Galaxy Zoo project (maybe) finds a "lopsided universe".

Oh No wrote:
The motion of the galaxies is
modelled as an ideal fluid, in which galaxies are treated as point-like
particles in the fluid. This is not a fundamental assumption of physics,
but simply a modelling assumption, and is only intended as an
approximation to reality. The chirality of galaxies has no particular
bearing on the motion of the fluid, taken as a whole. Nor do local
motions of galaxies and clusters, such as the motion of local clusters
toward the Great Attractor. One might regard such things as small scale
turbulence in the fluid. With respect to the cosmological principle, the
region we can see, inside the light cone, is small scale. Remember also
we are working in units in which the speed of light is 1, so the
velocity of turbulent motion is very low.

Francis and Dolan
This idea of 'particles in a fluid' cosmic or otherwise
has its roots at about the same time as Einstein's theories ~1910s
with the work of:
Miron Smoluchowski
Three Lectures on Diffusion, Brownian Motion
and Coagulation of Colloidal Particles
Phys. Z., 17, 557 (1916);
Trial of a Mathematical Theory
of the Coagulation Kinetics of Colloidal Solutions)
Z. Physik. Chem., 92, 129, 155 (1917).

Albert Einstein's son 'Hans Albert' worked in Berkeley
as professor for hydraulics at the University of California
from 1947 to 1971 and knew this subject very well.

One interesting concept is the idea of fluid shear dv/dx
and in hyraulics is usually designated by the letter G
and is defined as sqrt(Dissipating Power/(viscosity*volume)).
It is used in the design of mixing applications
wherein the power required to keep particles
in fluid (with a particular viscosity) suspension
at a particular dv/dx is computed.

It has the units of /time, the same as Hubble constant 'H'
so for argument in cosmic dimension use 'H'.

Another concept is the idea of particle kinetic collision:

J = (1/6)*n1*n2*H*(d1+d2)3

J = particle collisions/volume/time
n1 = number of particles 1 per volume
n2 = number of particles 2 per volume
d1 = diameter of particle 1
d2 = diameter of particle 2

A natural development of this logic is that
an equilibrium particle diameter d ~ 1/H.

The basic question is:
Can Hubble constant be looked upon
as a cosmic fluid with shear dv/dx
which plays a fundamental role
in establishing galactic size and distribution?

Given the visible universe size (limited by c)
and H = 2.31E-18 /sec (cm/sec/cm)
then the extremely low cosmic viscosity = 8.8E-32 poise (g/(cm sec))
all congruent with a cosmic density of ~6E-30 g/cc.

Like in any mixing situation, local variation is expected.

Richard Saam

In article , Kent Paul Dolan
writes:

Oh No wrote:

As I have explained, a 1% bias is hardly likely to
overturn cosmological isotropy.

Further review of the SDSS images shows that there
are galaxies capable of being classified by eye for
chirality out to at least z=20 (obviously those are
very large galaxies).

There have never been galaxies observed at this high a redshift.

I can't see how a trained statistician can dismiss a
1% bias in a sample of one million as anything less
than paradigm-shattering, though, brought to bear
against an isotropy claim on whicn most of cosmology
depends for its very existence. Perhaps you'd like
to explain why the odds against that happening don't
matter?.

Extraordinary claims require extraordinary evidence. Remember Nordland
and Ralston? http://www.jb.man.ac.uk/~jpl/screwy.html

In other words, a 1% bias, if real, would be very interesting, but a 1%
bias might be explained by other things. Of course, the same would
apply to a 50% bias, but it is more difficult to imagine this being due
to subtle effects.

Kent Paul Dolan wrote:
I can't see how a trained statistician can dismiss a
1% bias in a sample of one million as anything less
than paradigm-shattering, though, brought to bear
against an isotropy claim on whicn most of cosmology
depends for its very existence.

*If* the effect is genuinely present in light arriving at the top
of the atmosphere, then it might telling be us something interesting
about galaxies. If it's present all over the sky, over a wide range
in galaxy redshifts, it might be a lot more interesting.

But before getting too excited, I'd like to see solid evidence that
the effect is (for example)
(a) present in independent classifications of the same objects,
(b) not present if galaxies are randomly and double-blind-ly flipped
before being classified,
(c) not an artifact of atmospheric refraction or seeing,
(d) not an artifact of non-symmetric telescope optics, and
(e) not an artifact of the anisotropic CCD clocking combined with
imperfect charge transfer between pixels in the CCD readout
process.


For some ideas on how to do data analysis to look for tiny distortions
in the shapes of huge numbers of galaxies, it's useful to consider
measurements of weak gravitational lensing. These go back to Tyson
et al 1990 (well, they go back earlier, but I've seen that cited as
the first generally-agreed-to-be *successful* measurement). The weak
lensing measurements had to (painfully) overcome plenty of similar
error sources before they became reliable. [See, for example, the
chapter by P. Schneider in "Gravitational Lensing: Strong, Weak and
Micro", edited by P. Schneider, C. Kochanek, and J. Wambsganss,
proceedings of the Saas-Fee Advanced Course 33, Spring-Verlag 2006,
hardcover ISBN-10 3-540-30309-X, ISBN-13 978-3-540-30309-1.]

ciao,

--
-- Jonathan Thornburg (remove -animal to reply)
School of Mathematics, U of Southampton, England
"Trying to learn modern physics from popularizations is like trying to
learn to dance by watching the shadows flit by under the closed door
of a ballet school." -- John Baez, sci.physics.research, 22.Jan.2003

Phillip Helbig` wrote:
Kent Paul Dolan xanthian @ well.com writes:

Further review of the SDSS images shows that there
are galaxies capable of being classified by eye for
chirality out to at least z=20 (obviously those are
very large galaxies).

There have never been galaxies observed at this high
a redshift.

My error, you're quite correct. The site uses "z"
ambiguously, and in this case it seems to have meant
"optical magnitude in the far infrared", as can be
seen by hovering the cursor over the "z" entry in
the upper right hand widget he

http://cas.sdss.org/astro/en/tools/c...c=8.19761&opt=

Sorry to be the bearer of misinformation.

Extraordinary claims require extraordinary evidence.

Which is precisely why the operators have extended
the Galaxy Zoo project with months more classifying
time and a target of another 8,000,000
classifications (on a smaller set of candidates to
get lots more classifications per candidate (to
eliminate "sampling noise" as one possible source of
bias, I suspect)) in an attempt to eliminate
recognized possible sources of bias from the
classifications. These are real scientists running
the project, though we volunteers are mostly no such
creatures.

xanthian.

Kent Paul Dolan wrote:
Phillip Helbig` wrote:

Extraordinary claims require extraordinary
evidence.

Which is precisely why the operators have extended
the Galaxy Zoo project with months more
classifying time and a target of another 8,000,000
classifications (on a smaller set of candidates to
get lots more classifications per candidate (to
eliminate "sampling noise" as one possible source
of bias, I suspect)) in an attempt to eliminate
recognized possible sources of bias from the
classifications. These are real scientists running
the project, though we volunteers are mostly no
such creatures.

And, precisely why good scientists check their work,
_especially_ in the case of "extraordinary claims",
the universe seems not to be lopsided, just the
habits of the classifiers. This TouTube video
explains, more or less, that the bias check showed
that we classifiers are indeed biased, though not,
yet, why that is so.

http://chrislintott.net/2008/01/10/a...im-on-youtube/

To the tune of some large sighs of relief, isotopy
still lives.

xanthian.