On Mar 20, 10:33 pm, "Ahmed Ouahi, Architect"
wrote:
One way or an other, you do have an infinite empty space, due to your own
emptiness, the reason, that you are an empty from upstairs, as along your
case, that is a simply what is all about.

Be quiet, spewing moron.


--
Ahmed Ouahi, Architect
Think About That!

"Eric Gisse" wrote in message

oups.com...

On Mar 20, 12:43 am, "Ahmed Ouahi, Architect"
wrote:
It would be this, that it could makes you to feel better, or the pain is
somewhere else!?

Quiet, top-posting nutter.

--
Ahmed Ouahi, Architect
Think About That!

"EricGisse" wrote in message

roups.com...

On Mar 20, 12:25 am, "Ahmed Ouahi, Architect"
wrote:

[...]

I think it is time to, once again, ask you why you even bother posting
on this newsgroup when you have no grasp of physics at any level.

Google ate my post. It seems that it happens when the message is
too big. Note to myself use an editor ;-).


On Mar 20, 1:34 pm, "Eric Gisse" wrote:
wrote:
Denying the weak lensing results is even more closed minded than me
disagreeing with what you thinkMONDmeans.

I never denied weak lensing results. I just said that if MOND can
explain the Mass Discrepency in Galaxies, it is not very difficult to
assume that a proper quantum theory will account for the Mass
Discrepency in weak lensing data also.

I also am not against Dark Matter. I just dislike Cold Dark Matter. In
my opinion Cold Dark Matter means that it is not moving much. And if
there are huge amounts of it, it will clump. If it clumps there will
be collisions. How does one detect these collisions, if they do not
couple electromagnetically.

Neutrinos avoid this problem by being hot, which prevents their
coupling together.

Till yesterday I used to think that MOND will fail in Clusters but now
I think that MOND should apply within any gravitationally bound
structure. So now I think MOND should survive the KATRIN test. And
Neutrino oscillation will be able to provide the missing mass. But it
may not be true, and there may be another neutrino like particle that
is also present.

The thing is that all the evidence for Dark Matter is just Mass
Discrepency. The only proper evidence we have found for Dark Matter
is in Bullet Cluster and the dark galaxies. Both of these can be
explained currently by massive and fast Neutrinos. If neutrinos have
mass then they can make stable structures of Cluster sizes, given
MONDian force.


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.

Start paring the list down.

Of these, how many of them make testable predictions? No, I don't mean
"soon", I mean "right here link to paper".

All of them.

It is only DM that does not make testable prediction. Others can be
falsified. Mannheim's Conformal Gravity has already been falsified by
Bullet Cluster. But now I know what was wrong with it. He was using
dS/CFT instead of AdS/CFT. Now M.B.Paranjape and A.Edery are taking
that work forward, using AdS/CFT. But the work must now be done from
the beginning.

We also have LQG. I don't think that you believe that they are not
trying to make any testable predictions. It is the only viable Quantum
Gravity Theory. I don't consider String Theory at all. LQG till now
had been using GR. Which is not working very well. The main problem
is that Quantum theories are fundamentally at odds with any sort of
scale. There are a couple of LQG researchers that are moving towards
using Conformal Invariance instead of Lorentz Invariance. I am sure
something good will come out of it.

TeVeS is making testable predictions. I personally don't like TeVeS,
but it is not a bad idea. We may come up with a law for weak lensing
through it. This work is also needed for convincing GR proponents that
DM in Galaxies is redundant.


Of these, how many match _already verified_ predictions by general
relativity?

Conformal gravity matches GR very well in strong gravity. Nearly well
with MOND in the galaxies. Used to explain Cluster dynamics, but now
with the discovery of unambiguous proof of DM in Clusters will fail
there. And hence will be falsified.

MOND/TeVeS works well in strong gravity, as they are basically same as
GR. Works very well in Galaxies. Predicts HDM in Clusters, as required
by Bullet Cluster. Also is not against Dark Galaxies. It can be
falsified, but has not been falsified yet.

LQG is still in its infancy. Will have to wait for some testable
predictions. They have some explanation for the Ohmygod particles, but
I think little else.


Of the remaining, if any, match up with the area O' interest that is
the bullet cluster while removing the need for dark matter?

There is no need to remove Dark Matter in Bullet Cluster. It is an
unambiguous observation that Dark Matter exists in Bullet Cluster.
Also MOND has been predicting double the mass in most Clusters, which
should be the same Dark Matter which we see in Bullet Cluster. But
that doesn't mean that it has to be CDM, it could be HDM.


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.

Considering how hard it is to use GR without making a large series of
approximations, I can't help but wonder how many of these theories are
at the point where they can make useful predictions rather than
sweeping statements from toy models.

Just imagine how hard it will be using AdS/CFT for the calculations.
It is an Order Four theory, much more complex than the Order 2 GR. It
is possibly the biggest reason why we don't have a viable Quantum
Gravity theory yet.

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

Of course they aren't.

Keep in mind thatMONDoffers no explanation as to _why_ gravity is
being screwy, just that it _is_ screwy and that it _is_ a model of the
screwyness. There is no reason offered as to why dark matter can't
simply be modeled byMOND. It isn't as ifMONDis based off of bedrock
principles - it is an ad-hoc notion that fits the bill in certain
places.

MOND need not offer any explanation to be useful. It's main job is to
show that gravity is being screwy. The work is cut out for the
theoretical physicists to explain why it is screwy. But most are just
hoping that DM can explain anything. While even after 25 years there
is no model of DM that can explain MOND relationship.

I'm curious as to what the experiment described here will say.

http://physicsweb.org/articles/news/11/3/12/1

I don't know what they are trying to do. I think the person doesn't
know MOND. MOND will apply only when the total accelaration due to
gravity drops below a0. I don't know how on earth he found such a
place on earth. On earth acceleration due to gravity cannot go much
below or above g. Even earth can never expect gravity much less than
a0, unless it gets between Jupiter and Sun in such a way that both the
accelarations cancel exactly. Even then Moon will not let it fall
below a0.

The only place MOND can be tested is the L4 and L5 areas. In these
areas gravity due to Sun and Earth+Moon cancels exactly, so there must
be a smaller area within it where the total gravity falls below a0.
This area is called a Mondian bubble. And it is the nearest place
where MOND can be verified. The hope is that the bubble will be big
enough to accomodate a test machine ;-).

Do _NOT_ try to pull that "I'm fighting the establishment!" bull****
with me. The papers you cite are published in reputable journals.
Considering how _often_MONDis referred to in popular and technical
scientific articles,MONDis decidedly mainstream. The folks in here
who also cry about persecution have wet dreams about being given the
kind of attention thatMONDgets in the literature.

Sorry, will not do it again. It was an interesting comment in the
letter.

MONDis not a law.MONDis a model - it was designed as such, and
remains as such. The fact that it has any sort of success means
something - I think it means that it is keying in on the dark matter
distribution in galaxies at some level.

MOND is a law, it is only a single equation, just like Keplers laws
where. Or Newton's laws were. Mondian models are created to fit the
galaxy rotation curves. But these are not MOND. They are built over
MOND.

Think about the weak lensing results - where is most of the dark
matter? Out in the halo. Ignoring weak lensing - where does the dark
matter need to be to smooth out the velocities? Out in the halo. What
is the domain of application forMOND? Out...in the halo, where
gravity is thought to be "weaker".

I would think if most of the matter is out in a halo, the lens will
not be properly convex. It will be convex overall but near the center
there will be a concave circular portion. This will result in the
center part concentrating more light than a normal convex lens, so you
should see a brighter spot at the center of such a lens. Does any weak
lensing show this artifact.

Let me be clear - I accepted before and accept even more now thatMOND
is pointing to something important. What we seem to disagree on is
_what_ that important thing is.

Well now I can rejoice ;-). We have reached the most important part of
the discussion. You accept MOND effect as real.

Now consider the following points
1) MOND is real. This means that Dark Matter has no degrees of freedom
within a galaxy. This must be true because MOND can predict the
rotation curve based on normal matter alone, so if DM gives rise to
MOND, it cannot have any degrees of freedom. It must go where normal
matter tells it to.

2) We cannot be living in a special epoch, when DM matches MOND
everywhere. It must have been true for a very long time in the past.
And will
continue to do so for a very long time in the future.

3) Dark Matter cannot have been put by an intelligent agent to test
our faith ;-). It must have arisen based on some mechanism and using
the mechanisms of GR must have moved in such a way to always bring out
the MOND phenomenology.

4) If you see the 3 points above you see that DM in galaxies is
superfluous. It must satisfy too many features to be true, and top of
that it has no degrees of freedom, which makes it a superflous
concept. This is where Occam's Razor steps in to say that DM is not
simpler than MOND, and so must not be the true picture of the world.


2) Disk-Halo conspiracy

http://arxiv.org/PS_cache/astro-ph/pdf/9610/9610188.pdf[PDF is
slightly glitchy...]

One of the conclusions I thought was most intriguing was that the dark
matter halo shape under that model was something that was reasonably
constant.

It [disk halo conspiracy] is touched on indirectly as well by the
previous paper. Given there is an alternative explanation that is
entirely plausible, I don't see why folks are adopting the CDM
WROOOOOOOOONG stance. So far, it looks like the worst case is that the
CDM model needs tweaking - which doesn't surprise me, I do not believe
it was even geared as a model for scales so small.

What is your entirely plausible alternative explanation. I am dying to
know ;-).

What folks seem to be missing is that success ofMONDand success of
dark matter are not mutually contradictory goals.MONDseems to lend
itself fairly easily to a dark matter explanation, despite how angry
that probably makes theMONDcrew.

On the contrary, MOND is expected to make a lot of Relativists very
angry when they find that no DM model can work ;-).


The constant inclusion of the virial mass [200x universe critical
density] and the size associated with it amuses me for some odd
reason...I don't find anything wrong or objectionable, it just amuses
me.

I don't know what you mean exactly by "suitable definitions of
working", butMONDworks 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 number of free parameters isn't that big and you know it, if you
have actually been reading the papers you have been citing me.

Even 2 free parameters are too many when a competing theory can fit
the data without any free parameter. And most DM theories require 3 or
4 parameters. Remember that DM theories can fit the 20% cases where
the data is problematic. This indicates that the free parameters are
enough to fit any rotation curve even if they are not from a real
galaxy. This is what proves that there are too many parameters. Any
good model is one which is not able to work with bad data. DM models
are not good models.

The onus is on theoretical physicists to find the underlying reason.
IgnoringMONDdoes not help.

That much is now obvious.MONDis an excellent model for individual
galaxies, though I _suspect_ it fails for galaxies that are products
of or are in various stages of collision [eg, bullet cluster].

Keep in mind that nothing you have shown me or what I have found
conclusively, or even most likely, makes dark matter an incorrect
model. In fact, everything I have seen thus far either supports or
refines dark matter. Using theMONDfits along with the empirical data
gives some nice constraints on entirely plausible distributions of
dark mater where there were none before, which is quite useful.

I and possibly all of the MOND proponents are dying to know an
entirely plausible distribution of DM that can fit MOND.

Just remember that Occam's Razor is against you ;-).

regards,
-anandsr

On Mar 21, 8:37 am, "Eric Gisse" wrote:
[snip bs]

Eric Gisse is an idiot.

On Mar 20, 9:34 am, "Eric Gisse" wrote:
[snip]


Eric Gisse is an idiot.

wrote:
Google ate my post. It seems that it happens when the message is
too big. Note to myself use an editor ;-).


On Mar 20, 1:34 pm, "Eric Gisse" wrote:
wrote:
I'm curious as to what the experiment described here will say.

http://physicsweb.org/articles/news/11/3/12/1

I don't know what they are trying to do. I think the person doesn't
know MOND. MOND will apply only when the total accelaration due to
gravity drops below a0. I don't know how on earth he found such a
place on earth. On earth acceleration due to gravity cannot go much
below or above g. Even earth can never expect gravity much less than
a0, unless it gets between Jupiter and Sun in such a way that both the
accelarations cancel exactly. Even then Moon will not let it fall
below a0.

The only place MOND can be tested is the L4 and L5 areas. In these

This should be L1 point. Not L4 and L5. The forces don't cancel at
L4 and L5. They cancel at L1. Sorry for the mistake.

areas gravity due to Sun and Earth+Moon cancels exactly, so there must
be a smaller area within it where the total gravity falls below a0.
This area is called a Mondian bubble. And it is the nearest place
where MOND can be verified. The hope is that the bubble will be big
enough to accomodate a test machine ;-).


regards,
-anandsr

On Mar 19, 9:56 am, wrote:
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 that MOND works and proves that the
Limit of GR is a few kilo parsecs.

This may be replied by relativists but next my own judgment.

I suspect reason for strong rejection of MOND is that violates some
basic 'sacred' principles of GR. E.g. MOND breaks the equivalence
equivalence and maybe (I am not sure) introduces an absolute frame in
cosmology.

Your appeal to quantum gravity is very interesting. If I understand
you correctly, you think that relativists would accept MOND-like
corrections to GR somewhat like one wait quantum corrections to GR
(e.g. eliminating the concept of Black Hole and singularities). But
you are missing the point that relativists do not accept _any_ quantum
correction to GR; and this is related to why often they attack MOND
brutally.

Relativist community dislikes any theory (cosmology, particle,
galactic) violating they consider 'sacred' principles of GR. E.g. most
of relativists agree on the need for quantum corrections to GR, but
they dislike string theory. In fact, the relativist community promote
their own approach (saving the 'sacred' principles) to formulate a
quantum gravity: loop quantum gravity.

That belief on the 'sacred' principles is also the basis for the
rejection of alternative formulations and interpretations of GR as the
field one.

On Mar 20, 10:34 am, "Eric Gisse" wrote:

Personally I think MOND is indirectly mapping the actual dark matter
distribution. I have heard nothing that should dissuade me from that
notion.

MOND-like theories show us that dark matter distribution can be seen
like a ***mathematical*** artifact. Since rho_DM has only mathematical
sense DM does not need to be experimentally searched (it has never
appeared no matter how many time and effort devoted to search DM) and
no extension of SM of particle physicis is needed.

MOND is not a law. MOND is a model - it was designed as such, and
remains as such. The fact that it has any sort of success means
something - I think it means that it is keying in on the dark matter
distribution in galaxies at some level.

MOND is a law, not a model nor a theory.

Think about the weak lensing results - where is most of the dark
matter? Out in the halo. Ignoring weak lensing - where does the dark
matter need to be to smooth out the velocities? Out in the halo. What
is the domain of application for MOND? Out...in the halo, where
gravity is thought to be "weaker".

When R is larger the MOND law [1 / R] is stronger than [1 / R^2]. Why
do you claim gravity is weaker when is stronger?

What folks seem to be missing is that success of MOND and success of
dark matter are not mutually contradictory goals. MOND seems to lend
itself fairly easily to a dark matter explanation, despite how angry
that probably makes the MOND crew.

Fine, therefore a theory (MOND) claiming that DM does not exits is not
-for you-contradictory with a theory (GR+DM) claiming existence for
DM.

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

That much is now obvious. MOND is an excellent model for individual
galaxies, though I _suspect_ it fails for galaxies that are products
of or are in various stages of collision [eg, bullet cluster].

Pure GR fails for both galaxies and clusters.

GR+DM is not fine for galaxies and fails for bullet cluster unless
invoking now a unproven _ad hoc_ hypotesis about existence of a new
kind of interaction (NGI).

History: GR -- [GR + DM] -- [GR + DM + NGI] -- [GR + DM + NGI
+ ??]

How many unproven _ad hoc_ hypotesis will be needed before relativist
comunity begin to accept that GR is not so good like they believe?

On Mar 31, 3:56 am, "Juan R."
wrote:
On Mar 20, 10:34 am, "Eric Gisse" wrote:

Personally I think MOND is indirectly mapping the actual dark matter
distribution. I have heard nothing that should dissuade me from that
notion.

MOND-like theories show us that dark matter distribution can be seen
like a ***mathematical*** artifact. Since rho_DM has only mathematical
sense DM does not need to be experimentally searched (it has never
appeared no matter how many time and effort devoted to search DM) and
no extension of SM of particle physicis is needed.

Do you say things like this after carefully ignoring evidence that
disagrees with your interpretation?

If dark matter is an artifact, why is it that including dark matter
makes for such a good model of the large scale of the universe? How
about explaining _all_ of the weak lensing results of the past 5 years
or so that explicitly map out the distributions of dark matter?


MOND is not a law. MOND is a model - it was designed as such, and
remains as such. The fact that it has any sort of success means
something - I think it means that it is keying in on the dark matter
distribution in galaxies at some level.

MOND is a law, not a model nor a theory.

By what stretch of the imagination do you say that?

MOND _fails_ in the bullet cluster and it was invented as a _model_ to
explain rotation curves.


Think about the weak lensing results - where is most of the dark
matter? Out in the halo. Ignoring weak lensing - where does the dark
matter need to be to smooth out the velocities? Out in the halo. What
is the domain of application for MOND? Out...in the halo, where
gravity is thought to be "weaker".

When R is larger the MOND law [1 / R] is stronger than [1 / R^2]. Why
do you claim gravity is weaker when is stronger?

It might be a good idea to explain what the hell you are talking
about.


What folks seem to be missing is that success of MOND and success of
dark matter are not mutually contradictory goals. MOND seems to lend
itself fairly easily to a dark matter explanation, despite how angry
that probably makes the MOND crew.

Fine, therefore a theory (MOND) claiming that DM does not exits is not
-for you-contradictory with a theory (GR+DM) claiming existence for
DM.

MOND makes no such claim. The proponents of MOND make the claim - MOND
itself is simply a model. The proponents think that if MOND works,
there is no dark matter while ignoring the extremely likely
possibility that MOND is mapping out dark matter.


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

That much is now obvious. MOND is an excellent model for individual
galaxies, though I _suspect_ it fails for galaxies that are products
of or are in various stages of collision [eg, bullet cluster].

Pure GR fails for both galaxies and clusters.

GR+DM is not fine for galaxies and fails for bullet cluster unless
invoking now a unproven _ad hoc_ hypotesis about existence of a new
kind of interaction (NGI).

Go go gadget intellectual dishonesty.

You _KNOW_, assuming you actually read the paper, that the 'new kind
of interaction' is something that creeps in because the models they
picked can't quite explain how fast some parts of the bullet cluster
are moving by about 20%. That in no way means a 'new kind of
interaction' is necessary until a hell of a lot more research is done.


History: GR -- [GR + DM] -- [GR + DM + NGI] -- [GR + DM + NGI
+ ??]

How many unproven _ad hoc_ hypotesis will be needed before relativist
comunity begin to accept that GR is not so good like they believe?

How many unproven hypotheses [eg: new kinds of interaction] will you
latch on to? Every time someone comes up with an idea that contradicts
relativity - no matter how flimsy - you take it as the gospel truth.

Relativity has earned its' place in the scientific community. The very
tool that allows folks to probe the nature of dark matter -
gravitational lensing - is a relativity prediction.

wrote:
Google ate my post. It seems that it happens when the message is
too big. Note to myself use an editor ;-).

You should thank Juan R, he finally served a purpose. I had this reply
90% finished on my desktop, then forgot about it.



On Mar 20, 1:34 pm, "Eric Gisse" wrote:
wrote:
Denying the weak lensing results is even more closed minded than me
disagreeing with what you thinkMONDmeans.

I never denied weak lensing results. I just said that if MOND can
explain the Mass Discrepency in Galaxies, it is not very difficult to
assume that a proper quantum theory will account for the Mass
Discrepency in weak lensing data also.

So...shift the explanation of something that is unquestionably
observed and already has a well-understood explanation into the
indefinite future?

There is _no_ reason to doubt that our interpretation of the weak
lensing results is false. There is matter there and it curves light
and we detect it. That is remarkably direct compared to other
cosmological observations that are *heavily* model-dependent.


I also am not against Dark Matter. I just dislike Cold Dark Matter. In
my opinion Cold Dark Matter means that it is not moving much. And if
there are huge amounts of it, it will clump. If it clumps there will
be collisions. How does one detect these collisions, if they do not
couple electromagnetically.

Lensing.

Old in theory, new in implementation. I was just reading an article
about this earlier today - it has been postulated for years but has
been insanely difficult to apply because essentially what is being
measured is the degree of correlation between how elliptic galaxies
are over an area. Being able to reliably apply this to a required
patch of the sky was unable to be performed until the deployment of
CCDs in astronomy, and the measurements themselves have only been done
within the last 5 years or so.

There has already been an article published that gave an upper bound
on the mass of the clumps in a certain galaxy [I believe I gave you
the link before, actually] that was on the order of an Earth mass.
That result also neatly ruled out things like failed/dwarf stars,
large planets, and any class of black hole other than primordial. At
least in that one specific area - sample size of one and all.


Neutrinos avoid this problem by being hot, which prevents their
coupling together.

Neutrinos avoid the problem by having an insanely small scattering
cross section and by traveling within epsilon of light speed for
pretty much any plausible amount of energy. They avoid the problem so
well that they are horrible dark matter candidates - not enough of
them can be produced, and they are not capable of binding to galaxies
considering how fast they would be traveling. Neutrino dark matter
would form a background, not a halo.


Till yesterday I used to think that MOND will fail in Clusters but now
I think that MOND should apply within any gravitationally bound
structure. So now I think MOND should survive the KATRIN test. And
Neutrino oscillation will be able to provide the missing mass. But it
may not be true, and there may be another neutrino like particle that
is also present.

KATRIN isn't and never will be a test of MOND. Neutrino oscillations
simply shift the flavors around - they do not add mass. Neutrino mass
is constrained to be very tiny, and if the L-CDM model is even close
to being reasonable the total masses of all neutrinos is less than an
eV.

At any rate, a new type of neutrino is pretty much excluded by both
model [Standard / L-CDM], and a large body observation. Current fits
to the WMAP data only work for 3 neutrinos [this is discussed in the
implications for cosmology paper which I have linked to you before]
and Earth-based observations place the count at 3 as well.

http://pdg.lbl.gov/2006/reviews/lightnu_s007.pdf


The thing is that all the evidence for Dark Matter is just Mass
Discrepency. The only proper evidence we have found for Dark Matter
is in Bullet Cluster and the dark galaxies. Both of these can be
explained currently by massive and fast Neutrinos. If neutrinos have
mass then they can make stable structures of Cluster sizes, given
MONDian force.

No! Neutrinos _can not do it_!

Look back at that paper I linked to you the other day - remember how
everything was consistent with a HALO of dark matter? There are simply
not enough neutrinos and the ones whizzing around simply have too much
energy to be bound.

http://www.astro.ucla.edu/~wright/BBNS.html

The nucleosynthesis model is working thus far - and neutrino dark
matter is massively incompatible with it unless you have a real good
reason for explaining how neutrinos traveling nigh-indistinguishably
from lightspeed become bound to a galaxy.



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.

Start paring the list down.

Of these, how many of them make testable predictions? No, I don't mean
"soon", I mean "right here link to paper".

All of them.

My, that was quick. I thought LQG still had something on the order of
10^50 solutions?


It is only DM that does not make testable prediction. Others can be
falsified. Mannheim's Conformal Gravity has already been falsified by
Bullet Cluster. But now I know what was wrong with it. He was using
dS/CFT instead of AdS/CFT. Now M.B.Paranjape and A.Edery are taking
that work forward, using AdS/CFT. But the work must now be done from
the beginning.

Both DM and MOND were hypotheses created to explain galactic rotation
curves. MOND, however, can't handle the large scale structure of the
universe while DM is an fundamental part in something that makes a
very, very good fit. Remember what you told me - something that fits
that well has to have some fashion of truth to it?


We also have LQG. I don't think that you believe that they are not
trying to make any testable predictions. It is the only viable Quantum
Gravity Theory. I don't consider String Theory at all. LQG till now
had been using GR. Which is not working very well. The main problem
is that Quantum theories are fundamentally at odds with any sort of
scale. There are a couple of LQG researchers that are moving towards
using Conformal Invariance instead of Lorentz Invariance. I am sure
something good will come out of it.

LQG is loosely based off of GR, but I know precious little about it.
It is yet another approach to doing quantum theory in curved
spacetime. Quantum theory just does not play nice with gravitation.

It isn't that I don't believe they are _trying_, it is that I don't
believe they are _able_ to do anything but make general statements.


TeVeS is making testable predictions. I personally don't like TeVeS,
but it is not a bad idea. We may come up with a law for weak lensing
through it. This work is also needed for convincing GR proponents that
DM in Galaxies is redundant.

I wish them the best of luck - they have some severe hurdles to pass
through.

They have to describe *all* of the following self-consistently:

1) Make dark matter irrelevant.
2) Explain the bullet cluster.
3) A part of 2 - explain why current weak lensing results are so, so
wrong.
4) Do 3 without invalidating solar system tests of strong lensing.
5) Stay relativistic - not doing so makes a large, large body of
astrophysical observation and terrestrial experiment mad at you.



Of these, how many match _already verified_ predictions by general
relativity?

Conformal gravity matches GR very well in strong gravity. Nearly well
with MOND in the galaxies. Used to explain Cluster dynamics, but now
with the discovery of unambiguous proof of DM in Clusters will fail
there. And hence will be falsified.

Whups. 2 out of 3 ain't bad.


MOND/TeVeS works well in strong gravity, as they are basically same as
GR. Works very well in Galaxies. Predicts HDM in Clusters, as required
by Bullet Cluster. Also is not against Dark Galaxies. It can be
falsified, but has not been falsified yet.

Careful when you say 'required'. I have been trying to distinguish
between things that are observationally true and which are required to
be true within a specific hypothesis.

Hot neutrinos - it isn't something required by MOND, it is a
*hypothesis* that is added in to explain the bullet cluster within the
context of MOND.


LQG is still in its infancy. Will have to wait for some testable
predictions. They have some explanation for the Ohmygod particles, but
I think little else.

Last I heard, cosmic rays are getting blamed on black holes. We
already know jets can send planet-massed chunks of matter at a large
fraction of c...



Of the remaining, if any, match up with the area O' interest that is
the bullet cluster while removing the need for dark matter?

There is no need to remove Dark Matter in Bullet Cluster. It is an
unambiguous observation that Dark Matter exists in Bullet Cluster.

Zuh?

Are folks folks going with the King Solomon approach and splitting the
difference? Arguing both dark matter *AND* MOND is a little
contradictory to me.

Also MOND has been predicting double the mass in most Clusters, which
should be the same Dark Matter which we see in Bullet Cluster. But
that doesn't mean that it has to be CDM, it could be HDM.

....and how many HDM candidates are there? There aren't that many
stable particles which don't interact electromagnetically...



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.

Considering how hard it is to use GR without making a large series of
approximations, I can't help but wonder how many of these theories are
at the point where they can make useful predictions rather than
sweeping statements from toy models.

Just imagine how hard it will be using AdS/CFT for the calculations.
It is an Order Four theory, much more complex than the Order 2 GR. It
is possibly the biggest reason why we don't have a viable Quantum
Gravity theory yet.

I am not sure in what context "order 2 GR" is meant. GR's principle
equations are based on rank 2 tensors, but tensors of higher and lower
rank are scattered hither tither and yon. The differential equations
are second order, maybe that is what is meant.

The PDE folks will love a theory that is based off of fourth order
differential equations. "FINALLY! Something other than bending beams -
getting so ****ing tired of those!"


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

Of course they aren't.

Keep in mind thatMONDoffers no explanation as to _why_ gravity is
being screwy, just that it _is_ screwy and that it _is_ a model of the
screwyness. There is no reason offered as to why dark matter can't
simply be modeled byMOND. It isn't as ifMONDis based off of bedrock
principles - it is an ad-hoc notion that fits the bill in certain
places.

MOND need not offer any explanation to be useful. It's main job is to
show that gravity is being screwy. The work is cut out for the
theoretical physicists to explain why it is screwy. But most are just
hoping that DM can explain anything. While even after 25 years there
is no model of DM that can explain MOND relationship.

MOND is a model, and as such it has served excellently. I think MOND
should be the model for dark matter hosted in galaxies. Clusters not
so much.


I'm curious as to what the experiment described here will say.

http://physicsweb.org/articles/news/11/3/12/1

I don't know what they are trying to do. I think the person doesn't
know MOND. MOND will apply only when the total accelaration due to
gravity drops below a0. I don't know how on earth he found such a
place on earth. On earth acceleration due to gravity cannot go much
below or above g. Even earth can never expect gravity much less than
a0, unless it gets between Jupiter and Sun in such a way that both the
accelarations cancel exactly. Even then Moon will not let it fall
below a0.

I think the idea is silly but worth doing since some MOND proponents
think it is worth doing. You already explained why I think it is silly
- but if they want to go ahead, *shrug*.


The only place MOND can be tested is the L4 and L5 areas. In these
areas gravity due to Sun and Earth+Moon cancels exactly, so there must
be a smaller area within it where the total gravity falls below a0.
This area is called a Mondian bubble. And it is the nearest place
where MOND can be verified. The hope is that the bubble will be big
enough to accomodate a test machine ;-).

Do _NOT_ try to pull that "I'm fighting the establishment!" bull****
with me. The papers you cite are published in reputable journals.
Considering how _often_MONDis referred to in popular and technical
scientific articles,MONDis decidedly mainstream. The folks in here
who also cry about persecution have wet dreams about being given the
kind of attention thatMONDgets in the literature.

Sorry, will not do it again. It was an interesting comment in the
letter.

MONDis not a law.MONDis a model - it was designed as such, and
remains as such. The fact that it has any sort of success means
something - I think it means that it is keying in on the dark matter
distribution in galaxies at some level.

MOND is a law, it is only a single equation, just like Keplers laws
where. Or Newton's laws were. Mondian models are created to fit the
galaxy rotation curves. But these are not MOND. They are built over
MOND.

The whole discussion about whether or not it is a law irritates me
because it serves no purpose. It is semantic quibbling.


Think about the weak lensing results - where is most of the dark
matter? Out in the halo. Ignoring weak lensing - where does the dark
matter need to be to smooth out the velocities? Out in the halo. What
is the domain of application forMOND? Out...in the halo, where
gravity is thought to be "weaker".

I would think if most of the matter is out in a halo, the lens will
not be properly convex. It will be convex overall but near the center
there will be a concave circular portion. This will result in the
center part concentrating more light than a normal convex lens, so you
should see a brighter spot at the center of such a lens. Does any weak
lensing show this artifact.

I don't know.

It is not clear to me how the distribution of matter would influence
the lens. The true theory and application of weak lensing on galactic
scales is not as known to me as I would like.


Let me be clear - I accepted before and accept even more now thatMOND
is pointing to something important. What we seem to disagree on is
_what_ that important thing is.

Well now I can rejoice ;-). We have reached the most important part of
the discussion. You accept MOND effect as real.

Yes and no.

I accept that MOND is an accurate model over a surprisingly large
sample set. I rationalize it thusly: all galaxies appear to have
formed in the same way, more or less. So it stands to reason that DM
will be the same in each galaxy [less collisions and exotic
circumstances] if not more so due to the lack of interaction.

I do not accept that MOND is a physical theory unto itself. There are
too many results from weak lensing that make dark matter convincing in
my eye, as well as its' utility in cosmological modeling. The MOND
folkes probably would _not_ like that position.


Now consider the following points
1) MOND is real. This means that Dark Matter has no degrees of freedom
within a galaxy. This must be true because MOND can predict the
rotation curve based on normal matter alone, so if DM gives rise to
MOND, it cannot have any degrees of freedom. It must go where normal
matter tells it to.

I think there is an element of truth to that, but not exactly as
written.

http://www.journals.uchicago.edu/ApJ...610/58610.html

It appears that DM baryonic matter are nicely correlated.


2) We cannot be living in a special epoch, when DM matches MOND
everywhere. It must have been true for a very long time in the past.
And will
continue to do so for a very long time in the future.

I don't see why not - at least, the matching part. I am yet to hear a
convincing explanation as to why MOND *can't* be represenative of dark
matter.


3) Dark Matter cannot have been put by an intelligent agent to test
our faith ;-). It must have arisen based on some mechanism and using
the mechanisms of GR must have moved in such a way to always bring out
the MOND phenomenology.

Yea I think we can both agree on that one.


4) If you see the 3 points above you see that DM in galaxies is
superfluous. It must satisfy too many features to be true, and top of
that it has no degrees of freedom, which makes it a superflous
concept. This is where Occam's Razor steps in to say that DM is not
simpler than MOND, and so must not be the true picture of the world.

I don't think you are applying Occam's razor properly. DM as a concept
is quite simple - there is matter we can't see that explains otherwise
contradictory observations. The concept is not superfluous because
there is no alternative _physical_ explanation, nor is there an
explanation of lensing results.



2) Disk-Halo conspiracy

http://arxiv.org/PS_cache/astro-ph/pdf/9610/9610188.pdf[PDF is
slightly glitchy...]

One of the conclusions I thought was most intriguing was that the dark
matter halo shape under that model was something that was reasonably
constant.

It [disk halo conspiracy] is touched on indirectly as well by the
previous paper. Given there is an alternative explanation that is
entirely plausible, I don't see why folks are adopting the CDM
WROOOOOOOOONG stance. So far, it looks like the worst case is that the
CDM model needs tweaking - which doesn't surprise me, I do not believe
it was even geared as a model for scales so small.

What is your entirely plausible alternative explanation. I am dying to
know ;-).

....that MOND is mapping out dark matter.


What folks seem to be missing is that success ofMONDand success of
dark matter are not mutually contradictory goals.MONDseems to lend
itself fairly easily to a dark matter explanation, despite how angry
that probably makes theMONDcrew.

On the contrary, MOND is expected to make a lot of Relativists very
angry when they find that no DM model can work ;-).

*points to weak lensing*

That is what it is all coming back to - weak lensing. Why does weak
lensing keep showing a distribution of dark matter if it isn't there?



The constant inclusion of the virial mass [200x universe critical
density] and the size associated with it amuses me for some odd
reason...I don't find anything wrong or objectionable, it just amuses
me.

I don't know what you mean exactly by "suitable definitions of
working", butMONDworks 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 number of free parameters isn't that big and you know it, if you
have actually been reading the papers you have been citing me.

Even 2 free parameters are too many when a competing theory can fit
the data without any free parameter. And most DM theories require 3 or
4 parameters. Remember that DM theories can fit the 20% cases where
the data is problematic. This indicates that the free parameters are
enough to fit any rotation curve even if they are not from a real
galaxy. This is what proves that there are too many parameters. Any
good model is one which is not able to work with bad data. DM models
are not good models.

What happens when the competing theory fails in an unambigious way in
a different case?

I don't think DM is anywhere near the point to where one could say "So
what? I can fit any arbitrary curve with a large enough amount of
parameters!"


The onus is on theoretical physicists to find the underlying reason.
IgnoringMONDdoes not help.

That much is now obvious.MONDis an excellent model for individual
galaxies, though I _suspect_ it fails for galaxies that are products
of or are in various stages of collision [eg, bullet cluster].

Keep in mind that nothing you have shown me or what I have found
conclusively, or even most likely, makes dark matter an incorrect
model. In fact, everything I have seen thus far either supports or
refines dark matter. Using theMONDfits along with the empirical data
gives some nice constraints on entirely plausible distributions of
dark mater where there were none before, which is quite useful.

I and possibly all of the MOND proponents are dying to know an
entirely plausible distribution of DM that can fit MOND.

Read the papers I cited you previously. You will see where I'm coming
from.

Especially http://www.journals.uchicago.edu/ApJ...610/58610.html


Just remember that Occam's Razor is against you ;-).

regards,
-anandsr

Eric Gisse wrote:
wrote:


On Mar 20, 1:34 pm, "Eric Gisse" wrote:
wrote:
There is _no_ reason to doubt that our interpretation of the weak
lensing results is false. There is matter there and it curves light
and we detect it. That is remarkably direct compared to other
cosmological observations that are *heavily* model-dependent.

Just remember that I am arguing that there is no DM within Galaxy
scales. ie MOND explains Galaxy rotation curves so obviously
Weak Lensing will need to be explained by a quantum theory that
will derive MOND. In my GR+DM cannot explain MOND.

Neutrinos avoid this problem by being hot, which prevents their
coupling together.

Neutrinos avoid the problem by having an insanely small scattering
cross section and by traveling within epsilon of light speed for
pretty much any plausible amount of energy. They avoid the problem so
well that they are horrible dark matter candidates - not enough of
them can be produced, and they are not capable of binding to galaxies
considering how fast they would be traveling. Neutrino dark matter
would form a background, not a halo.

True for Galaxy scales but not true for Cluster scales.
So whats your point?

KATRIN isn't and never will be a test of MOND. Neutrino oscillations
simply shift the flavors around - they do not add mass. Neutrino mass
is constrained to be very tiny, and if the L-CDM model is even close
to being reasonable the total masses of all neutrinos is less than an
eV.

I don't understand this, the three flavours are supposed to have
weight
less than 2.2eV, 170KeV, and 15.5MeV. So even the lightest may be
heavier than 1eV. The others are much much more heavy.
Do you mean to say that KATRIN will falsify LCDM if electron neutrino
happens to have a weight more than 1eV. I don't believe that DM
theories are falsifiable. They are just curve fitting exercises. Add
as
much DM as you need whereever you need. LCDM theories need not
apply to Galactic level and the NFW halos need not have any
cosmological significance.

No! Neutrinos _can not do it_!

You mean that Neutrinos cannot make stable structures at Cluster
sizes.
This is as much an speculation as is my assertion as mine. We don't
yet know the masses and relative abundance of the three neutrinos.


Look back at that paper I linked to you the other day - remember how
everything was consistent with a HALO of dark matter? There are simply
not enough neutrinos and the ones whizzing around simply have too much
energy to be bound.

http://www.astro.ucla.edu/~wright/BBNS.html


It doesn't give any neutrino abundance. I would think that there may
be
a huge amount of neutrino as it is a very important part of the
reactions
below one second timeframe. Also I do not expect that all of it will
be
absorbed. It is entirely plausible to have a large amount of
neutrinos.


Both DM and MOND were hypotheses created to explain galactic rotation
curves. MOND, however, can't handle the large scale structure of the
universe while DM is an fundamental part in something that makes a
very, very good fit. Remember what you told me - something that fits
that well has to have some fashion of truth to it?

So give me one DM theory that works well at the large structure and
works well for the galaxies as well. We know that LCDM does not work
well at Galaxy level.

There is a difference between MOND and DM.
DM is a curve fitting exercise requiring the use of several free
parameters,
while MOND is a single equation that works well with a single
universal
parameter on all galaxies.

TeVeS is making testable predictions. I personally don't like TeVeS,
but it is not a bad idea. We may come up with a law for weak lensing
through it. This work is also needed for convincing GR proponents that
DM in Galaxies is redundant.

I wish them the best of luck - they have some severe hurdles to pass
through.

They have to describe *all* of the following self-consistently:


Well GR has to explain MOND. Unless it does so, it is a suspect
theory.
It needs to show how DM should be distributed to explain MOND.
It must show why it should have this distribution and not any other.
It must show why DM is required when the curves can be explained
based on only BM.

1) Make dark matter irrelevant.
Why???
Bullet Cluster shows that DM exists at the cluster scale, which was
already expected from previous MOND fits to other cluster.
You can change it to Make dark matter irrelevent at the galactic
scale.
It is certainly not required at the galactic scales.

I don't disagree with the rest of your list. They are certainly
required
by any quantum theory of gravity.


MOND/TeVeS works well in strong gravity, as they are basically same as
GR. Works very well in Galaxies. Predicts HDM in Clusters, as required
by Bullet Cluster. Also is not against Dark Galaxies. It can be
falsified, but has not been falsified yet.

Careful when you say 'required'. I have been trying to distinguish
between things that are observationally true and which are required to
be true within a specific hypothesis.

Hot neutrinos - it isn't something required by MOND, it is a
*hypothesis* that is added in to explain the bullet cluster within the
context of MOND.

It is *required* by MOND to fit Bullet Cluster or any Cluster data.
It may be that MOND is not the correct theory. But the Bullet Cluster
proves that there is dark matter at cluster scales.

There is no need to remove Dark Matter in Bullet Cluster. It is an
unambiguous observation that Dark Matter exists in Bullet Cluster.

Zuh?

Are folks folks going with the King Solomon approach and splitting the
difference? Arguing both dark matter *AND* MOND is a little
contradictory to me.

You have a lot of prejudice regarding MOND. I don't think I can rid
you
of your prejudice. You see the forest and cannot focus down to the
trees.
It is obvious that MOND and Dark Matter are not incompatible.
If you ask Milgrom himself, he will not agree with your statement.
The whole point of MOND is to show that a simple modification to
Newtons law can explain rotation curves of all galaxies. It doesn't
mean that we have seen everything, and that DM cannot exist in
clusters.

It only means that there is no need for DM in Galaxies. Nothing more
nothing less.

I don't think I can continue this discussion if you cannot grasp
this basic fact of MOND.


Also MOND has been predicting double the mass in most Clusters, which
should be the same Dark Matter which we see in Bullet Cluster. But
that doesn't mean that it has to be CDM, it could be HDM.

...and how many HDM candidates are there? There aren't that many
stable particles which don't interact electromagnetically...

And how many CDM candidates have been observed.
At least Neutrino has been observed and has now been shown to
oscillate
with some flavours having huge masses. Since we don't know the
average
mass we cannot yet conclude that it cannot make stable structures
yet.

Let me be clear - I accepted before and accept even more now thatMOND
is pointing to something important. What we seem to disagree on is
_what_ that important thing is.

Well now I can rejoice ;-). We have reached the most important part of
the discussion. You accept MOND effect as real.

Yes and no.

I accept that MOND is an accurate model over a surprisingly large
sample set. I rationalize it thusly: all galaxies appear to have
formed in the same way, more or less. So it stands to reason that DM
will be the same in each galaxy [less collisions and exotic
circumstances] if not more so due to the lack of interaction.

I do not accept that MOND is a physical theory unto itself. There are
too many results from weak lensing that make dark matter convincing in
my eye, as well as its' utility in cosmological modeling. The MOND
folkes probably would _not_ like that position.

Again the forest. Try to focus only on one aspect at one time. Looking
at trees only sometimes is useful.

It is obvious that MOND is not a physical theory. It is just a visible
artifact of the Quantum Theory of Gravity.

We know that Weak Lensing and Rotation Curves must have the same
origin. If it is GR+BM+DM then it is the same for both if it is QTG+BM
then it will be the same for both. Now if we can prove that GR+BM+DM
cannot fit the Rotation Curves as well or better than MOND, then we
have proved that GR+BM+DM is not the correct picture. And we must
look into finding a theory QTG that is compatible with MOND and also
explains weak lensing based only on BM.

The real solution is only to find a distribution of DM that has the
following
properties.
1) It can fit MOND at the currect epoch.
2) It can fit WMAP using a distribution that should be able to reach
the
MONDian distribution at the current epoch.
3) There must be some observable departures from MOND which we
can see to discard MOND. In other words there can be no DM theory
that will be indistinguishable from MOND, because DM cannot have
zero degrees of freedom.

2) We cannot be living in a special epoch, when DM matches MOND
everywhere. It must have been true for a very long time in the past.
And will
continue to do so for a very long time in the future.

I don't see why not - at least, the matching part. I am yet to hear a
convincing explanation as to why MOND *can't* be represenative of dark
matter.

We cannot be living in a special epoch because the galaxies we see are
in different stages of development. DM cannot fit MOND for all of them
unless it fits all of them at all times. So there can be no special
epoch.

I thought it was obvious so did not give my reasoning.

4) If you see the 3 points above you see that DM in galaxies is
superfluous. It must satisfy too many features to be true, and top of
that it has no degrees of freedom, which makes it a superflous
concept. This is where Occam's Razor steps in to say that DM is not
simpler than MOND, and so must not be the true picture of the world.

I don't think you are applying Occam's razor properly. DM as a concept
is quite simple - there is matter we can't see that explains otherwise
contradictory observations. The concept is not superfluous because
there is no alternative _physical_ explanation, nor is there an
explanation of lensing results.

I think you are not applying it properly.

DM is simple but DM mimicking MOND is not. MOND is the real crux of
the problem. Without MOND, there is no trouble for DM at all.
With MOND it becomes totally superfluous (Just to remind only at the
galaxy level, MOND doesn't fit Cluster data, so DM is not superfluous
there).

DM is a simple concept.
MOND is a more complex concept.
DM mimicking MOND is a very complex concept.

On the contrary, MOND is expected to make a lot of Relativists very
angry when they find that no DM model can work ;-).

*points to weak lensing*

That is what it is all coming back to - weak lensing. Why does weak
lensing keep showing a distribution of dark matter if it isn't there?

Weak Lensing is irrevelent, and I am not ignoring it while saying
that.

Even 2 free parameters are too many when a competing theory can fit
the data without any free parameter. And most DM theories require 3 or
4 parameters. Remember that DM theories can fit the 20% cases where
the data is problematic. This indicates that the free parameters are
enough to fit any rotation curve even if they are not from a real
galaxy. This is what proves that there are too many parameters. Any
good model is one which is not able to work with bad data. DM models
are not good models.

What happens when the competing theory fails in an unambigious way in
a different case?

I don't think DM is anywhere near the point to where one could say "So
what? I can fit any arbitrary curve with a large enough amount of
parameters!"

Actually it is at that stage. I had seen somewhere can't remember
whether
it was a paper or article, in which they had created a pseudo galaxy
by merging data of two real galaxies. MOND would not fit that data,
while LCDM halos where able to fit it.

I and possibly all of the MOND proponents are dying to know an
entirely plausible distribution of DM that can fit MOND.

Read the papers I cited you previously. You will see where I'm coming
from.

Especially http://www.journals.uchicago.edu/ApJ...610/58610.html

Which one do you mean?
PseudoIsothermal Halo or NFW Halo.

I don't think there is any large scale formation theory for either of
them.

The most popular theory that explains large scale structure formation
is LCDM which fails badly on most Galaxies.

You must understand that any distribution must have a valid formation
theory behind it. One is not complete without the other.

Just remember that Occam's Razor is against you ;-).