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  #11  
Old October 29th 17, 07:24 AM posted to sci.astro.research
Richard D. Saam
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Posts: 240
Default Dark matter is:

On 10/28/17 1:36 AM, jacobnavia wrote:
Yes, but after years of searches I think that is useless to go on
denying that we just have no idea how the universe works. No physical
counterpart of the supposed "dark matter" has been found in any lab.

There is no dark matter particle and hence exotic dark matter doesn't
exist. Normal matter could have unknown behaviour however, at big
scales. That is the logical conclusion.

Just one thing. Matter could be organized at big scales by forces that
at our level of being (1.8 meters, 5 watts brain freshly evolved from
some primate) are undetectable by our labs and particle accelerators.
Those forces acting at galactic or cluster scales could be determinant
for our understanding of the cosmic web.

Matter seems to be connected everywhere, and the size and forces that
make those connections and filaments are unknown to us but they exist,
since those filaments exist. There are filaments between the stars, and
filaments between the galaxies, and filaments between the clusters of
galaxies. Rivers of galaxies can be figured out, and astronomers have
followed those filaments to figure out the biggest being they have ever
seen, an incredible structure that you can see he

http://www.dailymail.co.uk/sciencete...Milky-Way.html

Its filamentary structure is evident in this drawing.

As also envisioned by your adopted countryman Vincent Van Gogh's 1889
painting The Starry Night
https://www.google.com/culturalinsti...bgEuwDxel93-Pg

The Fluid sky is connected to the rolling hills
and even the man made structures conform to this universal fluid.

Ernst Mach developed this universe connectivity
in the early 20th century

Sadly, our ideas about a big bang and the resulting explanations make
this hypothesis not so attractive for many people.

Your idea does not have to contradict the big bang idea.

Since observations indicate that a sea of galaxies extends away and away
from us in all directions, I consider that the CMB doesn't really imply
a big bang.

Although there is variation, the individual galaxies within the sea have
generally common rotational structure
as well as the star planetary systems within.
That has to be accounted for.

It is just that: Cosmic Background. The sea of galaxies is bathed in the
relic light from all uncountable galaxies extending till who knows
where. This explains why is so uniform.

But a common origin is needed to explain the uniformity.

Ambient light.

But adjacent to all of this universe matter(including us within it)
is the vacuum at Heisenberg uncertainty.
It is generally described as a chaotic random foam.
Your structured bathing environment would required a coherent vacuum
going back to the big bang
that goes against current thinking.

[[Mod. note -- Three points:
1. Yes, gravitomagnetism exists (experimental check: Gravity Probe B).
But the *magnitude* of that "connection" is really, really small!
2. The Galaxy Zoo project's analysis (arXiv:0803.3247 =
https://doi.org/10.1111/j.1365-2966.2008.13490.x) finds that
galaxy rotation directions are statistically random.
3. From CMBR anisotropy measurements, we know that the universe
isn't rotating to any significant extent. See, e.g., Collins and
Hawkings (1973) and Bunn, Ferreira, and Silk, Physical Review Letters
77, 2883 (1996) (https://doi.org/10.1103/PhysRevLett.77.2883).
-- jt]]
  #12  
Old October 29th 17, 06:51 PM posted to sci.astro.research
Nicolaas Vroom
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Posts: 216
Default Dark matter is:

On Saturday, 28 October 2017 06:24:42 UTC+2, Phillip Helbig wrote:
In article ,
Nicolaas Vroom writes:


This raises the question how important is nonbaryonic matter
for the evolution of the Universe?


Very. Without dark matter, the fluctuations observed in the CMB would
not have had time to form the structure we see today.


As far as I understand the fluctuations in the CMB we see to day are
caused by matter fluctuations of the Universe 300000 years after the BB.
To be more specific in the outer layer of the Universe.
(It is not the CMB that caused these fluctuations)
During that period apperently there was already a division between
baryonic versus non-baryonic matter which we can observe in the second and
third peak CMB power spectrum. See:
https://en.wikipedia.org/wiki/Cosmic...ary_anisotropy

The question is how exactly do we know that these peaks are caused
by baryonic and non baryonic matter, of which the last physical is an almost
bare landscape. For more detail see ref 52 and 53 (Wayne Hu).
Specific what is IMO the most tricky is the relation between the two.

Nicolaas Vroom

  #13  
Old October 30th 17, 01:11 AM posted to sci.astro.research
Phillip Helbig (undress to reply)[_2_]
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Posts: 273
Default Dark matter is:

In article ,
Nicolaas Vroom writes:

As far as I understand the fluctuations in the CMB we see to day are
caused by matter fluctuations of the Universe 300000 years after the BB.


Right.

To be more specific in the outer layer of the Universe.


Relative to us.

(It is not the CMB that caused these fluctuations)


Right; the anisotropies in the CMB are due to the fluctuations.

We know the magnitude of the fluctuations of baryonic matter, since that
is what we see. If there were no dark matter, there would not have been
time for these to have evolved to the structures we see today. The idea
is that dark matter can collapse sooner, since it is not stopped by
radiation pressure. The baryonic matter then falls into the dark-matter
potential wells.

During that period apperently there was already a division between
baryonic versus non-baryonic matter which we can observe in the second and
third peak CMB power spectrum. See:
https://en.wikipedia.org/wiki/Cosmic...ary_anisotropy


Right.

The question is how exactly do we know that these peaks are caused
by baryonic and non baryonic matter, of which the last physical is an almost
bare landscape.


I'm not sure what the last clause means. How do we know? Calculate the
power spectrum for various amounts of baryonic and non-baryonic matter
and compare to observations.
  #14  
Old October 30th 17, 01:14 AM posted to sci.astro.research
jacobnavia
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Posts: 105
Default Dark matter is:

Le 29/10/2017 =C3=A0 07:24, Richard D. Saam a =C3=A9crit=C2=A0:
As also envisioned by your adopted countryman Vincent Van Gogh's 1889
painting The Starry Night
https://www.google.com/culturalinsti...ry-night/bgEu=

wDxel93-Pg

The Fluid sky is connected to the rolling hills
and even the man made structures conform to this universal fluid.


Mmmm. Vincent had problems... Was he seeing dark matter?

Maybe.

Maybe he could see what we can't.

In any case I am not mystic when science is involved and I do not see
any "fluids" anywhere.

My point is that a massive web of connections could explain a lot of
things. Galaxies feed on dark gas, and the mass of that gas outside the
galaxies could be considerable. Its movements could determine the shape
of the visible part.

Is that all powered by gravity?

Gravity decreases as the square of distance, so at big scales is not so
important like other (possible) forces that could decrease much more
slowly and take over at big scales.
  #15  
Old October 30th 17, 07:51 PM posted to sci.astro.research
Steve Willner
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Posts: 1,172
Default Dark matter is:

In article ,
"Phillip Helbig (undress to reply)" writes:

It is just that: Cosmic Background. The sea of galaxies is bathed
in the relic light from all uncountable galaxies extending
till who knows where. This explains why is so uniform.


Your hypothesis cannot explain the power spectrum of the CMB.


That would be the power spectrum of the fluctuations.

Perhaps even more fundamentally, the "sea of light" cannot explain
why the spectral energy distribution of the CMBR is a perfect
blackbody with unit emissivity. This has been known since COBE.

Posters to this thread should watch and understand the Dan Hooper
colloquium I mentioned on Oct 20:
https://youtu.be/pPs_tvDYAl4

There are still many unknowns, but the unconventional suggestions
posted here are not new and are contrary to observations.

--
Help keep our newsgroup healthy; please don't feed the trolls.
Steve Willner Phone 617-495-7123
Cambridge, MA 02138 USA
  #16  
Old October 31st 17, 12:08 AM posted to sci.astro.research
jacobnavia
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Posts: 105
Default Dark matter is:

Le 30/10/2017 =C3=A0 19:51, Steve Willner a =C3=A9crit=C2=A0:
Perhaps even more fundamentally, the "sea of light" cannot explain
why the spectral energy distribution of the CMBR is a perfect
blackbody with unit emissivity. This has been known since COBE.


Why shouldn't be a black body spectrum?

A black body spectrum is the one of a body at thermal equilibrium, and
the sea of galaxies apparently is at thermal equilibrium...

Why not?

And if the CMB was just a PERFECT black body spectrum and all "wrinkles
in the face of god", as someone said, were just objects (or holes) of
incredible size?

Foreground objects or holes.

Now, you can take a spectrum of it and add whatever theories come to
mind but the physical reality must be taken into account...

Hubble observations point to a huge number of galaxies just beyond its
reach to detect. The sea of galaxies is not some invention I have
figured out.

[[Mod. note -- There are (at least) two problems with this
"sea of light/galaxies" explanation for the CMB:
1. Viewing a body at thermal equilibrium isn't enough to get a black-body
spectrum -- the body-being-viewd also has to be *optically thick*.
The set of galaxies is not optically thick at most CMB wavelengths
(we can see through it to see those more distant objects you just
mentioned).
2. Any viable explanation for the CMB needs to be able to *quantitatively*
match the CMB-anisotropy power spectrum, including the positions,
heights, and widths of the 5-or-so peaks visible in the observed data.
See, e.g., the nice graph in
https://en.wikipedia.org/wiki/Cosmic...ary_anisotropy
The fact that the hot big bang model *can* quantitatively match
this spectrum is a powerful argument in its favor. I've never seen
a similar match from a sea-of-light/galaxies model. Is there one?
-- jt]]

This observation (NASA) is one year old:

quote
Astronomers came to the surprising conclusion that there are at least 10
times more galaxies in the observable universe than previously thought.
end quote

See article at
https://www.nasa.gov/feature/goddard...vable-univers=
e-contains-10-times-more-galaxies-than-previously-thought

AT LEAST, they said carefully...

And all those galaxies are VERY far away. The Universe goes on and on
and on. We see no limit.
  #17  
Old November 1st 17, 09:43 PM posted to sci.astro.research
jacobnavia
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Posts: 105
Default There is nothing there (Xenon Collaboration)

First Dark Matter Search Results from the XENON1T Experiment:

quote from the abstract
A profile likelihood analysis shows that the data are consistent with
the background-only hypothesis.
end quote

There is it. One Ton of Xenon liquid/gas and years of effort show us
that there is nothing there. The detector doesn't detect anything but
background noise.

This means that since there is nothing exotic, matter has behaviours
that we do not understand at all.

WIMPS were tied to CDM cosmology and their absence means that many
theories are just wrong.

The logical conclusion (from a layman viewpoint) is that normal matter
has attractive forces that hold the galaxy together as a spinning disk.

Not gravity, since gravity decreases as the square of distance: it
doesn't go very far...

Like all forces actually. Nuclear force doesn't reach beyond 2.5 10E-15
meters. Each force has a range of masses and scales where it is active.

At each scale then, we can discover new forces that attract matter to
itself. At galactic scales this attractive force holds the disk spinning
like a rigid whole.

And no, I can't calculate that. Astronomers can, doesn't look (to me) a
very difficult undertaking. They have the mass distribution of the
galaxy, what can be accounted by gravity, and the rest. This rest is the
effects of that force.

But maybe things aren't so simple and that force could be very
complicated to figure out, like the nuclear force, that actually is a
derivative of other, stronger forces between the quarks, etc.

Only one thing is certain:

All cosmologies have failed but we always had one, since we left our
caves and started looking at the sky.

  #18  
Old November 2nd 17, 03:39 AM posted to sci.astro.research
Phillip Helbig (undress to reply)[_2_]
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Posts: 273
Default Dark matter is:

In article , jacobnavia
writes:

Hubble observations point to a huge number of galaxies just beyond its
reach to detect. The sea of galaxies is not some invention I have
figured out.


But you seem to think that this idea is somehow ignored by the
community.

We know that the universe is approximately flat. Assuming a simple
topology, that means that it is either infinite or very much larger
than the particle horizon (the theoretical limit of how far we can
see; in practice that limit is essentially the last scattering surface
[which is operationally defined as the surface at which the universe
becomes optically thick]). So, essentially all astronomers in the
world agree that there are more galaxies than we can see, even more
than we could see with arbitrarily powerful instruments.

The moderator commented:

# 1. Viewing a body at thermal equilibrium isn't enough to get a black-body
# spectrum -- the body-being-viewd also has to be *optically thick*.
# The set of galaxies is not optically thick at most CMB wavelengths
# (we can see through it to see those more distant objects you just
# mentioned).

Right. I think that it was Hoyle or Burbidge---before the measurement
of the black-body spectrum---who pointed out that the energy in the CMB
is approximately the same as that which has been radiated by stars, so
in terms of order-of-magnitude back-of-the-envelope calculations, the
recycled starlight idea was valid. It appears to be just a coincidence,
though, and fails several predictions (black-body spectrum, power
spectrum of observed anisotropies, etc).

# 2. Any viable explanation for the CMB needs to be able to *quantitatively*
# match the CMB-anisotropy power spectrum, including the positions,
# heights, and widths of the 5-or-so peaks visible in the observed data.
# See, e.g., the nice graph in
# https://en.wikipedia.org/wiki/Cosmic...ary_anisotropy
# The fact that the hot big bang model *can* quantitatively match
# this spectrum is a powerful argument in its favor. I've never seen
# a similar match from a sea-of-light/galaxies model. Is there one?

Note that the CMB power spectrum was a robust prediction long before any
peaks were observed. Yes, it depends on various parameters, but a) one
cannot just fit anything and b) the parameters which produce the best
fit have values which jibe well with other measurements.

quote
Astronomers came to the surprising conclusion that there are at least 10
times more galaxies in the observable universe than previously thought.
end quote


In the OBSERVABLE universe. They are talking about faint dwarf galaxies
here. Even in the intermediate neighbourhood of the Milky Way these are
hard to observe.

And all those galaxies are VERY far away. The Universe goes on and on
and on. We see no limit.


Yes, it might very well go on without limit, but a) this has nothing to
do with the number of galaxies in the OBSERVABLE universe and b) is
completely compatible with the big bang.
  #19  
Old November 2nd 17, 03:40 AM posted to sci.astro.research
Phillip Helbig (undress to reply)[_2_]
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Posts: 273
Default There is nothing there (Xenon Collaboration)

In article , jacobnavia
writes:

First Dark Matter Search Results from the XENON1T Experiment:

quote from the abstract
A profile likelihood analysis shows that the data are consistent with
the background-only hypothesis.
end quote

There is it. One Ton of Xenon liquid/gas and years of effort show us
that there is nothing there. The detector doesn't detect anything but
background noise.

This means that since there is nothing exotic, matter has behaviours
that we do not understand at all.


No. It means that this detector didn't detect what it could have
detected. It doesn't mean that dark matter is ruled out. It doesn't
even mean that WIMPs are ruled out.

WIMPS were tied to CDM cosmology and their absence means that many
theories are just wrong.


Where are WIMPs tied to CDM cosmology? Dark matter, yes, but dark
matter doesn't have to be WIMPs. In particular, it could be
self-interacting and form objects the size of a baseball, or a house, or
a mountain. Or it could be in primordial black holes of 100 solar
masses or so (smaller ones are ruled out by microlensing).

At each scale then, we can discover new forces that attract matter to
itself. At galactic scales this attractive force holds the disk spinning
like a rigid whole.


No. You are referring to flat rotation curves of galaxies. This
doesn't mean that the angular speed is constant with radius
(approximately, and above some minimum radius), but rather the actual
physical speed. Rigid rotation would imply that the speed of rotation
increases with distance.

And no, I can't calculate that. Astronomers can, doesn't look (to me) a
very difficult undertaking. They have the mass distribution of the
galaxy, what can be accounted by gravity, and the rest. This rest is the
effects of that force.


Yes, this is MOND, essentially.
  #20  
Old November 3rd 17, 03:56 AM posted to sci.astro.research
Nicolaas Vroom
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Posts: 216
Default Dark matter is:

On Thursday, 2 November 2017 03:39:27 UTC+1, Phillip Helbig wrote:

We know that the universe is approximately flat. Assuming a simple
topology, that means that it is either infinite or very much larger
than the particle horizon (the theoretical limit of how far we can
see; in practice that limit is essentially the last scattering surface
[which is operationally defined as the surface at which the universe
becomes optically thick]). So, essentially all astronomers in the
world agree that there are more galaxies than we can see, even more
than we could see with arbitrarily powerful instruments.


I do not fully agree with your argumentation.
When you want to understand what we can observe you have to use the
friedmann equations.
To see the results select:
http://users.telenet.be/nicvroom/friedmann's%20equation%20L=0.01155.htm
In Figure 1B it is the blue line what we can see/observe.
The black line is the maximum distance of the Universe as the result
of the Big Bang. I expect this is the particle/radiation limit.
At present the size of the Universe is roughly 35 bly.
From this simulation the claim that the expansion of the universe

undergoes acceleration is arbitrary.
The blue line (of what we can see at present) starts approx 300000 y
after the BB (See Figure 1C) and reaches it furtest distance 5 by
after the BB.
The blue line shows what we see of the Universe in the past
i.e. in some sense all the present day galaxies in the past.

This also means that if you have a more powerfull instrument
you can not see more galaxies but only the same galaxies (in the past)
more accurate.
With a more powerfull instrument you can see younger galaxies.
They are not further away (at that time) but at closer distance.

Nicolaas Vroom

[[Mod. note -- If you have a more sensitive instrument you can see
*fainter* galaxies at any given distance. Since there are a lot more
faint galaxies than bright galaxies in any given volume of space,
this means that you overall see more galaxies even within the same
volume of space.
-- jt]]
 




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