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MACHO Candidacy "Still Viable"
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Robert L. Oldershaw
Jan 26, 2012, 3:30:17 AM1/26/12
to
Shall we let someone knowledgeable inform us about the viability of
MACHOs as the dark matter objects?
http://arxiv.org/abs/1201.5262
I quote from the abstract:
"Microlensing is the tool of choice for the search and the analysis of
compact halo objects ("MACHOs"), a still viable class of dark matter
candidates at the galactic scale. Different analyses point towards an
agreement in excluding dark matter MACHOs of less than about 0.1 solar
mass; it remains however an ongoing debate for values in the mass
range (0.1-1) solar mass. The more robust constraints, though not all
in agreement, come from the observational campaigns towards the
Magellanic Clouds (the LMC and the SMC). The analyses towards the
nearby galaxy of M31, in the so called "pixel lensing" regime, have
expanded the perspectives in this field of research. In this
contribution first we draw a critical view on recent results and then
we focus on the pixel lensing analysis towards M31 of the PLAN
collaboration."
So, no matter what certain naysayers proclaim, the MACHO candidacy is
alive and well among professional astrophysicists, having far more
empirical support than WIMPs which have no empirical support.
And note that it is the very important 0.1 to 1.0 solar mass range
that is most viable and interesting.
Don't throw away your ticket stubs just yet. Nature may have some
surprises in store for us.
Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
Discrete Scale Relativity
MACHOs as the dark matter objects?
http://arxiv.org/abs/1201.5262
I quote from the abstract:
"Microlensing is the tool of choice for the search and the analysis of
compact halo objects ("MACHOs"), a still viable class of dark matter
candidates at the galactic scale. Different analyses point towards an
agreement in excluding dark matter MACHOs of less than about 0.1 solar
mass; it remains however an ongoing debate for values in the mass
range (0.1-1) solar mass. The more robust constraints, though not all
in agreement, come from the observational campaigns towards the
Magellanic Clouds (the LMC and the SMC). The analyses towards the
nearby galaxy of M31, in the so called "pixel lensing" regime, have
expanded the perspectives in this field of research. In this
contribution first we draw a critical view on recent results and then
we focus on the pixel lensing analysis towards M31 of the PLAN
collaboration."
So, no matter what certain naysayers proclaim, the MACHO candidacy is
alive and well among professional astrophysicists, having far more
empirical support than WIMPs which have no empirical support.
And note that it is the very important 0.1 to 1.0 solar mass range
that is most viable and interesting.
Don't throw away your ticket stubs just yet. Nature may have some
surprises in store for us.
Robert L. Oldershaw
http://www3.amherst.edu/~rloldershaw
Discrete Scale Relativity
eric gisse
Jan 26, 2012, 8:28:32 AM1/26/12
to
"Robert L. Oldershaw" <rlold...@amherst.edu> wrote in news:mt2.0-32699-
13275...@hydra.herts.ac.uk:
> Shall we let someone knowledgeable inform us about the viability of
> MACHOs as the dark matter objects?
>
> http://arxiv.org/abs/1201.5262
>
"Microlensing observational campaigns have robustly established that
compact halo objects do not constitute the main fraction of galactic
dark matter haloes."
Your theory is dead. Go away.
[snip rest]
13275...@hydra.herts.ac.uk:
> Shall we let someone knowledgeable inform us about the viability of
> MACHOs as the dark matter objects?
>
> http://arxiv.org/abs/1201.5262
>
compact halo objects do not constitute the main fraction of galactic
dark matter haloes."
Your theory is dead. Go away.
[snip rest]
Robert L. Oldershaw
Jan 26, 2012, 11:33:29 AM1/26/12
to
On Jan 26, 8:28 am, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>
> >http://arxiv.org/abs/1201.5262
>
> "Microlensing observational campaigns have robustly established that
> compact halo objects do not constitute the main fraction of galactic
> dark matter haloes."
>
> Your theory is dead. Go away.
---------------------------------------------------------------------------------------------
>
> >http://arxiv.org/abs/1201.5262
>
> "Microlensing observational campaigns have robustly established that
> compact halo objects do not constitute the main fraction of galactic
> dark matter haloes."
>
> Your theory is dead. Go away.
One might ask: What would these "surprises" be that might alter the
current estimates of the abundance of MACHOs [currently billions vs.
zero WIMPs, by the way]?
Here are 3 possibilities, in brief.
1. We have to assume the spatial distribution of the dark matter
objects in order to estimate the abundance. If this spatial
distribution is not what we assume, then the abundance estimate can
change. It could even be far from what we expect.
2. We have to assume a distribution of velocities for the dark matter
objects, and this has generally been assumed to be in the 100-1,000 km/
sec range. But I expect that the MACHOs can have velocities up to at
least 0.9 c, or 2.7 x 10^5 km/sec. If the velocity distribution is
radically different, or only significantly different, from the one we
assume then abundance estimates are radically changed, or
significantly changed.
3. Unknown unknowables [at this point in time]. It is a very unwise
person who neglects this whole category of possible errors.
I agree that something is "dead", Eric, but I do not think it is the
hypothesis that MACHOs make up at least a significant portion of the
dark matter. That is why professional astrophysicists are following
the new and surprising developments in microlensing research with
strong interest.
[Mod. note: this group frowns on the use of the argument from
authority: please stop telling us what you believe professional
astrophysicists to be doing and restrict yourself to arguments based
on the astrophysics -- mjh]
Phillip Helbig---undress to reply
Jan 27, 2012, 3:56:57 AM1/27/12
to
In article <mt2.0-32699...@hydra.herts.ac.uk>, "Robert L.
is, and there must be additional dark matter on larger scales.
> Different analyses point towards an
> agreement in excluding dark matter MACHOs of less than about 0.1 solar
> mass; it remains however an ongoing debate for values in the mass
> range (0.1-1) solar mass.
Right. This means not ruled out. But it doesn't mean ruled in.
> So, no matter what certain naysayers proclaim, the MACHO candidacy is
> alive and well among professional astrophysicists, having far more
> empirical support than WIMPs which have no empirical support.
The WIMPs should be irrelevant. If you say that your objects have more
support than, say, supernatural beings being the dark matter, that is
not much support. Can you make a case without comparing them to WIMPs.
> And note that it is the very important 0.1 to 1.0 solar mass range
> that is most viable and interesting.
It is "viable" because everything else is ruled out.
But the deciding question is whether such objects can make up a
substantial fraction of the cosmological dark matter, as you and Mike
Hawkins claim.
But one failed prediction can rule out a theory, right? What does DSR
have to say about the substructure of the electron?
Oldershaw" <rlold...@amherst.edu> writes:
> "Microlensing is the tool of choice for the search and the analysis of
> compact halo objects ("MACHOs"), a still viable class of dark matter
> candidates at the galactic scale.
Note the galactic scale. We know what the mass associated with galaxies
> "Microlensing is the tool of choice for the search and the analysis of
> compact halo objects ("MACHOs"), a still viable class of dark matter
> candidates at the galactic scale.
is, and there must be additional dark matter on larger scales.
> Different analyses point towards an
> agreement in excluding dark matter MACHOs of less than about 0.1 solar
> mass; it remains however an ongoing debate for values in the mass
> range (0.1-1) solar mass.
> So, no matter what certain naysayers proclaim, the MACHO candidacy is
> alive and well among professional astrophysicists, having far more
> empirical support than WIMPs which have no empirical support.
support than, say, supernatural beings being the dark matter, that is
not much support. Can you make a case without comparing them to WIMPs.
> And note that it is the very important 0.1 to 1.0 solar mass range
> that is most viable and interesting.
But the deciding question is whether such objects can make up a
substantial fraction of the cosmological dark matter, as you and Mike
Hawkins claim.
But one failed prediction can rule out a theory, right? What does DSR
have to say about the substructure of the electron?
Phillip Helbig---undress to reply
Jan 27, 2012, 3:58:14 AM1/27/12
to
In article <mt2.0-32439...@hydra.herts.ac.uk>, "Robert L.
Oldershaw" <rlold...@amherst.edu> writes:
> 2. We have to assume a distribution of velocities for the dark matter
> objects, and this has generally been assumed to be in the 100-1,000 km/
> sec range. But I expect that the MACHOs can have velocities up to at
> least 0.9 c, or 2.7 x 10^5 km/sec.
On what grounds?
> 2. We have to assume a distribution of velocities for the dark matter
> objects, and this has generally been assumed to be in the 100-1,000 km/
> sec range. But I expect that the MACHOs can have velocities up to at
> least 0.9 c, or 2.7 x 10^5 km/sec.
eric gisse
Jan 27, 2012, 4:01:50 AM1/27/12
to
"Robert L. Oldershaw" <rlold...@amherst.edu> wrote in
news:mt2.0-32439...@hydra.herts.ac.uk:
> On Jan 26, 8:28 am, eric gisse <jowr.pi.ons...@gmail.com> wrote:
>>
>> >http://arxiv.org/abs/1201.5262
>>
>> "Microlensing observational campaigns have robustly
>> established that compact halo objects do not constitute the
>> main fraction of galactic dark matter haloes."
>>
>> Your theory is dead. Go away.
> -----------------------------------------------------------------------
> ----------------------
>
> One might ask: What would these "surprises" be that might alter the
> current estimates of the abundance of MACHOs [currently billions vs.
> zero WIMPs, by the way]?
We do not care that you do not like WIMPs.
A bad theory does not make a wrong theory more palatable. Your numerology
is the wrong theory, by the way.
Stop arguing about WIMPs. They do not make you more likely to be right.
>
> Here are 3 possibilities, in brief.
>
> 1. We have to assume the spatial distribution of the dark matter
> objects in order to estimate the abundance. If this spatial
> distribution is not what we assume, then the abundance estimate can
> change. It could even be far from what we expect.
being some value of 'uniform'.
Since you have no description of the distribution anyway, I am unclear as
to what your point is...
>
> 2. We have to assume a distribution of velocities for the dark matter
> objects, and this has generally been assumed to be in the 100-1,000
> km/ sec range.
> But I expect that the MACHOs can have velocities up to
> at least 0.9 c, or 2.7 x 10^5 km/sec.
statement?
Would you like to stand by your claim that dark matter - bound to a
galaxy - is traveling at a significant fraction of light speed?
> If the velocity distribution is
> radically different, or only significantly different, from the one we
> assume then abundance estimates are radically changed, or
> significantly changed.
would quantitatively be altered were that the case.
That's a least publishable unit, in fact.
>
> 3. Unknown unknowables [at this point in time]. It is a very unwise
> person who neglects this whole category of possible errors.
When you can quantify one of them and show how it changes the previously
accepted answer, you have an argument. But until then, you are just
trying to inject uncertainty to the debate so your numerology 'has a
shot'.
>
> I agree that something is "dead", Eric, but I do not think it is the
> hypothesis that MACHOs make up at least a significant portion of the
> dark matter. That is why professional astrophysicists are following
> the new and surprising developments in microlensing research with
> strong interest.
statement.
What I really dislike at the moment is the implied notion that because
MACHOs are worth studying, it means they can explain dark matter. They
can't, and you have not as of yet put forth an argument that shows
otherwise.
In fact, every resource I have seen shows that MACHOs are NOT, in any
way, a significant portion (much less all of it) of dark matter. Even the
article you just cited.
Before you respond, note that every time you argue otherwise it is based
on faith rather than observation. When you have an _observation_ that
agrees with you, let us know.
Robert L. Oldershaw
Jan 27, 2012, 11:45:59 AM1/27/12
to
On Jan 27, 3:58 am, Phillip Helbig---undress to reply
<hel...@astro.multiCLOTHESvax.de> wrote:
> In article <mt2.0-32439-1327595...@hydra.herts.ac.uk>, "Robert L.
On the basic pinciples of Discrete Scale Relativity, which you can
study to your heart's content at:
http://www3.amherst.edu/~rloldershaw
Learning new things is such a joy,
RLO
[Mod. note: I've allowed this on the basis that it answers a question,
but please remember that discussion on this group should be based on
actual astrophysics grounded in observation, not on 'because I say so'
speculation -- mjh]
<hel...@astro.multiCLOTHESvax.de> wrote:
> In article <mt2.0-32439-1327595...@hydra.herts.ac.uk>, "Robert L.
>
> Oldershaw" <rlolders...@amherst.edu> writes:
> > 2. We have to assume a distribution of velocities for the dark matter
> > objects, and this has generally been assumed to be in the 100-1,000 km/
> > sec range. But I expect that the MACHOs can have velocities up to at
> > least 0.9 c, or 2.7 x 10^5 km/sec.
>
> On what grounds?
------------------------------------------------------------------------
> Oldershaw" <rlolders...@amherst.edu> writes:
> > 2. We have to assume a distribution of velocities for the dark matter
> > objects, and this has generally been assumed to be in the 100-1,000 km/
> > sec range. But I expect that the MACHOs can have velocities up to at
> > least 0.9 c, or 2.7 x 10^5 km/sec.
>
> On what grounds?
On the basic pinciples of Discrete Scale Relativity, which you can
study to your heart's content at:
http://www3.amherst.edu/~rloldershaw
Learning new things is such a joy,
RLO
[Mod. note: I've allowed this on the basis that it answers a question,
but please remember that discussion on this group should be based on
actual astrophysics grounded in observation, not on 'because I say so'
speculation -- mjh]
Phillip Helbig---undress to reply
Jan 27, 2012, 5:47:04 PM1/27/12
to
In article <mt2.0-24288...@hydra.herts.ac.uk>, "Robert L.
quantitative, concrete, not retrodictions, capable of being falsified by
observations etc (we agree on this). OK, DSR lives up to this. In the
paper referred to by http://adsabs.harvard.edu/abs/1987ApJ...322...34O
one can read, and I quote:
Two definitive predictions are also pointed out: (1) the model
predicts that the electron will be found to have structure with
radius 4x10^{-17} cm
http://en.wikipedia.org/wiki/Electron#Fundamental_properties says:
Observation of a single electron in a Penning trap shows the upper
limit of the particle's radius is 10^{-22} meters.
Of course, one shouldn't believe everything in Wikipedia, but this has a
reference: http://iopscience.iop.org/1402-4896/1988/T22/016/ .
This means that DSR's definitive prediction is wrong by a factor of at
least 4000. (The observation is an upper limit; there might not be any
structure at all. There might be tighter upper limits already.)
The second prediction was about MACHOs.
So, even if the MACHO observations supported DSR, it is still ruled out
because it made a definitive (your words) prediction which has now been
ruled out.
I see three choices:
o You could claim that the experiment with the Penning trap is
wrong.
o You could add an epicycle to DSR (but, on your own terms, this
would still be a failure).
o You could say that it was a good theory in the sense that it made
a testable prediction, but since the prediction was falsified, it
is time to move on.
Oldershaw" <rlold...@amherst.edu> writes:
> On Jan 27, 3:58 am, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
> > In article <mt2.0-32439-1327595...@hydra.herts.ac.uk>, "Robert L.
> >
> > Oldershaw" <rlolders...@amherst.edu> writes:
> > > 2. We have to assume a distribution of velocities for the dark matter
> > > objects, and this has generally been assumed to be in the 100-1,000 km/
> > > sec range. But I expect that the MACHOs can have velocities up to at
> > > least 0.9 c, or 2.7 x 10^5 km/sec.
> >
> > On what grounds?
> ------------------------------------------------------------------------
>
> On the basic pinciples of Discrete Scale Relativity, which you can
> study to your heart's content at:
>
> http://www3.amherst.edu/~rloldershaw
>
> Learning new things is such a joy,
You've said many times that theories should make testable predictions:
> On Jan 27, 3:58 am, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
> > In article <mt2.0-32439-1327595...@hydra.herts.ac.uk>, "Robert L.
> >
> > Oldershaw" <rlolders...@amherst.edu> writes:
> > > 2. We have to assume a distribution of velocities for the dark matter
> > > objects, and this has generally been assumed to be in the 100-1,000 km/
> > > sec range. But I expect that the MACHOs can have velocities up to at
> > > least 0.9 c, or 2.7 x 10^5 km/sec.
> >
> > On what grounds?
> ------------------------------------------------------------------------
>
> On the basic pinciples of Discrete Scale Relativity, which you can
> study to your heart's content at:
>
> http://www3.amherst.edu/~rloldershaw
>
> Learning new things is such a joy,
quantitative, concrete, not retrodictions, capable of being falsified by
observations etc (we agree on this). OK, DSR lives up to this. In the
paper referred to by http://adsabs.harvard.edu/abs/1987ApJ...322...34O
one can read, and I quote:
Two definitive predictions are also pointed out: (1) the model
predicts that the electron will be found to have structure with
radius 4x10^{-17} cm
http://en.wikipedia.org/wiki/Electron#Fundamental_properties says:
Observation of a single electron in a Penning trap shows the upper
limit of the particle's radius is 10^{-22} meters.
Of course, one shouldn't believe everything in Wikipedia, but this has a
reference: http://iopscience.iop.org/1402-4896/1988/T22/016/ .
This means that DSR's definitive prediction is wrong by a factor of at
least 4000. (The observation is an upper limit; there might not be any
structure at all. There might be tighter upper limits already.)
The second prediction was about MACHOs.
So, even if the MACHO observations supported DSR, it is still ruled out
because it made a definitive (your words) prediction which has now been
ruled out.
I see three choices:
o You could claim that the experiment with the Penning trap is
wrong.
o You could add an epicycle to DSR (but, on your own terms, this
would still be a failure).
o You could say that it was a good theory in the sense that it made
a testable prediction, but since the prediction was falsified, it
is time to move on.
eric gisse
Jan 28, 2012, 3:09:47 AM1/28/12
to
"Robert L. Oldershaw" <rlold...@amherst.edu> wrote in
news:mt2.0-24288...@hydra.herts.ac.uk:
> On Jan 27, 3:58 am, Phillip Helbig---undress to reply
> <hel...@astro.multiCLOTHESvax.de> wrote:
>> In article <mt2.0-32439-1327595...@hydra.herts.ac.uk>, "Robert L.
>>
>> Oldershaw" <rlolders...@amherst.edu> writes:
>> > 2. We have to assume a distribution of velocities for the dark
>> > matter objects, and this has generally been assumed to be in the
>> > 100-1,000 km/ sec range. But I expect that the MACHOs can have
>> > velocities up to at least 0.9 c, or 2.7 x 10^5 km/sec.
>>
>> On what grounds?
> -----------------------------------------------------------------------
> -
>
> On the basic pinciples of Discrete Scale Relativity, which you can
> study to your heart's content at:
>
> http://www3.amherst.edu/~rloldershaw
>
> Learning new things is such a joy,
I am noting a somewhat suspicious lack of observational evidence. Which,
curiously, is a very common theme when it comes to your claims.
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