Hubble makes 3D dark matter map

Kent Paul Dolan wrote:
Richard Saam wrote:


If such were the case, these objects surely would
not be observable from earth yet provide observed
gravitational lensing character.


Well, an interesting extension to your calculation
would be, how often would the disk of earth,
considered as a flyswatter, encounter an object at
each size scale, as earth sweeps through space both
in orbit around the sun and moving through the
galaxy with the solar system.

Now, is that in agreement with what is actually seen
impacting the earth or its atmosphere, in the "quiet
times" between major meteor showers with known
local-to-this-solar-system causes?

In other words, we can't see those objects in the
Bullet galaxy, but if they are "the dark matter in
general", should we be able to observe them if they
have that same needed density for lensing, close to
home, as would be expected? If so, do we?

FWIW

xanthian.

An interesting question.
Are such residual objects of sufficient size
that they can be observed locally??

The only way I know how to approach the fly swatter concept
is in terms of the mean free path concept
which has its roots back in the early 20th century
with Miron Smoluchowski and others
addressing particle collision data for particles
assuming other fields (electromagnetic, gravitational etc.)
contributing insignificantly.

mean free path = 1/(sqrt(2)*pi*N*d^2)

where N = 1 object/ rd^3
and object diameter (d) = rb

Extending previous calculations,
it appears plausible that there could be
asteroid like objects with a size
on the order of 1 kilometer (1E5 cm)
and 9E7 kilometers (9E+12 cm) from each other
with mean free path of 2E10 light years
(very few collisions)
dispersed in such a manner to form a stable lens
with density 1.213E-24 g/cc
and these asteroid like objects not observable
locally(interstellar medium)
or distantly(bullet cluster medium)
with insignificantly rare earth or even solar impacts.

As for collision of multiple sized objects(i & j),
Smoluchowski addressed that as:

collision rate/volume/time ~ Ni*Nj*(di+dj)^3 / time
perhaps someone can do the calculation
but it does not appear that stellar(i)-object(j) collisions
would significantly disrupt (swat) this stable lens.

space space object object object mean
rd rd rb mass solar free
(cm) (lt yr)(cm) (g) masses path (lt yr)
9E-01 1E-18 1E-08 1E-24 5E-58 2E-03 ~hydrogen
9E+00 1E-17 1E-07 1E-21 5E-55 2E-02 ~molecules
9E+01 1E-16 1E-06 1E-18 5E-52 2E-01
9E+02 1E-15 1E-05 1E-15 5E-49 2E+00
9E+03 1E-14 1E-04 1E-12 5E-46 2E+01
9E+04 1E-13 1E-03 1E-09 5E-43 2E+02
9E+05 1E-12 1E-02 1E-06 5E-40 2E+03
9E+06 1E-11 1E-01 1E-03 5E-37 2E+04 ~dust
9E+07 1E-10 1E+00 1E+00 5E-34 2E+05 ~dust
9E+08 1E-09 1E+01 1E+03 5E-31 2E+06 ~asteroid
9E+09 1E-08 1E+02 1E+06 5E-28 2E+07 ~asteroid
9E+10 1E-07 1E+03 1E+09 5E-25 2E+08 ~asteroid
9E+11 1E-06 1E+04 1E+12 5E-22 2E+09 ~asteroid
9E+12 1E-05 1E+05 1E+15 5E-19 2E+10 ~asteroid
9E+13 1E-04 1E+06 1E+18 5E-16 2E+11
9E+14 1E-03 1E+07 1E+21 5E-13 2E+12
9E+15 1E-02 1E+08 1E+24 5E-10 2E+13
9E+16 1E-01 1E+09 1E+27 5E-07 2E+14 ~earth
9E+17 1E+00 1E+10 1E+30 5E-04 2E+15
9E+18 1E+01 1E+11 1E+33 5E-01 2E+16 ~sun
9E+19 1E+02 1E+12 1E+36 5E+02 2E+17
9E+20 1E+03 1E+13 1E+39 5E+05 2E+18
9E+21 1E+04 1E+14 1E+42 5E+08 2E+19
9E+22 1E+05 1E+15 1E+45 5E+11 2E+20 ~Milky Way
9E+23 1E+06 1E+16 1E+48 5E+14 2E+21
9E+24 1E+07 1E+17 1E+51 5E+17 2E+22

wrote:
In article ,
Richard Saam wrote:

Joseph Lazio wrote:


"RS" == Richard Saam writes:


RS Isn't it proper to say that 'mass of the universe' not 'density of
RS universe matter' is larger than the 'mass of universe baryonic
RS matter' not 'density of universe baryonic matter'?

No. In order to compute a total mass, one has to know the diameter.
While we can estimate the diameter of the *observable* Universe, it is
possible (and quite likely) that the diameter of the Universe is
larger than the diameter of the observable Universe.

Yes, the diameter of the universe is not known
other than the diameter of the *observable* Universe
but we can still say
that the observed Mass (M) in any arbitrary multiple galactic scale volume
(1E21 cubic light years) in the *observable* Universe
is greater than the mass of baryonic matter in the same volume.


But that statement is precisely the same as the statement about the
densities!

Would you object to someone saying "the density of lead is greater
than the density of water," telling them instead that they should say
"the mass of lead within any arbitrary volume is greater than the
mass of water within the same volume"?

-Ted

The situation is a little different in the understood universe
where the critial matter 'Mc'
in arbitrary volume 'Vc'
with critical density (~10^-30 g/cc) 'rhoc'
is greater than baryonic matter 'Mb'
but does not displace the baryonic matter 'Mb'
in its volume 'Vb'
with density(~10^-24 g/cc) 'rhob'
but permeates it
where Vc Vb and Vb included in Vc.

Mc = rhoc*Vc

Mb = rhob*Vb

Mc Mb

and

rhoc*Vc rhob*Vb

therefo

rhoc/rhob Vb/Vc

and

rhoc (Vb/Vc)*rhob

so the critical mass (Mc) is greater than baryonic mass (Mb)
and the critical density (rhoc) is less than baryonic density (rhob)
if arbitrary volume Vc Vb.

Vc could typically have dimensions of (intergalactic distance)^3
and
Vb could typically have dimensions of (galactic diameter)^3

Richard

In article ,
Richard Saam wrote:

The situation is a little different in the understood universe
where the critial matter 'Mc'
in arbitrary volume 'Vc'
with critical density (~10^-30 g/cc) 'rhoc'
is greater than baryonic matter 'Mb'
but does not displace the baryonic matter 'Mb'
in its volume 'Vb'
with density(~10^-24 g/cc) 'rhob'
but permeates it
where Vc Vb and Vb included in Vc.

Mc = rhoc*Vc

Mb = rhob*Vb

Mc Mb

and

rhoc*Vc rhob*Vb

therefo

rhoc/rhob Vb/Vc

and

rhoc (Vb/Vc)*rhob

so the critical mass (Mc) is greater than baryonic mass (Mb)
and the critical density (rhoc) is less than baryonic density (rhob)
if arbitrary volume Vc Vb.

Vc could typically have dimensions of (intergalactic distance)^3
and
Vb could typically have dimensions of (galactic diameter)^3

I'm sorry, but I can't make any sense of this. I promise you that when
people compare the densities of baryonic matter and dark matter, they're
doing a fair comparison -- that is, they're comparing the mass of
all the baryons in some (suitably large) volume to the mass of dark matter
in the same volume.

The densities involved are average densities over large volumes:
in some small regions (such as, say, the interior of the Earth) the
density of dark matter is much less than the baryon density.

-Ted


--
[E-mail me at , as opposed to .]

wrote:

In article ,
Richard Saam wrote:


The situation is a little different in the understood universe
where the critial matter 'Mc'
in arbitrary volume 'Vc'
with critical density (~10^-30 g/cc) 'rhoc'
is greater than baryonic matter 'Mb'
but does not displace the baryonic matter 'Mb'
in its volume 'Vb'
with density(~10^-24 g/cc) 'rhob'
but permeates it
where Vc Vb and Vb included in Vc.

Mc = rhoc*Vc

Mb = rhob*Vb

Mc Mb

and

rhoc*Vc rhob*Vb

therefo

rhoc/rhob Vb/Vc

and

rhoc (Vb/Vc)*rhob

so the critical mass (Mc) is greater than baryonic mass (Mb)
and the critical density (rhoc) is less than baryonic density (rhob)
if arbitrary volume Vc Vb.

Vc could typically have dimensions of (intergalactic distance)^3
and
Vb could typically have dimensions of (galactic diameter)^3


I'm sorry, but I can't make any sense of this. I promise you that when
people compare the densities of baryonic matter and dark matter, they're
doing a fair comparison -- that is, they're comparing the mass of
all the baryons in some (suitably large) volume to the mass of dark matter
in the same volume.
I am sure you are correct for baryonic matter and dark matter
but the situation is different
in the context of critical density (rhoc) (below).
The densities involved are average densities over large volumes:
in some small regions (such as, say, the interior of the Earth) the
density of dark matter is much less than the baryon density.

-Ted



The above was attempt to address the other universe density
and that being the critical density (rhoc) ~1E-30 g/cc
and its relation to dark matter density ~1E-24 g/cc
and baryon densities ~1 g/cc
and that critical density (rhoc)
derived within the Friedman equations:

http://en.wikipedia.org/wiki/Friedmann_equations

expressed as:

rhoc= 3*H^2/(8*pi*G) ~ 1E-30 g/cc

where H is Hubble constant
and G is Newton Gravitational constant

rhoc*(large multi inter galactic volume) equals
the dominate mass in the universe.

I was assuming that dark matter density ~1E-24 g/cc
was composed of unobservable but real baryonic matter ~1 g/cc
distributed over a volume (typically a galaxy)
such that average density
in that volume is ~1E-24 g/cc

For more clarity,
changing 'b' for baryonic
to 'd' for dark then
critical matter 'Mc'
in arbitrary volume 'Vc'
with critical density (~1E-30 g/cc) 'rhoc'
is greater than dark matter 'Md'
but does not displace the dark matter 'Md'
in its volume 'Vd'
with density(~1E-24 g/cc) 'rhod'
but permeates it
where Vc Vd and Vd included in Vc.

Mc = rhoc*Vc

Md = rhod*Vd

Mc Md

and

rhoc*Vc rhod*Vd

therefo

rhoc/rhod Vd/Vc

and

rhoc (Vd/Vc)*rhod

so the critical mass (Mc) is greater than dark mass (Md)
and the critical density (rhoc) is less than dark density (rhod)
if arbitrary volume Vc Vd.

Vc could typically have dimensions of (intergalactic distance)3
and
Vd could typically have dimensions of (galactic diameter)3

Richard

"Kent Paul Dolan" wrote:
Hans Aberg wrote:

One idea that comes to my mind is that very
young, nearby galaxies are very hard to observe
for two reasons: they are faint, and quickly gets
absorbed into larger galaxies.

Why would any even exist? Surely after ~14 billion
years, most of the easily accumulated
intergalactic gas has long ago gathered into
galaxies, and the remaining cases gathering more
recently would be so thinly scattered throughout
the universe that the chance of even one being
"nearby" for useful meanings of that vague term
would be "slender to none"?

By the way, the article I URLed yesterday from
Scientific American:

http://www.sciam.com/article.cfm?cha...CA562C33C4F03C

[yes, I know that's not a refereed paper] describes
in part that dark energy expansion has indeed slowed
galaxy generation to a crawl,

"The central piece of evidence is the rough
coincidence in timing between the end of
most galaxy and cluster formation and the
onset of the domination of dark energy. Both
happened when the universe was about half
its present age."

slowed inflow of star-generation gases from the
intergalactic regions into large galaxies to a
non-issue, so probably all we have in dispute is
what "nearby young" means.

"The inexorable shift in the balance between
the two" [dark energy and gravity]
"eventually caused the expansion rate to
switch from deceleration to acceleration.
The structures in which galaxies reside were
then pulled apart, with a gradual decrease
in the galaxy merger rate as a result.
Likewise, intergalactic gas was less able to
fall into galaxies. Deprived of fuel, black
holes became more quiescent."

xanthian.

Also, it says we (the Local Group) aren't ever going
to reach the Virgo supercluster, because the dark
energy expansion is outrunning gravity's collapsing
effect at that distance, a factoid that is going to
make it lots easier for _me_ to sleep at night, boy
howdy.

"An example of how dark energy alters the
history of galaxy clusters is the fate of
the galaxies in our immediate vicinity,
known as the Local Group. Just a few years
ago astronomers thought that the Milky Way
and Andromeda, its closest large neighbor,
along with their retinue of satellites,
would fall into the nearby Virgo cluster.
But it now appears that we shall escape that
fate and never become part of a large
cluster of galaxies. Dark energy will cause
the distance between us and Virgo to expand
faster than the Local Group can cross it."

"re" == rloldershaw@amherst edu writes:

re On Feb 10, 2:02 pm, Joseph Lazio wrote:
The interested reader is referred to Schee (2006).

Other examples of such papers can easily be found by perusing the
Astronomical Data System or astro-ph.

re Millions of dollars and countless man-hours of effort have been
re expended in this effort to find hypothetical "WIMPS", CDM, sterile
re neutrinos, axions, etc. A vast literature on the subject exists.

re So far not one single shread of evidence for their existence has
re appeared.

This from the person constantly exhorting us to keep an open mind.

Given the forum, your argument seems far more rhetorical than
scientific. A small project involving only 20 people working for a
year could easily consume "millions of dollars" and "20 man-years of
effort."

A more persuasive approach would be to compare the expected density of
such particles with the current experimental limits. How do they
compare? What is required to produce even more stringent limits?
What's the acceptable risk-return balance? (In other words, we should
tolerate some high-risk, high-payoff experiments, ones that might be
wrong, but, if successful, would be incredibly important.)

--
Lt. Lazio, HTML police | e-mail:
No means no, stop rape. | http://patriot.net/%7Ejlazio/
sci.astro FAQ at http://sciastro.astronomy.net/sci.astro.html

"Joseph Lazio" schreef in bericht
...
"HA" == Hans Aberg writes:

I think somebody (Ted, Phillip?) has already discussed this.
Briefly, we have estimates for the density of baryonic matter and
the total density of matter in the Universe.

HA What might be pitfalls of those estimates is if they build on some
HA untested theory about formation from the Big Bang.

I think the methods of estimating both the density of baryonic matter
and the total density of matter have been discussed at length in this
newsgroup, as well as in various review papers that one could find on
astro-ph (for example).


[...]
There needs to be some non-baryonic dark matter. Indeed, we
already know of one kind of non-baryonic dark matter, neutrinos.
They are not baryons, they have mass, and they do not interact via
the electromagnetic force (...). If we know of one kind of
non-baryonic dark matter, it is not too difficult to think that
there might be other kinds.

HA I think that explaining dark matter as mainly composed of
HA neutrinos has been ruled out.

My point was not to claim that neutrinos explain dark matter. My
point is that neutrinos are a form of dark matter.

I think the onus is actually more on those who claim that there is no
dark matter. We know of one example already (neutrinos). How can one
be so certain that there are no other kinds of dark matter particles?

The onus is for the people who claim that there is dark matter
to demonstrate why such a solution is required
Our solar system consists of planets and the kuiper belt
Outside our solar system is the Oort Cloud to explain comets.
Both the kuiper belt and the Oort Cloud are filled with visible
matter.
The onus is for the people who claim that there is dark matter
to demonstrate why in our galaxy the disc can not be filled
like the kuiper belt with Oort Cloud type objects to explain
flat galaxy rotation curves.

See also sci.astro "Dark matter hides, physicists seek (Forwarded)"
http://groups.google.be/group/sci.sp...c1 f587a2fdf4

Nicolaas Vroom
http://users.pandora.be/nicvroom/

"Nicolaas Vroom" schreef in bericht
...

I think the onus is actually more on those who claim that there is no
dark matter. We know of one example already (neutrinos). How can one
be so certain that there are no other kinds of dark matter particles?

The onus is for the people who claim that there is dark matter
to demonstrate why such a solution is required
Our solar system consists of planets and the kuiper belt
Outside our solar system is the Oort Cloud to explain comets.
Both the kuiper belt and the Oort Cloud are filled with visible
matter.
The onus is for the people who claim that there is dark matter
to demonstrate why in our galaxy the disc can not be filled
like the kuiper belt with Oort Cloud type objects to explain
flat galaxy rotation curves.

See also sci.astro "Dark matter hides, physicists seek (Forwarded)"
http://groups.google.be/group/sci.sp...c1 f587a2fdf4


The sci.astro link is:
http://groups.google.be/group/sci.as...d29e03d1907fe4

Nicolaas Vroom
http://users.pandora.be/nicvroom/