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Thread: Pioneer Anomaly solved?

  1. #1
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    Pioneer Anomaly solved?

    long story short: it's caused by heat emission, not new physics.

    http://www.planetary.org/programs/pr.../20110722.html
    General request: If I ask a question, I'd like people who know about the subject to answer it with factual answers (preferably with references). Saying we don't know is fine if that's the case. However, I'm not really interested in guesses or personal opinions. Thanks!
    Website: http://www.evildrganymede.net

  2. #2
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    Quote Originally Posted by EDG View Post
    long story short: it's caused by heat emission, not new physics.

    http://www.planetary.org/programs/pr.../20110722.html
    That't a good find EDG, thanks.

  3. #3
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    Quote Originally Posted by Planetary Society
    The analysis of recovered telemetry data indicates that heat
    from the RTGs reflected off the backside of the big high-gain
    antenna and helped “push” the spacecraft back toward the sun.
    That's what I was arguing for in rather extensive discussions
    on Usenet about eight years ago. One of the authors of the
    paper (Craig Markwardt) was a participant in that discussion.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  4. #4
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    Quote Originally Posted by Jeff Root View Post
    That's what I was arguing for in rather extensive discussions
    on Usenet about eight years ago. One of the authors of the
    paper (Craig Markwardt) was a participant in that discussion.
    I believe the majority always thought it was tied into the heat budget of the spacecraft. What I find interesting about EDG's link is that they have found it is a decreasing effect vs the the thought that is was constant. But, since they now have the older tracking information, that makes some sense, as the greater decay rate of the RTG's, along with the higher heat production, would be during the earlier part of the mission. We'll have to wait a bit longer for the full analysis of the thermal recoil to see if there is still an the appearance of an acceleration in the data.

  5. #5
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    When I was in grad school about 12 years ago, one of the scientists in my department effectively argued this point and wrote a couple of articles on this. I was pretty convinced by his argument and had thought this was the case the whole time.

  6. #6
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    My concern was that heat conduction and emission and reflection
    of thermal radiation hadn't been modelled in sufficient detail. The
    RTGs were apparently being modelled as plain cylinders of uniform
    temperature, for example.

    I vaguely recall that DSN was never able to keep a lock on Pioneer's
    signal for more than about 8 or perhaps 16 hours, which reduced the
    quality of the data greatly. Did you find any indication that they were
    able to reliably combine separate but consecutive datasets so that
    they covered longer periods?

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  7. #7
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    Its not solved.

    The latest Turyshev paper has succeded in looking at a larger data set. What is now disfavored is the vector along the velocity axis which is suggested by various drag theories. The onset issue is not resolved. There is a small non-constant term seen in the data that is about 1/3 of the value expected from the radio-isotope decay. Perhaps this is the modelled heat assymetry instead or decay rates somehow depend on distance from the sun as a few have suggested regarding seasonal anomalies seen in some decay rates. Regarding the DSN, there are small diurnal and annual anomalies imposed upon the Pioneer Anomaly that implicate that the Earth should not be left out of consideration when looking at the total anomaly.

    Since the new paper came out, Iorio has written on whether the new inconstant term is of universal gravitational origin. He finds that such an effect upon other planets would be 2-3 orders greater than observed which disfavors a universal modified gravity theory that would affect planets as well as spacecraft.

  8. #8
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    Quote Originally Posted by borman View Post
    Its not solved.
    It's the way to bet.

    Quote Originally Posted by borman View Post
    The latest Turyshev paper has succeded in looking at a larger data set. What is now disfavored is the vector along the velocity axis which is suggested by various drag theories.
    Actually, the quote from the paper says: "We can exclude an anomaly directed along the spacecraft velocity vector...."

    That sounds a lot more than just disfavored.

    Quote Originally Posted by borman View Post
    The onset issue is not resolved.
    And due to the maneuvers does around Saturn, I don't think it ever will be.

    Quote Originally Posted by borman View Post
    There is a small non-constant term seen in the data that is about 1/3 of the value expected from the radio-isotope decay.
    There is another, non-modeled effect that Turyshev hints at, along with another hint that the final modeling may reduce the anomaly to below statistical significance. But, he says it will have to wait until the modeling is done. The actual quote is "Results of this meticulous study will be published soon."

    Quote Originally Posted by borman View Post
    Perhaps this is the modelled heat assymetry instead or decay rates somehow depend on distance from the sun as a few have suggested regarding seasonal anomalies seen in some decay rates.
    Actually, the decay rate claims, for distance, have been shown to be wrong here and here .

    Quote Originally Posted by borman View Post
    Regarding the DSN, there are small diurnal and annual anomalies imposed upon the Pioneer Anomaly that implicate that the Earth should not be left out of consideration when looking at the total anomaly.
    Yeah, that's still a possibility. I'm not sure how that would be taken into account however. If they are aware of that, then they should be able to take it out of the observations.

  9. #9
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    Quote Originally Posted by Tensor View Post
    It's the way to bet.



    Actually, the quote from the paper says: "We can exclude an anomaly directed along the spacecraft velocity vector...."

    That sounds a lot more than just disfavored.



    And due to the maneuvers does around Saturn, I don't think it ever will be.



    There is another, non-modeled effect that Turyshev hints at, along with another hint that the final modeling may reduce the anomaly to below statistical significance. But, he says it will have to wait until the modeling is done. The actual quote is "Results of this meticulous study will be published soon."



    Actually, the decay rate claims, for distance, have been shown to be wrong here and here .



    Yeah, that's still a possibility. I'm not sure how that would be taken into account however. If they are aware of that, then they should be able to take it out of the observations.
    Wishful thinking may be a motivator, but not a substitute for final results.

    Disfavored seems appropriate until someone can find an argument that argues a drag in a particular direction that might suggest otherwise.


    The Pioneer Anomaly also affected the other Pioneer after Jupiter gravity assist. This spacecraft never went near Saturn. Also about a 1/8 strength Pioneer Anomaly appeared in the cruise phase prior to Saturn gravity assist. The changing spin-up and spin-down anomaly perpendicular to the ecliptic would seem best modeled by hydrazine leaks after maneuvers. Telltale evidence should come from analysis of telemetry data.

    As regards the Fischbach idea, they have recently written a new paper regarding MESSENGER constraints. I have not been a fan of the idea as it does not apply to all species. A clue is the high energy daughter species in lieu of silicon. I have suspected these annual and diurnal anomalies that also include DSN and DAMA/LIBRA as well as the flyby anomalies might suffer from a common cause.

    It should be recalled that Turyshev et al have stated a portion of the anomaly still remains unexplained with maximum co-efficient given to internal heat assymetries.

    Lammerzahl et al have written a paper working both with the flyby and Pioneer Anomaly. While they agree with Turyshev that heat could make up a larger portion of the Pioneer Anomaly, it is orders of magnitude too small to account for the flyby anomaly. They also modeled solar pressure for one flyby and found it pointed in the opposite direction of the flyby anomaly meaning the reported magnitudes of the flyby anomaly are too small by almost 50%.

  10. #10
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    Pioneer Anomaly Solved!

    Over the course of the past two decades, all sorts of solutions have been proposed, some of which invoked exotic "new" physics. In the end, recovery of more data and years of painstaking work have shown that no such exotic solution is necessary, but rather that anisotropic (big word for not-symmetric-in-all-directions) thermal radiation (big words for heat) can explain the mystery. This solution had already been suggested, and examination of the problem over time had made it seem increasingly likely, but only careful analyses could check whether anisitropic radiation could explain the anomaly. The latest piece of this analysis appears in a new scientific article by Slava Turyshev and colleagues.
    Technical paper is here.
    Everything I need to know I learned through Googling.

  11. #11
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    Quote Originally Posted by ToSeek View Post
    Pioneer Anomaly Solved!



    Technical paper is here.
    Hehehehe, I don't think I've done this before ToSeeked . And mentioned by trinitree88 here

  12. #12
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    I view this as a progress report rather than a final conclusion. There still remain a number of unanswered questions brought up near the end of the paper. One important question has to do with the onset seemingly apparent that is not satisfied by their analysis. They critically depend upon an assumption that requires that mismodelling has occurred. However, no one of the Turyshev or Anderson teams has yet pointed out where the mismodelling has occurred. It remains speculation until the error is explicitly exposed and a new model is presented against which their data can be tested.

    The Zirconium Dioxide suffering space weathering from the sun facing side seems a good idea to peruse as regards the small counter term that is working against the anomaly. It also suggests space is rather devoid of micrometeorites of sufficient mass to compromise the 3 mil shield in the direction of motion. Compromise due to impact in the direction of motion would add and actually increase the magnitude of the anomaly over time which is contrary to observations.

    It should be noted that the value given the anomaly is cited from the Anderson paper which is also the result of speculations to try to make the anomaly universal for a possible gravity consideration. The actual data support two different but similar values for the anomaly, but even with the error bars, they do not overlap.

    It will be interesting to see more than 11 data points for Pioneer 11 to see if the onset is present for this craft as well quite some distance past Jupiter. I still suspect there is also a conventional thermal explanation for a significant portion of the anomaly at the so called onset distance due to a pseudogap phase transition of metal oxides mixed in the white paint of the HGA. Both the RTG and main body electronics are likely too warm for the transition to occur, but this is perhaps not true of the sun facing white painted surface of the HGA further from the heat sources. Pseudogap phase transitions occur at significantly higher temperatures than say, superconductivity. With the electrons behaving in a new way from other phase transitions, the HGA may work as a heat reflector rather than transmitter upon phase transition. This can be checked in an Earth low temperature lab if they can find an old bucket of paint left over from the HGA painting days.

  13. #13
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    Doppler: z = v/c;
    Thus the relative error: dz/z = dv/v - dc/c;

    and according to wikipedia there was a departure: -400 km / year,
    that is: dv = -400 km / yr = -1.25 cm / s;

    setting: v = 12.5 km/s, we get: dv/v = -1e-6;
    or dc / c = 1e-6 => dc = 300 m/s;

    Which is consistent with the anisotropy of the speed of light in the Milky Way.
    The direction of the trajectory of the Pioneers, is nearly radial with respect to the Galaxy.

    V = 250 km/s => V^2/c^2 = 0.7e-6 => dc = 210 m/s

    which gives about 2/3 of the anomaly.

  14. #14
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    Hetman,

    The Astronomy forum is not the place to offer against-the-mainstream explanations. Please confine those to the Against The Mainstream forum.
    Brett's the name. Peters Creek is the place.
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    We looked quite closely at the heat budget in the early data, and concluded that the acceleration was not consistant with the decay rate unless the transfer in the direction of acceleration was at saturation; which seemed unlikely. The purpose of the paper is not to reject 'unlikelies' but add up all the unlikelies into one 'not likely, but possible' solution set. For such a meager force, a possible solution is not necessarily the correct one - this is not the way of science.

    The way of science is to duplicate the experiment in a way that eliminates the uncontrolled variables. A repeated Pioneer mission with craft designed specifically to study small forces would be a much better approach.

  16. #16
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    Many of the following criticisms regarding the paper released by Turyshev et. al. appear to be shared:

    http://physicsfromtheedge.blogspot.c...f-pioneer.html

    The most difficult aspect for the thermal radiation model to account for, as mentioned above, is that it predicts the anomalous acceleration to be greatest in the early stages of the mission. But this is precisely where it is smallest. Simply ignoring this data because it doesn't fit the proposed model by claiming it is due to interpretation errors is a rather weasely way to dismiss it. Unless it can be shown clearly that the data itself has been corrupted or the interpretation of the data was flawed, it should not be discounted. Adjusting the fundamental data to fit the theory is not the right approach - adjusting the theory to fit the data is the correct approach.

    I would like to see the adjusted values for the anomalous acceleration clearly stated as a function of heliocentric distance so that we can compare them to the values published by Anderson et. al.


    juggler

  17. #17
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    Quote Originally Posted by juggler View Post
    Many of the following criticisms regarding the paper released by Turyshev et. al. appear to be shared:

    http://physicsfromtheedge.blogspot.c...f-pioneer.html

    Quote Originally Posted by McCullock
    More generally, I always find it difficult to accept a paper when a very complex and unrevealed process (over 3000 finite elements, not fully detailed in the paper) and with fitting parameters, is used to get to a previously known answer, and no experiment is suggested that might unambiguously test it against rivals. I dislike dark matter for similar reasons. I'd like to see them present a simplified order-of-magnitude calculation so others can reproduce what they have done on paper.

    juggler
    This is a general restatement of the Jerry principle: The same standard-of-evidence should be applied to any model that reaffirms the status quo as we apply to solutions that favor alternative physics. It is ok that a model has been developed that might explain the anomally without adjusting any physical laws; but it is a stretch to declare that the Pioneer anomally has been solved (As the Planetary Society Headline Proclaims) and therefore merits no further study.

    Finite element solutions are great for engineering because they provide real solutions to problems in which the underlying physics are too difficult to characterize. They are bad for science, because finding a solution with a thousand variable numeric code does not necessarily demonstrate that the underlying physical assumptions are valid.

    As Anderson has proposed, we should put together a deep space probe that is designed to test fundamental assumptions about the physical universe.

    Space is a wonderful proving ground. Sometimes, it proves we are wrong.

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    Unfortunately, a future space mission to perform such a test is extremely unlikely if the vast majority of scientists accept the results published by Turyshev et. al. and agree that asymmetrical heat emission is the root cause of the Pioneer anomaly. Any future study of this effect is likely dead in the water. Shame.

    juggler

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    Quote Originally Posted by Jerry View Post
    It is ok that a model has been developed that might explain the anomally without adjusting any physical laws...
    "Might"?...I don't think they were saying that it "might" explain the "anomally", but that it did explain it.
    Last edited by R.A.F.; 2012-Jun-01 at 03:52 PM. Reason: To delete last sentence...too "argumentative".

  20. #20
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    Quote Originally Posted by R.A.F. View Post
    Quote Originally Posted by Jerry View Post
    It is ok that a model has been developed that might
    explain the anomally without adjusting any physical laws...
    "Might"?...I don't think they were saying that it "might"
    explain the "anomally", but that it did explain it.
    No, Jerry's characterization is accurate, yours is not.

    I read the entire letter, though not nearly carefully
    enough to understand everything. However, it is clear
    that the authors are saying that the Doppler data is
    consistent with the the results of the thermal model,
    not that the Doppler data is explained by the thermal
    model. There is some overlap of the two error ellipses
    in figure 4 of the letter. That shows it is possible that
    thermal effects could account for the otherwise
    anomalous Doppler data.

    -- Jeff, in Minneapolis
    http://www.FreeMars.org/jeff/

    "I find astronomy very interesting, but I wouldn't if I thought we
    were just going to sit here and look." -- "Van Rijn"

    "The other planets? Well, they just happen to be there, but the
    point of rockets is to explore them!" -- Kai Yeves

  21. 2012-Jun-01, 11:16 PM
    Reason
    decided I just didn't care

  22. 2012-Jun-01, 11:27 PM

  23. #21
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    Quote Originally Posted by Jeff Root View Post
    No, Jerry's characterization is accurate, yours is not.
    Thanks for your opinion...

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