Why are the 'Fixed Stars' so FIXED?

On 4 Apr, 00:17, HW@....(Henri Wilson) wrote:
On 3 Apr 2007 07:02:49 -0700, "George Dishman" wrote:
On 3 Apr, 01:25, HW@....(Henri Wilson) wrote:
On Mon, 2 Apr 2007 22:51:01 +0100, "George Dishman" wrote:
"Henri Wilson" HW@.... wrote in message
George if you can tell me how much matter is falling into the star and what is
its relative angular momentum, I might be able to provide some kind of answer.
You would also have to assume something about magnetic damping and tidal
effects due to gaseous atmosphere around it. ..and what is the curvature of its
transverse motion?

How anyone can seriously claim that it is exactly in line with GR predictions
is really funny.

Nobody claimed it was in line with any GR predictions,
you said it was "exactly what the BaTh predicts".

That paper you referred me to claimed it was.

I'm surprised but I don't have that one handy. Are you sure you
aren't thinking of the Hulse and Taylor paper? Pulsar rate slowing
is due to the magnetic field and I don't think GR even comes into
it, nor does ballistic theory AFAICS.

If you read what I said in tyhe other message you will now know that the
VDoppler effect doesn't exist...as I originally thought.

We have since corrected that, your new numbers are
realistic.

The 'correction' is negligible.

Fit your model to the observed data. I think you will find
it is dominant.

I think there is a certain amount of circularity in the logic behind the
shapiro delay business.

None at all, just comparison against an empirical curve.

Are they delayed or advanced?

Ballistic theory says they should be advanced but they
are actually delayed.

No. The BaTh should be in agreement with GR.

It isn't, it ballistic theory predicts an advance, GR
predicts a delay.

There is a180 phase difference. How can anyone say which is right?

What is observed is a delay when the Sun is close to
the line of sight to spaecraft and when radar signals
are bounced off Venus and so on. There is no question
about the observation within the Solar system and both
GR and ballistic theory say the effect should be largest
when the light passes closest to the body (obviously).
The main difference is the sense of the effect.

George, the BaTh says all light leaving the pair will be slowed slightly,
causing an overall redshift that may or may not be counterbalanced by the blue
shift arising from its accelerated approach to our galaxy and Earth.

Henry, have a look at the earlier message in this thread where
we discussed this:

http://groups.google.co.uk/group/sci...3b2a017ef89b9b

Your conclusion was:

Right so the signal arrives earlier, it is not a delay.
The gravitational redshift is identical in each case as
is the eventual speed.

that's right.



When the star is on the near side, the bending of light by the dwarf more than
compensates for the increase in average light speed.
So The BaTh says that there should be a shapiro type slowing.

Let's see the maths Henry. If you are right then you can
add that curve to you program and then we will see if
you can really match the curves.

I don't even accept that this is the real source of pulses.

I don't really care what you accept, all that matters
is that pulses are produced and we can use them as a
testbed.

Fair enough...but the distance of their origin from the pulsar could be
important for the BaTh.

I doubt it unless it was well outside the binary system but
then there would be little variation in any of the parameters.

In reality, it is probably more like the earlier static picture
where the angle between the rotational and magnetic axes is
smaller. The second beam is always pointing away from us.

Maybe..but I would have thought the field is more like a broad plane than a
beam.

They seem to produce a cone shaped beam or pencil
beams, sometimes both. The whole thing is very
complex. See section 4 and Figure 2 of

http://www.arxiv.org/abs/astro-ph/0407149

Note the signal is low in the centre and highest along
the 'hourglass' shaped contour.

Yes.

Even the 'magnetic field' idea is an assumption.

There is a lot of evidence backing that up.

It could for instance be a beam of radiation that excites surounding gas..

No, the excitation would take far too long to decay
and the pulse would probably have a longer tail.

Anyway I suppose it doesn't matter much for our purposes.

Not really.

Yes, so the signals from the pulsar when it is on the far side
of the companion should be accelerated towards us and then
slowed to the original speed once it has passed the dwarf and
is en route to us. That would produce an advance of the arrival
time as we discussed some time ago. You appeared to agree the
mechanism then so can you go back and have another read, I don't
want to write all the same stuff again.

GR says the same.

No, it predicts a delay.

Then it has the star's position 180 out...that's all.

We see a delay that peaks like this:

_/\_____

An advance shifted by 180 degrees would look like this:
_____ _
\/

Not even close.

No. The BaTh expects the same kind of delay due to bending and increased light
path lengths. I was wrong about the 180 difference.

OK, so now show me the maths you used to find that there
is an overal delay.


One pulsar is blocked by the other. Remember this
was discussing the dual pulsar system.

The pulsar is barely moving.

You have no model fit that predicts that, it is just
handwaving and will turn out to be wrong when you do
the work.

I gave you some figures.

Yes, you have looked at a number of test scenarios most of
which I asked about to show how they could be eliminated
from consideration.

What I mean is that you haven't worked through the whole
problem to find a single set of numbers that fits all the
observational data. It's not a criticism Henry, we just
haven't reached that stage yet.

I'm a bit confused as to which pulsar we are discussing now.

The history is lost in the snipping but different bits
of the post refer to different systems. The eclipsing
system is J0737-3039 which is two pulsars.

..explain the phasing in diagram1 and I will try.

As I understand it, the phase is like this:

A

B + D Earth

C

A = 0.00 & 1.00
B = 0.25
C = 0.50
D = 0.75

I don't like their method anyway.

The terms are fairly standard and you should be able
to convert to other angles easily. These should help:

http://en.wikipedia.org/wiki/Longitu...ascending_node

you see I don't use this convention.

Maybe not but you need to understand it if you want
to know what a longitude of periastron of 155 degrees
means in your terms.

....
The truth is that the luminosity drops to near zero
for 2 degrees of the orbit, that is the data and it
is not an interpretation.

eclipses CAN occur.

And statistically we expect to see some. There is no
reason to think this isn't one and the Shapiro delay
matches.

Where is evidence of the eclipse?

The fact that the flux dips to near zero coincident
with the Shapiro delay maximum, point B on the above
diagram.

Is this still with reference to the dual pulsar system?

Yes.

If so there should be two Shapiro effects per cycle.

There should but the pulses from the second pulsar are
very hard to detect. They have only recently caught them
for a small part of the orbit. Again, being a thin beam
there is a finite chance that it won't sweep over us. Now
that it has been found there might be a more extensive
study in the future.

These are all areas of on-going research but it is
a fact that we see X-ray and gamma emissions and I
believe the spctra can give some indication of the
surface composition. Anyway, there is no reason why
we shouldn't see the surface, the free-fall speed
would be about half the speed of light so there
would be _significant_ gravitational redshift.

So what is the actual doppler shift of the EM that makes up the actual pulses
of a neutron star? It should be very heavily redshifted ..

AFAIK it is a continuum with no lines to be measured. Remember
we are talking about radio signals in the VHF to microwave bands.

and the pulses should
start out at maybe c/2. ...this is why I don't believe the pulses are actually
produced near the pulsar itself but at a considerable distance away.

The slow initial speed would just give an overall distance
value that is higher than actual, but only by a few light
hours at most and we don't know the distance better than
tens of light years, and since the error would be constant,
it doesn't have any effect we can measure.


Yes...but I hadn't forgotten. I'm trying to find velocity curves for so called
eclipsing binaries because they should reveal a great deal about this whole
approach.
I'm still not convinced that the 'compressible pulse width' method we're using
for pulsars applies to light from stars.

I am discussing J0737-3039 which is a double pulsar system
with an eclipse. The velocity curve should be easy to find
or perhaps figure out from the orbital elements (as before
work back using conventional theory to find the observations
then re-interpret using ballistic theory).

I'll see what I can find.

OK. If you can add a curve for the ballistic theory Shapiro effect,
then we can really see how well you can match the observations.

George