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
.. .
On 1 Apr 2007 07:57:46 -0700, "George Dishman"
wrote:

Pulsars are normally slowing very slightly but it
is _very_ gradual:

http://outreach.atnf.csiro.au/educat...ryone/pulsars/

"For example, a pulsar called PSR J1603-7202 is known to have
a period of 0.0148419520154668 seconds. However the periods
of all radio pulsars are increasing extremely slowly. The
period of PSR J1603-7202 increases by just 0.0000005 seconds
every million years!"

..which is exactly what the BaTh predicts for a pulsar that is in a very
large
orbit. ..but it is also to be expected that they should be slowing as they
lose
energy. I see no problem there.

"I expect" is not a mathematical prediction. Show the
maths that gives you a figure of 500 ns per million
years and I'll believe you.

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".

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.

Why aren't two pulses emitted per rotation?

You are probably thinking of something like the animation
on this page:

http://science.nasa.gov/newhome/help...als/pulsar.htm

Yes.
I would expect two pulses per rotation from many pulsars..

A smaller second pulse half a rotation later is seen
from some.

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.

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.

Even the 'magnetic field' idea is an assumption.

There is a lot of evidence backing that up.

"Therefore the most likely explanation is that a pulsar is a neutron star
that
spins rapidly and emits radio waves along its magnetic axis. However, not
all
neutron stars are necessarily detectable as pulsars. The beams from some
neutron stars may never pass the Earth and will therefore not be detected.
Also, other neutron stars may have been pulsars in the past, but the
process
that causes the beam of radiation (which is not fully understood) may have
turned off or is just too weak to be detected. "

In other words, they don't know.

In other words :

a) the beams are thin so we expect to see only a fraction of
the total number of pulsars.

Possibly,..maybe not.

Only if all the pulsars in the galaxy happen to
point at us. I doubt that.

b) the energy to produce the beam runs out eventually.

It will.

Both pretty obvious really.

Reasonably.

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.

Pound-Rebka showed that processes seem to go slower when
viewed from a higher potential. In GR the light seems to
move slower when it is close to the companion hence it
predicts a delay.

But the companion is orbiting the star....not vice versa...

Doesn't matter, only the relative speed matters. Move your
finger in front of a light or move the light behind your
finger and it gets blocked either way.

but it doesn't get blocked in the pulsar.

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.

Well if it can be positively identified let''s see its brightness curve.
Do you think we can ask someone to try to measure it for us?
Are you in touch with any astronomers?

No. I suspect they will try to get some telescope time
at some point but it will take its place in the priorities.

yes. I suppose so.

Well you got the VDoppler business wrong for a start...

Strange how you now agree with me.

I agree ..but it is a negligible effect .....and not related to
extinction.

It is not _related_ to extinction but it allows us to put
an upper limit on the distance over which extinction occurs.
Fit your model and you'll see what I mean.

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

http://www.lns.cornell.edu/~seb/cele...eadsheets.html

You might like this too, I came across it by accident

http://voyager2.dvc.edu/faculty/kcas...tar%20Dat3.htm

There's a bit of a glossary at the bottom.

Theories, theories...all based on wrong data...
What is the truth?

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.

Why do you say light cannot escape Henry, of course it
escapes or we couldn't receive the pulses.

I was under the impression that no light can escape from the neutron star
itself.

No, that only happens for black holes. In fact we see
some pulsars in x-ray and gamma produced by infalling
matter hitting the surface.

theories, theories, again George.

No Henry interpretations. You really should know what
the word "theory" means by now and not be using it
like a layman.

I'm not saying they are wrong...just suspicious...

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.


Go on then, show how your program produces a drop to zero
luninosity, or say by just five or six magnitudes, for just
two degrees of the orbit with no variation at any other time.
That is what the program is for isn't it?

Sure.
www.users.bigpond.com/hewn/narrow.jpg

Nice. However, don't you get the same shape for the
red velocity curve? I think you have used an extreme
eccentricity and you are forgetting that the red
velocity curve has to be a match to a Keplerian orbit
of a much lower value.

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
thenre-interpret using ballistic theory).

George