|
|
Thread Tools | Display Modes |
#611
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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
|
|||
|
|||
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~~ |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
30 Years of Pioneer Spacecraft Data Rescued: The Planetary Society Enables Study of the Mysterious Pioneer Anomaly | [email protected] | News | 0 | June 6th 06 05:35 PM |
New Horizon pluto mission might investigate Pioneer 10 anomaly | [email protected] | Astronomy Misc | 0 | November 6th 05 06:43 AM |
Pioneer anomaly x disappears.!! | brian a m stuckless | Policy | 0 | October 29th 05 10:16 AM |
Pioneer anomaly x disappears.!! | brian a m stuckless | Astronomy Misc | 0 | October 29th 05 10:16 AM |