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Pioneer Anomaly 2017



 
 
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  #21  
Old April 11th 17, 08:15 PM posted to sci.astro
Craig Markwardt[_2_]
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Posts: 137
Default Pioneer Anomaly 2017

On Tuesday, April 11, 2017 at 3:46:47 AM UTC-4, wrote:
Il giorno lunedì 10 aprile 2017 13:55:22 UTC+2, Craig Markwardt ha scritto:
On Sunday, April 9, 2017 at 9:24:25 AM UTC-4, wrote:
Il giorno venerdì 7 aprile 2017 16:03:50 UTC+2, Craig Markwardt ha scritto:
On Thursday, April 6, 2017 at 4:18:06 AM UTC-4, wrote:
...
.. Mr. Craig seems to me an interesting competitor .. we shall try to speak completely (?) in one point, each time ...
.. first point : is quantitatively similar the magnitude of acceleration of Pioneer and Hubble constant ?
No

.. i don't know the paper of Anderson 2002 .. modestly i know that the acceleration in the International Sistem is given in meter each sec * sec .. ..: if i translate the Pioneer 'datas 8.7cm * 10^-8 sec*sec in meter , i get 8.7 m *10^-10 sec*sec

Yes

..: if i tranlate the Hubble 'datas 25 km sec * M y , i get 25*10^3 sec *sec/ 3.1 *10^6 * 10 *6 or 8.2 m*10^-10 sec*sec ...and so the two accelerations are , in absolute value , very similar ..(NB: i have forgotten the M. y. l. , the l. of 'light' because also in Pioneer datas , this quantity was forgotten..)

Don't forget it, it's important. Hubble constant is about 75 km/s/Mpc (Mpc = megaparsec) That is a velocity change of 75 km/s for each megaparsec of distance increase. Typical escape speed for Pioneers is about 12 km/s, so (75 km/s/Mpc * 12 km/s) = 2.9e-14 m/s^2. No way this is close to 8.7e-10 m/s^2.

Now if Pioneers were traveling at the speed of light, then yes, the numbers would be comparable, but that is not the case.
CM

..i refer to the paper arxiv : gr ..q../010406..
1) Turyshev wrote that an other people (like me) had noted the similarity of the quantity of the Pioneer acceleration and the Hubble constant ..
2) at page 32 of the paper , the formula 15 keeps at denominator the c ( migth that authorize to write M.y.l. only M.y. ?


There is no equation 15 on page 32 of 0104064.pdf, but if you mean equation 57 on page 44... This was a throwaway line in the paper, and unfortunately stimulated too many people. It is meaningless numerology.

3) of course , i take the datas from the arxiv'paper , but the measures of distance are done with signals coming of light'speed in the two cases ( Pioneer and Hubble)
.. the tipical escape'speed of 12 km.sec is not inside the question , because the anomaly is an extraspeed , out of the 12k.s. (initial speed) and the gravitational 'speed adjustments..


Nope. Problem 1 of course is that the Hubble expansion is an expansion which accelerates "outward" with increased distance, whereas the Pioneer effect is an acceleration "inward." So of course the direction is totally wrong.

But even then the explanation fails. If one takes the Hubble effect as it is conventionally understood, it is an expansion of space which carries objects along with it. Hubble expansion alone at a single distance could never lead to the Pioneer effect, because the Hubble effect is a constant velocity at fixed distance (i.e. no acceleration). Fail. However, Pioneer is moving from smaller distance to larger distance at about 12 km/s so it does sample regions of smaller, then large expansion. That *does* lead to differential Hubble expansion, i.e. acceleration, *but* the magnitude is too small as already noted.

Your appeal to light speed of the measurement is not founded upon anything known about the Hubble effect. The Hubble effect is still a amount of speed change *per distance*. The Pioneer spacecraft just doesn't have a large distance (and distance is not increasing at a large rate).

CM


.. my reference 'paper is arxiv:qr-qc/0104064 19Apr2001 ..page 32 chapter 5 -Original detection... at half-page we have : formula 15 .. . Vobs=Vmodel(t)*(1-2ap*t/c)... can be interpreted like a detection at light'speed?


No. "expressed to first order in v/c" means it is indicative of the sign and magnitude of aP but not used for any analysis. You can't just ignore a factor of c.

.. the distance of the Pioneers was considered in UA (in Km=space ) and in Hours/light'speed ( in time=space? ): they made the two things togheter and that could carry some confusion ..can i have right at 10% ?


Light time is more observable to radiometric analysts, which is why it is discussed. Distance is inferred from the best-fit trajectory. But this still does not allow you to ignore a factor of c.

..so we go to discuss the second question :the sign of de-acceleration .. then the third : is Hubble an acceleration ? .


The Hubble "flow" is faster at larger distances. An object traveling from nearer to farther will move from slower to faster Hubble flow. In effect an acceleration. But the "direction" of the acceleration is outward for a craft moving from nearer to farther, so it is not the explanation. The Pioneers' outward speeds were *slowing* more than expected based on the 2002 understanding of the physics, not speeding up.

CM



  #22  
Old April 12th 17, 11:53 AM posted to sci.astro
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Posts: 73
Default Pioneer Anomaly 2017

Il giorno martedì 11 aprile 2017 09:46:47 UTC+2, ha scritto:
Il giorno lunedì 10 aprile 2017 13:55:22 UTC+2, Craig Markwardt ha scritto:
On Sunday, April 9, 2017 at 9:24:25 AM UTC-4, wrote:
Il giorno venerdì 7 aprile 2017 16:03:50 UTC+2, Craig Markwardt ha scritto:
On Thursday, April 6, 2017 at 4:18:06 AM UTC-4, wrote:
...
.. Mr. Craig seems to me an interesting competitor .. we shall try to speak completely (?) in one point, each time ...
.. first point : is quantitatively similar the magnitude of acceleration of Pioneer and Hubble constant ?
No

.. i don't know the paper of Anderson 2002 .. modestly i know that the acceleration in the International Sistem is given in meter each sec * sec .. ..: if i translate the Pioneer 'datas 8.7cm * 10^-8 sec*sec in meter , i get 8.7 m *10^-10 sec*sec

Yes

..: if i tranlate the Hubble 'datas 25 km sec * M y , i get 25*10^3 sec *sec/ 3.1 *10^6 * 10 *6 or 8.2 m*10^-10 sec*sec ...and so the two accelerations are , in absolute value , very similar ..(NB: i have forgotten the M. y. l. , the l. of 'light' because also in Pioneer datas , this quantity was forgotten..)

Don't forget it, it's important. Hubble constant is about 75 km/s/Mpc (Mpc = megaparsec) That is a velocity change of 75 km/s for each megaparsec of distance increase. Typical escape speed for Pioneers is about 12 km/s, so (75 km/s/Mpc * 12 km/s) = 2.9e-14 m/s^2. No way this is close to 8.7e-10 m/s^2.

Now if Pioneers were traveling at the speed of light, then yes, the numbers would be comparable, but that is not the case.
CM

..i refer to the paper arxiv : gr ..q../010406..
1) Turyshev wrote that an other people (like me) had noted the similarity of the quantity of the Pioneer acceleration and the Hubble constant ..
2) at page 32 of the paper , the formula 15 keeps at denominator the c ( migth that authorize to write M.y.l. only M.y. ?


There is no equation 15 on page 32 of 0104064.pdf, but if you mean equation 57 on page 44... This was a throwaway line in the paper, and unfortunately stimulated too many people. It is meaningless numerology.

3) of course , i take the datas from the arxiv'paper , but the measures of distance are done with signals coming of light'speed in the two cases ( Pioneer and Hubble)
.. the tipical escape'speed of 12 km.sec is not inside the question , because the anomaly is an extraspeed , out of the 12k.s. (initial speed) and the gravitational 'speed adjustments..


Nope. Problem 1 of course is that the Hubble expansion is an expansion which accelerates "outward" with increased distance, whereas the Pioneer effect is an acceleration "inward." So of course the direction is totally wrong.

But even then the explanation fails. If one takes the Hubble effect as it is conventionally understood, it is an expansion of space which carries objects along with it. Hubble expansion alone at a single distance could never lead to the Pioneer effect, because the Hubble effect is a constant velocity at fixed distance (i.e. no acceleration). Fail. However, Pioneer is moving from smaller distance to larger distance at about 12 km/s so it does sample regions of smaller, then large expansion. That *does* lead to differential Hubble expansion, i.e. acceleration, *but* the magnitude is too small as already noted.

Your appeal to light speed of the measurement is not founded upon anything known about the Hubble effect. The Hubble effect is still a amount of speed change *per distance*. The Pioneer spacecraft just doesn't have a large distance (and distance is not increasing at a large rate).

CM


.. my reference 'paper is arxiv:qr-qc/0104064 19Apr2001 ..page 32 chapter 5 -Original detection... at half-page we have : formula 15 .. . Vobs=Vmodel(t)*(1-2ap*t/c)... can be interpreted like a detection at light'speed?
..the Pioneer anomaly is 8.5*10^-8 cm*s*s .. is that like 8.5*10^-10 m*s*s ? and so and so ..untill 25 km*s * M.y. ?
.. the distance of the Pioneers was considered in UA (in Km=space ) and in Hours/light'speed ( in time=space? ): they made the two things togheter and that could carry some confusion ..can i have right at 10% ?
..so we go to discuss the second question :the sign of de-acceleration .. then the third : is Hubble an acceleration ? ...at the end we could discuss the dayly and yearly variations , when its occur (times of the maximum and minimum) and the amounts .. ok ? of course , you can change this order ..and thanks for your patience ..


...... the sign of acceleration
... a Pioneer , sending e.m. signals , is clearly in only one place ...with only one speed !
... but the indications of 1) the times go-and-back and 2) the Doppler shift are not coincident ..and the rocket slowering or increasing depends from the choice of the right referement , 1) or 2)? ...
I) i understood (correctly?) from Turishev that the Pioneer was like attracted by a possible mass in Kuiper belt ...: so its speed was increasing ..and the Doppler was lowering ..
II) at page 34 of my reference ' paper they wrote ''..a frequency drift about -(-!)6.. ,or 1.5Hz over 8 years .This equates to a clock acceleration -(-!) 2.8*10^18 '' ..: just like a clock lowering ..i can easily understand a discussion around the quantity , but difficultly around the sign ..
III) at page 73 ,again my paper, they consider the anomal acceleration 8.7*10^-8 cm*s^2 and that value can be increased by A)+0.03 for 'solar radiation pressure and mass' and B) +1.1 for 'radio beam reaction force' : these two effects can only push away from the sun ..there the anomaly is presented without sign ( it means + ..or not ?)..so the two contributions are increasing the rocket speed , like it is natural ...
... is all ok? no ..because an underextimated effect gives an undeextimated speed (acceleration) , but always the rocket has to show only one (new) position and one (new) speed ..: that thing was not verified ! i think that the e.m. signals are affected by a shift ,travelling in the vacuum and at very temperature, caused by a kind of Raman effect , like told before , and over that i shall riturn ..
  #23  
Old April 12th 17, 08:44 PM posted to sci.astro
Craig Markwardt[_2_]
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Posts: 137
Default Pioneer Anomaly 2017

On Wednesday, April 12, 2017 at 6:53:01 AM UTC-4, wrote:
..... the sign of acceleration

I note no response.

I take it you are done ignoring c?

.. a Pioneer , sending e.m. signals , is clearly in only one place ...with only one speed !

A truism - at one instant. But, we are considering the *acceleration* of the craft, which means we must analyze the trajectory over a long period of time, distance and range of velocity. So the craft does sample different regions of the Hubble flow, but it is not enough to explain the Pioneer anomaly.

[ examples deleted ]
Anderson et al considered many possible explanations, including both direction (sign) and amount (magnitude). But at the time none were sufficient to explain the measured sign or magnitude.

CM
  #24  
Old April 14th 17, 02:32 PM posted to sci.astro
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Default Pioneer Anomaly 2017

Il giorno mercoledì 12 aprile 2017 21:44:37 UTC+2, Craig Markwardt ha scritto:
On Wednesday, April 12, 2017 at 6:53:01 AM UTC-4, wrote:
..... the sign of acceleration

I note no response.

I take it you are done ignoring c?

.. a Pioneer , sending e.m. signals , is clearly in only one place ...with only one speed !

A truism - at one instant. But, we are considering the *acceleration* of the craft, which means we must analyze the trajectory over a long period of time, distance and range of velocity. So the craft does sample different regions of the Hubble flow, but it is not enough to explain the Pioneer anomaly.

[ examples deleted ]
Anderson et al considered many possible explanations, including both direction (sign) and amount (magnitude). But at the time none were sufficient to explain the measured sign or magnitude.

CM


... i understand English not very well ..
.. ok .. i can consider the c like a lost question for me , but the whole question is not clear ..
... can you answer for an hipothetic question ? : if you discover in the Kuiper belt a disomogeity ( or a gas leakage in the rocket ) , the Pioneeer 'anomaly is resolved ! ... so , should be the trajectory of the times go-back and of the Doppler shift coincident ?
... i rephrase : the two trajectories 'construction with go-back times and with Doppler shift should be always coincident , also without the knoledge of the path , i think ...
... but not if , in the space ' travel , the Doppler frequency is changed by some effect ( or some effect is changing the ticking of the clock inside the rocket ) .. you might think about in the Eastern holiday .. best wishes
  #25  
Old April 14th 17, 10:08 PM posted to sci.astro
Craig Markwardt[_2_]
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Posts: 137
Default Pioneer Anomaly 2017

On Friday, April 14, 2017 at 9:32:50 AM UTC-4, wrote:
....
.. can you answer for an hipothetic question ? : if you discover in the Kuiper belt a disomogeity ( or a gas leakage in the rocket ) , the Pioneeer 'anomaly is resolved ! ... so , should be the trajectory of the times go-back and of the Doppler shift coincident ?

....
I am not certain of your question. If one has a model of the Kuiper belt, or of the gas leaks, then yes one can go back and re-analyze the Doppler data.

Anderson et al. did consider these particular topics.

CM
  #26  
Old April 18th 17, 08:05 AM posted to sci.astro
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Default Pioneer Anomaly 2017

Il giorno venerdì 14 aprile 2017 23:08:19 UTC+2, Craig Markwardt ha scritto:
On Friday, April 14, 2017 at 9:32:50 AM UTC-4, wrote:
...
.. can you answer for an hipothetic question ? : if you discover in the Kuiper belt a disomogeity ( or a gas leakage in the rocket ) , the Pioneeer 'anomaly is resolved ! ... so , should be the trajectory of the times go-back and of the Doppler shift coincident ?

...
I am not certain of your question. If one has a model of the Kuiper belt, or of the gas leaks, then yes one can go back and re-analyze the Doppler data.

Anderson et al. did consider these particular topics.

CM


... i was rereading my reference paper .. and it comes out a prime question : have you controlled if the trajectory done with the times go-back , is coincident with the modeled trajectory ?
  #27  
Old April 19th 17, 10:50 AM posted to sci.astro
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Default Pioneer Anomaly 2017

On Saturday, April 1, 2017 at 7:47:20 AM UTC+11, Craig Markwardt wrote:
---
---
The question is what tolerance was required for the analysis. Anderson
et al's analysis was quite back of the envelope. A few Watts makes a
difference, so it was important to treat the analysis in more detail.


Solar Radiation Pressure and the Pioneer Anomaly

Stored here for convenience:
http://members.optusnet.com.au/mskeon/solr-rad.html

Fig.2 from this link
https://arxiv.org/pdf/1204.2507v1
apparently suggests that the Pioneer anomaly may only be the
result of mismodelling of the solar thermal contribution. But
such an error can't reside in the mismodelling of the solar
reflection/absorption characteristics of the HGA dish because
that was accurately determined prior to launch, and further
refined in the early stages of the mission. So where would it
be?

It's obvious that either Turyshev or Anderson made a fairly
significant error. But it's strange that Anderson is deemed
wrong when a significant number of others also demonstrated the
existence of the anomaly, including yourself (2002)? Why should
this new result override all others when the average result from
all contributors well and truly favors the anomaly's existence?
That's a funny way to do physics.

If Fig.2 from the above link was magnified by at least 20X the
true curve shapes for all the above elements would be more
obvious. Every one of them would follow a uniformly changing
curved path which can be traced right back to the sun. And the
same applies for every other source of acceleration to or from
the sun. The RTG's and on board thermal energy sources will
trace paths according to the rate at which their energies
diminish. The curves will never compare with the Pioneer
anomaly because there's nothing symmetrical about that curve
shape at all.

This image shows the relationship between the Pioneer anomaly and
solar radiation pressure, which can include any mix of residual
radiation from solar heating. Regardless of the mix, the general
curve shape never alters. The purpose of the raised curve is to
give a better comparison with the Pioneer anomaly (blue).

http://members.optusnet.com.au/mskeon/pnersolr.jpg

For John Anderson's analysis, each data point was obviously
generated using a common logic. There's no reason why anything
should change at any stage of the mission. The obvious point of
failure in Turyshev's analysis is between the sun and 20AU. How
can they possibly claim success while the very obvious change in
the "curve" direction between 5.2 and 6.9 AU, **which was
determined by Anderson's invariant logic,** is not addressed!!

The details in this image were generated from info given in
Fig.2 (above link).

http://members.optusnet.com.au/mskeon/watts.jpg

For reasons which should be obvious, the relationship between
solar heating and reflected solar radiation is taken from the
+50 watts line.

Reflected solar radiation contributes 60% of the driving force
away from the sun while solar heating emissions from the sun
facing surfaces contribute 40% of the total in that direction.
Which sets the total absorption rate at 400 watts on the graph
because thermal energy will freely conduct straight through the
HGA dish and into all contacting components of the clutter
attached to it. The reflection/absorption ratio is in fact 43%
reflection to 57% absorption.

If the dish alone was involved, absorbed solar radiation forces
driving to and from the sun would be equal. Reducing the HGA
reflection capability only slightly will affect the 8.74e-10
m/s^2 component of the Pioneer anomaly by almost 100% of the
change. Removing the anomaly would be a breeze.

An absorption rate of 57% of the total solar contribution doesn't
seem right to me either.

The Turyshev team have perhaps managed to squeeze out a positive
result within the error bars, but they certainly haven't managed
to remove the problem. They could only shift it down a little at
best.

The Pioneer anomaly is still a significant problem for current
theory. But an even bigger problem is that I can explain the
anomaly.

Two assumed realities can be compared as shown in this graph.
Gforce calculations for the true reality should trace a straight
line path along the zero line to the sun and the two theories
would compare as shown. The erroneous theory will not pass this
test. **Anomalies will emerge.**

http://members.optusnet.com.au/mskeon/pnerslr3.jpg

Theory 1 scribes the curve path shown while theory 2 follows a
straight line to the sun. Or theory 2 scribes the curved path
while theory 1 follows the straight line to the sun.

For the next graph, theory 1 is my theory and it plots the
straight line to the sun (zero gforce error) while current
theory (theory 2) plots the curved path (gforce errors). The zero
point for theory 2 is shifted downward. But it's actually shifted
upward from the zero point at the curve origin on the sun's
surface. At 1AU the curve passes by at 1.1e-6 m/s^2 below the
true zero point, which is only .00019 of the sun gforce at that
radius.

Current theory sets a new zero point at 6.34e-10 m/s^2 below the
true zero point. The data points for 5.2 and 6.9 AU are carried
upward with the curve.

http://members.optusnet.com.au/mskeon/pnerslr4.jpg

Increasing the mass of the sun will increase the orbital speed
for theory 2. But the increase is insignificant. And there's no
reason at all why it should be noticed.

e.g.
Sun mass = 1.99e30 kg (M)
Orbital speed v is proportional to sqr(G*M/r)
If the sun's mass = 1.99015522e+30 kg (Mx) in order to
maintain a common orbital speed, orbit radius (r2) boils
down to being proportional to Mx/(M/r).

The orbital speed at a 1.5e11 meter radius (r) around a
mass M, is 29747.045 m/sec. The same orbit speed is
generated for Mx at a radius of; Mx/(M/r) = 1.500117e+11
meters. Which is r2-r = 11700000 meters greater than r,
or .44 of a GPS satellite orbit radius.

Nobody would expect a radius increase, so why would anyone bother
looking for one so small?

The problem here is that the orbit cycle time is increased by 41
minutes. The obvious fix is to use the lesser orbit radius of
1.5e11 meters.

Any self consistent closed math loop can be designed with
absolute precision so that every element is perfectly
synchronized according to the chosen theory. But the loop will
be offset from reality if just one element is even slightly
inaccurate. One can't use the absolute precision of the loop as
some kind of proof of the credibility of each element.

i.e.
1.99e30 is far from being a precise figure for the mass of the
sun. The chances of 27 zeros aligning behind the 199 is almost
zero. It could just as well be 1990155220000000000000000000000
kg. It can all be varied to suit any theory. Nothing can be
proven here.

A theory will only fail when anomalies begin to appear in
nature.

-----

Max Keon

  #28  
Old April 19th 17, 10:36 PM posted to sci.astro
Craig Markwardt[_2_]
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Posts: 137
Default Pioneer Anomaly 2017

On Wednesday, April 19, 2017 at 5:50:36 AM UTC-4, wrote:
On Saturday, April 1, 2017 at 7:47:20 AM UTC+11, Craig Markwardt wrote:
---
---
The question is what tolerance was required for the analysis. Anderson
et al's analysis was quite back of the envelope. A few Watts makes a
difference, so it was important to treat the analysis in more detail.

....
Fig.2 from this link
https://arxiv.org/pdf/1204.2507v1
apparently suggests that the Pioneer anomaly may only be the
result of mismodelling of the solar thermal contribution.


Your interpretation of this paper is incorrect. This paper (Turyshev et al 2002) demonstrates that most if not all of the "anomalous" acceleration can be attributed to *internal* thermal emission, generated by the RTGs and internal electronics.

But such an error can't reside in the mismodelling of the solar
reflection/absorption characteristics of the HGA dish because
that was accurately determined prior to launch,


Just a side note, but thermal coatings do degrade over time, due to exposure to solar UV as well as ionizing radiation (white coatings become darker). So one can't be so certain about these properties. That was one of the aspects covered by the thermal analysis reported in Turyshev et al's 2012 paper.

It's obvious that either Turyshev or Anderson made a fairly
significant error. But it's strange that Anderson is deemed
wrong when a significant number of others also demonstrated the
existence of the anomaly, including yourself (2002)? Why should
this new result override all others when the average result from
all contributors well and truly favors the anomaly's existence?
That's a funny way to do physics.


What would be funny is to ALWAYS assume that the "average" of some papers is relevant. The truth is all those analysts who redemonstrated the existence of the anomaly did not really reconsider the thermal back-of-the-envelope calculations that Anderson et al 2002 did. I did not. I just assumed Anderson's group knew what they were doing, and said so. To average results of individuals doing the same thing does not necessarily provide new insight.
  #29  
Old April 22nd 17, 10:20 AM posted to sci.astro
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Posts: 73
Default Pioneer Anomaly 2017

Il giorno martedì 18 aprile 2017 09:05:25 UTC+2, ha scritto:
Il giorno venerdì 14 aprile 2017 23:08:19 UTC+2, Craig Markwardt ha scritto:
On Friday, April 14, 2017 at 9:32:50 AM UTC-4, wrote:
...
.. can you answer for an hipothetic question ? : if you discover in the Kuiper belt a disomogeity ( or a gas leakage in the rocket ) , the Pioneeer 'anomaly is resolved ! ... so , should be the trajectory of the times go-back and of the Doppler shift coincident ?

...
I am not certain of your question. If one has a model of the Kuiper belt, or of the gas leaks, then yes one can go back and re-analyze the Doppler data.

Anderson et al. did consider these particular topics.

CM


.. i was rereading my reference paper .. and it comes out a prime question : have you controlled if the trajectory done with the times go-back , is coincident with the modeled trajectory ?


.... i rephrase my last post : the Doppler 'shift can show the Pioneer ' speed and so the trajectory ... also the times go-back , in succession , can show the Pioneer 'speed , so the trajectory ..: is the modeled trajectory coincident with the second build trajectory ?
  #30  
Old April 24th 17, 12:17 PM posted to sci.astro
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Posts: 22
Default Pioneer Anomaly 2017

On Thursday, April 20, 2017 at 7:36:10 AM UTC+10, Craig Markwardt wrote:
On Wednesday, April 19, 2017 at 5:50:36 AM UTC-4, wrote:
On Saturday, April 1, 2017 at 7:47:20 AM UTC+11, Craig Markwardt wrote:
---
---
The question is what tolerance was required for the analysis. Anderson
et al's analysis was quite back of the envelope. A few Watts makes a
difference, so it was important to treat the analysis in more detail.

...
Fig.2 from this link
https://arxiv.org/pdf/1204.2507v1
apparently suggests that the Pioneer anomaly may only be the
result of mismodelling of the solar thermal contribution.


Your interpretation of this paper is incorrect. This paper
(Turyshev et al 2002) demonstrates that most if not all of the
"anomalous" acceleration can be attributed to *internal* thermal
emission, generated by the RTGs and internal electronics.

But such an error can't reside in the mismodelling of the solar
reflection/absorption characteristics of the HGA dish because
that was accurately determined prior to launch,


Just a side note, but thermal coatings do degrade over time, due
to exposure to solar UV as well as ionizing radiation (white
coatings become darker). So one can't be so certain about these
properties. That was one of the aspects covered by the thermal
analysis reported in Turyshev et al's 2012 paper.

It's obvious that either Turyshev or Anderson made a fairly
significant error. But it's strange that Anderson is deemed
wrong when a significant number of others also demonstrated the
existence of the anomaly, including yourself (2002)? Why should
this new result override all others when the average result from
all contributors well and truly favors the anomaly's existence?
That's a funny way to do physics.


What would be funny is to ALWAYS assume that the "average" of some
papers is relevant. The truth is all those analysts who
redemonstrated the existence of the anomaly did not really
reconsider the thermal back-of-the-envelope calculations that
Anderson et al 2002 did. I did not. I just assumed Anderson's
group knew what they were doing, and said so. To average results
of individuals doing the same thing does not necessarily provide
new insight.

But actually it's not true to say no one else was considering
thermal. The work of Bertolami et al 2008 (Phys. Rev. D 78,
103001) attempted to do a better job at thermal modeling and
found that thermal could contribute a significant amount towards
the "anomaly." But even then, they were still treating
simplifying point-like, sphere-like and plate-like approximation,
and not validating their radiation transfer against the actual
in-flight temperature records, which Turyshev et al (2012) did do.
But please do not pretend that every analyst was concluding the
"anomalous" acceleration was the same as Anderson et al.

If Fig.2 from the above link ...
... The curves will never compare with the Pioneer
anomaly because there's nothing symmetrical about that curve
shape at all.


Symmetric is not quite the best way to judge. However, the open
circle curve, is the best representation of the "pioneer anomaly,"
and traces the anomalous acceleration curve measured via Doppler,
as well as can be done.

The data points you display in your own "curve" are from different
years, different analysts, and different rigor of Doppler analysis.
The Anderson paper showed them as some kind of indication of what
may be an "onset" of the effect, but they cannot be used with the
same level of confidence as later analysis, which were done with
the same quality selections, in one complete batch, with the same
analyst.

For John Anderson's analysis, each data point was obviously
generated using a common logic. ...


Absolutely not. The data points you are referring to in your own
plot are taken from Anderson's paper, Figure 7. If you had read
the Anderson et al 2002 paper more carefully you would have
understood that this figure represented the early analysis, of
analysts working in an operational environment and trying to
navigate the spacecraft. The analysis was not performed in a
totally rigorous way by the same analysts or with the same criteria.

As they pointed out in the paper, when the spacecraft reached about
20 AU, the search for unmodeled accelerations could begin in more
earnest, and more attention to detail was made... but 20 AU is way
past the so-called "onset" around 5AU! At the time of the Anderson
et al 2002 paper, the early data was lost (unavailable) and only
those graphical figures remained, not the original data. Thus, when
it came time to do new, more careful work, their group had to begin
with data starting about 1980, and there was no way to look for a
putative onset around 5 AU which occurred in the early 1970s.
[ Later, after Anderson's work, a small amount of earlier data was
recovered. ]

Just to be clear, during the early to mid 1970s, the data formats,
the software, and the analysis teams were in much more flux. NASA
was in the business of navigating spacecraft (and not high
sensitivity spacecraft physics), and was just learning how powerful
the radiometric techniques could be. You can go back and read all
of the DSN status documents if you want: they are public and online.
But the point is that what we know and do today to navigate
spacecraft, does not and did not apply to what was done in the early
1970s when this was a new field. You cannot say that anything was
done with a "common logic" or "invariant" comparing today to then.


You act as though analysts from the 1970's were using a set of
physical laws that analysts of today are not familiar with. But
that's not the case at all. Even if modifications have been made
to some of the physical laws the analysts of today would still
know exactly how the first data points showing the onset of the
anomaly were derived.

The first data points indicating a discrepancy between current
theory and observation were noticed while the Pioneer missions
were in progress. Both Pioneer missions experienced exactly the
same problem. The analysts weren't stupid back then, they noticed
this error and reported it. They couldn't explain it and neither
could anyone else. Your suggestion that the analyst were too busy
trying to navigate the spacecraft to properly analyze the
evidence is absurd. They weren't exactly alone in the world were
they!

Even if the data from that era is missing, it can be resurrected
based on the physical laws the analyst were **known** to be
using. Whether you like it or not, an unresolved problem still
remains.

According to you, "when the spacecraft reached about 20 AU, the
search for unmodelled accelerations could begin in more earnest,
and more attention to detail was made". Why do you think a more
precise analysis of the more distant data points will be of any
use? It becomes quickly apparent where the curve is heading. But
so what? The horse has already bolted.

Ignoring the bolted horse problem, all one needs to do is pull
the data point at 20 AU downward enough to sneak within the
unnecessarily huge error margin, and the anomaly can just barely
be squeezed out of existence in some circumstances. ???

The unnecessarily huge error margin I'm referring to is of course
the 25% generated by the unknown performance of the RTG coating.
Precise details of the coating are well known, so why hasn't this
question been addressed years ago. In Turyshev's paper it was
stated that "the properties of the RTG paint are, in principle,
measurable by a thermal vacuum chamber test of a hot RTG
analogue". So how can this huge error still exist? After more
than 40 years!

Another Pioneer type mission may not be a practical option. But
the cost of this experiment would be virtually nothing. I could
do it for you if you can get me some 238/94 plutonium.

Why do I get the impression that huge error margins are a good
thing in the case of the Pioneer anomaly?

The Turyshev team have perhaps managed to squeeze out a positive
result within the error bars, but they certainly haven't managed
to remove the problem. They could only shift it down a little at
best.


You can believe what you wish, but the Turyshev result shows that
the thermal and doppler solutions are consistent - within the
tolerances (see their Figure 4).


"believe" is the key word here isn't it.

-----

Max Keon

 




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