Nduriri changes Pioneer claims.

[publius]

The thread is locked and Nduriri has been banned permanently, so I couldn't post this there, but it seems Nduriri has made some changes to his gravitomagnetic "theory" after our exchanges here.

He is now claiming it is the a Galactic B_g responsible for the Pioneer anomaly. Apparently we got through to him on how small the solar B_g was, so it has to be the Galaxy now. :) But he still can't get the sign right........

-Richard

[RussT]

The thread is locked and Nduriri has been banned permanently, so I couldn't post this there, but it seems Nduriri has made some changes to his gravitomagnetic "theory" after our exchanges here.

He is now claiming it is the a Galactic B_g responsible for the Pioneer anomaly. Apparently we got through to him on how small the solar B_g was, so it has to be the Galaxy now. :) But he still can't get the sign right........

-Richard

Good Job Publius:clap:

[publius]

I was looking over some papers by Dr. Stanley Robertson, one of the ECO/MECO proponents, and found he had written up a possible GEM-like extension of Newtonian gravity (mostly for the purposes of what it would predict for GPB, to be falsified).

This is what Nduriri was actually trying to do, but done right. :lol: And the author doesn't even believe in it, just playing around. :)

http://arxiv.org/PS_cache/gr-qc/pdf/0502/0502088.pdf

Now here's the rub. Note that for the source mass, one has to use the gamma*m, the relativistic mass, as the gravitational mass, but, at least for gravitomagnetic purposes, one must define the force on the test mass by using the rest mass alone, no gamma (see the details).

And he goes on to put in a geodetic-like term as well.

-Richard

[BigDon]

Galactic B_g?

[captain swoop]

Bag? Bog? Bug?

[Celestial Mechanic]

Galactic B_g?
The underscore is commonly used in text environments to denote subscript. This notation is borrowed from TeX, a mathematics typesetting language. So what is really meant here is Bg, for the gravitational (g) magnetic induction, as opposed to the ordinary magnetic induction, which would be written without a subscript.

[captain swoop]

thanks

[grav]

He is now claiming it is the a Galactic B_g responsible for the Pioneer anomaly. Apparently we got through to him on how small the solar B_g was, so it has to be the Galaxy now. But he still can't get the sign right........

But I thought that the extra acceleration was directed toward the center of the solar system. However, I have recently learned that the centrifugal force created by a revolving object is added to its relative rotation as if it were part of the rotation itself. In other words, it is the same as the total absolute rotation of the object itself, stemming directly from its center. Of course, the extra centrifugal force of the solar system revolving around the galaxy would add a negative acceleration to its relative rotation, unless, perhaps, it was rotating in the opposite direction of this, but it would still be proportional to the distance from the center of the solar system. Do you think that the pioneer anamoly is something similar to this? What is the angle of the plane of rotation of the solar system to the plane of rotation of the galaxy? Are they about the same?

[BigDon]

Wow, I didn't think this happened on a galactic scale. I knew about induction and about AGN but didn't connect the two. (I googled about after Celestial Mechanic was kind enough to explain)

[publius]

Grav,

About the sign -- I was referring to Nduriri getting the sign of the gravitomagnetic force backwards. Like mass currents repel, rather than attract as like electric currents do. This makes like gravitomagnetic "poles" attract, and opposites repel, which agrees with the minus sign on Newton.

He just can't get that right. The anomalous Pioneer acceleration is toward the sun. However, the sun's (miniscule) rotational gravitomagnetic field would cause acceleration *away* from the sun for prograde motion.

Big Don,

The galactic gravitomagnetic field is nowhere big enough to cause this, and the motion would be a lot more complex than simple radial acceleration (if B_g were this large, the whole darn solar system would be precessing like crazy). Nduriri just invoked it to hold on to his idea.

However, I'm sure there is big time frame dragging going on near the central BHC. But out here where we are, that B_g is neglible.

-Richard

[grav]

The anomalous Pioneer acceleration is toward the sun. However, the sun's (miniscule) rotational gravitomagnetic field would cause acceleration *away* from the sun for prograde motion.
That is interesting. The extra acceleration toward the sun would appear to be about 8.8*10-10 m/sec2. This is very close to that for the galaxy of 1.2*10-10 m/sec2 in MOND theory. Let's say for the moment that they are the same and denote it with a0 (the difference may be found in the angles between the planes of rotation or some such). Now, as you said, the acceleration for the solar system is toward the sun and is additive, so the total acceleration is a'=a+a0, as found in the Pioneer expeditions. Now let's say the prograde motion is -a0. So I assume you mean that the factor of a0 cancels out for bodies in orbit. But what if they don't? The MOND value for orbitting stars remains (a) for large (a) and (a*a0)1/2 for a<<a0. Now what if the force vectors are a+a0 for the resultant force and -a0 in the direction of orbit, so that the force directly toward the center of revolution is found with [(a+a0)2-(-a0)2]1/2, since they act at right angles? The formula becomes a'=[(a+a0)2-(-a0)2]1/2=[(a2+2a*a0+a02)-a02]1/2=[a2+2a*a0]1/2=[a(a+2a0)]1/2. You will notice that for (a) is large, the formula reduces to a, but when a<<a0, the formula becomes [2a*a0]1/2, the same as with MOND. Of course, this value is twice as great, while the actual value is a few times smaller. So I'm not making any theories. Just throwing out some possibilities for the relation.

[publius]

Grav,

I'm not sure of the details because I don't know MOND, but Pioneer is outside the MOND regime for the solar gravity. What matters is the total gravitational acceleration. While the Pioneer "anomalous acceleration" is about equal to the MOND "magic number", the total is not.

If this extra acceleration were affecting the outer planets, it would show up in their orbits, but it does not.

Now, one of the speculative alternate gravity theories, a so-called "scalar tensor vector" (note this one is different from TeVeS, tensor-vector-scalar -- it's the same concept but the STV is different), claims to account for it with its extra terms (above GR gravity). In this theory, the extra acceleration is cancelled for circular orbits and is maximum for straight line radial trajectories. It is high for hyperbolic as well as highly elliptical orbits.

By tweaking that behavior they can keep the planets behaving as observered, but the effect should be seen in any highly elliptic or hyperbolic comets. I read over a paper on this, and they were calling for better observations of such comets as way to test it.

-Richard

[Celestial Mechanic]

[Snip!] Now, one of the speculative alternate gravity theories, a so-called "scalar tensor vector" (note this one is different from TeVeS, tensor-vector-scalar -- it's the same concept but the STV is different), claims to account for it with its extra terms (above GR gravity). In this theory, the extra acceleration is cancelled for circular orbits and is maximum for straight line radial trajectories. It is high for hyperbolic as well as highly elliptical orbits.

By tweaking that behavior they can keep the planets behaving as observered, but the effect should be seen in any highly elliptic or hyperbolic comets. I read over a paper on this, and they were calling for better observations of such comets as way to test it.
I'm familiar with TeVeS, but I haven't heard of this one. Do you have a number for a preprint?

Also, we may be able to get something of value from observations already made. If this effect is present for highly elliptical orbits, then this may be a factor in comets (such as Halley) returning earlier or later than predicted. It would be interesting to know what the effect integrated over one orbit would be.

[publius]

CM,

Here is a paper on it by Moffat. A Brownstein is another one involved with this.

http://arxiv.org/PS_cache/gr-qc/pdf/0506/0506021.pdf

This paper doesn't go into the Pioneer anomaly and comets, but there is one somewhere that does and I'm searching for it.

ETA: While this is something I don't really understand and therefore I'm talking out of school, the STV, adds a vector and scalar "combination" that would allow for more than one type of "graviton" -- we'd have a spin 1 as well as the traditional spin-2 carrier. Tajmar and deMattos' speculate on a "spin 1" graviton with their superconducting B_g work. Heck, Heim Theory proposes some "graviphoton" (but this thing would be a coupling between EM and gravity).

Anyway, all the above may be indicate a convergence to some real new gravity. But I'm not going to hold my breath or get too excited.

-Richard

[publius]

CM,

Here you go:

http://www.arxiv.org/PS_cache/gr-qc/pdf/0511/0511026.pdf


"A gravitational solution to the Pioneer 10/11 anomaly" by Moffat and Brownstein. This is very interesting reading.

ETA: I don't see anything in the above two specifically about highly ellipitcal vs circular. I know I read that somewhere, but now I wonder if was for some other theory. But I'm sure I read somewhere that "long period comets" would be a good test of this STVG (which Moffat may also call MSTG for "metric skew tensor gravity" -- this alphabet soup drives me nuts!)
-Richard

[publius]

I think I've figured out the "circular vs elliptical" thing. STVG comes up with a distance dependent "anomalous acceleration" -- if I'm interpreting their graphs correctly, the predict an additional radial acceleration that is essentially zero for small r, then increases to a maximum and then goes back down are r --> infinity. But, again if I'm reading it right, there remains a small asymptotic "anomaly", just smaller than in the middle.

The effect on the inner planets is too small to matter, but for the outer planets it should be there. However, the main effect of the additional acceleration will be to cause an orbital precession. But, if the orbit is nearly circular, well, you can't tell a circle is precessing. If perihelion is not too much different from aphelion, then you've got wiggle room in the observational errors of the outer planets to allow for it.

But, for a highly elliptical orbit, you'd see it.

-Richard

[nutant gene 71]

The effect on the inner planets is too small to matter, but for the outer planets it should be there. However, the main effect of the additional acceleration will be to cause an orbital precession. But, if the orbit is nearly circular, well, you can't tell a circle is precessing. If perihelion is not too much different from aphelion, then you've got wiggle room in the observational errors of the outer planets to allow for it.

But, for a highly elliptical orbit, you'd see it.
From Moffat-Browstein's paper on Pioneer Anomaly, they mentioned our ephemeris data for outer planets ends at about Saturn, and that beyond 10AU were are only estimating. This would apply to very highly elliptical comets that go out beyond the Kuiper Belt and back into inner solar system. We sort of know where they are out there beyond Saturn, but don't really have a hard fix on them. If we had a probe fixed on Halley's, for example, we'd get better ephemeris readings, and really know what anomalous acceleration is doing out there, assuming that it would show up as a distant orbital anomaly in the outer solar system.

That said, I never figured out if Keplerian orbits for highly elliptical objects would not already have anomalous acceleration, as a function of distance from the Sun (Moffat et al), already worked in. Would there actually be a different orbital behavior if a variable G out there is already part of that orbit? Would the Equivalence Principle somehow square out the anomolous acceleration so that the elliptic already has this factored in? I never figured out the answers to this.

[Nereid]

From Moffat-Browstein's paper on Pioneer Anomaly, they mentioned our ephemeris data for outer planets ends at about Saturn, and that beyond 10AU were are only estimating. This would apply to very highly elliptical comets that go out beyond the Kuiper Belt and back into inner solar system. We sort of know where they are out there beyond Saturn, but don't really have a hard fix on them.

[snip]Are you sure?

According to this 3-year old ESA PR (http://www.eso.org/outreach/press-rel/pr-2003/phot-27-03.html), Halley was observed at distances of ~18 and ~28 au (and could be detected at aphelion, with the VLT!)

Or maybe it's that comet ephemeres (-ises?) can't be as good as space probes, ever, because of the limitations of ground-based optical images, or bumps etc from the comet itself (e.g. 'the rocket effect')?

[nutant gene 71]

Are you sure?

According to this 3-year old ESA PR (http://www.eso.org/outreach/press-rel/pr-2003/phot-27-03.html), Halley was observed at distances of ~18 and ~28 au (and could be detected at aphelion, with the VLT!)

Or maybe it's that comet ephemeres (-ises?) can't be as good as space probes, ever, because of the limitations of ground-based optical images, or bumps etc from the comet itself (e.g. 'the rocket effect')?

From the Moffat-Brownstein paper, pp 5-7, http://www.arxiv.org/PS_cache/gr-qc/...11/0511026.pdf
here is what it said:
Since known reliable data from the
ephemerides of the outer planets ends with the data for Pluto at a distance from the Sun,
r = 39.52AU = 5.91 × 1012m, we could claim that for our range of values47AU < (r) < ∞, we predict
(r) and (r) values consistent with the un-extrapolated fifth force bounds.
...
For the nine planets, we obtain the values of PL shown in Table 1. We see that
we are able to obtain agreement well within the bounds of possible variation of GM⊙
consistent with the data [9, 10] for Mercury, Venus, Mars and Jupiter. No observational
limit on PL for Saturn or the outer planets has yet been established; but this is
precisely where the deviation G(r)/G0 leads to a sizable contribution in the theoretical
prediction for PL. The reason for the uncertainty beyond the orbit of Saturn and the
lack of observational limits on PL is that the ephemerides for the outer planets is based
on optical measurements. (bold mine)
I remember this had been discussed on some earlier thread, but I'm only reporting what the paper said, and extrapolated to our 'visual' optical measurements for Halley's.

[Celestial Mechanic]

[Snip!] Or maybe it's that comet ephemeres (-ises?) [Snip!]
One ephemeris, many ephemerides. Pronounced eff-eh-MARE-i-deez.

[publius]

All,

That's how I read it: outer solar system ephimerides are based on optical observations which have a much larger margin of error, and current data can accomodate their theory.

They predict an additional radial acceleration which is a function of radius. One can think of it as a variable G (anything could be considered this way -- just divide the predicted g(r), whatever it is, by the Netwonian expression ~1/r^2, and that ratio can be seen as a variable G).

Anyway the additional acceleration is small within the inner solar system, then starts kicking up somewhere around Saturn, reaches a peak, then decays to something still larger than G for infinite r, but smaller than the peak.
They call this G_infinity. I assume G_infinity converges to MONDian gravity, but the behavior in between has additional features. See the claimed fits to galactic clusters and all that stuff. I don't know enough about all that to appreciate it.

-Richard

[Nereid]

All,

That's how I read it: outer solar system ephimerides are based on optical observations which have a much larger margin of error, and current data can accomodate their theory.

They predict an additional radial acceleration which is a function of radius. One can think of it as a variable G (anything could be considered this way -- just divide the predicted g(r), whatever it is, by the Netwonian expression ~1/r^2, and that ratio can be seen as a variable G).

Anyway the additional acceleration is small within the inner solar system, then starts kicking up somewhere around Saturn, reaches a peak, then decays to something still larger than G for infinite r, but smaller than the peak.
They call this G_infinity. I assume G_infinity converges to MONDian gravity, but the behavior in between has additional features. See the claimed fits to galactic clusters and all that stuff. I don't know enough about all that to appreciate it.

-RichardI guess the good news is that we will soon(ish) have data with much smaller error bars ... from the New Horizons mission, and (later) from other missions.

I'm curious to know why Cassini data didn't help constrain the ideas, anyone know?

There are also ways to get much tighter 'optical' data - occultations, especially if the star occulted was in the HIPPARCOS primary catalogue (and not the Tycho supplement).

Too, perhaps radar astronomy - of objects beyond Saturn - will help?

And finally, if LISA (http://sci.esa.int/science-e/www/area/index.cfm?fareaid=27) lives, then we'll have all the data we could possibly want, right?

[BigDon]

I thought LISA was much sooner than 2015. Now I'm disappointed. I wanted to see the science from that one.

[publius]

Nutant_gene,

I'm too lazy to hunt it down, but I think I saw that L. Iorio had a paper on these "error bars" and the wiggle room it gives for alternate gravitational theories when I was hunting for this STVG/MSTG/Whatever-the-heck-they-call-it-now. From what I've read of his, he would be "The Man" on how the observational errors would let the actual trajectories be, and what an orbit could be doing vs what we think it is doing applying pure inverse square.

Observational astronomy and "what it looks like to us on earth" is not my forte at all, but I would think it would be a matter of knowing distance and speed precisely. I mean, if you see a point of light moving against the celestial backdrop, you have to know distance to know speed. And, you might use Newtonian gravity to calculate the one better if you know the other, and that effect might be in some of the "charts".

But I would think that if you could accurately measure both distance and speed (and over a number of points on the orbit for good measure) indepedently, you would nail this down. And we have that for the inner planets, and so have tight constaints.

-Richard

[Thanatos]

Think binary neutron star orbital decays. Papers available upon request. GPB will produce no surprises. GR will pass this test with flying colors. How many tests must GR pass? GPB is the biggest waste of research funds ever devised, IMO. I'm not up for any grants, so I need not sugar coat my opinions.

[nutant gene 71]

Nutant_gene,

I'm too lazy to hunt it down, but I think I saw that L. Iorio had a paper on these "error bars" and the wiggle room it gives for alternate gravitational theories when I was hunting for this STVG/MSTG/Whatever-the-heck-they-call-it-now. From what I've read of his, he would be "The Man" on how the observational errors would let the actual trajectories be, and what an orbit could be doing vs what we think it is doing applying pure inverse square.

Observational astronomy and "what it looks like to us on earth" is not my forte at all, but I would think it would be a matter of knowing distance and speed precisely. I mean, if you see a point of light moving against the celestial backdrop, you have to know distance to know speed. And, you might use Newtonian gravity to calculate the one better if you know the other, and that effect might be in some of the "charts".

But I would think that if you could accurately measure both distance and speed (and over a number of points on the orbit for good measure) indepedently, you would nail this down. And we have that for the inner planets, and so have tight constaints.

-Richard
Thanks, I printed out Lorenzo Iorio and G. Giudice paper titled "What do the orbital motions of the outer planets of the Solar System tell us about the Pioneer anomaly? http://www.arxiv.org/PS_cache/gr-qc/pdf/0601/0601055.pdf

Only glanced it over, but I notice how the proposal to study this anomaly at the 20-40 AU distance is hindered by the very small eccentricity for Uranus and Neptune. So only Pluto with high eccentricity lends itself for study, but with a 248 year orbital cycle, we had not yet had much time to observe it for anomalies. Otherwise, that leaves us Kuiper Belt objects and highly eccentric comets, such as Halley's 0.947 (vs. Pluto's 0.248, Neptune's 0.008, and Uranus' 0.047). We know we can see Halley's observably out near Neptune to be within 1 arc second of where it was predicted (per Nereid's ESA report above) with Newtonian gravity, but I do not know how many kilometers within Halley's orbital distance this represents, nor if this is one arc second ahead or behind (?). So a lot of unanswered questions, as usual.

Thanks for refering Iorio's work, I printed out list of his 77 papers, reading #65, out of order, of course. :)

[Tassel]

I'm too lazy to hunt it down, but I think I saw that L. Iorio had a paper on these "error bars" and the wiggle room it gives for alternate gravitational theories
Yes, he does: What do the orbital motions of the outer planets of the Solar System tell us about the Pioneer anomaly? (http://arxiv.org/PS_cache/gr-qc/pdf/0601/0601055.pdf)

I also found a more detailed paper by Kjell Tangen: Could the Pioneer anomaly have a gravitational origin? (http://arxiv.org/PS_cache/gr-qc/pdf/0602/0602089.pdf) which references the Iorio paper. Both conclude that if gravitational in origin, the Pioneer anomaly ought to be seen as a disturbance in the orbits of the outer planets.

But I would think that if you could accurately measure both distance and speed (and over a number of points on the orbit for good measure) indepedently, you would nail this down.
Me too. I don't see why I should assume optical measurements of the outer planets are too inaccurate to detect the Pioneer anomaly. What struck me as weird is that Moffat-Brownstein seem to claim that's the case, but provide no support for that claim. :think:

[publius]

Me too. I don't see why I should assume optical measurements of the outer planets are too inaccurate to detect the Pioneer anomaly. What struck me as weird is that Moffat-Brownstein seem to claim that's the case, but provide no support for that claim. :think:

I have no idea what the resolution of optical measurements of the outer planets is. This a very good question. It certainly depends on telescope optics, that's for sure. We see a point of light on a 2D surface. To how many arcseconds are we certain of the center of that point? We see that point of light moving at some angular speed as well on that 2D surface, which is a flat projection of its actual velocity vector.

The actual error in the position of the center of the point of light is certainly going to increase with distance, some r*theta, where theta is the uncertainty in angular position. And the speed is going to scale with distance as well.

Yep, those are good questions. Does anyone here know the answers?

-Richard

[Nereid]

I have no idea what the resolution of optical measurements of the outer planets is. This a very good question. It certainly depends on telescope optics, that's for sure. We see a point of light on a 2D surface. To how many arcseconds are we certain of the center of that point? We see that point of light moving at some angular speed as well on that 2D surface, which is a flat projection of its actual velocity vector.

The actual error in the position of the center of the point of light is certainly going to increase with distance, some r*theta, where theta is the uncertainty in angular position. And the speed is going to scale with distance as well.

Yep, those are good questions. Does anyone here know the answers?

-RichardFor the individual observations, best to check out a website such as MPC (Minor Planet Centre), and do some reading.

In general, any good observations, made using an optimal set of background stars, etc, should be accurate to better than 0.1" (absolute, for the photocentre), and may be as good as 0.01" (10 mas).

While not planetary data, SDSS DR5 (http://www.sdss.org/dr5/) is a good example of the accuracy that should be easily attainable: "Astrometry < 0.1" rms absolute per coordinate"

[Edit: this MPC page (http://cfa-www.harvard.edu/iau/special/residuals.txt) contains an analysis of a great deal of raw data, from a great many different sources, over more than five decades. Note the difference between the absolute astrometric accuracy of an observation (or a series of observations) and the residuals - observation minus prediction from 'best orbit'.]

[publius]

Nereid,

Thanks! That's some fascinating reading.


-Richard

[publius]

Tassel,

Thanks for those papers.

Well, well, Iorio and Tangen conclude that the Pioneer anomaly can't be gravitational (unless the Pioneers are somehow violating the equivalence principle!), because its perturbations would be larger than the error bars. That's a direct contradiction to Moffat and Brownstein's claim in their papers.
And, I think I'll take Iorio's word on this unless someone can show a flaw in his analysis.

I love a good mystery, and this Pioneer thing is a good one!


-Richard

[Thanatos]

Iorio publishes some intersting papers, but I find them fundamentally flawed. Assumes facts not in evidence. I expect to be bombarded with counter claims on this point, so let me make it clear . . . this is merely my opinion. Why? As usual, it disregards the laws of thermodynamics. I find that totally unacceptable. Einstein made this a central issue in his relativity talks. Read all you want into it, the message was clear.

[newton]

Grav,

About the sign -- I was referring to Nduriri getting the sign of the gravitomagnetic force backwards. Like mass currents repel, rather than attract as like electric currents do. This makes like gravitomagnetic "poles" attract, and opposites repel, which agrees with the minus sign on Newton.

He just can't get that right. The anomalous Pioneer acceleration is toward the sun. However, the sun's (miniscule) rotational gravitomagnetic field would cause acceleration *away* from the sun for prograde motion.

Big Don,

The galactic gravitomagnetic field is nowhere big enough to cause this, and the motion would be a lot more complex than simple radial acceleration (if B_g were this large, the whole darn solar system would be precessing like crazy). Nduriri just invoked it to hold on to his idea.

However, I'm sure there is big time frame dragging going on near the central BHC. But out here where we are, that B_g is neglible.

-Richard
I read Nduriri paper but there is not sign error. His is the only scientist who has written a rational theory. He has solved the 7 cosmological blunders of Einstein, Einstein is wrong
See his new gravitational radiation equation www.gravitomagnetism.com

[antoniseb]

newton has been banned as a sock puppet of ndurri and jndurri.