Pioneer Effect

[little_star]

In the paper this morning I read an article about "the Pioneer Effect." Basically, the probes aren't where they "ought" to be, and the article reported that this was indeed an observable and real thing, but the explination was up for grabs, being anything from a mechanical thing that they have yet to identify, or from an interaction with so far undescribed forces.<br /><br />My question is this:<br />The article says that they tried to confirm it using Voyager's data but it used a different navigation system and the data were useless for comparison. Why can't there be a computer program or something that can convert between the two? <br /><br />(I'm trying to find the link but dial up will be the death of me... the article was in the LA times, called "gravity may be losing its pull" or something catchy.)

 

[alexblackwell]

<i>The article says that they tried to confirm it using Voyager's data but it used a different navigation system and the data were useless for comparison.</i><br /><br />Rule No. 1: Never trust a newspaper article for accurate <i>science</i> information.<br /><br />The "Pioneer Effect" does not show up in the Voyager radio tracking data because, unlike Pioneer 10 and 11, the two Voyagers were not spin-stabilized but rather three-axis stabilized. Also, the two Voyagers have, unlike the two Pioneers, conducted many propulsive maneuvers that have overwhelmed the tiny gravitational acceleration noted in the Pioneer data.

 

[alexblackwell]

borman points to a good resource. For those who want to know more about this subject, there are plenty of preprints on arXiv. For example. go to the LANL arXiv preprint server and select<br /><br />Archives: Search All<br />Years: All Years<br /><br />In the "Abstract" box type "Pioneer" and show, say, "100 hits per page" and hit "Do Search." One should then get a fairly good listing of related preprints, especially if one scrolls back to the 1998 time frame when Anderson <i>et al</i>. first published about the anomaly. Many of these preprints have subsequently been published in peer-reviewed journals, but be advised that many <i>have not</i>.<br /><br />That said, however, below is just one recent example of a good paper that shows the arXiv- />journal route:<br /><br /><b>Finding the origin of the Pioneer anomaly</b><br />Michael Martin Nieto and Slava G Turyshev<br /><i>Class. Quantum Grav</i>. <b>21</b>, 4005-4023, (2004).<br />Abstract<br /><br />See also the accompanying news story:<br /><br />Pioneer anomaly put to the test<br /><i>Physics in Action</i> (September 2004)<br /><br />For those without access to this particular journal, there is, not surprisingly, a preprint of this paper available on the LANL arXiv server.<br /><br />I've got the journal paper, so I'm not sure of the differences, if any, between the last preprint version and the final published version.

 

[little_star]

Thanks for the links, I'll be sure to check them out!<br /><br />I know about newspaper articles and their questionable accuracy. Just noticing oversimplifications and omissions in the few things I know something about boggles me, let alone more complicated subjects. <img src="/images/icons/smile.gif" />

 

[newtonian]

borman- I can't get the link to work.<br /><br />On your older post on the lost SDC thread you had indicated that the cosmological constant might be the cause, and that the seeming reverse effect was due to frame of reference.<br /><br />Can you remind me of the basics of that model?<br /><br />Meanwhile, I was thinking that the cause is related to the fact that the slowing space probes are not gravitationally bound.<br /><br />If I remember correctly: gravitationally bound objects, such as planets and moons, are not exhibiting this effect.<br /><br />My model (just a thought) would liken gravity to a rigid bar or bond between the gravitionally bound objects.<br /><br />When the bonds hold fast, dark energy cannot effect the objects.<br /><br />Once the bond is broken, a weaker form of energy can now effect the object that has achieved escape velocity.<br /><br />Just a thought.<br /><br />In the illustration, when the bond is broken, the objects can now move closer together than would otherwise be possible when gravitationally bound.<br /><br />This is not friction, but you could compare friction as another variable effect - when two objects are too close ( in contact)......

 

[newtonian]

borman - As usual, a little over my head. It is the unfamiliar words, not the concepts, that slow me so I will have to study your posts before responding properly.<br /><br />Thank you, btw.<br /><br />Meanwhile, a few basic questions:<br /><br />You distinguish Hubble flow from dark energy. I assume it is theoretical.<br /><br />What is it exactly (or approximately)?<br /><br />Why would the effect be difficult to measure for a planet in closed orbit while measurable for the Pioneers?<br /><br />Does a mathematical comparison between the distances of closer galaxies which are not receeding from us, including the river of galaxies heading for the Great Attractor, and the greater distances where expansion predominates - is there a correlation between this ratio and the Pioneer effect?<br /><br />Yes, I see the similarity between the gravity well distinction of effect and my crude illustration - thought.<br />And yes, I have a slow dial-up (sometimes very slow) plus a virus infected computer.

 

[newtonian]

borman - I like the model I just learned concerning gravity being caused not just by mass but also by pressure.<br /><br />This is one of many models discussed simply and concisely in "Science News," 5/22/04, pp. 230-232.<br /><br />[notably the box on page331 by Ron Cowen; not to be confused with models that have dark energy varying with time or those models which have gravity leaking into other dimensions {e.g. by Gia Dvali of New York University} or that the energy-mass of dark energy and neutrinos are on the same level for a reason other than coincidence - all discussed in said article]<br /><br />However, the article does not mention the Pioneer effect.<br /><br />That's the problem with becoming too specialized when doing research.<br /><br />The point where I see a possible connection is that this model indicates that gravity has a component which varies depending on pressure, and this component is positive with positive pressure, and negative with negative pressure.<br /><br />The article considered this as an explanation for acceleration of expansion in the more distant environment where negative pressure would predominate.<br /><br />Correct me if I am wrong, but this sounds like a possible explanation for the Pioneer effect locally. <br /><br />The drawback (pun intended):<br /><br />This should also effect gravitationally bound objects like the planets- I have noted your point that this may simply not have been measured yet for those bodies.

 

[vogon13]

I do like to see an exhaustive search for explaing the effect before resorting to 'new physics'.<br />Have often wondered if the Long duration Exposure Facility results have ever been crossed referenced to the materials Pioneer was made from? Granted the sunlight is weak where they were at when last heard from, but considering the radiation dosages they were exposed to, I can't help but wonder about continued outgasing of the plastics/composites used on Pioneers, perhaps catalyzed by the the Jupiter radiation flux or perhaps the mechanical effects of the particle flux have damaged the materials to a greater depth, again resulting in more outgasing than the models predict. Due to rotation of radiation belts, and high velocity of Pioneer probes, is the radiation damage more pronounced on the 'leading' or 'trailing' surfaces of Pioneer, and does the unexpected acceleration vector correlate to this? <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[telfrow]

Just found this regarding the "Pioneer Effect":<br /><br />http://www.newscientist.com/article.ns?id=mg18624984.700 <div class="Discussion_UserSignature"> <strong><font color="#3366ff">Made weak by time and fate, but strong in will to strive, to seek, to find and not to yeild.</font> - <font color="#3366ff"><em>Tennyson</em></font></strong> </div>

 

[vogon13]

Any chance of hydrazine 'frost' on anti-sunward side of Pioneers? What percentage of thruster plume would return to craft due to scattering, static, subsequent manuveurs into path of prior firing?<br /><br />Suspect amount is tiny squared, but then the anomalous force is pretty teeny too. <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[flynn]

<b>Lost asteroid clue to Pioneer puzzle</b><br /><i>10 May 2005 <br />Special Report from New Scientist Print Edition <br />Stuart Clark </i><br /><br /><br />FAR-FLUNG asteroids could help reveal the nature of the mysterious force that has nudged NASA's 33-year-old Pioneer 10 spacecraft about 400,000 kilometres off course.<br /><br />The so-called Pioneer anomaly could be accounted for by a force pulling the probe towards the sun with a strength of just one ten-billionth of the gravity at Earth's surface. But no one has managed to explain the nature of this force, and many suspect that it is just a systematic error in the data or a fault of the spacecraft design. Others have suggested sending another spacecraft to study the effect, at a cost of hundreds of millions of dollars.<br /><br />But there might be a cheaper way to find an explanation. Gary Page of George Mason University in Fairfax, Virginia, and his colleagues have identified 15 asteroids that might also be subjected to the mysterious force. The asteroids' orbits all stretch far into the outer solar system. This is crucial because the Pioneer anomaly only shows up beyond about twice the distance from the sun to Saturn.<br /><br />Of the 15 candidates, the best is 1995SN55. This 370-kilometre-wide space rock has spent the past 54 years in the anomaly zone, so it should have experienced the largest perturbation. And tantalisingly, it is not where predictions say it should be. "It could be lost because of the Pioneer effect," says Page. "Asteroids are just big and dumb and go where gravity tells them."<br /><br />Michael Martin Nieto of the Los Alamos National Laboratory in New Mexico thinks the asteroid study is a great idea, but cautions that it is unlikely to reveal the whole truth. "It will only test whether gravity is the cause," he says. "The anomaly could also be caused by a subtle effect in inertia or even time." So a spacecraft mission may still be needed.<br /><br />Page and his colleagues are applying for telesco <div class="Discussion_UserSignature"> <font color="#800080">"All God does is watch us and kill us when we get boring. We must never, ever be boring" - <strong>Chuck Palahniuk</strong>.</font> </div>

 

[bonzelite]

ya'll need to shave with a razor. <br /><br /><br />

 

[bonzelite]

this may be an outlandish idea, yet simple: what if solar radiation literally bounces off the heliopause region and turns back into the sun? you have enough of this stuff piling up like a wound spring at the boundary and it can spring back for eons, perpetually and wth cumulative force. <br /><br />the heliopause, as well, is believed to vary in size, growing like a bubble then shrinking, as if to breathe in and out. perhaps the heliosphere is contracting and this sends tremendous shock waves propagating back inward to the solar system. in this idiom, Pioneer 10 and 11 are swimming upstream, so to speak, of the current. and they're meeting resistance and slowing down. <br /><br />as for me, i am forever skeptical and nearly a non-believer in any convoluted scenario that involves contrived proof of evidence for dark energy or dark matter being responsible for anything.

 

[vogon13]

Hubble Space Telescope sees objects down to magnitude 30 (IIRC), as in the Hubble deep field pictures.<br /><br />Any significant 'heliopause photon rebound' would fog these pictures if strong enough to effect Pioneer trajectory.<br /><br /><br /><br /><br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[bonzelite]

that is an interesting educated guess. we could only speculate if that would actually happen. <br /><br />how about then the idea is somewhat the same, but it is low energy charged particles comprised of neutral cosmic rays entering the solar system and thus heliosphere (as they do anyway already): the solar wind impinges upon the extrasolar cosmic rays coming in, charges them, throws them at the termination shock. they hit the heliopause boundary and are kicked back in towards the sun. <br /><br />this process is believed to have been happening for eons, as the Voyagers' low energy charged particle instruments have detected such occurences at the magnetospheres of the outer planets. and is evident to be happening generally within the heliosphere of the sun.

 

[vogon13]

-----------------------------<br />...neutral cosmic rays...<br />-----------------------------<br /><br /><br />Sorry, no such thing.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[bonzelite]

then remove the neutral part and consider it.

 

[vogon13]

How will an already charged cosmic ray charge?<br /><br />Likes repel.<br /><br /> <div class="Discussion_UserSignature"> <p><font color="#ff0000"><strong>TPTB went to Dallas and all I got was Plucked !!</strong></font></p><p><font color="#339966"><strong>So many people, so few recipes !!</strong></font></p><p><font color="#0000ff"><strong>Let's clean up this stinkhole !!</strong></font> </p> </div>

 

[bonzelite]

tis true. <br /><br />then i'd go back with the contracting heliopause then. as it contracts, it takes all contents of the heliosphere with it. and the closer the matter or objects are to the edge of the heliosphere, the more exaggerated is their movement back towards the sun. <br /><br />if the heliosphere could be somehow confirmed to be actually in a contraction phase by some other means than to say that Pioneer 10 is the evidence (which it may not be), then it would maybe support the idea. <br /><br />it's the simplest idea i can come up with that is not a whacko fringe idea. the heliosphere is simply "breathing" in and out. and it's inhaling at this point, sucking things back in to the center.

 

[CalliArcale]

There's actually some evidence that may support that, although I don't understand it well enough to say for sure. You've heard, I'm sure, that there has been some controversy over whether or not Voyager 1 has actually passed the heliopause? This is because its instruments saw the expected data not once but several times. (Well, at least twice. I don't actually know how many times.) There are several possible explanations for this. The two leading ones are:<br /><br />* the heliopause is complex and has several layers to be traversed<br /><br />* the heliopause is moving in and out, and so the boundary itself passed across Voyager 1<br /><br />Both are appealing in my mind. The latter certainly is consistent with the fact that other similar structures (such as the Earth's magnetosphere) tend to be very dynamic. This may also have something to do with the interstellar "wind" acting upon the heliopause, just as the solar wind acts upon the Earth's magnetosphere, but on a different scale.<br /><br />Again, I don't understand all the science behind this very well, so take this all as the ramblings of a fascinated layperson. <img src="/images/icons/wink.gif" /> <div class="Discussion_UserSignature"> <p> </p><p><font color="#666699"><em>"People assume that time is a strict progression of cause to effect, but actually from a non-linear, non-subjective viewpoint it's more like a big ball of wibbly wobbly . . . timey wimey . . . stuff."</em>  -- The Tenth Doctor, "Blink"</font></p> </div>

 

[nojocujo]

I think it is in front of your face. <br />The pioneer anomaly is: <br />"The space within galaxies does not appear to be expanding like the space between them". <br />To quote Borman. <br />If we were to reverse inflation we would have deflation and how exactly would it work?<br />Would it or could it be associated with galaxies and black holes? Could empty spacetime or relatively empty be stretched and/or consumed by (matter occupied spacetime) below the schwartzchild radius FTL and above at a rate exceeding that which is predicted due to its' elasticity? Would this effect account for dark energy (illusion), the pioneer effect and the cosmological redshift as well as inflation with no new energy inputs?

 

[bonzelite]

that's cool, calli, that my simpleton layman idea is possibly already discussed by professionals. whether it is correct or not is another story. but i like the idea. it's very simple and seemingly plausible. <br /><br /><font color="yellow"> If we were to reverse inflation we would have deflation and how exactly would it work? <br />Would it or could it be associated with galaxies and black holes? Could empty spacetime or relatively empty be stretched and/or consumed by (matter occupied spacetime) below the schwartzchild radius FTL and above at a rate exceeding that which is predicted due to its' elasticity? Would this effect account for dark energy (illusion), the pioneer effect and the cosmological redshift as well as inflation with no new energy inputs?</font><br /><br />i'd lean to simple breathing excercises to achieve inner peace and balance: heliopause in out, heliopause out. <img src="/images/icons/smile.gif" /><br /><br />

 

[nojocujo]

I wasn't speaking of the heliopause! I think it has to do with the schwartzchild radius and its' use in GR.

 

[bonzelite]

then i must have misunderstood you.

 

[bonzelite]

<font color="yellow">This may also have something to do with the interstellar "wind" acting upon the heliopause, just as the solar wind acts upon the Earth's magnetosphere, but on a different scale. </font><br /><br />you mean interstellar plasma. there is no wind.