pioneer 10 acceleration

Did anyone find the reason for the anomalous acceleration of pioneer 10
( 10 ^ - 8 cm/s/s ) towards the Sun?

Dear alistair:

"alistair" wrote in message
om...
Did anyone find the reason for the anomalous acceleration of pioneer 10
( 10 ^ - 8 cm/s/s ) towards the Sun?

A half dozen different explanations that are "reasonable", and dozens more
that are really cranky.

A reasonable one, is that the spacecraft moved into an area of more dense
material.

A cranky one is that it moved beyond some concentration of Dark Matter in
orbit around the Sun, and so the resultant attraction was towards a higher
mass than expected.

David A. Smith

In message sMAlc.58549$Jy3.33316@fed1read03, "N:dlzc D:aol T:com
(dlzc)" writes
Dear alistair:

"alistair" wrote in message
. com...
Did anyone find the reason for the anomalous acceleration of pioneer 10
( 10 ^ - 8 cm/s/s ) towards the Sun?

A half dozen different explanations that are "reasonable", and dozens more
that are really cranky.

A reasonable one, is that the spacecraft moved into an area of more dense
material.

A cranky one is that it moved beyond some concentration of Dark Matter in
orbit around the Sun, and so the resultant attraction was towards a higher
mass than expected.

And a far more simple one is that the original authors did not correctly
model thermal emission from the radioisotope thermal generators (RTG)
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"N:dlzc D:aol T:com \(dlzc\)" N: dlzc1 D:cox wrote in message news:sMAlc.58549$Jy3.33316@fed1read03...
Dear alistair:

"alistair" wrote in message
om...
Did anyone find the reason for the anomalous acceleration of pioneer 10
( 10 ^ - 8 cm/s/s ) towards the Sun?

A half dozen different explanations that are "reasonable", and dozens more
that are really cranky.

A reasonable one, is that the spacecraft moved into an area of more dense
material.

A cranky one is that it moved beyond some concentration of Dark Matter in
orbit around the Sun, and so the resultant attraction was towards a higher
mass than expected.

David A. Smith

Isnt the anomolous acceleration measured as a steady increase over
time which implies the density is increasing gradually and not in one
large jump as you imply above?
Sean

Jonathan Silverlight wrote in message ...
In message sMAlc.58549$Jy3.33316@fed1read03, "N:dlzc D:aol T:com
(dlzc)" writes
Dear alistair:

"alistair" wrote in message
. com...
Did anyone find the reason for the anomalous acceleration of pioneer 10
( 10 ^ - 8 cm/s/s ) towards the Sun?

A half dozen different explanations that are "reasonable", and dozens more
that are really cranky.

A reasonable one, is that the spacecraft moved into an area of more dense
material.

A cranky one is that it moved beyond some concentration of Dark Matter in
orbit around the Sun, and so the resultant attraction was towards a higher
mass than expected.

And a far more simple one is that the original authors did not correctly
model thermal emission from the radioisotope thermal generators (RTG)

This is not correct, since not only Pioneer 10 (and 11, which is the
same design), but also the probes Galileo and Ulysses exhibit the same
phenomena (http://arxiv.org/abs/gr-qc/9808081) What is happening here
is a measurement of a global cosmological geometry feature and not a change in
the velocity of the probes.

The correct explanation was recently presented at NKS 2004. You can
reference it he

http://forum.wolframscience.com/show...=&threadid=406

Please note, this was an 'interactive' presentation, so it is a little
condensed. However, the expected effect can be calculated to around
0.15% accuracy, and is shown in the presentation.

Alastair

"N:dlzc D:aol T:com \(dlzc\)" N: dlzc1 D:cox writes:

Dear alistair:

"alistair" wrote in message
om...
Did anyone find the reason for the anomalous acceleration of pioneer 10
( 10 ^ - 8 cm/s/s ) towards the Sun?

A half dozen different explanations that are "reasonable", and dozens more
that are really cranky.

A reasonable one, is that the spacecraft moved into an area of more dense
material.

Unlikely. The Pioneer spacecraft itself has a dust measuring device,
so it is possible to estimate the dust density, and hence any drag.
Example calculations:



A cranky one is that it moved beyond some concentration of Dark Matter in
orbit around the Sun, and so the resultant attraction was towards a higher
mass than expected.

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

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!

There is a simple and elegant explanation (see post above):
Essentially, the apparent acceleration is caused by a change in the
Planck scale and not from a change in radial velocity. This could be
proved by attaching a bright light to the probe and measuring the
change in brightness as the probe travels away from the observer.
Since the brightness is related to unit volume, where the photon
number is constant even as the space expands, there would be no change
in radial velocity. However, the type of Doppler ranging used to
measure the velocity of these probes *is* affected by the change in
Planck length, so you would *expect* to see an acceleration towards
the observer.

The predicted theoretical value is (8.143 +/- 0.013)*10^8 cm/s^2 (yes
that is to an accuracy of 0.16%, not a typo). This is fully
consistant with Anderson's measurement.

This feature of the universe has also been observed as an apparent
acceleration in the expansion of space. Here the process works
backwards: there is the same difference between what you would expect
from a redshift measurement, and a measurement of SN1a brightness.
Things will appear to be further away than the ought to be, based on
the redshift expectation.

No "dark energy" required! However you can predict what you would see
if you modelled it this way:

Hubble sphere Rc=cto (where to is age of universe),
Therefore Hoto = 1 (where Ho is hubble parameter),
However, for dust EdS @ critical density Hoto = 2/3
So, solve for Hoto = 1 =
(2/(3*sqrt(omega_lambda)))*arcsinh(sqrt(omega_lamdba/omega_M))
Gives you omega_lambda = 0.737 and omega_m = 0.263

etc...

Pretty simple, but I doubt anyone cares.. too busy with those
epicycles of LambdaCDM and inflation!

Alastair

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.

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As indicated on my page http://www.physicsmyths.org.uk/lightspeed.htm
, the apparent anomalous acceleration could be due to a systematic
error in relating the travel time of the communication signal to the
distance of the spacecraft.

Thomas Smid wrote:
As indicated on my page http://www.physicsmyths.org.uk/lightspeed.htm
, the apparent anomalous acceleration could be due to a systematic
error in relating the travel time of the communication signal to the
distance of the spacecraft.

Nice crank site, much better than most.

DaveL