Ranging and Pioneer

Oh No wrote:
Thus spake "John (Liberty) Bell"

2) I have yet to see an adequately satisfactory explanation of how that
proposed effect can produce a red shift on one side of a galaxy, and a
blue shift on the opposite side, whilst still giving the observed
Pioneer blue shift, on both sides of the Solar System.

What is measured is a shift in the wavefunction corresponding to an
eigenstate of acceleration. For a general motion in radial coordinates a
Newtonian acceleration toward the origin is given by -r^dotdot + r w^2,
where r is radial distance and w is angular velocity. In the case of
Pioneer the motion is principally radial and the first term dominates;
the result is an illusory radial acceleration. For a star in orbit the
motion is approximately circular, so the second term dominates. The
actual calculation is a little more complicated, but the net result for
a star in orbit is an apparent increase in orbital velocity, or rather a
shift in the wave function equivalent to such an increase.

Am I understanding correctly that you are saying the both the shapes of
galaxy rotation curves and the Pioneer blue shift are aspects of a
quantum phenomenon? Several questions beg in this case.

1. Which objects are you treating classically and which quantum
mechanically?

2. Can you rephrase all your references to "wave functions" in terms of
the language of an abstract Hilbert space of states and operators
observables?

3. If you are proposing a quantum treatment of macroscopic objects like
stars or the Pioneer space craft, can you demonstrate with a
back-of-an-envelope estimate that said quantum effects would be
observable?

Answers that are short and to the point would be best.

Igor

Oh No wrote:
Thus spake Igor Khavkine
Oh No wrote:

1. Which objects are you treating classically and which quantum
mechanically?

I treat the emission of a photon from a distant object and its detection
on Earth quantum mechanically. The distant object is a conglomeration of
quantum particles.

That is a very complicated way to model anything big, bigger than, say,
a few millimeters. For macroscopic objects, we usually have the
relation

(quantum treatment) = (classical treatment) * (1 + C*hbar/N + ...),

where N is roughly the number of particles in the object. If you assert
that a quantum treatment is necessary, then you have to provide an
estimate of the constant C and compare it to hbar/N in magnitude.
That's what I asked in question (3.). However, I still don't see how C
would be large enough.

2. Can you rephrase all your references to "wave functions" in terms of
the language of an abstract Hilbert space of states and operators
observables?

Yes. In fact that is where I come in. I find that it is necessary to use
coordinates which are conformally flat in the time-radial plane in order
to do this, so that quantum mechanics is effectively formulated on a
Penrose diagram in the time-radial plane.

First, I'm not sure what a coordinate choice has to do with Hilbert
spaces and operator observables. So, I can't see how my question was
answered. Second, what if I don't like your choice of coordinates, can
I or someone else redo your calculations in global inertial coordinates
(if in Minkowski space) or in arbitrary coordinates (if in arbitrary
space-time)?

3. If you are proposing a quantum treatment of macroscopic objects like
stars or the Pioneer space craft, can you demonstrate with a
back-of-an-envelope estimate that said quantum effects would be
observable?

The quantum effects are observable when the accuracy of measurement of
position is less than the effective wavelength of the Doppler signal.
For Mars we have measurement accurate to about 10m, so the shift should
be present in optical frequencies in measurement of Mars, [...]

Hold on there... What if I use my naked eye to look at Mars? Then the
measurement uncertainty would be much larger, on the order of AU even!
Do you mean that I will then observe an overall shift in Mars' spectrum
by some very small frequency? Usually when two observers (say, at the
same place and at the same time) make the same measurement, but with
different instruments, they get different uncertainties (depending on
the instruments). But their uncertainty ranges should at least overlap.
Doesn't look like that's happening in what you are describing.
According to what you are saying, two obsevers may easily get
non-overlapping uncertainty ranges for the shift measurement.

[...] Potentially this can be
tested from the original Pioneer tapes, because cycle slip is a
prediction of the model (associated with collapse of the wave function).

Can your model distinguish between a "collapse induced" cycle slip and
one that's due merely to noise during detection?

Igor

Thus spake Igor Khavkine
Oh No wrote:
Thus spake Igor Khavkine
Oh No wrote:

1. Which objects are you treating classically and which quantum
mechanically?

I treat the emission of a photon from a distant object and its detection
on Earth quantum mechanically. The distant object is a conglomeration of
quantum particles.

That is a very complicated way to model anything big, bigger than, say,
a few millimeters. For macroscopic objects, we usually have the
relation

(quantum treatment) = (classical treatment) * (1 + C*hbar/N + ...),


where N is roughly the number of particles in the object. If you assert
that a quantum treatment is necessary, then you have to provide an
estimate of the constant C and compare it to hbar/N in magnitude.
That's what I asked in question (3.). However, I still don't see how C
would be large enough.

This indicates to me that you take a very different approach to quantum
theory from me. My starting point is to use axiomatic quantum theory, in
the manner of Von Neumann, and to set up a Fock space of quantum
particles. I take a classical object to have properties of a large
population of such particles. Classical properties can be found by
taking expectation values of quantum observables. But as far as the red
shift relation is concerned, I am only looking at individual photons.


2. Can you rephrase all your references to "wave functions" in terms of
the language of an abstract Hilbert space of states and operators
observables?

Yes. In fact that is where I come in. I find that it is necessary to use
coordinates which are conformally flat in the time-radial plane in order
to do this, so that quantum mechanics is effectively formulated on a
Penrose diagram in the time-radial plane.

First, I'm not sure what a coordinate choice has to do with Hilbert
spaces and operator observables. So, I can't see how my question was
answered.

The coordinate choice is fixed because I require plane wave motions in
the time-radial plane, or more properly that momentum in the final state
is teleparallel to momentum in the initial state.

Second, what if I don't like your choice of coordinates, can
I or someone else redo your calculations in global inertial coordinates
(if in Minkowski space) or in arbitrary coordinates (if in arbitrary
space-time)?

No (see above). In Minkowski space the formulation reduces to standard
quantum mechanics - but then there is no expansion and cosmological
redshift is 0, so the results are null. To write down the wave function
I am using a closed FRW space-time, with global coordinates given by

ds^2 = a^2(4(dt^2 - dr^2) - 1/4 sin^2(r)(dtheta^2 + sin^2(theta)dphi^2))

Teleparallel displacement of momentum imposes that dt^2 and dr^2 have
the same coefficient. The factors 4 and 1/4 come in because teleparallel
displacement results in cosmological redshift being proportional to the
square of the expansion parameter (I think this is related to electrons
having spin 1/2 but I have not explored that). A classical motion is
considered to be continuously observable and so is modelled as a
sequence of quantum motions

initial state - final state = initial state for next part of motion

When the final state becomes the initial state for the next part of the
motion the quantum theory has to be rescaled, with the consequence that
momentum is renormalised. This removes a factor of the expansion
parameter. Since the initial state and final state are infinitesimally
close together the connection reduces to the standard affine connection
of classical gtr at this point.

3. If you are proposing a quantum treatment of macroscopic objects like
stars or the Pioneer space craft, can you demonstrate with a
back-of-an-envelope estimate that said quantum effects would be
observable?

The quantum effects are observable when the accuracy of measurement of
position is less than the effective wavelength of the Doppler signal.
For Mars we have measurement accurate to about 10m, so the shift should
be present in optical frequencies in measurement of Mars, [...]

Hold on there... What if I use my naked eye to look at Mars? Then the
measurement uncertainty would be much larger, on the order of AU even!
Do you mean that I will then observe an overall shift in Mars' spectrum
by some very small frequency? Usually when two observers (say, at the
same place and at the same time) make the same measurement, but with
different instruments, they get different uncertainties (depending on
the instruments). But their uncertainty ranges should at least overlap.
Doesn't look like that's happening in what you are describing.
According to what you are saying, two obsevers may easily get
non-overlapping uncertainty ranges for the shift measurement.

No. The observed shift in Mars spectrum is equivalent to the Doppler
shift of ~0.4 m/s, way below the resolution of any apparatus we have to
measure it.

[...] Potentially this can be
tested from the original Pioneer tapes, because cycle slip is a
prediction of the model (associated with collapse of the wave function).

Can your model distinguish between a "collapse induced" cycle slip and
one that's due merely to noise during detection?

I don't see how, but I am not an expert on data analysis. I think
collapsed induced cycle slip should take place at approximately equal
intervals dependent on the apparatus used to measure it, but I would
think it is likely to be drowned by noise. If a test could be set up
with very low noise, then perhaps.



Regards

--
Charles Francis
substitute charles for NotI to email

Craig Markwardt wrote:
"John (Liberty) Bell" writes:

I refer you to my communications with Jonathan Silverlight, and to
gr-qc/0104064 for confirmation that spacecraft transmissions were
indeed "switched off." repeatedly (and switched on again successfully).

Hmm, I had misunderstood your original post to claim that the
transponder was switched of for long periods of time.

That was my mistake. I had originally mis-remembered that particular
detail within the quoted paper.

However, even so, turning the Pioneer 10 transponder off and on for
fifteen minute maneuvers (Anderson et al, sect. II.B.) a few times a
year is not a viable way to do ranging.

Perhaps not. However, my original point was that Pioneer 10 contains
limited 'smarts' which can potentially be exploited or subverted in
order to place it in a superior position to a 'dumb' rock such as an
extraterrestrial asteroid, for obtaining ranging data. Those limited
'smarts' comprise a directional antenna which can be turned off (and on
again) via ground control to provide a (highly) amplified response
signal.

The fact that such _off_ control was only used by NASA/JPL to provide
extra power for manoeuvres, does not restrict humanity to blindly
following that precise procedure in perpetuity. My point was that we
might potentially exploit our own intelligence and originality to
perform an experiment which was not part of the original Pioneer plan.
Whether or not practicalities allow / allowed that potential to become
reality is another matter, as I believe I touched on in my original
posting. However, nothing you have said thus far has explicitly ruled
out the possibility of obtaining adequately accurate ranging data (for
present purposes) via the simple expedient of turning _off_ the signal
via ground control and measuring the resultant delay before loss of
signal is observed (and repeating this experiment, if necessary).

The spacecraft signal is
already weak (which is the reason to perform a conscan maneuver in the
first place).

Agreed

The spacecraft is being maneuvered, which means the
spacecraft antenna beam pattern changes with respect to earth in a
non-trivial way.

That is an absolutely unnecessary and counterproductive complication
for the experiment I proposed.

The traveling wave tube amplifier, the device that
is turned off and then on again after the maneuver, is a macroscopic
device with elements that must warm up and stabilize.

That is also irrelevant, if the proposed measured action is a switch
_off_, not switch on, as I suggested, originally to overcome the signal
lock time uncertainty.

The spacecraft
and ground receiver have acquisition and tracking loops which are not
totally deterministic (and take at least several seconds to acquire).
Such a technique would also only produce one estimate of the light
travel time. Thus, your proposed technique is totally unreliable for
precision navigation.

You seem to have misunderstood the purpose of the proposal. It was not
to provide precise navigation. It was to establish whether the apparent
anomalous acceleration was demonstrably real, in the sense of resulting
in a different elapsed distance, or illusory, as suggested by Charles
Francis.

It would indeed be unfortunate if there was, in fact, no technical
reason why such a crude experiment could not have been performed before
Pioneer 10 was out of range, to resolve that question. (Beyond the fact
that nobody thought of it in time).

NASA/JPL have already established that accurate ranging data and the
Doppler technique gave adequately consistent results for closer (and
later) spacecraft. However, that does not appear to help here because
the window of uncertainty in the solar wind at such closer distances,
is too large to unambiguously establish whether the observed Pioneer
effect existed this close to the Sun.

As far as I can tell, Charles Francis's proposed effect has not been
presented formulaically, so I don't know whether this level of
correspondence closer to the Sun rules out that proposed effect or not.

"Real" spacecraft ranging is done by modulating a pseudo random
ranging code on the carrier signal.

Of course, but such 'smarts' were not included on Pioneer 10, which is
why such a crude alternative option was proposed as the only
possibility for resolving that question, in this particular instance.

[snip]

Your second paragraph appears to confirm that the lack of accuracy in
the already recorded light time data is due to the time taken to
achieve a signal lock. This would seem to suggest that, once a signal
lock has been achieved, the primary obstruction to obtaining more
accurate ranging data has already been overcome.

However, since turning spacecraft traveling wave tube amplifier off
and then on again during the maneuver causes the signal to vanish,
achieving lock *is* the primary obstruction.

I don't see why. Once signal lock has been achieved, delay time to loss
of signal should be reasonably unambiguous. It is irrelevant how long
signal re-lock takes, following switch back on, since, by then the
relevant information would already have beeen extracted from the
experiment. I stress again, it is completely pointless to attempt a
manoeuvre _within_ the experiment I proposed.


Whilst it is true that signal levels are, by now, already below the
noise threshold, that problem too can potentially be overcome, via the
development of still lower noise detectors.

Perhaps, but unlikely. Without regular ground-commanded maneuvers,
the spacecraft antenna becomes more and more misaligned with the
earth,

I am inclined to agree. The beam width specification suggests we would
need an extra 3 dB improvement in s/n ratio if Pioneer 10 orientation
drifts (uncorrected) by 3.6 degrees.

I don't have a clue how rapid a drift we can expect in practice.
However, I note that although Pioneer 10's star sensor has failed, its
Sun sensor has not (as of 2002). Consequently the possibility might
still exist for executing alignment procedures based on this data, 'in
the blind' from earth, provided, of course, that that potential was
built into the space-borne equipment.

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)

John (Liberty) Bell wrote:
Craig Markwardt wrote:
"John (Liberty) Bell" writes:

snip

"Real" spacecraft ranging is done by modulating a pseudo random
ranging code on the carrier signal.

Of course, but such 'smarts' were not included on Pioneer 10, ...

No 'smarts' on the craft are needed beyond the ability to
act as a transponder, which the Pioneers did have. The
'smarts' are in the ground segment. However, on Pioneer 10
the technique caused loss of lock at the craft for some reason.

snip

... Once signal lock has been achieved, delay time to loss
of signal should be reasonably unambiguous.

There are two feasible methods of switching off the
transmitter, either based on an on-board clock using
a pre-loaded schedule or by direct command from
the ground. I am sure the former would have been
available in the command set but I don't know if the
latter was. There would be a small risk of inadvertent
loss of the signal if an uplink message was corrupted
so the design may not have allowed for it.

The problem with scheduled turn-off is that of clock
synchronisation and with the latter the ambiguity in
the communications protocol.

What would be ideal would be to enable a turn-off
function with a high reliability command which was
not time critical and then trigger it with a PRBS
bit sequence data packet where timing could be
extracted over multiple bits to get round the SNR
jitter.

At a data rate of 16bps, one bit is 18750 km and
over 8 years the anomaly was only 27800 km so
timing would need to be extracted to a fraction
of a data bit to be useful. The method would require
a change to fundamental communications protocols.
I believe the Pioneer computers only had 49 kb of
memory and whether the comms programs could
be updated at such a low level is unclear. It would
certainly carry a significant risk of losing comms
if the code wasn't right.

The technique would also have required a dedicated
new ground device to produce the synchronised
PRBS on the uplink data and remember that signal
was being sent from one station, say Madrid, and
the loss of signal detected at another, for example
Canberra, and millisecond accuracy would have been
needed at both ends.

Going back to the scheduled method, again you
need to synchronise the clock to a few ms with
a data stream where each bit lasts 62.5ms.

Finally you have perhaps the biggest problem of
measuring the switch-off of the signal with millisecond
accuracy through a receiver chain with a bandwidth of
less than 1 Hz which is what was needed to hold lock
on the carrier. That applies whichever method of timing
you use at the transmitter.

snip

... The beam width specification suggests we would
need an extra 3 dB improvement in s/n ratio if Pioneer 10 orientation
drifts (uncorrected) by 3.6 degrees.

I don't have a clue how rapid a drift we can expect in practice.

The orbit of the Earth is 3 degrees wide at about 38 AU.
Within that they had to repoint every six months or more.

George

wrote:
John (Liberty) Bell wrote:

... Once signal lock has been achieved, delay time to loss
of signal should be reasonably unambiguous.

[snip]

At a data rate of 16bps, one bit is 18750 km and
over 8 years the anomaly was only 27800 km so
timing would need to be extracted to a fraction
of a data bit to be useful.

The anomaly was observed for 20 years, thus giving an accumulated
round trip difference of ~ 400,000 km hence time difference of
1second.
This makes the timing constraint somewhat more relaxed than you suggest
here. Furthermore, although an accurate figure for this distance
discrepancy would be ideal, it is only necessary to establish whether
there is any unambiguous distance discrepancy or not, within the
available timing uncertainties, in order to answer the question of
whether the apparent anomalous acceleration had real consequences or
not. This, I suggest, makes any total timing uncertainty of 1 second
adequate for answering that question.

and remember that signal
was being sent from one station, say Madrid, and
the loss of signal detected at another, for example
Canberra, and millisecond accuracy would have been
needed at both ends.

Why?

Finally you have perhaps the biggest problem of
measuring the switch-off of the signal with millisecond
accuracy through a receiver chain with a bandwidth of
less than 1 Hz which is what was needed to hold lock
on the carrier. That applies whichever method of timing
you use at the transmitter.

A 1 Hz bandwidth allows a signal to pass from maximum to zero and back
again in 1 second. This suggests that detecting a change from maximum
to zero in ~ half a second is, in fact, perfectly feasible with such a
receiver chain. (Possible phase shifts implicit this close to the
bandwidth limit are not a problem since a Pioneer response can be
mocked up on Earth, and tested through that receiver chain to determine
in advance what that phase shift will be.)

snip

... The beam width specification suggests we would
need an extra 3 dB improvement in s/n ratio if Pioneer 10 orientation
drifts (uncorrected) by 3.6 degrees.

I don't have a clue how rapid a drift we can expect in practice.

The orbit of the Earth is 3 degrees wide at about 38 AU.
Within that they had to repoint every six months or more.

Yes, I had noticed that the timing of repointing seemed to be related
at least as much to the motion of the Earth as to any drift in the
probe per se - which is, of course, spin stabilised.

Thanks for your additional comments.

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)

Spud wrote:
John (Liberty) Bell wrote:
Yes, I understand how they arrive at an effective inward acceleration
when the expansion of spacetime is scaled out. What does not make sense
is the implied assumption that this leads to an observable blue shift,
since that would appear to require that we do not, therefore, observe
the cosmological redshift. (A conclusion that is contradicted by
empirical observation).

The authors do not, in fact, claim a blue shift, but this claim is
implied by equating the derived inward acceleration with the pioneer
anomalous acceleration, since the latter was deduced from an observed
blue shift.

gr-qc/0102103 is worth a look

Spud

Quite so. The Hubble dependency then becomes "~10^ - 33 m/s^2". "Too
small by many orders of magnitude to account for the Pioneer 10/11
anomaly."

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)

Spud wrote:
John (Liberty) Bell wrote:

What does not make sense
is the implied assumption that this leads to an observable blue shift,
since that would appear to require that we do not, therefore, observe
the cosmological redshift. (A conclusion that is contradicted by
empirical observation).

The authors do not, in fact, claim a blue shift, but this claim is
implied by equating the derived inward acceleration with the pioneer
anomalous acceleration, since the latter was deduced from an observed
blue shift.

The cosmological redshift is still accounted for by these theories but
ignored

Precisely my point. Although these theories thus provide an inward
acceleration relative to their chosen coordinate system, this can only
produce a detectable blue shift if you pretend the Hubble red shift
doesn't exist!

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)

Igor Khavkine writes

Can your model distinguish between a "collapse induced" cycle slip and
one that's due merely to noise during detection?

Charles can answer for himself.

However I would observe that the 'collapse induced' stuff is not
critical to charles' arguments and is not something he has discussed in
any detail. Personally I think he is wrong and this is in some sense a
fiction of the quantum argument he uses.

The really critical things, which I am unable to argue either way due
ignorance a

1) Is his theoretical argument valid given his starting points. That is,
is it mathematically sound. I think it probably is, although I would be
astonished if there were not some areas that could be tightened up with
a little help/criticism. This refers to his initial and almost entirely
mathematical paper(s).

2) Given (1) then there is (if I have it right) a preferred set of co-
ordinate systems for doing distant QM in curved spacetime. In particular
for two linked quantum events (ie an emission and a detection) there is
only one, and even this is 'seen differently' by the emitter and
detector (simplistically because space has expanded between the events).

3) The resulting theory IS CONSISTENT with BOTH QM and GR.
Clearly it must be slightly different to existing theory.

Now, the above 3 items should be amenable to criticism (and repair) by
reasonably competent mathematical physicists with a reasonably wide
knowledge spectrum. I would be astonished if one person working alone
and part time would get everything right straight off.

Item (2) has a small second order difference from 'conventional'
interpretation. Clearly for consistency to exist where before it didn't
this is a necessity. Its clearly greatest when there has been a lot of
expansion between emission and detection.

In effect it introduces an extra term in expansion redshift.
So that existing redshift measurements must be re-evaluated in the light
of this extra term.

What I find astonishing is that there doesn't seem to be any mutual
incompatibility or self-contradiction with the observation data.

I also find it astonishing that a rather wide raft of astrophysical
explanations that are explained by somewhat unconvincing tweaking of
data and theory (not to mention inventing dark fixes as required) simply
cease to be a problem. Pioneer, dark matter and dark energy (not
required), galactic rotation curves, galaxies and stars that look old
when they should be young, and so on, become simple explanations.

Now it could be that Charle's theoretical basis may be incorrectly
founded. I am not qualified to judge. However the results need
explanation in the same way that Lorentz had the equations but Einstein
had the insight. I suspect Charles has both.

--
Oz
This post is worth absolutely nothing and is probably fallacious.

wrote:

Finally you have perhaps the biggest problem of
measuring the switch-off of the signal with millisecond
accuracy through a receiver chain with a bandwidth of
less than 1 Hz which is what was needed to hold lock
on the carrier. That applies whichever method of timing
you use at the transmitter.

Notwithstanding my prior comment on this point, it is obvious that many
positions in this receiver chain have much higher frequency responses
than 1 Hz. Ther frequency response you quote refers to a point in the
receiver chain and feedback loop(s) which behaves as an active low pass
filter. Whilst I am not familiar with the exact electronics used by
NASA, I do know from other active feedback circuits, that an active low
pass filter configuration can also be used as a band pass, high pass,
and even all pass circuit, depending on the point in the loop you
choose to define as output (and appropriately buffer).

In this context, it is pertinent to ask:- what do we mean by a
frequency responses of 1 Hz?

I suggest this merely means that we can be confident that the receiver
will remain locked on the last transmitted signal frequency for 1/2
second after that signal has terminated. Far from being a disadvantage,
this is, therefore, an advantage, sice we can now monitor a higher
frequency output of the chain, (storing and subsequently analysing if
necessary), around, say, a 2 second window of the predicted turn off
time, with confidence that any observed sustained loss of signal is not
due to a loss of signal lock.

John (Liberty) Bell
http://global.accelerators.co.uk
(Change John to Liberty to respond by email)