Re: MOND

On Mar 20, 8:42 am, "Eric Gisse" <jowr...@xxxxxxxxx> wrote:
On Mar 19, 12:56 am, anands...@xxxxxxxxx wrote:



On Mar 17, 9:05 pm, "Juan R." <juanrgonzal...@xxxxxxxxxxxxxxxxxxxx>
wrote:

On Mar 17, 5:35 am, anands...@xxxxxxxxx wrote:

On Mar 10, 11:28 pm, "Juan R." <juanrgonzal...@xxxxxxxxxxxxxxxxxxxx>
wrote:


It is not off-topic, if the question was "is there an interaction
which increases with distance", because there is an interaction.
It doesn't matter if it is microscopic or macroscopic. After all
microscopic does affect the macro world. And we know that the
microscopic makes up the world.

I should have been more clear. I knew about quark confinement, I just
expected a shade more thought to be given to the subject than was
actually given.

"microscopic" is still a half dozen orders of magnitude too large for
the strong force interactions. Strong force interactions are of the
femtometer range - and DO NOT EXIST outside it because the strong
force mediating particle [whatever the *** it is] is massive.

What I *meant* was name one verified macroscopic interaction which
_increases_ with distance with emphasis on both _verified_ and
_macroscopic_.


But when there are only four known interactions, if even one of them
increases with distance, why would you want to neglect that.
Also QED (the Electro Magnetic interaction) also has a weird
interaction, called entanglement that does weird things even at a
huge distance, and instantly without coming into conflict with
superluminal expectations. I guess that is very macroscopic, and
it very much conflicts with GR. But you can chose to ignore that,
saying that some GR expectations like causality are not broken.

I know that you actually mean only the gravitational interaction,
but in my opinion GR is already broken. I think the accelerated
expansion of the universe is due to repulsive force of gravitation,
and that will have to occur only if it increases with gravity. Its
all speculation, but you know that we don't have the quantum theory
of gravity.



[ii] My personal experience replying EricGisseposts recommended
avoiding advanced topics. I doubt he has studied QCD.

I wouldn't know about that. But when we are talking about the failures
of GR, then Quantum Theory definitely comes into the picture because
it is GR's biggest failure. Some may say that it is QCD's failure but
I doubt many will see it that way. It is definite that GR will be
found in the limit of a Quantum Theory of Gravity, rather than
QCD to be found in the limit of GR ;-).

I think it is premature to worry about GR being the limiting case of
anything because we haven't truly found it to be failing. I know your
position on dark matter and you know mine. That aside, it must break
down _somewhere_ but we haven't actually seen it happen yet.


GR has broken down and miserably. But you are turning a blind eye
to it. MOND is the indicator. You chose to ignore MOND because you
cannot explain it. If you could you would have done so. But it is a
fact that GR+DM cannot explain MOND LAW. It is not possible to
explain such a tight correlation between the Mass Discrepancies and
the observed accelerations. If you have a theory you can do so.
Nobody has done that till now. And nobody who has measured the
closeness of the correlation will believe that it can be done.

You will again say that I am ignoring weak lensing. But I will say
what's so different about weak lensing, it also shows Mass
Discrepancy which is also an indication that GR has broken down, we
are again seeing Mass Discrepancies. Then you will say WMAP, again
the same Mass Discrepancy. Of course all these mean that there is
something wrong with GR, but you think that you are seeing different
confirmation of Dark Matter while the reason for all the
Mass Discrepancy, is the same. GR does not work in weak gravity
regimes.

To you it doesn't matter that the Mass Discrepancy is increasing
with the scale. At the Galaxy level it depends on the size and
density (basically the weakness of gravity), at the cluster level
it is 10 times. At the Cosmic level it is 100 times. But you will
see all these similar failings as confirmation of Dark Matter.

You will also ignore the only thing that can open your mind.
Because it is so much more easy to live with the status quo.
You don't want to face the possibility that we don't know any
theory that can account for weak gravity regimes. This is
actually a great time for theoretical physicists to try and
find the correct theory, and quite a few are working towards
them, and I am not talking about crackpots. Search for papers
on TeVeS, Conformal Loop Quantum Gravity, AdS/CFT gravity.
But it is a difficult thing to do, you have to be great at
mathematics. These theories are much more difficult to work
with mathematically than GR.

Why don't you study MOND results. The MOND people cannot be
pulling numbers out of thin air. You can test them out. You can
try to make a model of DM that will fit MOND. But you won't do
that, you will simply ignore all the evidence, because that's
the easy thing to do.



So we start with the statement that GR is true in a limit of a
Quantum Theory of Gravity, which means that GR is not the true
picture. So I don't know why Relativists find it so difficult to
come to terms with the fact thatMONDworks and proves that the
Limit of GR is a few kilo parsecs. Although Pioneer may mean that
something is wrong there too. But Pioneer seems to be a fluke
rather than an indication of something wrong.

My money is on outgassing and/or asymmetric RTG heat reflection.

MONDworking, for suitable definitions of working, does not prove
anything other thanMONDis a halfway decent model under certain
conditions.

I beg to differ here. MOND is not a "halfway decent model", as a
model it is pathetic. It is simply a law, just like Kepler's
Laws, that for some underlying reason works well on the galaxy
scales. We need somebody like Newton or Einstein to explain MOND,
just like Newton explained Kepler's laws and Einstein explained
precession of Mercury. I guess they had it easier, because there
was no scientific establishment to fight with.

http://www.astro.umd.edu/~ssm/mond/daverussellletter.html
The above is a letter that gives 8 reasons why CDM should be
considered falsified within Galaxy limits.

The above also links to an interesting paper. In the initial
version, it concluded that DM+GR cannot explain the correlation.
But by the time it got published the conclusion had changed a
lot. I guess the referee convinced them of the utility of not
ignoring DM in any case ;-). This is a case where the
establishment does prevent publishing of unbiased papers.

http://www.citebase.org/abstract?id=oai%3AarXiv.org%3Aastro-ph%2F0403206
(Cores of Dark Matter Halos Correlate with Disk Scale Lengths)

I don't know what you mean exactly by "suitable definitions of
working", but MOND works very well without any exceptions on the
scale of galaxies. In 80% of galaxies it gives very good fits,
for the rest of the 20%, it is known that there are problems with
the data. And the important thing is that it cannot fit those 20%,
as would be expected for a theory with no free parameters, a0 is
no longer free. Another important thing is that DM models can fit
those 20% cases also to the same degree of accuracy as the other
80%, because of the large number of free parameters.

The onus is on theoretical physicists to find the underlying reason.
Ignoring MOND does not help.

regards,
-anandsr

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