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The Pioneer Anomoly
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Anon E. Mouse
Apr 25, 2012, 4:15:30 PM4/25/12
to
From;
Exotic explanation for Pioneer anomaly ruled out
http://physicsworld.com/cws/article/news/2012/apr/16/exotic-explanation-for-pioneer-anomaly-ruled-out
"Pioneer 10 and 11 probes are following trajectories that cannot be
explained by conventional physics. Known as the "Pioneer anomaly",
both craft seem to be experiencing an extra acceleration towards the
Sun as they exit the solar system that is 10 billion times weaker than
the Earth's gravitational pull."
and
Efficient acceleration
The simulation reveals that the two main sources of thermal emissions
on the spacecraft are the RTG itself and the scientific instruments
that it powers. These instruments, which are mostly mounted on the
back of the spacecraft, face away from the Sun and, according to the
simulations, their thermal emissions have a relatively high efficiency
of accelerating the spacecraft towards the Sun.
"Benny Rievers of the University of Bremen in Germany. With his
colleague Claus L?mmerzahl, Rievers has also used computer modelling
to show that directional thermal emissions are the likely cause of the
Pioneer anomaly. "I think that we now completely understand what is
going on with the spacecraft and that the anomaly is completely down
to anisotropic heat radiation," says Rievers."
I personally form no hypothesis as to the cause of the anomaly, but
ansitropic thermal radiation seems exotic to me. How does either the
cooling of the instruments or the radiation of the heat do work upon
the momentum of the space-craft. I'm sorry, I just don't get it. Does
anyone else?
AAG
[[Mod. note --
The basic idea is simple: the Pioneer spacecraft were (are) powered
by Pu-238 radioactive generators which produced about 2500 Watts of
power at launch (decaying with the well-known Pu-238 half-life of
88 years). The question is, what happens to that power? A tiny bit
of it (about 8 Watts) leaves the spacecraft as radio power directed
back towards the Earth; all the rest ultimately leaves the spacecraft
as thermal radiation.
We know that photons carry momentum as well as energy, so the radio
beam and thermal radiation also carry momentum away from the spacecraft,
i.e., they can accelerate the spacecraft. If you work out the numbers,
it turns out that only about 60 Watts or so of beamed power would be
enough to give a recoil acceleration matching the measured anomolous
acceleration of the Pioneer spacecraft. Or more realistically, a
rather small anisotropy in the overall (~2500-Watt) thermal radiation
flux would suffice to explain the anomolous acceleration.
So, the question is, how isotropic or anisotropic is the thermal
radiation flux leaving the spacecraft? That basically depends on the
temperature distribution in the spacecraft. (Recall that the Pu-238
parts are very hot, and some other parts of the spacecraft are very
cold, so there are large temperature gradients across the spacecraft
structure.)
This recent research is the development of a more-accurate-than-before
thermal model of the spacecraft, and its calibration against the available
telemetry from temperature sensors at various places on the spacecraft.
The researchers find that the temperature does indeed vary a lot between
different parts of the spacecraft, and they calculate that the thermal
flux is in fact just anisotropic enough to explain the measured anomolous
acceleration of the Pioneer spacecraft.
For a more detailed account, see the recent technical paper:
Turyshev etal
"Support for the thermal origin of the Pioneer anomaly"
arXiv:1204.2507.
-- jt]]
Exotic explanation for Pioneer anomaly ruled out
http://physicsworld.com/cws/article/news/2012/apr/16/exotic-explanation-for-pioneer-anomaly-ruled-out
"Pioneer 10 and 11 probes are following trajectories that cannot be
explained by conventional physics. Known as the "Pioneer anomaly",
both craft seem to be experiencing an extra acceleration towards the
Sun as they exit the solar system that is 10 billion times weaker than
the Earth's gravitational pull."
and
Efficient acceleration
The simulation reveals that the two main sources of thermal emissions
on the spacecraft are the RTG itself and the scientific instruments
that it powers. These instruments, which are mostly mounted on the
back of the spacecraft, face away from the Sun and, according to the
simulations, their thermal emissions have a relatively high efficiency
of accelerating the spacecraft towards the Sun.
"Benny Rievers of the University of Bremen in Germany. With his
colleague Claus L?mmerzahl, Rievers has also used computer modelling
to show that directional thermal emissions are the likely cause of the
Pioneer anomaly. "I think that we now completely understand what is
going on with the spacecraft and that the anomaly is completely down
to anisotropic heat radiation," says Rievers."
I personally form no hypothesis as to the cause of the anomaly, but
ansitropic thermal radiation seems exotic to me. How does either the
cooling of the instruments or the radiation of the heat do work upon
the momentum of the space-craft. I'm sorry, I just don't get it. Does
anyone else?
AAG
[[Mod. note --
The basic idea is simple: the Pioneer spacecraft were (are) powered
by Pu-238 radioactive generators which produced about 2500 Watts of
power at launch (decaying with the well-known Pu-238 half-life of
88 years). The question is, what happens to that power? A tiny bit
of it (about 8 Watts) leaves the spacecraft as radio power directed
back towards the Earth; all the rest ultimately leaves the spacecraft
as thermal radiation.
We know that photons carry momentum as well as energy, so the radio
beam and thermal radiation also carry momentum away from the spacecraft,
i.e., they can accelerate the spacecraft. If you work out the numbers,
it turns out that only about 60 Watts or so of beamed power would be
enough to give a recoil acceleration matching the measured anomolous
acceleration of the Pioneer spacecraft. Or more realistically, a
rather small anisotropy in the overall (~2500-Watt) thermal radiation
flux would suffice to explain the anomolous acceleration.
So, the question is, how isotropic or anisotropic is the thermal
radiation flux leaving the spacecraft? That basically depends on the
temperature distribution in the spacecraft. (Recall that the Pu-238
parts are very hot, and some other parts of the spacecraft are very
cold, so there are large temperature gradients across the spacecraft
structure.)
This recent research is the development of a more-accurate-than-before
thermal model of the spacecraft, and its calibration against the available
telemetry from temperature sensors at various places on the spacecraft.
The researchers find that the temperature does indeed vary a lot between
different parts of the spacecraft, and they calculate that the thermal
flux is in fact just anisotropic enough to explain the measured anomolous
acceleration of the Pioneer spacecraft.
For a more detailed account, see the recent technical paper:
Turyshev etal
"Support for the thermal origin of the Pioneer anomaly"
arXiv:1204.2507.
-- jt]]
Anon E. Mouse
Apr 26, 2012, 6:38:49 PM4/26/12
to
> Exotic explanation for Pioneer anomaly ruled outhttp://physicsworld.com/cws/article/news/2012/apr/16/exotic-explanati...
I considered thermal or optical photon momentum exchange and the sign
came out wrong. Heat doing work, normal thermodynamics makes sens if
and only if there is enough atmospheric kinetic, which seems unlikely.
An anisotropic thermal field creating a potential in space time
(gravitation) is not per se impossible, but it is certainly exotic.
Perhaps somebody with hot balls would like to validate the Cavendish
experiment under this condition...
I do know that both probes measure the velocity of the Solar wind
going to zero. This would at least have the correct vector sign for
the effect described. Perhaps their sails have just run out of wind? I
sail, and so this is an effect I am all too familiar with...
AAG
came out wrong. Heat doing work, normal thermodynamics makes sens if
and only if there is enough atmospheric kinetic, which seems unlikely.
An anisotropic thermal field creating a potential in space time
(gravitation) is not per se impossible, but it is certainly exotic.
Perhaps somebody with hot balls would like to validate the Cavendish
experiment under this condition...
I do know that both probes measure the velocity of the Solar wind
going to zero. This would at least have the correct vector sign for
the effect described. Perhaps their sails have just run out of wind? I
sail, and so this is an effect I am all too familiar with...
AAG
Anon E. Mouse
Apr 26, 2012, 6:39:10 PM4/26/12
to
> different parts of the spacecraft, and they calculate that the thermal
> flux is in fact just anisotropic enough to explain the measured anomolous
> acceleration of the Pioneer spacecraft.
>
> For a more detailed account, see the recent technical paper:
> Turyshev etal
> "Support for the thermal origin of the Pioneer anomaly"
> arXiv:1204.2507.
> -- jt]]
This reference plus a little extra did the trick. I had never heard of
> flux is in fact just anisotropic enough to explain the measured anomolous
> acceleration of the Pioneer spacecraft.
>
> For a more detailed account, see the recent technical paper:
> Turyshev etal
> "Support for the thermal origin of the Pioneer anomaly"
> arXiv:1204.2507.
> -- jt]]
Thermal recoil force. I understood the anisotropy and momentum
transfer, the source of the momentum transfer, anisotropic molecular
vibrations associated with black body radiations was something I had
never considered.
This seems to bear on understanding Casmir force, (understood as
momentum transfer) and some of the odd laboratory measures of G
experimental results I have seen not reported. (People do not tend to
report failures to confirm.) Someone of my experience (U of W) tried
to repeat Cavendish's experiment in a vacuum, the cooling caused by
removing the air may have been the source of the measured anomalies
they found but could not explain. This is quite interesting. Thank you
for the references. I had been a skeptic because I could not see a
kinetic basis. Now, I believe I can.
Sincerely,
AAG
Dr J R Stockton
Apr 27, 2012, 3:35:11 AM4/27/12
to
In sci.physics.research message <94d8eab1-6ef0-453a-89ec-c82241b42a66@c4
g2000yqj.googlegroups.com>, Wed, 25 Apr 2012 16:15:30, Anon E. Mouse
<agal...@gmail.com> posted:
>
>[[Mod. note --
>
>The basic idea is simple: the Pioneer spacecraft were (are) powered
>by Pu-238 radioactive generators which produced about 2500 Watts of
>power at launch (decaying with the well-known Pu-238 half-life of
>88 years). The question is, what happens to that power? A tiny bit
>of it (about 8 Watts) leaves the spacecraft as radio power directed
>back towards the Earth; all the rest ultimately leaves the spacecraft
>as thermal radiation.
One should perhaps add that the efficiency of the thermocouples is
decaying faster than the Pu-238. Presuming the voltage regulators to be
in the body of the craft and not beside the Pu-238, that obviously
affects the distribution of heat across the surface of the system. When
that, and possible variations in the number of instruments powered, is
taken into account, the anomalous propulsion and its more rapid
variation with time is sufficiently well explained. That's all from
memory; if it matters to readers, they should look it up.
--
(c) John Stockton, near London. *@merlyn.demon.co.uk/?.?.Stockton@physics.org
Web <http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, and links.
g2000yqj.googlegroups.com>, Wed, 25 Apr 2012 16:15:30, Anon E. Mouse
<agal...@gmail.com> posted:
>
>[[Mod. note --
>
>The basic idea is simple: the Pioneer spacecraft were (are) powered
>by Pu-238 radioactive generators which produced about 2500 Watts of
>power at launch (decaying with the well-known Pu-238 half-life of
>88 years). The question is, what happens to that power? A tiny bit
>of it (about 8 Watts) leaves the spacecraft as radio power directed
>back towards the Earth; all the rest ultimately leaves the spacecraft
>as thermal radiation.
decaying faster than the Pu-238. Presuming the voltage regulators to be
in the body of the craft and not beside the Pu-238, that obviously
affects the distribution of heat across the surface of the system. When
that, and possible variations in the number of instruments powered, is
taken into account, the anomalous propulsion and its more rapid
variation with time is sufficiently well explained. That's all from
memory; if it matters to readers, they should look it up.
--
(c) John Stockton, near London. *@merlyn.demon.co.uk/?.?.Stockton@physics.org
Web <http://www.merlyn.demon.co.uk/> - FAQish topics, acronyms, and links.
Richard D. Saam
Apr 29, 2012, 5:39:55 AM4/29/12
to
On 4/27/12 2:35 AM, Dr J R Stockton wrote:
> In sci.physics.research message<94d8eab1-6ef0-453a-89ec-c82241b42a66@c4
> g2000yqj.googlegroups.com>, Wed, 25 Apr 2012 16:15:30, Anon E. Mouse
> <agal...@gmail.com> posted:
>
>>
>> [[Mod. note --
>>
>> The basic idea is simple: the Pioneer spacecraft were (are) powered
>> by Pu-238 radioactive generators which produced about 2500 Watts of
>> power at launch (decaying with the well-known Pu-238 half-life of
>> 88 years). The question is, what happens to that power? A tiny bit
>> of it (about 8 Watts) leaves the spacecraft as radio power directed
>> back towards the Earth; all the rest ultimately leaves the spacecraft
>> as thermal radiation.
>
> One should perhaps add that the efficiency of the thermocouples is
> decaying faster than the Pu-238. Presuming the voltage regulators to be
> in the body of the craft and not beside the Pu-238, that obviously
> affects the distribution of heat across the surface of the system. When
> that, and possible variations in the number of instruments powered, is
> taken into account, the anomalous propulsion and its more rapid
> variation with time is sufficiently well explained. That's all from
> memory; if it matters to readers, they should look it up.
>
>
But these simultaneous decay mode half lives(T) add as:
> In sci.physics.research message<94d8eab1-6ef0-453a-89ec-c82241b42a66@c4
> g2000yqj.googlegroups.com>, Wed, 25 Apr 2012 16:15:30, Anon E. Mouse
> <agal...@gmail.com> posted:
>
>>
>> [[Mod. note --
>>
>> The basic idea is simple: the Pioneer spacecraft were (are) powered
>> by Pu-238 radioactive generators which produced about 2500 Watts of
>> power at launch (decaying with the well-known Pu-238 half-life of
>> 88 years). The question is, what happens to that power? A tiny bit
>> of it (about 8 Watts) leaves the spacecraft as radio power directed
>> back towards the Earth; all the rest ultimately leaves the spacecraft
>> as thermal radiation.
>
> One should perhaps add that the efficiency of the thermocouples is
> decaying faster than the Pu-238. Presuming the voltage regulators to be
> in the body of the craft and not beside the Pu-238, that obviously
> affects the distribution of heat across the surface of the system. When
> that, and possible variations in the number of instruments powered, is
> taken into account, the anomalous propulsion and its more rapid
> variation with time is sufficiently well explained. That's all from
> memory; if it matters to readers, they should look it up.
>
>
1/TF = 1/T1 + 1/T2 + 1/T3
let T1 = RTF decay = 87.74 years
T2 = electrical decay = 39 years
T3 = nearly linear deceleration component = 10,000 years
Then TF = 27 years as observed.
Decay modes with their observed half lifes
can mask a constant deceleration T3.
Richard D. Saam
blanclar
May 1, 2012, 5:08:29 PM5/1/12
to
> Exotic explanation for Pioneer anomaly ruled outhttp://physicsworld.com/cws/article/news/2012/apr/16/exotic-explanati...
To my knowledge this solution has been claimed first by Orfeu
Bertolami:
http://arxiv.org/abs/1103.5222
>
> "Pioneer 10 and 11 probes are following trajectories that cannot be
> explained by conventional physics. Known as the "Pioneer anomaly",
> both craft seem to be experiencing an extra acceleration towards the
> Sun as they exit the solar system that is 10 billion times weaker than
> the Earth's gravitational pull."
>
> and
>
> Efficient acceleration
>
> The simulation reveals that the two main sources of thermal emissions
> on the spacecraft are the RTG itself and the scientific instruments
> that it powers. These instruments, which are mostly mounted on the
> back of the spacecraft, face away from the Sun and, according to the
> simulations, their thermal emissions have a relatively high efficiency
> of accelerating the spacecraft towards the Sun.
>
> "Benny Rievers of the University of Bremen in Germany. With his
> colleague Claus L?mmerzahl, Rievers has also used computer modelling
> to show that directional thermal emissions are the likely cause of the
> Pioneer anomaly. "I think that we now completely understand what is
> going on with the spacecraft and that the anomaly is completely down
> to anisotropic heat radiation," says Rievers."
>
> I personally form no hypothesis as to the cause of the anomaly, but
> ansitropic thermal radiation seems exotic to me. How does either the
> cooling of the instruments or the radiation of the heat do work upon
> the momentum of the space-craft. I'm sorry, I just don't get it. Does
> anyone else?
[Long quoted moderator's note providing some background snipped.]
> "Pioneer 10 and 11 probes are following trajectories that cannot be
> explained by conventional physics. Known as the "Pioneer anomaly",
> both craft seem to be experiencing an extra acceleration towards the
> Sun as they exit the solar system that is 10 billion times weaker than
> the Earth's gravitational pull."
>
> and
>
> Efficient acceleration
>
> The simulation reveals that the two main sources of thermal emissions
> on the spacecraft are the RTG itself and the scientific instruments
> that it powers. These instruments, which are mostly mounted on the
> back of the spacecraft, face away from the Sun and, according to the
> simulations, their thermal emissions have a relatively high efficiency
> of accelerating the spacecraft towards the Sun.
>
> "Benny Rievers of the University of Bremen in Germany. With his
> colleague Claus L?mmerzahl, Rievers has also used computer modelling
> to show that directional thermal emissions are the likely cause of the
> Pioneer anomaly. "I think that we now completely understand what is
> going on with the spacecraft and that the anomaly is completely down
> to anisotropic heat radiation," says Rievers."
>
> I personally form no hypothesis as to the cause of the anomaly, but
> ansitropic thermal radiation seems exotic to me. How does either the
> cooling of the instruments or the radiation of the heat do work upon
> the momentum of the space-craft. I'm sorry, I just don't get it. Does
> anyone else?
To my knowledge this solution has been claimed first by Orfeu
Bertolami:
http://arxiv.org/abs/1103.5222
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