Doppler Tests on Local Stars

On Mar 1, 12:43 pm, Oh No wrote:
Thus spake Kent Paul Dolan

"Oh No" wrote

restricting to stars ... within 100pc of the Sun

By doing so you've selected this tiny ball of
stars (compared to the size of the galaxy) all in
essentially the same part of the galaxy, all going
essentially in the same direction around the center
of the galaxy.

I am looking at the essentially random differences in orbit, due largely
to differences in eccentricity and the alignments of the axes.



It seems to me, then, that essentially _all_ you
are seeing is proper motion of those stars with
respect to the sun,

I am not sure if you know what proper motion is. It is the visible
movement of a star over time, measured in milliarcsecs per year. I am
converting that, together with radial velocity measurements into
velocities in km/s relative to the Sun. Now there is no a priore reason
why, on any axis we look out into space, there should be a stronger
alignment of velocities along that axis than there is perpendicular to
it, both for stars approaching and for stars going away, but that is
what must be happening if the standard model is right.

I've been studying,
http://arxiv.org/abs/gr-qc/0604047

and focused on the "Alf & Beth" diagrams therein,
very clear, and see the cosmological expansion factor
in Eq.(2.5), that is the basis of "teleconnection".
((correct me if I'm wrong)).

You further stipulate Alf & Beth are in communication,
via photons. Let's suppose Alf & Beth are at relative
rest, defined as the Number of wavelengths in that
communication is constant. That's basically how
the interferometry of the LIGO apparatus works, so
let's permit a hypothetical "arm" of an interferometer
to span from Alf to Beth.

For some rigority, that Number of wavelengths or
cycles can be defined by a "proper time" invariant
like S^2 = g_uv x^u x^v, with S being that Number.

So here's what I understand, while N remains constant,
the frequency of that light used to communicate between
Alf & Beth will reduce, and thus the wavelength increases,
due to the hypothetical cosmological expansion.

Is that ok with you?
Regards
Ken S. Tucker

Thus spake Ken S. Tucker

I've been studying,
http://arxiv.org/abs/gr-qc/0604047

and focused on the "Alf & Beth" diagrams therein,
very clear, and see the cosmological expansion factor
in Eq.(2.5), that is the basis of "teleconnection".
((correct me if I'm wrong)).

You further stipulate Alf & Beth are in communication,
via photons. Let's suppose Alf & Beth are at relative
rest, defined as the Number of wavelengths in that
communication is constant. That's basically how
the interferometry of the LIGO apparatus works, so
let's permit a hypothetical "arm" of an interferometer
to span from Alf to Beth.

For some rigority, that Number of wavelengths or
cycles can be defined by a "proper time" invariant
like S^2 = g_uv x^u x^v, with S being that Number.

So here's what I understand, while N remains constant,
the frequency of that light used to communicate between
Alf & Beth will reduce, and thus the wavelength increases,
due to the hypothetical cosmological expansion.


More or less, but to clarify, this was a one way communication from Alf
to Beth across cosmological distances. The cosmological expansion is not
hypothetical. It is a standard prediction of general relativity and red
shift is measured in practice. The thing I find is a different amount of
red shift than standard general relativity.


Regards

--
Charles Francis
moderator sci.physics.foundations.
substitute charles for NotI to email

Thus spake Steve Willner
Oh No wrote:
They use VLBI to determine the motion.

Actually, they use VLBI to determine the position on the sky. The
change in position over several years determines the motion.

they are counting interference fringes, and it is
still a quantum effect.

You mean in the teleconnection model? In standard theory, radio
interferometry is all classical: good old Maxwell's equations.

Indeed, that is the standard theory. Quantum theory has a way of being
much more inexplicable and bizarre.

My expectation is that whatever the
overstatement in velocity we get from Doppler measurement of globular
clusters, we will get the same overstatement from any other method which
depends on quantum wave effects.

Quasar positions measured by VLBI agree with those measured by
classical astrometry.

Yes, but in quantum theory when you do a classical measurement the wave
function collapses. There is a discontinuity in the description of
motion at the time of measurement. I am also expecting a discontinuity
in VLBI measurements when carried out over a sufficient time that
classical astronometry becomes possible. Whether the apparent
discontinuity in motion of IM Pegasi is an instance of that, I would not
like to say.

Regards

--
Charles Francis
moderator sci.physics.foundations.
substitute charles for NotI to email

Thus spake Steve Willner
Oh No wrote:
They use VLBI to determine the motion.

Actually, they use VLBI to determine the position on the sky. The
change in position over several years determines the motion.

they are counting interference fringes, and it is
still a quantum effect.

You mean in the teleconnection model? In standard theory, radio
interferometry is all classical: good old Maxwell's equations.

My expectation is that whatever the
overstatement in velocity we get from Doppler measurement of globular
clusters, we will get the same overstatement from any other method which
depends on quantum wave effects.

Quasar positions measured by VLBI agree with those measured by
classical astrometry.


It is probable others understand a lot more about VLBI than I do. When
the position of SgrA* is measured do they have to take into account
gravitational red shift of light emanating from the centre of the
galaxy? Of course this would not affect distant quasars.

In the standard model the contained mass in a given radius, r, including
CDM, should be roughly given by

v^2/r = GM/r^2

For a rotation speed of ~235km/s at 8kpc, as determined by Reid and
Brunthaler, I think that gives a contained mass of a little over 100Bill
Suns. What would the effect on the VLBI calculation of orbital motion be
if there were only 55 Bill solar masses within that radius?

Regards

--
Charles Francis
moderator sci.physics.foundations.
substitute charles for NotI to email

Thus spake Martin Hardcastle
In article ,
Oh No wrote:
A prediction of the teleconnection is that the reason for the flattening
of galaxy rotation curves is that radial velocity measured using Doppler
requires a correction due to cosmological expansion. If this is true
then the orbital velocity of the sun about the Milky Way is ~160km/s,
not ~220km/s as is usually stated

You need to worry about how these results are consistent with the
observed parallactic motion of the galactic centre -- see e.g. Reid &
Brunthaler 2004 ApJ 616 872.

Martin

I think it worth remarking that Reid and Brunthaller get a figure for
proper motion of SgrA* of 6.379+-0.024 mas/yr. That corresponds to an
orbital velocity of the Sun of 241+-1km/s at a radius of 8kpc. Even
allowing for the uncertainty of +-0.5kpc in the distance to SgrA*, it is
a little high compared to other measurements of Solar velocity, usually
about 220km/s, and noticeably high compared to the determination of the
galactic rotation rate at the solar circle of Loktin and Beshenov from
open clusters (Astronomy Reports, 2003, 47, 1, pp6-10), which comes to
197+-6.4km/s at 8kpc.

There are other small inconsistencies in astronomical measurements
within the Milky Way. The Hipparcos parallax distance of the Plaeides
springs to mind. Possibly that is to be expected at the current state of
the art, but I would love to be able to carry out a few of these
calculations to find out whether the teleconnection gives greater
consistency. Unfortunately for most of them it helps to be a trained
astronomer, which I am not.

Regards

--
Charles Francis
moderator sci.physics.foundations.
substitute charles for NotI to email

Oh No wrote:
When
the position of SgrA* is measured do they have to take into account
gravitational red shift of light emanating from the centre of the
galaxy? Of course this would not affect distant quasars.

All that's measured (for a point source) is its instantaneous position
on the sky. ("Instantaneous" means over the interval of observation,
typically a few hours.) Gravitational redshift is irrelevant; the
_received_ frequency is determined by the instrument setup, but the
_emitted_ frequency could have been anything. The same applies to
quasars.

In the standard model the contained mass in a given radius, r, including
CDM, should be roughly given by
v^2/r = GM/r^2

If the mass distribution is spherically symmetric -- supposedly a good
approximation for galactic haloes.

For a rotation speed of ~235km/s at 8kpc, as determined by Reid and
Brunthaler, I think that gives a contained mass of a little over 100Bill
Suns. What would the effect on the VLBI calculation of orbital motion be
if there were only 55 Bill solar masses within that radius?

It wouldn't change the measurement at all. Presumably one would have
to adopt a disk-like or at least flatter distribution of matter to be
consistent with the measured speed. Whether theory could explain such
a distribution would remain to be seen. It doesn't look easy, but
theorists can be pretty clever when the data force to be.

At the moment, there doesn't seem to be any reason to believe that the
dark matter mass is so much lower than theory says.

"ON" == Oh No writes:

ON Thus spake Steve Willner

Quasar positions measured by VLBI agree with those measured by
classical astrometry.

ON Yes, but in quantum theory when you do a classical measurement the
ON wave function collapses. There is a discontinuity in the
ON description of motion at the time of measurement. I am also
ON expecting a discontinuity in VLBI measurements when carried out
ON over a sufficient time that classical astronometry becomes
ON possible. Whether the apparent discontinuity in motion of IM
ON Pegasi is an instance of that, I would not like to say.

You'll have to define your terms quantitatively. Brisken et
al. (2003, AJ, 126, 3090) report observations of pulsars over a
minimum time baseline of 7 years. At least one pulsar (B1237+25) has
a proper motion in excess of 0.1 arcsec/year; over the course of their
observations it moved a distance of about 0.8 arcseconds.

Does 7 years and 0.8 arcseconds qualify as sufficient for "classical"
astrometry? If not, what does?

--
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"ON" == Oh No writes:

ON It is probable others understand a lot more about VLBI than I
ON do. When the position of SgrA* is measured do they have to take
ON into account gravitational red shift of light emanating from the
ON centre of the galaxy? Of course this would not affect distant
ON quasars.

No, for two reasons. First, the VLBI observations of Sgr A* are
continuum measurements. They observe at 43 GHz with several 8-MHz
bandwidths, processing everything within each 8-MHz bandwidth. For
the sake of illustration, suppose that one of these bands is 43.0 GHz
to 43.008 GHz. Pick your favorite value for the expected redshift, z,
from the environment of Sgr A*. Provided that Sgr A* emits between
43.0*(1+z) and 43.008*(1+z), their analysis is unchanged. Given that
Sgr A* is seen at frequencies much higher than 43 GHz, ignoring z in
this case is not a problem.

Second, assuming that general relativity is correct (or approximately
so), the radiation we see as Sgr A* of course does not come from the
black hole itself but its environment. I'm not sure we know the
actual distance, but my vague recollection is that it must be several
tens if not a few hundred gravitational radii away from the hole.
Without plugging in the numbers, I suspect that the gravitational
redshift at several tens of gravitational radii from a black hole is
not all that large.

ON In the standard model the contained mass in a given radius, r,
ON including CDM, should be roughly given by

ON v^2/r = GM/r^2

ON For a rotation speed of ~235km/s at 8kpc, as determined by Reid
ON and Brunthaler, I think that gives a contained mass of a little
ON over 100Bill Suns. What would the effect on the VLBI calculation
ON of orbital motion be if there were only 55 Bill solar masses
ON within that radius?

Note that the VLBI calculation is the reverse. The measured quantity
is (v/r). There are a variety of estimates for r, but 8 kpc is a
reasonable value. In order to obtain your value of M, they would have
had to have made a serious error in their analysis.

--
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Oh No wrote:
The thing I find is a different amount of
red shift than standard general relativity.

Did you mean what you wrote?

Red shift is a _measurement_, of displacement of
spectral lines of well known absorbing or
emitting atoms and molecules; within measurement
error, it isn't susceptable to you finding a
"different amount" of it.

xanthian.

Thus spake Kent Paul Dolan
Oh No wrote:
The thing I find is a different amount of
red shift than standard general relativity.

Did you mean what you wrote?

Red shift is a _measurement_, of displacement of
spectral lines of well known absorbing or
emitting atoms and molecules; within measurement
error, it isn't susceptable to you finding a
"different amount" of it.

Clearly I need to be more precise. I find a different amount of red
shift than standard general relativity for a given
age/distance/velocity of the source. Since the measured redshift is
clearly fixed, the measurement yields a different value for the
age/distance/velocity.


Regards

--
Charles Francis
moderator sci.physics.foundations.
substitute charles for NotI to email