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Why are the 'Fixed Stars' so FIXED?



 
 
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Old April 2nd 07, 10:51 PM posted to sci.physics.relativity,sci.astro
George Dishman[_1_]
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Default Why are the 'Fixed Stars' so FIXED?


"Henri Wilson" HW@.... wrote in message
...
On 1 Apr 2007 07:57:46 -0700, "George Dishman"
wrote:

On 26 Mar, 00:56, HW@....(Henri Wilson) wrote:
On Sun, 25 Mar 2007 00:31:31 -0000, "George Dishman"
wrote:
"Henri Wilson" HW@.... wrote in message
.. .
On Sat, 24 Mar 2007 13:45:26 -0000, "George Dishman"
wrote:

...
We know the pulsar produces pulses regularly every
2.285ms and it doesn't matter whether that is one
or two or 27 per rotation, all that matters is that
we can measure that they are emitted with a regularity
almost as good as an atomic clock.

I was under the imp[ression that the observed pulse was slowly changing
too.
Not to worry...


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.

The VDoppler contribution is negligible...forget it.

Nope, the simple indication from the phase is that
it is completely dominant. If you want to forget it
you have to show an alternative model, such as a
higher eccentricity, that explains the phase. I'm
not saying you can't, only that you cannot just wave
your hands and pretend the phase data doesn't exist.

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 don't really care about that, I want to know why they
are delayed after they have been created.

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.

All we have is a
theory. It might be completely wrong.
How do YOU explain the existence of pulses.

The source emits a beam and spins like a lighthouse, you
know that already.

I don't know that any more. I dont think that explains what is observed.
Do you think the beam is a narrowly focussed 'pencil'... or is it a
plane?


See the illustration here

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

In one of the papers I cited some time ago, there was a
diagram shoing a cross-section where precession means we
have stripes across the beam, like the scan lines of a TV.


It's a pretty crappy article.


It is not intended as technical.

Quote:
"The time between pulses, the period, is the time that it takes for the
neutron
star to rotate once. "

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

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.

and:

"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.

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

Both pretty obvious really.

George, GR and the BaTh have the same equations as regards the
slowing of
light
or the distortion of space to maintain its speed at c.

No they don't Henry, nothing like it.

George, the BaTh says light speed increases when light falls down a
gravitty
wwell just like anyhting else does.


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.

GR effectively says the light s[p]eed remains
constant and SPACE contracts to make that so.
As the Pound- Rebka experiment showed, both approaches give the same
answer.


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.

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.

We see a bright dot in the sky George. It could be anything.


No Henry, it could not "be anything", it is a white dwarf
because it has the spectrum that falls into that
classification.


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.

Back to the abuse Henry? I'm just applying Kepler's
laws and you say your program uses them so it should
agree.

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.

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.

...but there can also be eclipse-like dips in brightness curves caused
purely
by c+v.


But the field rotates hundreds of times a second and the
eclipse last 48 seconds every 2.4 hours (figures estimated
from memory but right order of magnitude).

But what is the form of the magnetic field? How can a magnetic field
escape a
neutron star when light cannot?


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.

An eclipse isn't hard to interpret.

Oh but it is.
The Bath expects many orbiting stars to appear as though they are
eclipsing.
All that is required is a moderately eccentric orbit and a periastron
approx.
nearest to the observer.


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.

George


 




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