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  #611  
Old August 24th 06, 08:38 PM posted to sci.physics,sci.astro
dlzc
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Posts: 1,426
Default Pioneer : Anomaly Still Anonymous

Dear George Dishman:

Thought you might be interested in this latest from John Anderson.
Don't know if you've seen it yet:
http://arxiv.org/PS_cache/astro-ph/pdf/0608/0608087.pdf
.... 23 page pdf regarding orbital boosting and the onset of the Pioneer
Anomaly

I can't believe it wasn't mentioned here yet... maybe google.groups
search was temporarily blinded.

David A. Smith

PS: I'm still reading it...

  #612  
Old August 25th 06, 03:49 AM posted to sci.physics,sci.physics.relativity,sci.astro
GSS
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Posts: 245
Default Pioneer : Anomaly Still Anonymous


Lester Zick wrote:
On 24 Aug 2006 05:18:09 -0700, "GSS"
wrote:


Craig Markwardt wrote:
"GSS" writes:
Craig Markwardt wrote:
"GSS" writes:
Craig Markwardt wrote:
"GSS" writes:

...
... Why can't we consider the observed state as a
steadily collapsing state?

Primarily, because the observations show that the globular clusters
are not presently collapsing: per the examples I cited, via Doppler
shift, the motions of the stars can be decomposed into a rotating
component and a random component (i.e. both inward- and
outward-going).


How can the observation of motions of the stars *show* that the GC is
not collapsing? ...

In particular, they show clusters where the individual stars that are
both moving inward and outward from the center of the cluster. I.e. a
rapid collapse of the entire cluster is not occurring. Computer
simulations verify that such a collapse does not occur.

... If a particular GC is steadily collapsing at present
and is bound to finally collapse in about a billion years from now,
what difference in the current observations do you visualize in that
case?
.....

You suddenly jump from a time scale of one million years to one
billion years? There is probably no direct observational signatures
presaging such an event.

OK, let us reduce the time scale to about 100 million years. If a
particular GC is steadily collapsing at present and is bound to finally
collapse in about 100 million years from now, will there be any direct
observational signatures presaging such an event. Probably none. And
that confirms my original point that current observations of the
motions of stars *cannot show* that the GC is not collapsing. Hence our
presumptions of *equilibrium state* in uncollapsed GCs may actually be
ill founded.

Since the original supposition by Zick was that the cluster would
collapse "wholesale" (i.e. presumably in free-fall), the observations
do exclude that possibility. Your question basically hinges on the
long-term dissipation processes in a cluster. Those issues have
certainly been studied very extensively, which is why I recommended
that you consult some of the excellent review articles. Apparently
you are still not interested.

... snip ...


Dear Craig,
You are right. As I pointed out earlier, I am an
'outsider' to this field. Thanks for participating in these
discussions so patiently. Through these discussions, I have developed
an interest in this field and that is enough.


GSS, please excuse the comment but are you seriously suggesting gc's
with zero angular momentum are not collapsing wholesale? At least
since this seems to be the thrust of Craig's preceeding comment and as
you reply to Craig "You are right" this would be my interpretation.
All Craig has really done so far is to rework various "zooming"
"buzzing" and "whizzing" hypotheses with technical KE/PE jargon and
claimed zero aggregate angular momentum and non zero KE/PE are somehow
incompatible.


Dear Lester Zick,
In my reply to Craig, "You are right" was a
specific response to his observation "Those issues have certainly been
studied very extensively, which is why I recommended that you consult
some of the excellent review articles. Apparently you are still not
interested." Obviously if I am either not interested or just unable to
consult the existing research material on the subject, I should not
keep repeating the same arguments again and again.

GSS



Originally I had started following this thread out of my curiosity to
understand the Pioneer Anomaly. However, since the discussions drifted
to globular clusters, original subject of this thread has been almost
forgotten.

Let us revive the discussions on the Pioneer Anomaly.

GSS


Lester Zick
~v~~


  #613  
Old August 25th 06, 09:23 AM posted to sci.physics,sci.astro
George Dishman[_1_]
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Posts: 2,509
Default Pioneer : Anomaly Still Anonymous


"dlzc" wrote in message
ups.com...
Dear George Dishman:

Thought you might be interested in this latest from John Anderson.
Don't know if you've seen it yet:


I hadn't, thanks David, I appreciate the heads-up.
I will need to see how that affects my own thoughts.

George


  #614  
Old August 25th 06, 07:20 PM posted to sci.physics,sci.physics.relativity,sci.astro
Lester Zick
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Posts: 735
Default Pioneer : Anomaly Still Anonymous

On 24 Aug 2006 19:49:26 -0700, "GSS"
wrote:


Lester Zick wrote:
On 24 Aug 2006 05:18:09 -0700, "GSS"
wrote:


Craig Markwardt wrote:
"GSS" writes:
Craig Markwardt wrote:
"GSS" writes:
Craig Markwardt wrote:
"GSS" writes:

...
... Why can't we consider the observed state as a
steadily collapsing state?

Primarily, because the observations show that the globular clusters
are not presently collapsing: per the examples I cited, via Doppler
shift, the motions of the stars can be decomposed into a rotating
component and a random component (i.e. both inward- and
outward-going).


How can the observation of motions of the stars *show* that the GC is
not collapsing? ...

In particular, they show clusters where the individual stars that are
both moving inward and outward from the center of the cluster. I.e. a
rapid collapse of the entire cluster is not occurring. Computer
simulations verify that such a collapse does not occur.

... If a particular GC is steadily collapsing at present
and is bound to finally collapse in about a billion years from now,
what difference in the current observations do you visualize in that
case?
.....

You suddenly jump from a time scale of one million years to one
billion years? There is probably no direct observational signatures
presaging such an event.

OK, let us reduce the time scale to about 100 million years. If a
particular GC is steadily collapsing at present and is bound to finally
collapse in about 100 million years from now, will there be any direct
observational signatures presaging such an event. Probably none. And
that confirms my original point that current observations of the
motions of stars *cannot show* that the GC is not collapsing. Hence our
presumptions of *equilibrium state* in uncollapsed GCs may actually be
ill founded.

Since the original supposition by Zick was that the cluster would
collapse "wholesale" (i.e. presumably in free-fall), the observations
do exclude that possibility. Your question basically hinges on the
long-term dissipation processes in a cluster. Those issues have
certainly been studied very extensively, which is why I recommended
that you consult some of the excellent review articles. Apparently
you are still not interested.

... snip ...

Dear Craig,
You are right. As I pointed out earlier, I am an
'outsider' to this field. Thanks for participating in these
discussions so patiently. Through these discussions, I have developed
an interest in this field and that is enough.


GSS, please excuse the comment but are you seriously suggesting gc's
with zero angular momentum are not collapsing wholesale? At least
since this seems to be the thrust of Craig's preceeding comment and as
you reply to Craig "You are right" this would be my interpretation.
All Craig has really done so far is to rework various "zooming"
"buzzing" and "whizzing" hypotheses with technical KE/PE jargon and
claimed zero aggregate angular momentum and non zero KE/PE are somehow
incompatible.


Dear Lester Zick,
In my reply to Craig, "You are right" was a
specific response to his observation "Those issues have certainly been
studied very extensively, which is why I recommended that you consult
some of the excellent review articles. Apparently you are still not
interested." Obviously if I am either not interested or just unable to
consult the existing research material on the subject, I should not
keep repeating the same arguments again and again.

GSS


Thanks for the clarification, GSS. Best of luck to you.

Originally I had started following this thread out of my curiosity to
understand the Pioneer Anomaly. However, since the discussions drifted
to globular clusters, original subject of this thread has been almost
forgotten.

Let us revive the discussions on the Pioneer Anomaly.

GSS


Lester Zick
~v~~


~v~~
 




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