Galaxy mix: No dark matter required

On Feb 19, 3:00*pm, YKhan wrote:
On Feb 19, 2:35*am, Eric Gisse wrote:

If someone finds a theory that explains the large scale structure of
the universe, properly fits the CMBR, suggests a credible theory for
galaxy formation, galactic rotation curves, and replicates observed
results for colliding galaxies, but does not involve dark matter or
dark energy - I'll honestly consider it.

Unfortunately every 'alternative' works in one of two aspects and none
of the others, MOND and such.

And those problems are equally a problem working against Dark Matter,
isn't it? If you're saying DM describes more scenarios and examples,
that's simply not true. Some colliding clusters seem to be described
by DM, while others seem to have DM in all of the wrong places.

Since when? The only example I've seen is Abel 520 [from memory, it's
close] in which it is an /unlikely/ prospect that the cluster formed
via a DM model. However, 'unlikely' is the order of the day when
considering how unlikely that Earth would get a plane-on view of a
cluster of galaxies colliding.

View the events with respect to the whole, not just in isolation.
Cherry picking is bad.

And
making a case that DM describes the CMBR any better than any other
theory is pointless.

Considering I am yet to hear of a reasonable alternative that does so,
I'm gonna disagree.

And of course DM completely falls apart in every
case of dwarf galaxies, cannot begin to describe them, but the
alternatives can.

The current model of galaxy formation appears to fall apart. There's a
difference.

Again - cherry picking. Grabbing the corner case and using it as
represenative of the whole isn't a good idea.


What this result tells me is that we really have no idea how dwarf
galaxies form and that our ideas on how galaxies themselves form may
be wrong.

Which if you think about it, then you're damning Dark Matter models
implicitly. If you say we have no idea how dwarf galaxies and galaxies
in general form, then that's a damnation of all Dark Matter models.

All models, not just DM models.

Because all of Dark Matter's competitors can easily describe how dwarf
galaxies form, and they can also describe how galaxies of any and all
sizes can form without the asterisks, fine print, or footnotes.

So? The Ballmer formla can easily describe the spectra of Hydrogen.

Explaining one particular thing in isolation is not a major
accomplishment!


* Yousuf Khan

On Feb 20, 7:59*pm, Eric Gisse wrote:
And those problems are equally a problem working against Dark Matter,
isn't it? If you're saying DM describes more scenarios and examples,
that's simply not true. Some colliding clusters seem to be described
by DM, while others seem to have DM in all of the wrong places.

Since when? The only example I've seen is Abel 520 [from memory, it's
close] in which it is an /unlikely/ prospect that the cluster formed
via a DM model. However, 'unlikely' is the order of the day when
considering how unlikely that Earth would get a plane-on view of a
cluster of galaxies colliding.

View the events with respect to the whole, not just in isolation.
Cherry picking is bad.

Abel 520 is an example of cherry picking against DM, but the Bullet
Cluster is also an example of cherry picking for DM. The vast majority
of clusters so far can be explained by either DM or DM-alternatives
equally.

And
making a case that DM describes the CMBR any better than any other
theory is pointless.

Considering I am yet to hear of a reasonable alternative that does so,
I'm gonna disagree.

I think most DM-alternative theories also lay claim to being able to
explain the CMBR variations, just as much as DM lays claim to it.
Really, it's a wash, many of the theories can explain the CMBR
variations just as well as DM does. Like for example, in the following
link, they are showing how TeVeS can explain the CMBR data pretty well
too:

The Third Peak in TeVeS
"One can see, by inspection, that the scalar field plays the role
usually ascribed to CDM of providing a driving term in the
oscillations. "
http://www.astro.umd.edu/~ssm/mond/CMB6.html

And of course DM completely falls apart in every
case of dwarf galaxies, cannot begin to describe them, but the
alternatives can.

The current model of galaxy formation appears to fall apart. There's a
difference.

You mean like the current model of galaxy formation, involving Dark
Matter?

Again - cherry picking. Grabbing the corner case and using it as
represenative of the whole isn't a good idea.

snip
Which if you think about it, then you're damning Dark Matter models
implicitly. If you say we have no idea how dwarf galaxies and galaxies
in general form, then that's a damnation of all Dark Matter models.

All models, not just DM models.

How is it damning of /all/ models? The DM alternatives seem to be able
to explain the dwarf galaxy formations pretty well, it's only the DM
models that fail.

Because all of Dark Matter's competitors can easily describe how dwarf
galaxies form, and they can also describe how galaxies of any and all
sizes can form without the asterisks, fine print, or footnotes.

So? The Ballmer formla can easily describe the spectra of Hydrogen.

Explaining one particular thing in isolation is not a major
accomplishment!

If it were only one isolated example of explaining something well, but
the DM alternatives can explain all cases that DM explains well, and
then gets the stuff right that DM gets wrong.

Yousuf Khan

On Feb 28, 4:33*pm, YKhan wrote:
On Feb 20, 7:59*pm, Eric Gisse wrote:

And those problems are equally a problem working against Dark Matter,
isn't it? If you're saying DM describes more scenarios and examples,
that's simply not true. Some colliding clusters seem to be described
by DM, while others seem to have DM in all of the wrong places.

Since when? The only example I've seen is Abel 520 [from memory, it's
close] in which it is an /unlikely/ prospect that the cluster formed
via a DM model. However, 'unlikely' is the order of the day when
considering how unlikely that Earth would get a plane-on view of a
cluster of galaxies colliding.

View the events with respect to the whole, not just in isolation.
Cherry picking is bad.

Abel 520 is an example of cherry picking against DM, but the Bullet
Cluster is also an example of cherry picking for DM. The vast majority
of clusters so far can be explained by either DM or DM-alternatives
equally.

Since you claim the 'vast majority' can be explained w/o DM, name
two.

I only know of one, and that non-DM explanation makes assumptions that
I believe to have been invalidated in solar system scale tests.


And
making a case that DM describes the CMBR any better than any other
theory is pointless.

Considering I am yet to hear of a reasonable alternative that does so,
I'm gonna disagree.

I think most DM-alternative theories also lay claim to being able to
explain the CMBR variations, just as much as DM lays claim to it.

They lay claim but completely fail to deliver, like MOND.

Really, it's a wash, many of the theories can explain the CMBR
variations just as well as DM does. Like for example, in the following
link, they are showing how TeVeS can explain the CMBR data pretty well
too:

The Third Peak in TeVeS
"One can see, by inspection, that the scalar field plays the role
usually ascribed to CDM of providing a driving term in the
oscillations. "http://www.astro.umd.edu/~ssm/mond/CMB6.html

"That said, it remains to be seen whether a tolerable fit to the WMAP
data can be obtained. The authors showed plots at the conference that
made it clear it was possible to obtain a third peak comparable to the
data, but are still in the process of trying to fit the best cosmic
parameters. There is no guarantee that this will work out. "

How unconvincing.


And of course DM completely falls apart in every
case of dwarf galaxies, cannot begin to describe them, but the
alternatives can.

The current model of galaxy formation appears to fall apart. There's a
difference.

You mean like the current model of galaxy formation, involving Dark
Matter?

Even if what you said was 100% true, it still doesn't make DM wrong.
It makes the model for formation wrong, which is somewhat different.




Again - cherry picking. Grabbing the corner case and using it as
represenative of the whole isn't a good idea.

* snip
Which if you think about it, then you're damning Dark Matter models
implicitly. If you say we have no idea how dwarf galaxies and galaxies
in general form, then that's a damnation of all Dark Matter models.

All models, not just DM models.

How is it damning of /all/ models? The DM alternatives seem to be able
to explain the dwarf galaxy formations pretty well, it's only the DM
models that fail.

Again, cherry picking! The DM alternatives DO NOT WORK except in
carefully chosen corner cases.

[...]

Stop wasting your time. Eric is convinced that DM is the true picture
of the universe and you cannot reason with that.

I had once got him to admit that MOND does explain Galaxies very well
although it does not work well at bigger scales.

But then he explained it away as an artifact of DM. I don't understand
how can anybody assume a matter to have zero degrees of freedom. If
any equation with a single global free parameter can explain all
galaxy rotation based on just the Baryonic Mass then how can DM be
responsible for anything.

-anand

On Apr 6, 3:32*am, wrote:
Stop wasting your time. Eric is convinced that DM is the true picture
of the universe and you cannot reason with that.

Until there's a better explanation, I'll stick with the one I have.



I had once got him to admit that MOND does explain Galaxies very well
although it does not work well at bigger scales.

Of course I admitted it. The success of MOND for modeling certain
behaviors of certain galaxies is well documented.


But then he explained it away as an artifact of DM. I don't understand
how can anybody assume a matter to have zero degrees of freedom. If

If you are going to whine, at least be right. DM has density and
temperature as degrees of freedom.

any equation with a single global free parameter can explain all
galaxy rotation based on just the Baryonic Mass then how can DM be
responsible for anything.

Is that a complaint against DM...or MOND?


-anand

On Apr 7, 2:49*am, Eric Gisse wrote:
On Apr 6, 3:32*am, wrote:

If you are going to whine, at least be right. DM has density and
temperature as degrees of freedom.

How do you observe the Density and Temperature at the Galaxy level.

If it has temperature then it should be fairly easy to detect as any
object with temperature higher than Absolute Zero will give of some
radiation. That is why we call it the CDM model in that the DM is cold
at Absolute Zero. There is no degree of freedom there.

And it is always modeled to have a uniform density to give exactly the
kind of observation that is predicted by MOND. Which really is having
no freedom at all as the baryons are deciding where the DM will be
through MOND.


any equation with a single global free parameter can explain all
galaxy rotation based on just the Baryonic Mass then how can DM be
responsible for anything.

Is that a complaint against DM...orMOND?

It is a complaint against the thinking that DM can somehow give MOND
phenomenology.
It cannot period.

For the record I am not against DM (cold or hot). Its just that MOND
does not allow it at Galactic levels.
I also don't think TeVeS is in any way a good theory it is just trying
to put MOND phenomenology into a theory, which will not work.

We will have to get a theory from the first principles. Recovering the
MOND phenomenology at Galactic levels is an additional test.

I am not saying that GR is wrong, it could be that we don't understand
it very well. The LQG guys are trying to use GR at the quantum level.
But the current form does not give MOND which is a fatal problem.

Till we get a good enough theory, trying to answer any cosmological
questions is meaning less.
In essence, Cosmologists are just blundering in the dark, and wasting
there time. I don't know why they don't do something constructive like
trying to find a theory that does work, rather than wasting their time
predicting the age of the universe without even knowing how mass
moves.

-anand

On Apr 7, 2:49*am, Eric Gisse wrote:
On Apr 6, 3:32*am, wrote:

If you are going to whine, at least be right. DM has density and
temperature as degrees of freedom.

How do you observe the Density and Temperature at the Galaxy level.

If it has temperature then it should be fairly easy to detect as any
object with temperature higher than Absolute Zero will give of some
radiation. That is why we call it the CDM model in that the DM is cold
at Absolute Zero. There is no degree of freedom there.

And it is always modeled to have a uniform density to give exactly the
kind of observation that is predicted by MOND. Which really is having
no freedom at all as the baryons are deciding where the DM will be
through MOND.


any equation with a single global free parameter can explain all
galaxy rotation based on just the Baryonic Mass then how can DM be
responsible for anything.

Is that a complaint against DM...orMOND?

It is a complaint against the thinking that DM can somehow give MOND
phenomenology.
It cannot period.

For the record I am not against DM (cold or hot). Its just that MOND
does not allow it at Galactic levels.
I also don't think TeVeS is in any way a good theory it is just trying
to put MOND phenomenology into a theory, which will not work.

We will have to get a theory from the first principles. Recovering the
MOND phenomenology at Galactic levels is an additional test.

I am not saying that GR is wrong, it could be that we don't understand
it very well. The LQG guys are trying to use GR at the quantum level.
But the current form does not give MOND which is a fatal problem.

Till we get a good enough theory, trying to answer any cosmological
questions is meaning less.
In essence, Cosmologists are just blundering in the dark, and wasting
there time. I don't know why they don't do something constructive like
trying to find a theory that does work, rather than wasting their time
predicting the age of the universe without even knowing how mass
moves.

-anand

On Apr 7, 2:49*am, Eric Gisse wrote:
On Apr 6, 3:32*am, wrote:

I had once got him to admit thatMONDdoes explain Galaxies very well
although it does not work well at bigger scales.

Of course I admitted it. The success ofMONDfor modeling certain
behaviors of certain galaxies is well documented.


So you don't agree that all known galaxy types are modelled well with
MOND.
Can I know an instance of types that have been proved to not work with
MOND.
Or even one which have not been attempted to be explained by MOND.
I am sure it will be a good pointer for Dr. Stacy McGaugh.

regards,
-anand

On Apr 7, 2:49*am, Eric Gisse wrote:
On Apr 6, 3:32*am, wrote:

I had once got him to admit thatMONDdoes explain Galaxies very well
although it does not work well at bigger scales.

Of course I admitted it. The success ofMONDfor modeling certain
behaviors of certain galaxies is well documented.


So you don't agree that all known galaxy types are modelled well with
MOND.
Can I know an instance of types that have been proved to not work with
MOND.
Or even one which have not been attempted to be explained by MOND.
I am sure it will be a good pointer for Dr. Stacy McGaugh.

regards,
-anand

On Apr 6, 11:02*pm, wrote:
On Apr 7, 2:49*am, Eric Gisse wrote:

On Apr 6, 3:32*am, wrote:
If you are going to whine, at least be right. DM has density and
temperature as degrees of freedom.

How do you observe the Density and Temperature at the Galaxy level.

Lensing to observe density, and density + gravitation to determine
temperature.


If it has temperature then it should be fairly easy to detect as any
object with temperature higher than Absolute Zero will give of some
radiation. That is why we call it the CDM model in that the DM is cold
at Absolute Zero. There is no degree of freedom there.

You think dark matter can radiate electromagnetically because.....?


And it is always modeled to have a uniform density to give exactly the
kind of observation that is predicted by MOND. Which really is having
no freedom at all as the baryons are deciding where the DM will be
through MOND.

MOND no more decides anything than the Ballmer formula for the
Hydrogen spectrum determines where the spectral lines will be. Curve
fitting is not predictive, BULLET CLUSTER.




any equation with a single global free parameter can explain all
galaxy rotation based on just the Baryonic Mass then how can DM be
responsible for anything.

Is that a complaint against DM...orMOND?

It is a complaint against the thinking that DM can somehow give *MOND
phenomenology.
It cannot period.

That's personal conjecture on my part that has no validation. It might
be worth demonstrating, though.


For the record I am not against DM (cold or hot). Its just that MOND
does not allow it at Galactic levels.

MOND does not ALLOW? HA HA HA

I also don't think TeVeS is in any way a good theory it is just trying
to put MOND phenomenology into a theory, which will not work.

How do you know? Have you tried?


We will have to get a theory from the first principles. Recovering the
MOND phenomenology at Galactic levels is an additional test.

Why? MOND isn't an observation, its a curve fit to /other/
observations.


I am not saying that GR is wrong, it could be that we don't understand
it very well. The LQG guys are trying to use GR at the quantum level.
But the current form does not give MOND which is a fatal problem.

Even more fatal is the lack of testable predictions.


Till we get a good enough theory, trying to answer any cosmological
questions is meaning less.
In essence, Cosmologists are just blundering in the dark, and wasting
there time. I don't know why they don't do something constructive like
trying to find a theory that does work, rather than wasting their time
predicting the age of the universe without even knowing how mass
moves.

A handful of plane-on galactic cluster collisions plus the CMBR is
rather compelling in my mind. Plus the individual lensing observations
of galaxies not involved in collisions...


-anand