pioneer 10 acceleration

(Nodem Info. Sys.) wrote in message ...
Jonathan Silverlight wrote in message ...
In message , Nodem Info.
Sys. writes
Craig Markwardt wrote in message
...
**SNIP**
Also unlikely. An extra concentration of (dark) matter around the sun
should have been detectable in the motions of the planets, but has not
been. This is discussed in the Anderson et al (2001) paper.

The most mundane explanation is, as mentioned already, improper
modeling of the spacecraft radiative properties.

CM

There are three totally different space craft designs, all showing the
same effect, in the same direction, at the same magnitude. This can't
be a radiative effect and be *that* consistant. Come on!

One problem with that argument is that the later and much more
comprehensive paper by Anderson et al.
http://xxx.lanl.gov/abs/gr-qc/0104064 notes that the effect for
Ulysses is highly correlated with solar radiation pressure, and the
effect for Galileo is highly inconsistent, probably due to gas leaks.
One of the tasks of the Cassini probe was to act as a platform for this
sort of acceleration measurement (to measure gravity waves and
relativistic effects) and Cassini shows no anomaly.

I've had time to study the Cassini measurements and yes, there is no
anomaly. However, the reason for this is the way the measurement
methos differs from the other probes. The Cassini time-delay
measurement should show no real change in the velocity, which is
expected and fully consistent with my result.

What my result refers to is an apparent geometry feature of space-time
which only effects measurements made via Doppler ranging. This
results in an apparent acceleration towards the observer, and does not
represent a real change in the velocity of the probe.

[REF: NKS 2004 proceedings, Alastair Hewitt, "A Cosmological Model
Utilizing Causal-temporal Mobile Automaton", Materials 2]
http://www.wolframscience.com/confer.../ahewitt-2.pdf

As for the other probes, yes these could all be various different
kinds of errors. All these errors are all similar in magnitude and
all towards the observer. Let's just say that's quite a
coincidence...

Your argument is typical of the failures of modern cosmology, where
people try to fit observations to existing theoretical assumptions.
Progress will only ever be made when people question their assumptions
and fit theory to observation. BTW, this is how real science gets
done.

Real science seems to be a very slowly maturing thing.

The problem is that when people have made up their mind in whatever
direction, they never requestion. This is an age old problem.

With unswerving consistency through the ages, questioning of
accepted assumptions always was done by young yet undecided
individuals as they were making the round of what options
were offered to them. But once they chose a prefered option,
they keep it for life, rationalizing all exceptions so they
would fit their choice.

Planck nicely summed it up in 1900:

"A new scientific truth doesn't triumph by convincing it opponents
and making them see the light, but rather because its opponents end
up dying, and the following generation grows, becoming familiar
with it."

Unfortunately, a rational solution for the Pioneer 10/11 anomaly
(and apparently, an anomaly that seems to be the lot of all very
small orbiting bodies) has no chance of being accepted until a
coherent theory explaining it becomes familiar to a sufficient
number in one of the up coming generations.

André Michaud

Craig Markwardt wrote in message ...
(Nodem Info. Sys.) writes:

The Cassini spacecraft doesn't make the best platform to test the
Pioneer anomaly, but it has shown that this anomaly is not a real
change in velocity (ruling out alternative gravity theories).

How has the Cassini spacecraft shown that the Pioneer anomaly is not a
real change in velocity?

CM

I believe that there is a discrepancy between the time-delay and
Doppler ranging measurements. The modeled acceleration can be
measured from the time-delay, however, the Pioneer anomaly will only
show up on the Doppler ranging (in addition to the modeled
acceleration). If the anomaly was due to a real change in velocity,
then both measurement methods would give the same result.

I thought there was something about this in the paper I referenced,
but it looks like it was withdrawn from the archives. I've contacted
John Anderson to see if he can shed any light on this matter.

I'll keep you posted.

Alastair

(Andr? Michaud) wrote in message ...
(Nodem Info. Sys.) wrote in message ...

Your argument is typical of the failures of modern cosmology, where
people try to fit observations to existing theoretical assumptions.
Progress will only ever be made when people question their assumptions
and fit theory to observation. BTW, this is how real science gets
done.

Real science seems to be a very slowly maturing thing.

The problem is that when people have made up their mind in whatever
direction, they never requestion. This is an age old problem.

With unswerving consistency through the ages, questioning of
accepted assumptions always was done by young yet undecided
individuals as they were making the round of what options
were offered to them. But once they chose a prefered option,
they keep it for life, rationalizing all exceptions so they
would fit their choice.

Planck nicely summed it up in 1900:

"A new scientific truth doesn't triumph by convincing it opponents
and making them see the light, but rather because its opponents end
up dying, and the following generation grows, becoming familiar
with it."

Unfortunately, a rational solution for the Pioneer 10/11 anomaly
(and apparently, an anomaly that seems to be the lot of all very
small orbiting bodies) has no chance of being accepted until a
coherent theory explaining it becomes familiar to a sufficient
number in one of the up coming generations.

André Michaud

This is very true. Scientific change typically takes two generations
to make a real impact. This is why few scientists see the true
benefits of breakthrough discoveries within their lifetime.

The existing generation of scientists will always resist any change to
the foundations of their field. They are convinced that what they
know represents some form of truth and it is human nature to never
admit that one's deepest beliefs are false. The next generation has
the opportunity to contrast the old and the new paradigms before
committing to either. Their careers will bring the new ideas to the
mainstream and from there the following generation will be taught
correctly from the outset.

This process takes about 50 years, but scientific change that
challenges philosophical foundations takes much longer. Quantum
theory is a good example of this: I can only think of a tiny number
of scientists who have even attempted to take it's implications
seriously.

The good news is that things do eventually change, but it's an
excruciatingly slow process at times!

Alastair

[s.a.r. mod. note: more discussion along these lines should really be
carried out outside the moderated groups -- followups set. --mjh]

(Nodem Info. Sys.) writes:
Craig Markwardt wrote in message ...
(Nodem Info. Sys.) writes:

The Cassini spacecraft doesn't make the best platform to test the
Pioneer anomaly, but it has shown that this anomaly is not a real
change in velocity (ruling out alternative gravity theories).

How has the Cassini spacecraft shown that the Pioneer anomaly is not a
real change in velocity?

CM

I believe that there is a discrepancy between the time-delay and
Doppler ranging measurements. The modeled acceleration can be
measured from the time-delay, however, the Pioneer anomaly will only
show up on the Doppler ranging (in addition to the modeled
acceleration). If the anomaly was due to a real change in velocity,
then both measurement methods would give the same result.

You are incorrect. All the measurement methods are the same, i.e.,
Cassini and the other spacecraft mentioned in this thread *all* use
Doppler tracking. The published paper in Nature does *not* use
"time-delay" (ranging). There is no such thing as "Doppler ranging,"
since Doppler tracking and ranging are quite independent techniques.

It is likely that any conclusions drawn from your incorrect premises
are thus irrelevant.

CM

Craig Markwardt wrote in message ...
(Nodem Info. Sys.) writes:

I believe that there is a discrepancy between the time-delay and
Doppler ranging measurements. The modeled acceleration can be
measured from the time-delay, however, the Pioneer anomaly will only
show up on the Doppler ranging (in addition to the modeled
acceleration). If the anomaly was due to a real change in velocity,
then both measurement methods would give the same result.

You are incorrect. All the measurement methods are the same, i.e.,
Cassini and the other spacecraft mentioned in this thread *all* use
Doppler tracking. The published paper in Nature does *not* use
"time-delay" (ranging). There is no such thing as "Doppler ranging,"
since Doppler tracking and ranging are quite independent techniques.

It is likely that any conclusions drawn from your incorrect premises
are thus irrelevant.

CM

Sorry about using the wrong terminology, I guess I confused you a bit
there.

Let me clarify things he

According to the Nature article you mention, there is a 'modeled'
acceleration considered to be due entirely to the non-isotropic
radiation from the RTGs. The article states this as around 30 x 10^-8
cm/s^2, which is almost 4 times the Pioneer anomaly (the sign is the
same for both). According to the article, "Deriving this acceleration
from a model of the spacecraft is a difficult task". Therefore it
must be measured, and then the measurement is *assumed* to relate to
*known* parameters such as the radiation from RTGs.

So what we have is something that contains the Pioneer anomaly, but
because it is labeled as 'modeled'... poof!.. the 'unmodeled' Pioneer
anomaly is not there. Now that's a great bit of science!

The time-delay *ranging* measurements (assume we will make a series of
them over a period of time) can be used to measure the velocity of the
probe, and the change in velocity of the probe (acceleration). This
acceleration can be used to gain a true measurement of what is
considered as the 'modeled' acceleration (this would come out around
19 x 10^-8 cm/s^2).

The Doppler *tracking* measurements will contain an additional effect
caused by the curvature of space time, resulting in an additional
apparent acceleration of 8.143 x 10^-8 cm/s^2 towards the observer.
The combined 'modeled' and 'Pioneer anomaly' acceleration would add up
to around the 27 x 10^-8 cm/s^2 figure quoted in the article.

So how did that article show there was no Pioneer anomaly?

Dark energy could be causing the anomalous acceleration of pioneer 10.
The solar system is surrounded by the spherical Oort cloud.If dark
energy consists of particles that flow into the galaxy, the Oort cloud
would shield
the solar system from those particles.However a gap in the Oort cloud
would allow some dark energy particles to flow into the solar system.
Dark energy accounts for up to 70 per cent of the mass of the universe
and the universe has an approximate average mass density of 10 ^ -27
kg/ m^3.So, as an approximation, dark energy has a mass density of
about
10 ^ -27 kg/ m^ 3 too.If dark energy particles move at close to the
speed of light then 10 ^ -27 kg of them will move through one metre in
10 ^ -8 seconds. The particles will have a total momentum of 10 ^ -27
x 10 ^ 8 = 10 ^ -19.
The maximum force the particles can exert in 10 ^ -8 seconds on one
square metre of pioneer 10 is given by Force = rate of change of
momentum / time
Force = (10 ^ -19 minus 0 ) / 10 ^ - 8 = 10 ^ -11 Newtons.
Now assuming pioneer 10 has an area facing the direction of travel of
the dark energy particles through the Oort cloud and that area is at
most 100 square metres (perhaps someone on sci.physics.research knows
the exact area!)
then the total force on pioneer 10 due to dark energy is 10 ^ -11 x
100 Newtons = 10 ^ - 9 Newtons.Since acceleration = force / mass and
assuming pioneer 10 has a mass of about 1000 kg ( again, perhaps
someone on sci.physics.research can put an exact figure to this), then
the acceleration of pioneer 10 towards the sun caused by dark energy
particles would be about
10 ^ - 9 / 1000 = 10 ^ -12 m / s ^2.The figure Nasa gives is 10 ^ -10
m / s ^2.
If the exact mass and area of pioneer 10 are used, the answer given
for the acceleration of pioneer 10 due to dark energy flowing through
a gap in the Oort cloud could well be a lot closer to the value Nasa
gives.

In message , alistair
writes
Dark energy could be causing the anomalous acceleration of pioneer
10.
The solar system is surrounded by the spherical Oort cloud.If dark
energy consists of particles that flow into the galaxy, the Oort
cloud
would shield
the solar system from those particles.However a gap in the Oort cloud
would allow some dark energy particles to flow into the solar system.


ANDRE?MICHAUD wrote:

There are a few problems with this idea :-)

The paper by Anderson et al. which everyone cites is available online
at
http://xxx.lanl.gov/abs/http://www....gr-qc/0104064. It has figures
for the mass of
the Pioneers (223 kg dry mass) and their surface area (or at least
that
of the dish antenna, which accounts for nearly all of it. It's a 2.74
meter dish giving an area of 5.9 square meters.
Also, the two Pioneers are going in nearly opposite directions.


ALISTAIR writes:

The mass and surface area you quote for Pioneer 10 would give an
acceleration for Pioneer 10 that is roughly only one third smaller
than the figure I calculated of 10^ -12 m/s^2.The correct figure NASA
gives is 10^-10 m /s^2.
However, if dark energy consists of particles with rest mass and these
particles in our part of the Milky Way move at 99.9999 per cent the
speed of light then there would be a relativistic mass increase by a
factor of 10000 compared to the average expectation for dark energy
mass which would have to be moving at a speed of around 1/3 that of
light.Whether or not dark energy actually has a different mass density
in galaxies compared to intergalactic space,I couldn't say.There is
also the possibility that dark energy coming through a gap in the Oort
cloud could pick up speed and mass if it has fluid like properties (
though I think such a Bernouilli flow is unlikely given how large the
mass increase would be).Both these factors could give the acceleration
NASA quotes.The fact that the Pioneers are moving in opposite
directions is irrelevant because the Oort cloud could have other gaps
in it which allow dark energy particles into the solar sytem.

JONATHAN SILVERLIGHT said in reply to ALISTAIR:

What sort of particle density are you
assuming - how many per m^3 for instance?
It looks to me as though you're proposing some sort of relativistic
particle, a new sort of cosmic ray, and I'm sure they would have been
detected in other ways. I don't see how they could be blocked by
anything in the outer solar system to produce the sort of localised
flux
you need, or how they could deliver momentum to the Pioneers.
It gets worse! I've already mentioned Galileo, and the "Pioneer
effect"
has also been reported for Ulysses. That's four probes in different
parts of the solar system.

ALISTAIR writes:

I'm assuming about 10^42 dark energy particles per cubic metre.
I derived this figure from the following logic:
If dark energy particles at some time in the future will change
themselves in such a way as to either stop or reverse the acceleration
of the universe, then presumably they will do this because they are
currently in a high energy state that will become a lower energy
state.Assuming that no dark energy particles have lowered their
energy since the Big Bang which was 10 ^18 seconds from today,and
using Heisenberg's relation E x t = hbar, then 10^18 x E = 10^ -34
so the energy change has a magnitude of 10^ -52 Joules per dark energy
particle.
Using E =mc^2 this amounts to a rest mass per dark energy particle of
10^-69 kg .
Since there is about 10^-27 kg of dark energy mass per cubic metre on
average throughout the universe, this means that there are 10^ - 27 /
10^ -69 dark energy particles per cubic metre i.e 10^ 42 dark energy
particles / m ^3.
Such a large concentration of particles, some of them carrying a tiny
positive electrical charge ( many orders of magnitude smaller than the
charge of an electron or proton) and some of them carrying a tiny
negative electric charge, could be "sticky" enough to flow like a
fluid.The electric charges would enable the dark energy particles to
transfer momentum to the Pioneer 10.The number of probes in different
parts of the
solar system does not falsify my idea because the Oort cloud is so
large that it is highly likely to have gaps that dark energy can flow
through all over its surface.
Individual dark energy particles would be very difficult to detect
because they are so light and have such a weak electric charge and
positive and negative charges could
also nearly cancel one another for large particle aggregations.
Since dark energy has a density equal to roughly the mass of one
proton per cubic metre, if a proton was split into 10^42 pieces, it
would yield particles of mass 10^-69 kg
and assuming the ratio of charge to mass for a proton is preserved in
the particles then dark energy particles would carry a coulomb charge
of 10^ - 61 Coulombs.

JONATHAN SILVERLIGHT said in reply to ALISTAIR:

What sort of particle density are you
assuming - how many per m^3 for instance?
It looks to me as though you're proposing some sort of relativistic
particle, a new sort of cosmic ray, and I'm sure they would have been
detected in other ways. I don't see how they could be blocked by
anything in the outer solar system to produce the sort of localised
flux
you need, or how they could deliver momentum to the Pioneers.
It gets worse! I've already mentioned Galileo, and the "Pioneer
effect"
has also been reported for Ulysses. That's four probes in different
parts of the solar system.

ALISTAIR writes:

I'm assuming 10^42 dark energy particles per cubic metre.
This is why:
If dark energy particles carry electric charge and spin and exist in a
magnetic field associated with the universe as a whole,
then some of those particles will be in a higher energy spin state
than the others.
Since the universe is 10^18 seconds old and using E x t = hbar
we get E = x 10^18 = 10^ -34
E = 10^ -52 J.

Assuming dark energy particles were put in high energy spin states at
the time of the Big Bang and are still in high energy states, this
means that the maximum energy a dark energy particle can emit is
10^-52 J.It can't emit more energy than is associated with its own
rest mass.So a dark energy particle would have a rest energy of at
least 10^-52 J.This is at least 10^-69 kg (using E=mc^2).
Now since dark energy has a density of 10^-27 kg / m^3 this means
there is a maximum of 10^-27 / 10^-69 dark energy particles per cubic
metre.
i.e 10^42 particles per cubic metre.

(alistair) wrote in message ...
JONATHAN SILVERLIGHT said in reply to ALISTAIR:

What sort of particle density are you
assuming - how many per m^3 for instance?
It looks to me as though you're proposing some sort of relativistic
particle, a new sort of cosmic ray, and I'm sure they would have been
detected in other ways. I don't see how they could be blocked by
anything in the outer solar system to produce the sort of localised
flux
you need, or how they could deliver momentum to the Pioneers.
It gets worse! I've already mentioned Galileo, and the "Pioneer
effect"
has also been reported for Ulysses. That's four probes in different
parts of the solar system.

ALISTAIR writes:

I'm assuming 10^42 dark energy particles per cubic metre.
This is why:
If dark energy particles carry electric charge and spin and exist in a
magnetic field associated with the universe as a whole,
then some of those particles will be in a higher energy spin state
than the others.
Since the universe is 10^18 seconds old and using E x t = hbar
we get E = x 10^18 = 10^ -34
E = 10^ -52 J.

Assuming dark energy particles were put in high energy spin states at
the time of the Big Bang and are still in high energy states, this
means that the maximum energy a dark energy particle can emit is
10^-52 J.It can't emit more energy than is associated with its own
rest mass.So a dark energy particle would have a rest energy of at
least 10^-52 J.This is at least 10^-69 kg (using E=mc^2).
Now since dark energy has a density of 10^-27 kg / m^3 this means
there is a maximum of 10^-27 / 10^-69 dark energy particles per cubic
metre.
i.e 10^42 particles per cubic metre.


CORRECTIONS TO ALISTAIR'S post:

The first three lines of the following text are nonesense:

Assuming dark energy particles were put in high energy spin states at
the time of the Big Bang and are still in high energy states, this
means that the maximum energy a dark energy particle can emit is
10^-52 J.It can't emit more energy than is associated with its own
rest mass.So a dark energy particle would have a rest energy of at
least 10^-52 J.This is at least 10^-69 kg (using E=mc^2).
Now since dark energy has a density of 10^-27 kg / m^3 this means
there is a maximum of 10^-27 / 10^-69 dark energy particles per cubic
metre.
i.e 10^42 particles per cubic metre.

THE TEXT SHOULD READ:

A dark energy particle can't emit more energy than is associated with its own
rest mass.So a dark energy particle would have a rest energy of at
least 10^-52 J.This is at least 10^-69 kg (using E=mc^2).
Now since dark energy has a density of 10^-27 kg / m^3 this means
there is a maximum of 10^-27 / 10^-69 dark energy particles per cubic
metre.
i.e 10^42 particles per cubic metre.