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dark matter

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  dark matter RichD <r_delaney2001@yahoo.com> - 2016-05-03 10:14 -0700
    Re: dark matter Tom Roberts <tjroberts137@sbcglobal.net> - 2016-05-03 12:41 -0500
      Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-03 23:53 -0700
        Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-03 23:54 -0700
        Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-04 07:34 -0700
          Re: dark matter Gary Harnagel <hitlong@yahoo.com> - 2016-05-04 09:55 -0700
            Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-04 12:37 -0700
              Re: dark matter Gary Harnagel <hitlong@yahoo.com> - 2016-05-04 14:52 -0700
          Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-04 10:32 -0700
          Re: dark matter Tom Roberts <tjroberts137@sbcglobal.net> - 2016-05-06 10:38 -0500
            Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-06 10:25 -0700
        Re: dark matter Tom Roberts <tjroberts137@sbcglobal.net> - 2016-05-06 10:27 -0500
          Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-06 10:42 -0700
            Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-06 10:58 -0700
            Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-06 11:33 -0700
              Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-06 12:51 -0700
                Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-06 12:58 -0700
                  Re: dark matter Francis Oldogf <francisoldogf@gmail.com> - 2016-05-08 03:11 -0700
                    Re: dark matter Alan Folmsbee <omnilobe@gmail.com> - 2016-05-08 03:44 -0700
                      Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-08 11:22 -0700
                        Re: dark matter Francis Oldogf <francisoldogf@gmail.com> - 2016-05-09 07:19 -0700
                          Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-09 11:40 -0700
      Re: dark matter RichD <r_delaney2001@yahoo.com> - 2016-05-04 10:54 -0700
        Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-04 12:00 -0700
          Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-04 12:40 -0700
        Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-04 12:47 -0700
        Re: dark matter Tom Roberts <tjroberts137@sbcglobal.net> - 2016-05-09 11:16 -0500
          Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-09 11:52 -0700
          Re: dark matter RichD <r_delaney2001@yahoo.com> - 2016-05-10 11:36 -0700
            Re: dark matter Gary Harnagel <hitlong@yahoo.com> - 2016-05-10 12:11 -0700
    Re: dark matter Odd Bodkin <bodkinodd@gmail.com> - 2016-05-03 12:57 -0500
    Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-03 12:17 -0700
      Re: dark matter Tom Roberts <tjroberts137@sbcglobal.net> - 2016-05-03 17:58 -0500
        Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-03 17:03 -0700
    Re: dark matter Alan Folmsbee <omnilobe@gmail.com> - 2016-05-03 17:37 -0700
      Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-03 17:46 -0700
        Re: dark matter Alan Folmsbee <omnilobe@gmail.com> - 2016-05-04 13:20 -0700
    Re: dark matter The Starmaker <starmaker@ix.netcom.com> - 2016-05-03 20:46 -0700
    Re: dark matter dlzc <dlzc1@cox.net> - 2016-05-04 07:39 -0700
      Re: dark matter "Ross A. Finlayson" <ross.finlayson@gmail.com> - 2016-05-04 10:36 -0700
    Re: dark matter Carl Susumu <numbernumber1212@gmail.com> - 2016-05-04 13:26 -0700
    Re: dark matter Carl Susumu <numbernumber1212@gmail.com> - 2016-05-09 12:57 -0700
    Re: dark matter alsor@interia.pl - 2016-05-10 12:38 -0700
      Re: dark matter Francis Oldogf <francisoldogf@gmail.com> - 2016-05-11 03:54 -0700
        Re: dark matter nero <oldogf@yahoo.it> - 2016-05-14 08:05 -0700
    dark matter David Fuller <fuller.david@hotmail.com> - 2016-05-11 06:30 -0700
      Re: dark matter The Starmaker <starmaker@ix.netcom.com> - 2016-05-11 12:41 -0700
        Re: dark matter The Starmaker <starmaker@ix.netcom.com> - 2016-05-11 18:47 -0700

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#383116

We suspected the dark matter yesterday ( almost 100 years ago !) when we discovered that the galaxies and the clusters were spinning too quickly ( 5 times more! )..
 Today shall we anwer in that same way ?
 To measure the distance of a star is not easy : the light of the neatest star takes more than 4 years for arriving to us . So we use   m any kinds of aproximation for having its distance when we cannot use the parallax methodical  ( it gives the real distance measuring the angle earth-star at six mounths time distance ; of course that angle can be very little depending to space-distance , but always positive for definition )
 Untill the year 2000 we knew the parallaxes of only 300 near stars.. then the HST came and it measured half million of parallaxes .....   the hidden problem is that the 49% are impossibly negative !
 Which rigth meaning to give to that realty , i think , is the challenge .. More than the dark matter ?
 ( if something is not clear or uncorrect , please write it.! Tomorrow we shall continue )

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#383136

On Monday, May 9, 2016 at 7:19:22 AM UTC-7, Francis Oldogf wrote:
> We suspected the dark matter yesterday ( almost 100 years ago !) when we discovered that the galaxies and the clusters were spinning too quickly ( 5 times more! )..
>  Today shall we anwer in that same way ?
>  To measure the distance of a star is not easy : the light of the neatest star takes more than 4 years for arriving to us . So we use   m any kinds of aproximation for having its distance when we cannot use the parallax methodical  ( it gives the real distance measuring the angle earth-star at six mounths time distance ; of course that angle can be very little depending to space-distance , but always positive for definition )
>  Untill the year 2000 we knew the parallaxes of only 300 near stars.. then the HST came and it measured half million of parallaxes .....   the hidden problem is that the 49% are impossibly negative !
>  Which rigth meaning to give to that realty , i think , is the challenge .. More than the dark matter ?
>  ( if something is not clear or uncorrect , please write it.! Tomorrow we shall continue )

When you say "it's a hidden problem" 
that "49% are impossibly negative" of 
the sky survey - doesn't that correspond 
with "almost" a steady state universe 
and "barely" an expanding universe, just 
like space-time these days is almost flat 
and barely curving, with a "mathematical 
infinitesimal" for the cosmological constant?

Thank you

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#382777

On May 3, tjrob137 wrote: 
>> we don't know what this 'dark matter' stuff is, 
>> and there's a worldwide race to detect it. My question 
>> is, what DO we know about it? Or, what are the working assumptions? 
>
> That it comprises a great majority of all matter in the universe. 
> This is based on cosmological models.... 

You mean, Big Bang theory? I thought it was unexplained galaxy rotation. 

>> For instance, is it supposed to fit into the existing 
>> fermion/boson structure? 
> 
> No, because we think we understand "the existing fermion/boson 
> structure" as it is well modeled by the standard model. There are 
> no bound states or elementary particles in the standard model that 
> could plausibly be dark matter. 

Not known particles, but maybe new fermions... what makes 6 the magic number?

>> There seems to be an assumption that it's uncharged... reason? 
>> Perhaps it does carry electric charge, which all cancels out.
>
> It does not interact with light; all charged particles do. 
> But atoms have net neutral charge, yet still interact with 
> light and other E&M phenomena.

How do they know?  If the stuff is floating in space, 
thermalized with the CMB radiation, Hubble wouldn't see it.

>> Or, maybe it's some kind of field, which fills the universe, 
>> a la Higgs. Is there reason to reject this? 
>
> _ALL_ "particles" in the standard model are quantum excitations 
> of an underlying field. So we don't "reject" this, we EXPECT it. 

Well, not a 'local field', as in EM or QCD, but rather akin 
to the Higgs, a scalar field which fills the universe, with 
non-zero value everywhere.

>> Also, its distribution is unclear - it binds galaxies, 
>> does that necessarily mean it's uniformly distributed? 
>
> No. It is definitely NOT uniformly distributed. There are many 
> maps of dark  matter distributions, obtained via gravitational 
> lensing of more distant luminous objects. 

Not uniformly distributed throughout all space, but 
uniformly distributed within each galaxy.  How do we 
know it isn't concentrated at the center, for instance?

>> There are some allusions to a "halo", whatever that means. 
>
> It means that the dark matter distribution of most galaxies 
> has a wider distribution than the luminous matter. 

How do they know? 

-- 
Rich

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#382779

On Wednesday, May 4, 2016 at 10:54:51 AM UTC-7, RichD wrote:
> On May 3, tjrob137 wrote: 
> >> we don't know what this 'dark matter' stuff is, 
> >> and there's a worldwide race to detect it. My question 
> >> is, what DO we know about it? Or, what are the working assumptions? 
> >
> > That it comprises a great majority of all matter in the universe. 
> > This is based on cosmological models.... 
> 
> You mean, Big Bang theory? I thought it was unexplained galaxy rotation. 
> 
> >> For instance, is it supposed to fit into the existing 
> >> fermion/boson structure? 
> > 
> > No, because we think we understand "the existing fermion/boson 
> > structure" as it is well modeled by the standard model. There are 
> > no bound states or elementary particles in the standard model that 
> > could plausibly be dark matter. 
> 
> Not known particles, but maybe new fermions... what makes 6 the magic number?
> 
> >> There seems to be an assumption that it's uncharged... reason? 
> >> Perhaps it does carry electric charge, which all cancels out.
> >
> > It does not interact with light; all charged particles do. 
> > But atoms have net neutral charge, yet still interact with 
> > light and other E&M phenomena.
> 
> How do they know?  If the stuff is floating in space, 
> thermalized with the CMB radiation, Hubble wouldn't see it.
> 
> >> Or, maybe it's some kind of field, which fills the universe, 
> >> a la Higgs. Is there reason to reject this? 
> >
> > _ALL_ "particles" in the standard model are quantum excitations 
> > of an underlying field. So we don't "reject" this, we EXPECT it. 
> 
> Well, not a 'local field', as in EM or QCD, but rather akin 
> to the Higgs, a scalar field which fills the universe, with 
> non-zero value everywhere.
> 
> >> Also, its distribution is unclear - it binds galaxies, 
> >> does that necessarily mean it's uniformly distributed? 
> >
> > No. It is definitely NOT uniformly distributed. There are many 
> > maps of dark  matter distributions, obtained via gravitational 
> > lensing of more distant luminous objects. 
> 
> Not uniformly distributed throughout all space, but 
> uniformly distributed within each galaxy.  How do we 
> know it isn't concentrated at the center, for instance?
> 
> >> There are some allusions to a "halo", whatever that means. 
> >
> > It means that the dark matter distribution of most galaxies 
> > has a wider distribution than the luminous matter. 
> 
> How do they know? 
> 
> -- 
> Rich

"DAMA, a collaboration of physicists from Italy and China, 
says it has directly observed dark matter in a sodium-iodide 
detector located beneath Gran Sasso mountain east of Rome. 
The basis for its claim is a seasonal variation in the number 
of tiny flashes of light that should occur when dark matter 
collides with nuclei in the detector. The group argues that 
this variation - which peaks in June and has a minimum in 
December - is just what would be expected as the Earth moves 
through a "halo" of dark matter surrounding the Milky Way."

 -- http://physicsworld.com/cws/article/news/2015/jan/12/new-calculations-support-dark-matter-discovery-by-dama-say-physicists

Peaking at summer solstice and dropping at winter solstice 
mostly is pointing to a solar effect, not "halo of dark 
matter about the Milky Way" galaxy.  That looks like a 
gamma-ray detector.  What kinds of radiation cause sodium 
iodide in solution to fluoresce?

Gran Sasso definitely looks like a cosmic ray detector.  

"Del Nobile stops short of arguing that his group's analysis 
now makes it more likely that DAMA has seen dark matter, 
cautioning that the work involved simplifying the properties 
of the galactic dark-matter halo. But he says the onus is now 
on rival experimental groups to "spell out their assumptions" 
when claiming to have ruled out the DAMA result. "

That's a gamma-ray (or cosmic ray) detector.

Framing the results in terms of some "abstract galaxy halo" 
can be as simply refuted as "measurement effect" or "not 
classical, not relativistic", also "lacking scientific grounds".

Reading the article helps clarify that finding "new" particles 
is as much finding what the interactions of the existing particles 
_are_, and calling those "virtual" particles, as they are not 
particles but denotational conveniences and book-keeping place-holders 
for explanations in effect.  This is the "fill in the blank" approach 
instead of "final cause as first principle" approach, to theoretical 
physics, it's "trial-and-error" or "experimental theoretical physics", 
which should be "theoretical physics backed by experimental physics".

http://adsabs.harvard.edu/full/1977ICRC....5...76B

That is to say, references to "dark matter" are a manner of speaking, 
but really it is the mysterious effects and regimes to which it 
collectively refers that theoretical physics writ large should 
honestly and conscientiously spell out as not fitting the model, 
instead of fitting the model to it.

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#382783

Dear Ross A. Finlayson:

On Wednesday, May 4, 2016 at 12:01:02 PM UTC-7, Ross A. Finlayson wrote:
...
>  -- http://physicsworld.com/cws/article/news/2015/jan/12/new-calculations-support-dark-matter-discovery-by-dama-say-physicists

What about Dark Matter should vary seasonally?  What about Earth changes with the seasons?  Its distance from the Sun... and its neutrino outflow.  Its orientation with respect to the Milky Way, for a smaller effect.

...
> http://adsabs.harvard.edu/full/1977ICRC....5...76B
> 
> That is to say, references to "dark matter" are a
> manner of speaking, but really it is the mysterious
> effects and regimes to which it collectively refers
> that theoretical physics writ large should honestly
> and conscientiously spell out as not fitting the
> model, instead of fitting the model to it.

Amen.

David A. Smith

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#382784

Dear RichD:

On Wednesday, May 4, 2016 at 10:54:51 AM UTC-7, RichD wrote:
> On May 3, tjrob137 wrote: 
...
> >> There are some allusions to a "halo", whatever that means. 
> >
> > It means that the dark matter distribution of most
> > galaxies has a wider distribution than the luminous
> > matter. 
> 
> How do they know? 

Understand that "knowing" is something we can never achieve, by sitting on Earth.  We are limited to observation.  In our galaxy, some of the Dark Matter is above and below the ecliptic.  We can see its effects.  Here is (one way) how:
http://arxiv.org/abs/1604.05493

David A. Smith

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#383124

On 5/4/16 5/4/16 - 12:54 PM, RichD wrote:
> On May 3, tjrob137 wrote:
>>> we don't know what this 'dark matter' stuff is,
>>> and there's a worldwide race to detect it. My question
>>> is, what DO we know about it? Or, what are the working assumptions?
>> That it comprises a great majority of all matter in the universe.
>> This is based on cosmological models....
>
> You mean, Big Bang theory? I thought it was unexplained galaxy rotation.

The need for dark matter is based on several completely different 
considerations; remarkably all require (or are at least consistent with) similar 
amounts:
  * galaxy rotation curves
  * big-bang nucleosynthesis
  * /\CDM cosmological models
  * models of galaxy formation in the early universe


>>> For instance, is it supposed to fit into the existing
>>> fermion/boson structure?
>>
>> No, because we think we understand "the existing fermion/boson
>> structure" as it is well modeled by the standard model. There are
>> no bound states or elementary particles in the standard model that
>> could plausibly be dark matter.
>
> Not known particles, but maybe new fermions... what makes 6 the magic number?

	[I don't know where you get "6". The standard model has 3
	 generations, each with two quarks and two leptons (plus
	 antiparticles); plus many bosons.]

Basing the standard model on N generations of fermions, each of which contains 
two quarks and two leptons, permits the straightforward cancellation of 
anomalies (which if not canceled would restrict the domain of the model to a 
rather useless low-energy region much smaller than is already explored).

Measurements of the width of the Z put a limit on the number N of neutrino 
generations, and that limit is 2.98+-0.01. Of course three flavors of neutrinos 
have been observed, a well as 3 generations of both quarks and leptons. This 
implies that any 4th generation neutrino must have a mass much greater than the 
Z (91 GeV) -- given that the known neutrinos all have masses << 1 eV, this seems 
unlikely.

	An exception would be a "sterile neutrino" which does not
	couple to the Z, and therefore not to the quarks and other
	leptons. There are some experimental limits on this, but
	they are not very compelling.

Bottom line: the standard model has no room for any particle that could 
plausibly be dark matter. Extensions to the SM, notably supersymmetry, have many 
plausible candidates.


>>> There seems to be an assumption that it's uncharged... reason?
>>> Perhaps it does carry electric charge, which all cancels out.
>>
>> It does not interact with light; all charged particles do.
>> But atoms have net neutral charge, yet still interact with
>> light and other E&M phenomena.
>
> How do they know?  If the stuff is floating in space,
> thermalized with the CMB radiation, Hubble wouldn't see it.

We know it is not gas, as telescopes can see that. We know it is not an enormous 
number of planets [#] because micro-lensing searches would see them. No 
hypothesis that dark matter is like anything we have seen on earth is viable, 
given the experimental and observational record.

	[#] How many jupiter-sized planets would be required in the
	solar system to exceed the sun's mass by a factor of 5-10?
	How many earth-sized planets? Compare to how many there
	actually are.


>>> Also, its distribution is unclear - it binds galaxies,
>>> does that necessarily mean it's uniformly distributed?
>>
>> No. It is definitely NOT uniformly distributed. There are many
>> maps of dark  matter distributions, obtained via gravitational
>> lensing of more distant luminous objects.
>
> Not uniformly distributed throughout all space, but
> uniformly distributed within each galaxy.  How do we
> know it isn't concentrated at the center, for instance?

We _DO_ know that in several galaxies for which the dark-matter distribution is 
known (from gravitational lensing), it is concentrated at the center.


>>> There are some allusions to a "halo", whatever that means.
>>
>> It means that the dark matter distribution of most galaxies
>> has a wider distribution than the luminous matter.
>
> How do they know?

By measuring the dark-matter distributions of several galaxies via gravitational 
lensing.


Tom Roberts

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#383138

On Monday, May 9, 2016 at 9:16:05 AM UTC-7, tjrob137 wrote:
> On 5/4/16 5/4/16 - 12:54 PM, RichD wrote:
> > On May 3, tjrob137 wrote:
> >>> we don't know what this 'dark matter' stuff is,
> >>> and there's a worldwide race to detect it. My question
> >>> is, what DO we know about it? Or, what are the working assumptions?
> >> That it comprises a great majority of all matter in the universe.
> >> This is based on cosmological models....
> >
> > You mean, Big Bang theory? I thought it was unexplained galaxy rotation.
> 
> The need for dark matter is based on several completely different 
> considerations; remarkably all require (or are at least consistent with) similar 
> amounts:
>   * galaxy rotation curves
>   * big-bang nucleosynthesis
>   * /\CDM cosmological models
>   * models of galaxy formation in the early universe
> 
> 
> >>> For instance, is it supposed to fit into the existing
> >>> fermion/boson structure?
> >>
> >> No, because we think we understand "the existing fermion/boson
> >> structure" as it is well modeled by the standard model. There are
> >> no bound states or elementary particles in the standard model that
> >> could plausibly be dark matter.
> >
> > Not known particles, but maybe new fermions... what makes 6 the magic number?
> 
> 	[I don't know where you get "6". The standard model has 3
> 	 generations, each with two quarks and two leptons (plus
> 	 antiparticles); plus many bosons.]
> 
> Basing the standard model on N generations of fermions, each of which contains 
> two quarks and two leptons, permits the straightforward cancellation of 
> anomalies (which if not canceled would restrict the domain of the model to a 
> rather useless low-energy region much smaller than is already explored).
> 
> Measurements of the width of the Z put a limit on the number N of neutrino 
> generations, and that limit is 2.98+-0.01. Of course three flavors of neutrinos 
> have been observed, a well as 3 generations of both quarks and leptons. This 
> implies that any 4th generation neutrino must have a mass much greater than the 
> Z (91 GeV) -- given that the known neutrinos all have masses << 1 eV, this seems 
> unlikely.
> 
> 	An exception would be a "sterile neutrino" which does not
> 	couple to the Z, and therefore not to the quarks and other
> 	leptons. There are some experimental limits on this, but
> 	they are not very compelling.
> 
> Bottom line: the standard model has no room for any particle that could 
> plausibly be dark matter. Extensions to the SM, notably supersymmetry, have many 
> plausible candidates.
> 
> 
> >>> There seems to be an assumption that it's uncharged... reason?
> >>> Perhaps it does carry electric charge, which all cancels out.
> >>
> >> It does not interact with light; all charged particles do.
> >> But atoms have net neutral charge, yet still interact with
> >> light and other E&M phenomena.
> >
> > How do they know?  If the stuff is floating in space,
> > thermalized with the CMB radiation, Hubble wouldn't see it.
> 
> We know it is not gas, as telescopes can see that. We know it is not an enormous 
> number of planets [#] because micro-lensing searches would see them. No 
> hypothesis that dark matter is like anything we have seen on earth is viable, 
> given the experimental and observational record.
> 
> 	[#] How many jupiter-sized planets would be required in the
> 	solar system to exceed the sun's mass by a factor of 5-10?
> 	How many earth-sized planets? Compare to how many there
> 	actually are.
> 
> 
> >>> Also, its distribution is unclear - it binds galaxies,
> >>> does that necessarily mean it's uniformly distributed?
> >>
> >> No. It is definitely NOT uniformly distributed. There are many
> >> maps of dark  matter distributions, obtained via gravitational
> >> lensing of more distant luminous objects.
> >
> > Not uniformly distributed throughout all space, but
> > uniformly distributed within each galaxy.  How do we
> > know it isn't concentrated at the center, for instance?
> 
> We _DO_ know that in several galaxies for which the dark-matter distribution is 
> known (from gravitational lensing), it is concentrated at the center.
> 
> 
> >>> There are some allusions to a "halo", whatever that means.
> >>
> >> It means that the dark matter distribution of most galaxies
> >> has a wider distribution than the luminous matter.
> >
> > How do they know?
> 
> By measuring the dark-matter distributions of several galaxies via gravitational 
> lensing.
> 
> 
> Tom Roberts

Like there is a fluid model for charge, 
and a color model for flavour, still it 
might be that really it's that fluids 
have a charge model and colors, a flavour 
model (as it were), that the non-classical 
effects of the charge (or wave) and flavour 
(or colour) have to roll-up these notions 
of the sum-of-histories or path integral.

Again this is about that equipping the 
mathematical model automatically equips 
the physical model.

Thank you for helping to clarify what 
dark matter "isn't".

About supersymmetry (instead of symmetry-
breaking, and besides that this can be in 
something besides anti-de Sitter space where 
instead there is a "hologram symmetry" of the 
3-D basically to-and-from the N-D in continuum 
mechanics), I wonder how it might be said that 
the gravitic (for no other force) effects might 
be so framed in the theory.

(This is with a notion of "gravific" force or 
fall gravity instead of pull gravity and how 
that has all the same classical solutions for 
classical inertia and momentum.)

Then, back to the "lensing" model about wave and 
geometric optics of light, besides that stellar 
bodies might have a Fresnel-like effect, there 
is that there may be "focii" instead of just one 
focus in terms of duplicated and off-centered 
images and intervening material.

Finding how to equip the mathematical models of 
waves, light, color space, and etcetera with these 
"point, local, global, total" considerations for 
particle/wave interactions as of a field theory 
seems to offer possibilities for application or 
tractable means of physical prediction.

That is to say, our classical model is a result of 
the absolute and relativistic model (while it's 
also still the center).

Thank you

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#383212

On May 9, tjrob137 wrote:
>>>> My question is, what DO we know about it? Or, what are the working 
>>>>assumptions?
>
>>> That it comprises a great majority of all matter in the universe.
>>> This is based on cosmological models....
>
>> You mean, Big Bang theory? I thought it was unexplained galaxy rotation.
> 
> The need for dark matter is based on several completely different 
> considerations; remarkably all require (or are at least consistent 
> with) similar amounts:
>   * galaxy rotation curves
>   * big-bang nucleosynthesis

hmmm, I haven't seen that.  The usual tale is, appearance 
of particle plasma, nucleon synthesis, hydrogen atoms, then 
light breaks loose.  No place for the enigmatic dark matter. 
If it was created at Genesis, it should have a dramatic impact 
from time zero -  

>   * /\CDM cosmological models
>   * models of galaxy formation in the early universe
> 
> >>> For instance, is it supposed to fit into the existing
> >>> fermion/boson structure?
>
> >> No, because we think we understand "the existing fermion/boson
> >> structure" as it is well modeled by the standard model. There are
> >> no bound states or elementary particles in the standard model that
> >> could plausibly be dark matter.
> >
>> Not known particles, but maybe new fermions... what makes 6 the 
>> magic number?
>  
> Basing the standard model on N generations of fermions, each of which 
> contains two quarks and two leptons, permits the straightforward 
> cancellation of anomalies 
> Measurements of the width of the Z put a limit on the number N of neutrino 
> generations, and that limit is 2.98+-0.01. Of course three flavors of 
> neutrinos have been observed, a well as 3 generations of both quarks and 
> leptons. This implies that any 4th generation neutrino must have a mass 
> much greater than the Z (91 GeV) -- given that the known neutrinos all 
> have masses << 1 eV, this seems unlikely.

Is there a way to detect such heavy neutrinos?  They 
don't cage very helpfully - 
 
> Bottom line: the standard model has no room for any particle that could 
> plausibly be dark matter. Extensions to the SM, notably supersymmetry, 
> have many plausible candidates.
> 
> >>> There seems to be an assumption that it's uncharged... reason?
> >>> Perhaps it does carry electric charge, which all cancels out.
> >>
> >> It does not interact with light; all charged particles do.
> >> But atoms have net neutral charge, yet still interact with
> >> light and other E&M phenomena.
> >
> > How do they know?  If the stuff is floating in space,
> > thermalized with the CMB radiation, Hubble wouldn't see it.
> 
> We know it is not gas, as telescopes can see that. 

We see nebula, so presumably this new matter would be similarly visible.

> No hypothesis that dark matter is like anything we have seen on earth is 
> viable, given the experimental and observational record.

Space is cold, at CMB temperature...  how about if the 
stuff is in a superconducting phase?  Then it would have 
electrical properties, but maybe invisible.
 
> >>> Also, its distribution is unclear - it binds galaxies,
> >>> does that necessarily mean it's uniformly distributed?
> >>
> >> No. It is definitely NOT uniformly distributed. There are many
> >> maps of dark  matter distributions, obtained via gravitational
> >> lensing of more distant luminous objects.
> >
> > Not uniformly distributed throughout all space, but
> > uniformly distributed within each galaxy.  How do we
> > know it isn't concentrated at the center, for instance?
> 
> We _DO_ know that in several galaxies for which the dark-matter 
> distribution is known (from gravitational lensing), it is concentrated 
> at the center.
>
> >>> There are some allusions to a "halo", whatever that means.
> >>
> >> It means that the dark matter distribution of most galaxies
> >> has a wider distribution than the luminous matter.
> >
> > How do they know?
> 
> By measuring the dark-matter distributions of several galaxies via 
> gravitational lensing.

Interesting, as this implies that its distribution is not 
uniform, from galaxy to galaxy.  Might this be very significant?
 
--
Rich

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#383214

On Tuesday, May 10, 2016 at 12:36:41 PM UTC-6, RichD wrote:
>
> On May 9, tjrob137 wrote:
> >
> > The need for dark matter is based on several completely different 
> > considerations; remarkably all require (or are at least consistent 
> > with) similar amounts:
> >   * galaxy rotation curves
> >   * big-bang nucleosynthesis
> 
> hmmm, I haven't seen that.  The usual tale is, appearance 
> of particle plasma, nucleon synthesis, hydrogen atoms, then 
> light breaks loose.  No place for the enigmatic dark matter. 
> If it was created at Genesis, it should have a dramatic impact 
> from time zero -  
> 
> >   * /\CDM cosmological models
> >   * models of galaxy formation in the early universe
> > 
> > Basing the standard model on N generations of fermions, each of which 
> > contains two quarks and two leptons, permits the straightforward 
> > cancellation of anomalies 
> > Measurements of the width of the Z put a limit on the number N of neutrino 
> > generations, and that limit is 2.98+-0.01. Of course three flavors of 
> > neutrinos have been observed, a well as 3 generations of both quarks and 
> > leptons. This implies that any 4th generation neutrino must have a mass 
> > much greater than the Z (91 GeV) -- given that the known neutrinos all 
> > have masses << 1 eV, this seems unlikely.
> 
> Is there a way to detect such heavy neutrinos?  They 
> don't cage very helpfully - 
>  
> > Bottom line: the standard model has no room for any particle that could 
> > plausibly be dark matter. Extensions to the SM, notably supersymmetry, 
> > have many plausible candidates.
> > 
> > We know it is not gas, as telescopes can see that. 
> 
> We see nebula, so presumably this new matter would be similarly visible.

That depends on what you mean by "visible."  They found matter in the
galactic halo about equal to half the mass of all the stars in the galaxy:
The absorption of light from distant sources was measured:

http://hubblesite.org/newscenter/archive/releases/2015/15/full/

Of course, that's still not enough to account for velocity curves by about
an order of magnitude, but it teaches us that dark matter doesn't have to
be one thing.  Or maybe it teaches us that we may not need to account for
as much as originally thought.

> > No hypothesis that dark matter is like anything we have seen on earth is 
> > viable, given the experimental and observational record.
> 
> Space is cold, at CMB temperature...  how about if the 
> stuff is in a superconducting phase?  Then it would have 
> electrical properties, but maybe invisible.

> > We _DO_ know that in several galaxies for which the dark-matter 
> > distribution is known (from gravitational lensing), it is concentrated 
> > at the center.
> > 
> > By measuring the dark-matter distributions of several galaxies via 
> > gravitational lensing.
> 
> Interesting, as this implies that its distribution is not 
> uniform, from galaxy to galaxy.  Might this be very significant?
>  
> --
> Rich

Personally, I favor mirror matter as a candidate:

http://arxiv.org/abs/hep-ex/0311031

or maybe matter in adjacent branes.

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#382713

On 5/3/2016 12:14 PM, RichD wrote:
> OK, we don't know what this 'dark matter' stuff is,
> and there's a worldwide race to detect it.  My question
> is, what DO we know about it?  Or, what are the working assumptions?

That it is not baryonic.
Not neutrinos.
Does not react electromagnetically (hence not charged).

Have you tried online resources, even something like wikipedia?

>
> For instance, is it supposed to fit into the existing
> fermion/boson structure?  There seems to be an assumption
> that it's uncharged... reason?  Perhaps it does carry
> electric charge, which all cancels out, per the usual
> 'no net universal charge' pseudo-law of science.
>
> Or, maybe it's some kind of field, which fills the universe,
> a la Higgs.  Is there reason to reject this?
>
> Also, its distribution is unclear - it binds galaxies,
> does that necessarily mean it's uniformly distributed?
> There are some allusions to a "halo", whatever that means.
>
> I'm trying to figure out what's known, and what's ruled out -
>
> --
> Rich
>


-- 
Odd Bodkin --- maker of fine toys, tools, tables

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#382724

Dear Rich D:

On Tuesday, May 3, 2016 at 10:14:47 AM UTC-7, RichD wrote:
> OK, we don't know what this 'dark matter' stuff is, 
> and there's a worldwide race to detect it.  My question 
> is, what DO we know about it?  Or, what are the working
> assumptions?

The fact is, it is called Dark, because it is not represented by the bare, bright stars found at the center of a spiral galaxy.  They for a simple ratio of mass (based on rotation curve at that radius), and luminosity from that region, and apply that formula across the entire disk.  When they do, they find they have too much mass to get the curve based on the light being produced.

So it is a "mystery envelope" that contains:
- plasma (invisible at visible and longer wavelengths),
- dust (decreases luminosity),
- planets, stars with photospheres (appears cooler, and the "center" does not have these),
- black holes (not the central one, already factored in),
- cold neutrinos (have to move slow enough to orbit), and
- exotic matter

> For instance, is it supposed to fit into the existing
> fermion/boson structure?

*Some* of it can.

> There seems to be an assumption that it's uncharged...
> reason?

Exotic matter cannot have charge, because the "exotic matter" answer would interact with light, so could have friction, could NOT behave like the "fairy story" that "all Dark Matter is non-baryonic".

> Perhaps it does carry electric charge, which all
> cancels out, per the usual 'no net universal charge'
> pseudo-law of science.

*Some* of it can.

> Or, maybe it's some kind of field, which fills the
> universe,  a la Higgs.  Is there reason to reject this?

It is not uniformly distributed, but orbits around mass centers.

> Also, its distribution is unclear - it binds galaxies,

Internally, and in streamers between galaxies.

> does that necessarily mean it's uniformly distributed?

Well, Dark Energy is such a "field" (or boundary condition), and is Universally uniformly distributed, at each epoch.  No spatial variance.
  
> There are some allusions to a "halo", whatever that means.

It means it orbits the center of a spiral galaxy.

> I'm trying to figure out what's known, and what's
> ruled out - 

What is known, is Dark Matter:
- *must* be passing through our solar system (essentially) all the time;
http://www.iflscience.com/space/star-passed-less-light-year-earth
... and you can *bet* this does not show up in "luminosity" figures.
- is not WIMPs of up to TeV energy levels (based on astronomical observations);
- decreases in total quantity with (essentially) each determination as we find surprising amounts of normal matter, in places we did not expect to find it;
- is a work in progress.

So basically, it is *still* a mystery envelope.

David A. Smith

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#382751

On 5/3/16 5/3/16   2:17 PM, dlzc wrote:
> The fact is, it is called Dark, because it is not represented by the bare,
> bright stars found at the center of a spiral galaxy.  They for a simple ratio
> of mass (based on rotation curve at that radius), and luminosity from that
> region, and apply that formula across the entire disk.  When they do, they
> find they have too much mass to get the curve based on the light being
> produced. So it is a "mystery envelope" that contains:
> - plasma (invisible at visible and longer wavelengths),

No, not at all. Plasma interacts very strongly with light and E&M phenomena.

> - dust (decreases luminosity),

Ditto.


> - planets, stars with photospheres (appears cooler, and the "center" does not
> have these),

This might be possible, except that big bang nucleosynthesis implies it is not
baryonic, and therefore this is excluded.

> - black holes (not the central one, already factored in),
> - cold neutrinos (have to move slow enough to orbit), and
> - exotic matter

These are all possible.


> So basically, it is *still* a mystery envelope.

Yes.


Tom Roberts

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#382754

Dear tjrob137:

On Tuesday, May 3, 2016 at 3:58:35 PM UTC-7, tjrob137 wrote:
> On 5/3/16 5/3/16   2:17 PM, dlzc wrote:
> > The fact is, it is called Dark, because it is not
> > represented by the bare, bright stars found at the
> > center of a spiral galaxy.  They for a simple ratio
> > of mass (based on rotation curve at that radius),
> > and luminosity from that region, and apply that
> > formula across the entire disk.  When they do, they
> > find they have too much mass to get the curve based
> > on the light being produced. So it is a "mystery
> > envelope" that contains:
> > - plasma (invisible at visible and longer wavelengths),
> 
> No, not at all. Plasma interacts very strongly with
> light and E&M phenomena.

Not true.  *Recombining* plasma, sure.  But we know where the "missing normal matter" is, because it only interacts with X-rays from quasars, so is oxygen missing 5 electrons, and ionized hydrogen.  So it *doesn't* emit, and only weakly scatters light.  If it is as strong a player as you feel, how did we not know about all this matter before?

> > - dust (decreases luminosity),
> 
> Ditto.

Look at the equation for evaluating matter by using luminosity, Tom.  Decrease the luminosity, and it looks like there "must be less normal matter".

> > - planets, stars with photospheres (appears cooler,
> > and the "center" does not have these),
> 
> This might be possible, except that big bang
> nucleosynthesis implies it is not baryonic, and
> therefore this is excluded.

Tom, we have seen lots and lots of this near us, and we *know* that none of this is at the center of a spiral galaxy.  That area is clear of dust (by observation), it can have no planets when the next nearest star is light days away, and even the photospheres are stripped by tidal forces.  Where we are is *different*, *cooler* than the center of a spiral galaxy.  Naturally less luminous.  So we know we have lots more normal matter "out here", that is not represented by hot, bright stars near the center.

BB nucleosynthesis (BBn) may die because of facts, but not because I have an agenda here, other than to correctly point out the "problems in calibrating" at the center of a spiral galaxy.  Has BBn even worked out how we ended up with mostly matter, and not equal amounts of antimatter yet?

> > - black holes (not the central one, already factored in),
> > - cold neutrinos (have to move slow enough to orbit), and
> > - exotic matter
> 
> These are all possible.

And some of all of them are in the "envelope".

> > So basically, it is *still* a mystery envelope.
> 
> Yes.

Dark Matter is more a proclamation of ignorance ("Hyere Be Dragons"), than it is substance.

Couple this with our inability to image individual stars, because they approach "point light sources", and we simply play at the fringe of understanding even yet...

David A. Smith

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#382755

David asked, "Or, what are the working assumptions? "

Mach had an idea about frame dragging. An illusion of dark matter could be related to that inertial affect. For example, two black holes each has a spin in a direction opposing the galactic spin. The black holes collide at an angle which drags and lifts the frame of the galactic rotation. That will "de-spin the core of the galaxy" more than it will de-spin the perimeter.  The Bernoulli Equation for Lift and Drag can be extended to Lift the core spin of some galaxies, while Dragging other galaxies into a tighter spiral.

Alan asks, "If you find no dark matter, in which decade do you plan on reassigning the researchers?"

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#382756

On Tuesday, May 3, 2016 at 5:38:00 PM UTC-7, Alan Folmsbee wrote:
> David asked, "Or, what are the working assumptions? "
> 
> Mach had an idea about frame dragging. An illusion
> of dark matter could be related to that inertial
> affect.

Not seen in the laboratory.

> For example, two black holes each has a spin in a
> direction opposing the galactic spin. The black holes
> collide at an angle which drags and lifts the frame of
> the galactic rotation.

Yet *every* spiral galaxy has this "Dark Matter problem", and not all of them are likely to have contrary black holes.

> That will "de-spin the core of the galaxy" more than
> it will de-spin the perimeter.

No, it won't.  Its effects will be strongest near the merger.

> The Bernoulli Equation for Lift and Drag can be
> extended to Lift the core spin of some galaxies,
> while Dragging other galaxies into a tighter spiral.

An "odd" effect is simply not required.  It is at heart just a calibration error, from all appearances.

> Alan asks, "If you find no dark matter, in which
> decade do you plan on reassigning the researchers?"

Answer: Never.  It isn't Science if you don't look.

If no matter where yo shine your light, you never find darkness, do you stop looking for darkness... or do you just stop using your light?

David A. Smith

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#382787

On Tuesday, May 3, 2016 at 2:46:28 PM UTC-10, dlzc wrote:
> > That will "de-spin the core of the galaxy" more than
> > it will de-spin the perimeter.
> 
> No, it won't.  Its effects will be strongest near the merger.
> 
> > The Bernoulli Equation for Lift and Drag can be
> > extended to Lift the core spin of some galaxies,
> > while Dragging other galaxies into a tighter spiral.
> 
> An "odd" effect is simply not required.  It is at heart just a calibration error, from all appearances.

David, You do not even know what causes gravity on Earth, but you enforcers of old science make careers about oddities far away. Open you mind to progress. Read about Gravity Volume Theory. You expect to never stop your search for distant freakish measurements, but you ignore what is presented on a silver platter here on Earth.

The volume of baryons in Earth is equal to the volume of a fallen shell every 5 nanoseconds. Baryons shrink space and grow time. That is gravity. If you are not aware of that, call it a dark idea until you read about it.

5.1315 ns is the Universal Constant for the Conservation of Graviticspansive Continuum. Learn it from my website today, or be re-educated by an app in October.

Alan Folmsbee

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#382759

RichD wrote:
> 
> OK, we don't know what this 'dark matter' stuff is,
> and there's a worldwide race to detect it.  My question
> is, what DO we know about it?  Or, what are the working assumptions?
> 
> For instance, is it supposed to fit into the existing
> fermion/boson structure?  There seems to be an assumption
> that it's uncharged... reason?  Perhaps it does carry
> electric charge, which all cancels out, per the usual
> 'no net universal charge' pseudo-law of science.
> 
> Or, maybe it's some kind of field, which fills the universe,
> a la Higgs.  Is there reason to reject this?
> 
> Also, its distribution is unclear - it binds galaxies,
> does that necessarily mean it's uniformly distributed?
> There are some allusions to a "halo", whatever that means.
> 
> I'm trying to figure out what's known, and what's ruled out -
> 
> --
> Rich


what binds galaxies is gravity.


That which they call 'dark matter' is actually just...Gravity.

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#382771

On Tuesday, May 3, 2016 at 10:14:47 AM UTC-7, RichD wrote:
> OK, we don't know what this 'dark matter' stuff is, 
> and there's a worldwide race to detect it.  My question 
> is, what DO we know about it?  Or, what are the working assumptions?
> 
> For instance, is it supposed to fit into the existing 
> fermion/boson structure?  There seems to be an assumption 
> that it's uncharged... reason?  Perhaps it does carry 
> electric charge, which all cancels out, per the usual 
> 'no net universal charge' pseudo-law of science.
> 
> Or, maybe it's some kind of field, which fills the universe, 
> a la Higgs.  Is there reason to reject this?
> 
> Also, its distribution is unclear - it binds galaxies, 
> does that necessarily mean it's uniformly distributed?  
> There are some allusions to a "halo", whatever that means.
> 
> I'm trying to figure out what's known, and what's ruled out - 

If you look at the intensity of radiation of a black body, does it tell you how much matter is at that particular temperature?

Or does it just tell you the average temperature of the "biggest" surface?

David A. Smith

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#382776

On Wednesday, May 4, 2016 at 7:39:04 AM UTC-7, dlzc wrote:
> On Tuesday, May 3, 2016 at 10:14:47 AM UTC-7, RichD wrote:
> > OK, we don't know what this 'dark matter' stuff is, 
> > and there's a worldwide race to detect it.  My question 
> > is, what DO we know about it?  Or, what are the working assumptions?
> > 
> > For instance, is it supposed to fit into the existing 
> > fermion/boson structure?  There seems to be an assumption 
> > that it's uncharged... reason?  Perhaps it does carry 
> > electric charge, which all cancels out, per the usual 
> > 'no net universal charge' pseudo-law of science.
> > 
> > Or, maybe it's some kind of field, which fills the universe, 
> > a la Higgs.  Is there reason to reject this?
> > 
> > Also, its distribution is unclear - it binds galaxies, 
> > does that necessarily mean it's uniformly distributed?  
> > There are some allusions to a "halo", whatever that means.
> > 
> > I'm trying to figure out what's known, and what's ruled out - 
> 
> If you look at the intensity of radiation of a black body, does it tell you how much matter is at that particular temperature?
> 
> Or does it just tell you the average temperature of the "biggest" surface?
> 
> David A. Smith

This reminds of the opposite of a quantum effect, or quantum banding, 
of albedo or otherwise the aggregate effect.  In quantum banding, there 
are only discrete energy levels.  In this aggregate effect, the channels 
are indistinguishable.  In a way that is about the parity and opposition 
of the continuous and discrete, and here uncertainty (of momentum and 
position as channels) and quantized (as quantized or where a continuous 
spectrum would "add up" to infinite energy, for also the notion of a 
"continuity integral" that adds up the same as spectral lines, of the 
continuous spectrum).

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