also
appear naturally.
The model is unique, is unmodifiable, is consistent with all known
data, and makes numerous testable predictions, including the absence
of other interactions, of grand unification and of higher dimensions.
A method for calculating coupling constants seems to appear
naturally. "
This idea appears to only work in three dimensions. Should string
theorists be looking for a new job?
Thanks for your thoughts.
Robert L. Oldershaw
> The model is unique, is unmodifiable, is consistent with all known
> data, and makes numerous testable predictions, including the absence
> of other interactions, of grand unification and of higher dimensions.
> A method for calculating coupling constants seems to appear
> naturally. "
>
How about giving us details on one or two definitive predictions,
which are:
Feasible
Prior to the tests
Unique to the theory being tested
Quantitative
NON-ADJUSTABLE
Thanks,
RLO
www.amherst.edu/~rloldershaw
Hans-Peter Schmidt
wrote:
Copy-paste from http://www.motionmountain.net/research/index.html
Some predictions of the model (with their timing), made before
conclusive experiments (at the LHC, on neutrinos, on electric dipole
moments, about QCD, and in astrophysics):
* No additional elementary particle will be discovered: the Higgs
boson does not exist. The unitarity of scattering for longitudinal W
and Z bosons is maintained at all energies. (On website and 6th
volume, August 2009.)
* Non-local and non-perturbative effects in longitudinal W and Z
boson scattering will be observed. (On website and 6th volume, October
2009.)
* Gauge couplings, particle masses, mixing angles and their
running can be calculated with help of knot, polymer or cosmic string
simulation programs. (Website, March 2009, manuscript 4 and 6th
volume.)
* All neutrinos have mass and differ from their antiparticles.
Neutrinoless double-beta decay will not be observed. (On website and
6th volume, August 2009.)
* Hadron form factors can be calculated ab initio. (On website and
6th volume, October 2009.)
* The light scalar mesons are mostly tetraquarks; knotted two-
quark states and knotted glueballs are ruled out. (Website, November
2008, and 6th volume.)
* The probable non-existence of glueballs needs a better argument.
(Website, October 2008, changed to opposite in April 2009; see
manuscript 4 and the 6th volume.)
* Dark matter is compatible with the standard model. Dark matter
detectors will not detect anything new. (Website, September 2008, and
the 6th volume.)
* The electric dipole moment of elementary fermions is of the
order of the Planck length times the elementary charge. (Website,
November 2008, and manuscript 4.)
* The quark mixing and the neutrino mixing matrices are unitary.
(Website, November 2008, and 6th volume.)
* The coupling constants, particle masses and mixing angles are
constant in time. (Website, November 2008, manuscript 4 and 6th
volume.)
* There are only three fermion generations. The proton and the
positron charge are equal. (Website, November 2008, and 6th volume.)
* The highest chromoelectric (and chromomagnetic) field in nature
is given by the highest force divided by the colour charge; similar
limits exist for the weak interaction. The limits can be checked in
neutron/quark stars or other astrophysical objects. (Website,
September 2008, and manuscript 4.)
* No gauge groups other than those of the standard model exist in
particle physics. No form of GUT, technicolour or supersymmetry is
valid. No other interaction exists. Protons do not decay. (Website,
August 2008, manuscript 4 and 6th volume.)
* No additional elementary gauge bosons, preons, superpartners,
magnetic monopoles, axions, sterile neutrinos, additional fermion
families or leptoquarks exist. (Website, August 2008, manuscript 4 and
6th volume.)
* No additional spatial dimensions, fermionic coordinates, non-
commutative spacetime or different vacua exist in nature. No dilaton
exists. (Website, August 2008, and manuscript 4.)
* No quantum gravity effect will ever be observed - not counting
the cosmological constant and the masses of the elementary particles.
(Website, September 2009, and volume VI.)
* No deviations from QCD and almost none from the standard model
appear for any measurable energy scale. In particular, the strand
model implies that SU(2) is broken and P, C and CP are violated in the
weak interaction, and that SU(3), confinement and asymptotic freedom
are properties of the strong interaction. Longitudinal W and Z
scattering is slightly changed at LHC energies. (Website, August 2008,
manuscript 4 and 6th volume.)
* No deviations from quantum theory or quantum electrodynamics
appear for any measurable energy scale. The QED energy dependence of
the fine structure constant is reproduced. (Manuscript 3, April 2008,
and manuscript 4.)
* No deviations from thermodynamics appear for any measurable
energy scale. (Manuscripts 2 and 3, April 2008.)
* The universe's integrated luminosity is c^5/4G. (Manuscript 2,
April 2008.)
* If the cosmological constant is nonvanishing, it decreases with
time. (Manuscript 2, April 2008.)
* If the cosmological constant is nonvanishing, minimal electric
and magnetic fields, a minimum force and a minimum acceleration exist.
(Manuscript 2, March 2008.)
* The universe has trivial topology at all measurable energies.
(Manuscript 2, April 2008.)
* No singularities, wormholes, time-like loops, negative energy
regions, cosmic strings, cosmic domain walls, information loss,
torsion or MOND exist; inflation did not occur. (Manuscript 2, April
2008.)
* No deviations from special or general relativity appear for any
measurable energy scale. No doubly or deformed special relativity
arises in nature. (Manuscript 2, April 2008.)
* There are maximal electric and magnetic fields in nature.
(Manuscript 1, March 2008.)
* No deviations from electrodynamics appear for any measurable
energy scale. (Manuscript 1, March 2008.)
* The Planck values are the smallest measurable length and time
intervals, the Planck momentum and energy are the highest measurable
values for elementary particles. A maximum curvature exists and the
generalized indeterminacy principle holds. (As predicted by many.)
* The highest force and power values measurable locally in nature
are c^4/4G and c^5/4G. (Proved independently by Gary Gibbons, and
suggested by several others.)
* The smallest entropy in nature is given by k ln 2. (As stated by
many.)
* The quantum of action, hbar, is the smallest action value
measurable in nature. (As stated by Niels Bohr.)
* The speed of light, c, is the highest energy speed measurable
locally in nature. (As stated by Hendrik Lorentz, Albert Einstein and
others.)
Phillip Helbig---undress to reply
<a5bc6bcf-36cf-4c1c...@p28g2000vbi.googlegroups.com>,
Hans-Peter Schmidt <hanspeter...@googlemail.com> writes:
> > How about giving us details on one or two definitive predictions,
> > which are:
> >
> > Feasible
> > Prior to the tests
> > Unique to the theory being tested
> > Quantitative
> > NON-ADJUSTABLE
> Copy-paste from http://www.motionmountain.net/research/index.html
>
> Some predictions of the model (with their timing), made before
> conclusive experiments (at the LHC, on neutrinos, on electric dipole
> moments, about QCD, and in astrophysics):
>
> * No additional elementary particle will be discovered:
Many of the predictions are of this type. While not necessarily wrong,
they do not distinguish between theories. In other words, we don't know
if we haven't found the Higgs because it doesn't exist or because we
haven't found it yet. So, predictions that essentially say that we
won't discover anything new in a certain area are not very useful (even
though they might be true). Yes, they are falsifiable in that if we
discover something which this theory says we won't, then the theory is
falsified. However, if we don't discover them, then we aren't any
better off than we are now. Better would be a prediction such that we
could discover something which another theory doesn't predict or,
better, predicts that we won't discover. While this could serve to
falsify the standard theory, rather than the one above (of course, if
the discovery is made, our confidence in the theory above would be
strengthened), it is probably more important to go out on a limb with a
new theory and make predictions which could in principle falsify the new
theory.
In other words, "Unique to the theory being tested" is probably not true
of such predictions, since saying that we won't discover anything new in
a certain area is a conceivable prediction of many theories.
andyeverett
wrote:
>
> How about giving us details on one or two definitive predictions,
> which are:
>
> Feasible
> Prior to the tests
> Unique to the theory being tested
> Quantitative
> NON-ADJUSTABLE
>
> Thanks,
> RLOwww.amherst.edu/~rloldershaw
I was not clear, this is not my work, it is the work of Christoph
Schiller. If I understood this idea better I might be able to address
your concerns. I find this idea intriguing and though others might as
well, requires more study on my part.
Thanks.
X-Phy
This posting is borderline of being unscientific since it contains unjustified
claims. I've let it through since I think we could have an interesting discussion
on the foundation and empirical status of the Standard Model of elementary particles
which is of unprecedented precision in description of the world data and it's
a very timely discussion since the LHC has its first beam (at injector energy)
since the big crash last year, and we all hope that the first run with half the
design CM energy of 7 TeV will happen in January 2010!
On 24 nov, 10:25, hel...@astro.multiCLOTHESvax.de (Phillip Helbig---
undress to reply) wrote:
> In other words, "Unique to the theory being tested" is probably not true
> of such predictions, since saying that we won't discover anything new in
> a certain area is a conceivable prediction of many theories.
In other words, the standard theory isn't falsifyable since it
predicts new particles. If the Higgs isn't observed at the energy it
should be, some ingenious man will say we don't renormalize properly,
or any other convoluted calculational argument, and will predict a
higher energy. That already happened a few times.
Phillip Helbig---undress to reply
> > of such predictions, since saying that we won't discover anything new in
> > a certain area is a conceivable prediction of many theories.
>
> In other words, the standard theory isn't falsifyable since it
> predicts new particles.
We can't falsify it by not discovering them, true, unless they are
firmly predicted at a certain energy or whatever. One the other hand,
if they are discovered, the confidence in the theory will increase.
> If the Higgs isn't observed at the energy it
> should be, some ingenious man will say we don't renormalize properly,
> or any other convoluted calculational argument, and will predict a
> higher energy. That already happened a few times.
Something similar happened with proton half-lives. Each failed
prediction which is "saved" by some epicycle decreases faith in the
theory, of course.
Of course, it can happen that experimental data are so good that so much
parameter space is ruled out that no fudge factor can compensate, and
the only way out is to accept new physics. This happened with neutrino
oscillations after other ideas (wrong solar models, problems with
neutrino detectors) were ruled out. It should be noted that this led to
an extension of the standard model, not to throwing it out completely
like, say, the ptolemaic system or the idea of phlogiston was thrown
out.
Gordon Stangler
<hanspeter.f.schm...@googlemail.com> wrote:
> On 22 Nov., 08:51, "Robert L. Oldershaw" <rlolders...@amherst.edu>
> Copy-paste fromhttp://www.motionmountain.net/research/index.html
Hans,
The problem with the motion mountain ideas, is that knots only exist
in three dimensions. My understanding of string theory is that it
strictly requires more than the four dimensions of spacetime. Thus,
the idea of knotted strings falls apart, and everything that rests on
knotted strings does too.
Admittedly, neither string theory nor knot theory are familiar to me,
I just remember that unique little tidbit of info.
======== Moderator's note ================================
I shortened the full quote somewhat.
Dirk Bruere at NeoPax
> On 22 Nov., 08:51, "Robert L. Oldershaw" <rlolders...@amherst.edu>
> wrote:
>> On Nov 21, 6:23 am, andyeverett <andyeveret...@gmail.com> wrote:
>>
>>> The model is unique, is unmodifiable, is consistent with all known
>>> data, and makes numerous testable predictions, including the absence
>>> of other interactions, of grand unification and of higher dimensions.
>>> A method for calculating coupling constants seems to appear
>>> naturally. "
>> How about giving us details on one or two definitive predictions,
>> which are:
>>
>> Feasible
>> Prior to the tests
>> Unique to the theory being tested
>> Quantitative
>> NON-ADJUSTABLE
>>
>> Thanks,
>> RLOwww.amherst.edu/~rloldershaw
>
> Copy-paste from http://www.motionmountain.net/research/index.html
>
> Some predictions of the model (with their timing), made before
> conclusive experiments (at the LHC, on neutrinos, on electric dipole
> moments, about QCD, and in astrophysics):
What it seems to imply is the end of experimental physics.
Am I mistaken?
[[Mod. note -- I do believe that there are other areas of experimental
physics besides elementary-particle physics.
-- jt]]
--
Dirk
http://www.transcendence.me.uk/ - Transcendence UK
http://www.theconsensus.org/ - A UK political party
http://www.blogtalkradio.com/onetribe - Occult Talk Show
Robert L. Oldershaw
<hanspeter.f.schm...@googlemail.com> wrote:
>
I repeat my request:
How about giving us details on one or two definitive predictions,
which are:
Feasible
Prior to the tests
Unique to the theory being tested
Quantitative
NON-ADJUSTABLE
--------------------------------------------------------------------------------
I am asking for the ONE or TWO best and most definitive predictions.
I do not have months to wade through the pile of material you posted.
Cut to the chase, man!
RLO
www.amherst.edu/~rloldershaw
[[Mod. note -- If I may add to this poster's request:
How about a prediction for the neutrino mixing angle theta_13?
Fermilab and K2K are both gearing up to measure it in the next
few years...
-- jt]]
X-Phy
> This posting is borderline of being unscientific since it contains
> unjustified claims. I've let it through since I think we could have an
> interesting discussion on the foundation and empirical status of the
> Standard Model of elementary particles which is of unprecedented
> precision in description of the world data and it's a very timely
> discussion since the LHC has its first beam (at injector energy) since
> the big crash last year, and we all hope that the first run with half
> the design CM energy of 7 TeV will happen in January 2010!
Dear moderator, I'm afraid we are getting a bit religious here. Of
course the standard model is a success, of course many predictions
have been verifyed, and of course it is falsifyable. But it isn't
falsifyable in that it predicts new particles, I was making my point a
bit mischievously. Now, it isn't an unjustified claim that
historically, once the Higgs was not seen some physicist raised the
Higgs mass. What would be a really unjustified claim is that the
Higgs exists. The Higgs is predicted for more than 25 years, and for
25 years it hasn't been seen. So for more and more people that means
it doesn't exist, and some are at work to find a theory beyond the
standard model, that anyway isn't fully satisfying (too many arbitrary
parameter etc.) Now, wait and see, but don't anticipate.
FrediFizzx
news:e3362796-c12c-4ece...@p32g2000vbi.googlegroups.com...
A better idea is to read the Vol. 6 book at,
http://www.motionmountain.net/research/index.html
Very comprehensive and mostly complete as a unification concept. A must
read for all those interested in fundamental physics.
> This idea appears to only work in three dimensions. Should string
> theorists be looking for a new job?
:-) It only _needs_ three dimensions and one of time to work. If SUSY
is found at LHC or even hints of SUSY show up, then the strand idea is
probably dead unless those knots and tangles can make higher mass
particles but doesn't look like it can elementary-wise. That is one of
the things that bugs me about it is that of the high energy desert. I
was always leaning towards a Randall-Sundrum type of concept only with
intersecting 3-branes.
Best,
Fred Diether
moderator sci.physics.foundations
Hans-Peter Schmidt
> "andyeverett" <andyeveret...@gmail.com> wrote in message
>
> http://www.motionmountain.net/research/index.html
>
> Very comprehensive and mostly complete as a unification concept. �A must
> read for all those interested in fundamental physics.
>
> > This idea appears to only work in three dimensions. Should string
> > theorists be looking for a new job?
>
> :-) �It only _needs_ three dimensions and one of time to work. �If SUSY
> is found at LHC or even hints of SUSY show up, then the strand idea is
> probably dead unless those knots and tangles can make higher mass
> particles but doesn't look like it can elementary-wise. �That is one of
> the things that bugs me about it is that of the high energy desert. �I
> was always leaning towards a Randall-Sundrum type of concept only with
> intersecting 3-branes.
>
> Best,
>
> Fred Diether
> moderator �sci.physics.foundations
I just found out that Christoph is answering questions on his model
at http://www.physicsforums.com/showthread.php?t=318155
and at
http://www.physicsforums.com/showthread.php?t=356491
Both threads are about his model. (I hope these links are
ok with the moderators.)
I hope he will give more details on how to calculate the
fine structure constant, which should be the definite
check of all this.
Gordon Stangler
>
> [[Mod. note -- If I may add to this poster's request:
> How about a prediction for the neutrino mixing angle theta_13?
> Fermilab and K2K are both gearing up to measure it in the next
> few years...
> -- jt]]
Moderator, do you mean the Tokai-to-Kamioka neutrino experiment
overviewed <a href="http://aitj-co.com/gcsgz5/blog/?p=608">here</a>?
eric gisse
[...]
> * No additional elementary particle will be discovered: the Higgs
> boson does not exist. The unitarity of scattering for longitudinal W
> and Z bosons is maintained at all energies. (On website and 6th
> volume, August 2009.)
[...]
> * Dark matter is compatible with the standard model. Dark matter
> detectors will not detect anything new. (Website, September 2008, and
> the 6th volume.)
Reconciling the previous two claims is going to take some fancy footwork.
[...]
> * If the cosmological constant is nonvanishing, it decreases with
> time. (Manuscript 2, April 2008.)
How this is reconciled with the accelerated expansion of the universe is
going to be interesting.
[...]
> * No singularities, wormholes, time-like loops, negative energy
> regions, cosmic strings, cosmic domain walls, information loss,
> torsion or MOND exist; inflation did not occur. (Manuscript 2, April
> 2008.)
I wonder what the implications for black holes are under this construct.
Especially when you take the next block into account.
> * No deviations from special or general relativity appear for any
> measurable energy scale. No doubly or deformed special relativity
> arises in nature. (Manuscript 2, April 2008.)
[...]
> * The smallest entropy in nature is given by k ln 2. (As stated by
> many.)
> * The quantum of action, hbar, is the smallest action value
> measurable in nature. (As stated by Niels Bohr.)
> * The speed of light, c, is the highest energy speed measurable
> locally in nature. (As stated by Hendrik Lorentz, Albert Einstein and
> others.)
Consistency with previous works is always nice.
Jonathan Thornburg [remove -animal to reply]
| [[Mod. note -- If I may add to this poster's request:
| How about a prediction for the neutrino mixing angle theta_13?
| Fermilab and K2K are both gearing up to measure it in the next
| few years...
| -- jt]]
Gordon Stangler <gordon....@gmail.com> asked
> Moderator, do you mean the Tokai-to-Kamioka neutrino experiment
> overviewed <a href="http://aitj-co.com/gcsgz5/blog/?p=608">here</a>?
Yes. "K2K" was a brain glitch on my part; the new experiment is T2K.
There's a bit more information about T2K at
http://en.wikipedia.org/wiki/T2K
and at
http://jnusrv01.kek.jp/public/t2k/
--
-- "Jonathan Thornburg [remove -animal to reply]" <jth...@astro.indiana-zebra.edu>
Dept of Astronomy, Indiana University, Bloomington, Indiana, USA
"The view of the bankers is that the financial crisis did not stem from
the fact that the banks made lots of bad loans and invested in dubious
securities; it was caused by accounting rules that required disclosure
when the losses began to mount." -- Floyd Norris
Phillip Helbig---undress to reply
<3e988b94-e2be-4207...@p19g2000vbq.googlegroups.com>,
X-Phy <xphys...@gmail.com> writes:
> Now, it isn't an unjustified claim that
> historically, once the Higgs was not seen some physicist raised the
> Higgs mass. What would be a really unjustified claim is that the
> Higgs exists. The Higgs is predicted for more than 25 years, and for
> 25 years it hasn't been seen.
Keep in mind that the neutrino was first detected a couple of decades
after it was first theoretically postulated. Isaac Newton mentioned the
bending of light by gravitation, and it took over 200 years before that
was observed.
JohnMS
<jth...@astro.indiana-zebra.edu> wrote:
> In a moderator's note earlier in this thread, I wrote
> | [[Mod. note -- If I may add to this poster's request:
> | How about a prediction for the neutrino mixing angle theta_13?
> | Fermilab and K2K are both gearing up to measure it in the next
> | few years...
> | -- jt]]
>
>
> > Moderator, do you mean the Tokai-to-Kamioka neutrino experiment
> > overviewed <a href="http://aitj-co.com/gcsgz5/blog/?p=608">here</a>?
>
> Yes. "K2K" was a brain glitch on my part; the new experiment is T2K.
> There's a bit more information about T2K at
> http://en.wikipedia.org/wiki/T2K
> and at
> http://jnusrv01.kek.jp/public/t2k/
I see that Schiller writes about neutrino mixing on pages 280 to 281
of http://www.motionmountain.net/research/index.html .
He predicts neutrino mixing from the model,
and he states that knot calculations can determine
the numbers. Hm...
John
Chalky
<hanspeter.f.schm...@googlemail.com> wrote:
> * If the cosmological constant is nonvanishing, it decreases with
> time. (Manuscript 2, April 2008.)
Then why is it called "constant" within the context of GR.
> * No deviations from special or general relativity appear for any
> measurable energy scale.
Your above two statements contradict each other.
Disregarding the above criticism, if your later statement is correct,
why is the best GR fit to Sn1a data a closed dark energy model,
whereas the best GR fit to WMAP data is a flat dark energy model?
Phillip Helbig---undress to reply
<2dc773dc-5a1f-413c...@j14g2000yqm.googlegroups.com>,
Chalky <chalk...@bleachboys.co.uk> writes:
> On Nov 24, 8:57 am, Hans-Peter Schmidt
> <hanspeter.f.schm...@googlemail.com> wrote:
>
> > * If the cosmological constant is nonvanishing, it decreases with
> > time. (Manuscript 2, April 2008.)
>
> Then why is it called "constant" within the context of GR.
The cosmological constant is, as you point out, called a constant
because its value doesn't change with time. Since the density of matter
(and radiation (even faster) drops with time, and the cosmological
constant is, errmm, constant, the cosmological constant becomes more and
more important as time goes on.
People have now started investigating generalisations of the idea of a
cosmological constant, in particular time-dependent ones. While it is
somewhat confusing to speak of a time-varying cosmological constant,
calling it something else (such as "dark energy") really doesn't
increase one's understanding either. The contradictory name at least
points out that it is basically the same as the traditional cosmological
constant, but time-dependent.
Of course, merely the fact that it is constant in GR doesn't mean that
it must be constant in reality. As you point out below, a
time-dependent cosmological constant would require some new physics.
I think it is worth looking for, i.e. see if some generalisation fits
the data better than the traditional cosmological constant. (15 years
ago, I urged people not to assume that the cosmological constant is
zero, which many people did.) One can't measure any deviation from the
standard theory if one doesn't see if such a variation fits the data
better than the standard model. As Yogi Berra said, one can see a lot
by looking. However, up until now, those who have looked at more
complicated forms of the cosmological "constant" find that the traditional
really constant cosmological constant gives the best fit to the data.
> > * No deviations from special or general relativity appear for any
> > measurable energy scale.
>
> Your above two statements contradict each other.
Yes, if a time-varying cosmological constant is deemed to go beyond GR.
> Disregarding the above criticism, if your later statement is correct,
> why is the best GR fit to Sn1a data a closed dark energy model,
> whereas the best GR fit to WMAP data is a flat dark energy model?
If I have several observations and express the results in some parameter
space (say Omega and lambda, the density parameter and cosmological
constant, respectively), then almost always the best-fit values will NOT
be the same. The interesting question is whether they are compatible.
One way of looking at this is to see if the best-fit values of one model
are within a certain confidence range (say, 2 or 3 sigma) of those of
the other model. If so, then no problem. There is for this reason no
contradiction in your example.
With regard to your particular example, the direction of strongest
sensitivity in the lambda-Omega plane for the two observations you
mention are almost orthogonal. This is good, since it means that
combining them gives much better constraints than either observation
alone. However, it also means it is not surprising that the best-fit
values are different, since the goodness of fit remains relatively
constant if one moves in a certain direction in the lambda-Omega plane.
(Note on terminology: The Hubble Constant is in general NOT constant in
time. However, it is called the Hubble Constant since it is the
proportionality constant in a linear relationship. At a given moment of
cosmic time, it is constant at every location in the universe, but in
general it changes its value with cosmic time. Another potential source
of confusion is that one usually doesn't work with the density and
cosmological constant directly, but rather defines Omega and lambda
(lower case) as "observable" quantities. These contain the Hubble
constant (basically, since many things are known modulo H) and thus vary
in time since H varies in time (in the case of Omega, additionally
because the density varies with time).)
Chalky
undress to reply) wrote:
> If I have several observations and express the results in some parameter
> space (say Omega and lambda, the density parameter and cosmological
> constant, respectively), then almost always the best-fit values will NOT
> be the same. �The interesting question is whether they are compatible. �
> One way of looking at this is to see if the best-fit values of one model
> are within a certain confidence range (say, 2 or 3 sigma) of those of
> the other model. �If so, then no problem. �
You would have a point if, within that parameter space, both sets of
observations resulted in comparably sized standard deviations which
could then be combined to span that gap. However, iirc this is not the
case here. Consideration of a 2 or even 3 sigma spread in the WMAP
data makes no difference to the fact that its projected implications
still intersect the Sn1a data space between its 2 and 3 sigma
boundaries.
As you know, a 2 standard deviation uncertainty spread has unambiguous
statistical and probabilistic meaning. It means that if the
theoretical model is correct, there is less than one chance in 20 that
the data will lie further away than this.
The graphs to which you refer thus appears to confirm, on the basis of
statistical analysis of observational evidence, that the theory is
inaccurate to a level of confidence of somewhere between 95% and
99.5%. Or, if you prefer it the other way round, the probability that
the theory is accurate is currently better than one chance in 200, but
significantly worse than one chance in 20.
Chalky
> <2dc773dc-5a1f-413c-ab3e-bf717d399...@j14g2000yqm.googlegroups.com>,
> The cosmological constant is, as you point out, called a constant
> because its value doesn't change with time. �Since the density of matter
> (and radiation (even faster) drops with time, and the cosmological
> constant is, errmm, constant, the cosmological constant becomes more and
> more important as time goes on.
Quite. However, given the assertion of the OP that it decreases with
time (which I have no conceptual problems with, a priori) it would be
interesting to discover what he actually means by this, in terms of
observable dynamics. I.E.
1) it becomes less important with increasing time
2) it becomes more important, but more slowly than classically
predicted
3) on balance, its importance does not change with time, at all.
It would be particularly interesting to discover what the implications
of 1,2 and 3 might be for BBN
> People have now started investigating generalisations of the idea of a
> cosmological constant, in particular time-dependent ones. �
Quite so. However, since these (outside of the frame of reference of
the OP), appear to be attempts to retrofit-adjust classical theory to
better match observation, via a further increase in the number of free
parameters, one might be justified in concluding that these are merely
heroic (and, thus far, unsuccessful) attempts to verify, by analogy,
Von Neumann's assertion that, with 4 free parameters he could make an
elephant, and with 5, he could make it wave its trunk.
Phillip Helbig---undress to reply
<583eb683-04e4-463d...@s31g2000yqs.googlegroups.com>,
Chalky <chalk...@bleachboys.co.uk> writes:
> > The cosmological constant is, as you point out, called a constant
> > because its value doesn't change with time. ?Since the density of matter
> > (and radiation (even faster) drops with time, and the cosmological
> > constant is, errmm, constant, the cosmological constant becomes more and
> > more important as time goes on.
>
> Quite. However, given the assertion of the OP that it decreases with
> time (which I have no conceptual problems with, a priori) it would be
> interesting to discover what he actually means by this, in terms of
> observable dynamics. I.E.
> 1) it becomes less important with increasing time
> 2) it becomes more important, but more slowly than classically
> predicted
> 3) on balance, its importance does not change with time, at all.
Obviously, this depends on the exact way in which it decreases with
time. A prediction for a decreasing cosmological constant which is then
confirmed would be quite interesting in its own right, regardless of the
details.
> It would be particularly interesting to discover what the implications
> of 1,2 and 3 might be for BBN
Probably none at all. At that time, the scale factor is so small that
the value of the cosmological constant plays essentially no role.
> > People have now started investigating generalisations of the idea of a
> > cosmological constant, in particular time-dependent ones. ?
>
> Quite so. However, since these (outside of the frame of reference of
> the OP), appear to be attempts to retrofit-adjust classical theory to
> better match observation, via a further increase in the number of free
> parameters, one might be justified in concluding that these are merely
> heroic (and, thus far, unsuccessful) attempts to verify, by analogy,
> Von Neumann's assertion that, with 4 free parameters he could make an
> elephant, and with 5, he could make it wave its trunk.
These attempts are not motivated by trying to fit observations, since
observations are best fit by a traditional cosmological constant.
However, it is always good to look whether an additional parameter gives
a better fit. There is a trade off, of course. This was discussed in
the context of cosmological parameters in a paper by Andrew Liddle; the
paper is worth looking up.
Nicolaas Vroom
schreef in bericht news:heque7$poe$1...@online.de...
> (Note on terminology: The Hubble Constant is in general NOT constant in
> time. However, it is called the Hubble Constant since it is the
> proportionality constant in a linear relationship. At a given moment of
> cosmic time, it is constant at every location in the universe, but in
> general it changes its value with cosmic time. Another potential source
> of confusion is that one usually doesn't work with the density and
> cosmological constant directly, but rather defines Omega and lambda
> (lower case) as "observable" quantities. These contain the Hubble
> constant (basically, since many things are known modulo H) and thus vary
> in time since H varies in time (in the case of Omega, additionally
> because the density varies with time).)
Hubble's Law describes the relation between redshift and distance.
The distance being the length of the straight distance that light has
travelled going from the point of emission in the past to the observer
at present.
The redshift being a frequency shift a measured by the observer
at present.
The question is: what is this relation?
The redshift as measured by the Observer is first of all a function
of the difference between the relative speed of the source
and the observer (at present). The source being the speed of
the Galaxy in the past at the point of emission.
For Galaxies very close to us like Andromeda Galaxy the redshift
is almost fot 90 % explained by this difference in speed.
For Galaxy NGC 4258 this influence is also large.
We assume an expanding Universe or space expansion.
The result is that Galaxies in the early universe had a high speed
relative to the present situation, which partly explains
the present measured value of z. (maybe for 10%).
If that last number is correct than 90% for those galaxies
is explained by space expansion.
The question is that space expansion linear with distance ?
IMO it is easy to assume No. With the assumption that space
expansion in the past close to the source was much larger
as at present close to the observer.
The problem is you need independent distance measurements
for far away distances to find the requested relation.
Those measurements are difficult and only possible
relative close to us. This makes any distance prediction
for high values of z very unreliable
For more information:
http://arxiv.org/abs/0811.4345
For more information by the author:
http://users.telenet.be/nicvroom/Hubble-Faq.htm
Nicolaas Vroom
Phillip Helbig---undress to reply
<nicolaa...@pandora.be> writes:
> Hubble's Law describes the relation between redshift and distance.
I replied in detail to a similar question in sci.astro.research. Please
do not post the same message (or very similar messages) to more than one
newsgroup. If you want it to appear in both newsgroups, put both
newsgroups (separated by a comma with no space) in the Newsgroups:
header.
My reply can be read here.
http://groups.google.
de/group/sci.astro.research/msg/012848a891c0aaab?hl=de&dmode=source
I suggest that replies to this message, if there are any, quote from the
sci.astro.research posting linked to above and be cross-posted (see
above for how to do it) to both groups.