Talk:Pioneer anomaly

New research

Should this be added to the page?
Exotic cause of 'Pioneer anomaly' in doubt
I'd do it, but I can't be bothered to absorb the entire page well enough to put this in the right place. :)
— Aristotle 11:48, 22 June 2007 (UTC)

This used to be on the page, though in a paper by Iorio rather than the paper referenced in the article (though they have exactly the same conclusion). I checked and it was removed by an anonymous editor 63.130.192.57 on 25 May, while also removing some more dubious stuff. I've re-added it to the possibility of gravitational causes. LouScheffer 15:33, 22 June 2007 (UTC)

Deceleration of Pioneer 10

This page has been traduce in french and I noticed this mistake. Pioneer 10 is actually decelerating.

Bah, deceleration is a subset of acceleration, and the latter has more meaning in a relative universe. *grumblemutter* :) Thanks for your interest. -- JTN 11:34, 2004 Nov 29 (UTC)

A second mistake is the way to stabilise the spacecrafts. Only Pioneers are spin-stabilised. Voyagers or Ulysse are stabilised by using a gyroscope and an embarked propulsion system. That is the reason why the speedness is more precisely known on Pioneers. I let you modificate this and sorry for my english. A friend from France known as JohnD. -- 62.147.99.73 13:07, 2004 Nov 27

I think this English version of the page is correct in that regard (referring to Voyagers etc as three-axis-stabilised)? -- JTN 11:34, 2004 Nov 29 (UTC)

I forgot a third mistake. Given that the spacecrafts are decelerating, dark matter cannot explane this, it is dark energy. -- 62.147.99.73 13:15, 2004 Nov 27

I don't understand this -- why is dark energy, as opposed to dark matter, necessary to explain an apparent Sunwards force? Anyway, I'm just reporting what has been considered by others (e.g., in the second cited paper -- which incidentally argues against a dark matter explanation). Have you seen discussion of a dark energy hypothesis? I'd be interested. -- JTN 11:34, 2004 Nov 29 (UTC)

You were true. I had confirmation (http://www.obs-nice.fr/Mignard/Grex/Presentations_pdf/Grex04_S_Turyshev.pdf) that one of the theory to explane Pioneer anomaly is dark matter, unless it is thought at the moment to explane only galaxies dynamics. | JohnD

New Horizons

According to Alan Stern, prime investigator of New Horizons space probe (former Pluto-Kuiper Express), this probe will be spin-stabilized during cruise and thus his radio team is hoping to look for the Pioneer Anomaly in their data. -- Mandevil 09:15, 24 Feb 2005 (UTC)

Interesting. Do you have a reference for this? I couldn't find any coverage.

Dr. Stern's info is in this thread in New Horizons forum on MER forum; it is a reply to my direct question about this matter.-- Mandevil 16:37, 8 Mar 2005 (UTC)

That's brilliant, thanks. I've mentioned it. -- JTN 21:10, 2005 Mar 8 (UTC)

The last reference in Pioneer anomaly states:

In addition, many of the deep-space missions that are currently being planned either will not provide the needed navigational accuracy and trajectory stability of under 10⁻⁸ cm c⁻² (i.e. Pluto Express) [...]

but then it is drumming up support for a dedicated mission, and also they refer to "Pluto Express" which seems a bit outdated.

-- JTN 13:00, 2005 Feb 24 (UTC)

' As far as i have heard, the radiation pressure from the rtg should mask the 'anomaly' for new horizons. nevertheless, people might try to use the REX instrument (which is basically a radio transmission expreriment as a "probe") and to compute precisely the thermal radiation pressure.

a recent reference for that : New Horizons and the Onset of the Pioneer Anomaly, Michael Martin Nieto http://arxiv.org/abs/0710.5135v1

OK, added this to the article. -- LouScheffer (talk) 21:16, 16 November 2007 (UTC)

Are all already known effects accounted for?

I just wonder have the scientists accounted for Sol gravitational well when estimating the drift? What i mean is that electromagnetic wave increase/decrease in frequency when escaping/incoming the gravity center

one more thing to be careful about is the speed of the pioneer - how big the relativistic effects are at that speed (time dilation) - have this effect been accounted for?

one more question - "The drift can be interpreted as due to a constant acceleration of (8.74 ± 1.33) × 10−10 m/s2 directed towards the Sun." could this be caused by the masses of all the planets and asteroids in the solar system (especialy the Jupiter) ?

Regarding your questions: yes, the gravitational Doppler effect has been accounted for in the calculations, and introduces a negligible correction which cannot explain the anomaly. This is a standard procedure in telemetry and Doppler analysis of any spacecraft.

Also, the crafts are travelling at a speed that is many order of magnitudes lower than the speed of light, so that time dilation cannot account for the effect. Furthermore, since the effect reveals itself through the unexplained Doppler shift, the relevant relativistic correction is the aforementioned gravitational Doppler effect.

Finally: although the numbers don't match, it could be possible that, at a certain time and position throughtout its voyage, the probes were subject to a gravitational pull from Jupiter and other bodies that equals the anomaly. However, the key word here is "constant acceleration": all gravitational forces decrease with the inverse of the distance squared, so it appears impossible to describe a constant effect through it. And, of course, all known gravitational effects were previously accounted: NASA engineers do mean business (Anderson et. al.)!

A slightly more convoluted discussion involves the gravitational force due to objects in the Kuiper belt. It has been shown (Bertolami and Vieira) that only a exceedingly odd density profile for these objects could approximate the effect, and even so only within a narrow region of space.

Hope I was of some help.

Jorge

The source of the constant acceleration could simply be due to the earth's rotation. The uncertainty with which the latter is known corresponds practically exactly to the observed discrepancy (see my page http://www.physicsmyths.org.uk/pioneer.htm for more).

Thomas

Thomas your page has one additional piece of information, that the beam of the antenna is not wide enough to deduce anything but a earth directed acceleration, if that is true the story is possibly a hoax , as it tends to digress to sun-pointing accelleration instead. Anyway i can imagine gravitational drags or magnetic shifts of some influence, I would also not be surprised if it was the shadow of the antenna. perhaps the relevance of the earth magnetic field naturally gets more pronounced on certain trajectorys but i would think that had very limited windows.(1g per au is suggestive) I don't know in how far metal molds correspond to the overall earth magnetic field(not to bad i think) and i can't imagine it would matter this much(the flyby effect seems the effect of earth magnetic (gravitational) variation but i dont know if that could induce that variety, i would think yes since the effect is small and the earth is big, perhaps eg. it matters if the part you fly over is warm).77.248.56.242 23:34, 13 June 2007 (UTC)

Dedicated Mission to Study the Pioneer Effect

Please, somebody, add a reference to this: (http://arxiv.org/abs/gr-qc/0506139)

John Baez 1 July 2005 03:16 (UTC)

no effect measured on Voyagers

"the effect is harder to accurately measure with three-axis stabilised craft such as the Voyagers." Is this really a problem with making a measurement from Voyager, or does it suggest that the anamaly is because of the construction of the spacecraft rather than an unknown force? Bubba73

It makes it much more complicated to calculate where the spacecraft should be. Since it is stabilised along three axes it's essentially spinning all over itself through space. If astronomers wanted Voyager to take a picture of a planet, they have to use a thruster to position it correctly. Since one doesn't know exactly where in a spin the Voyager craft is when it uses the thruster, one doesn't know exactly in what directly it will respond. One might have a good idea, but it will increase the uncertainty of Voyager's theoretical position. This uncertainty is so high that the acceleration from the Pioneer probes would easily be masked. Splat 06:26, 11 July 2005 (UTC)

OK, thank you! Bubba73 15:01, July 11, 2005 (UTC)

unfortunately...

this article has just been featured on /., so prepare for vandals & trolls invasion... --Vla d 16:22, 25 July 2005 (UTC)

2003 EL61

The newly discovered Kuiper Belt planet 2003 EL61 has been listed as a possible cause of the Pioneer Anomaly. However, since 2003 EL61 is only a single object and can effectively be treated as a point in celestial mechanics it could only decelerate one probe. Because both probes are decelerating at approximately the same rate and are travelling in perpendicular directions, a single point such as 2003 EL61 can be ruled out as a possible source. Additionally, as 2003 EL61 is a Kuiper Belt object, it would be included under "Unknown gravitational forces from the Kuiper Belt and Oort Cloud." Splat 06:01, 30 July 2005 (UTC)

Another Possibilty

Has anyone considered the acelleration of the universe?

• It is possible and has been considered. One of the remarkable properties of the acceleration is that its magnitude is very close to cH (the speed of light times Hubble's Constant). However, while it has been noted as a possibility, no sound mechanism for the acceleration of the universe resulting in a deceleration of the probe has been proposed. Splat 22:27, 6 October 2005 (UTC)

Pioneers Anomaly 2 - another alternative idea

FYI, for illustration only, since new article on "Pioneers Anomaly" is scheduled for delete, as of December 2005, as such a page already exists:

ANOMALOUS ACCELERATION OF PIONEERS 10 AND 11 may be modeled on a gravitational delta effect, per the Equivalence Principle

By I. D. Alexander December 16, 2005

The Pioneers Anomaly (1), as measured by John D. Anderson, M.M. Nieto, S.G. Turyshev, P.A. Laing, et al, shows a constant rate of acceleration towards the Sun at $-a=~8E-8cm/s^{2}$. This can be interpreted, conversely, as a gravitational delta effect, where Newton's G constant is not so, but grows at the same steady rate as the anomalous acceleration towards the Sun. The rate of growth of delta G of ~1G per 1AU (here shown 'hypothetically as if') translates into the anomalous rate of acceleration of a (hypothetical) delta $-(G/AU)=6.4E-11m^{2}/kg.s^{2}$, as a function of a variable 'phantom' Newton's G for our solar system.

The falsifiable test of Newton's G in the outer solar system has been proposed by the group working with the European Space Agency (3). At present, assuming a universal constant Newton's G, all calculations for distant mass and density of astronomical bodies had been determined using this constant. If there should be a 'phantom' G phenomenon at work in space, away from Earth's known 1G, it may not have been detectable until the Pioneers revealed their anomalous acceleration. This anomalous acceleration is made more poignant in that both probes, Pioneer 10 and 11, are moving out of the solar system in opposite directions, both showing the same constant rate acceleration. Both probes are being pulled back towards the Sun by the same rate. Though this measured rate at present remains unexplained with know physics, it is compelling enough to be researched further. Another anecdotal evidence (possibly supported by the constant delta G growth rate for our solar system), is the atmosphere of Saturn's largest moon, Titan. Titan's atmosphere, according to Nature (2), is ten times the 'thickness' of Earth's atmosphere. Both are largely nitrogen in composition, though residing on bodies of vastly disproportionate mass and temperature. It may be a function of the gravitational 'constant' G being greater at Saturn's orbital region than on Earth. The fact that the Cassini-Huygens mission to Saturn, and successful landing the Huygens probe on Titan, shows that whether G is a constant, as now believed, or a variable, as may be evidenced by Pioneers, is not relevant to our space missions. However, it may prove relevant to understanding planetary atmospheric density, as evidenced by Titan's atmosphere, for example. All this, however, is a subject for future study.

Translating Pioneers's Anomalous acceleration into a constantly growing G with distance from the Sun, it could be illustrated (hypothetically) as follows:

delta G'/G = 1, where G' represents 1G per 1AU, at a constant rate.

delta G'/G = 1 divided by 1AU in meters (1.5E+11 m) = delta 0.6667E-11 (per $m/s^{2}$ for acceleration)

which translate in centimeters to: delta $-a=~66.67E-15cm/s^{2}$

Where did the $cm/s^{2}$ come from? It's not at all clear how you are implementing your variable G idea, but regardless the number you arrived at is certainly not an acceleration. You can prove this to yourself by forgetting the actual numbers and simply working through your equation with just the units. You will find that the units you end up with are not $m/s^{2}$. --Fringec 00:22, 24 January 2006 (UTC)

9 February, 2006:

Thanks Fringec, for pointing out the inconsistency in the $cm/s^{2}$, in my above. In taking (delta)G'/G, which per reason G' increases 1G per 1AU, I used (delta)G'/G = 1, which still retains SI units $m^{3}kg^{-}1s^{-}2$ for Newton's G. To make the unit analysis work, it would have to imply that the (delta)G'/G relationship per AU invokes somehow that $m^{3}kg^{-}1s^{-}2$ be multiplied by $kg.s^{-}2$ (though I have no way to explain this) to make the units work out: $m^{3}kg/kg.s^{-}4$. When this is divided by AU, which is in "m", then the result is $m^{2}s^{-}4$, which taking square root is our familiar acceleration unit: $m/s^{2}$. That said, I have no way to justify why Newton's G (hypothetically) growing at the rate of 1G per 1AU should invoke the needed $kg.s^{-}2$ units. --Ivan Alexander, 9 Feb. 2006.

---

Of course you can't justify the needed units. The method you are using to determine what you are trying to determine doesn't make any sense! The fact that the units don't balance should be a sanity check that is telling you that you are doing something wrong.

You're trying to compute the difference in acceleration predicted by standard Newtonian physics and some variable G concept. Clearly the way to do this is to first calculate the acceleration predicted by Newtonian physics. Naturally this is done all the time so you can do it too. Next you would perform the same calculation factoring in this variable gravitational constant. This will be more interesting to hash out, but perhaps you could look to existing variable G theories to see how they do it.

The difference between the two results is the value you are looking for.

The point is that there is a mathematically sound way to do what you're trying to do. Granted, it would require a lot of research and work to perform these calculations with any kind of accuracy, but you ought to be able to get in the ballpark just modelling a simple Sun-Pioneer system, with Pioneer travelling straight out of the solar system. In any case, what you've done here is just not correct.--Fringec 22:35, 21 February 2006 (UTC)

---

Admittedly, Fringec, it does appear peculiar to apply kg/s^2 to Newton's G, as I did here, even to me. But upon further reflection, it may not be that odd. If "per second per second" is rate of change, then m/s^2 means rate of acceleration "in terms of distance"; likewise, kg/s^2 would mean rate of acceleration "in terms of mass". This could be applicable to the Pioneer Anomaly if the two are contingent upon a commensurate increase in the "inertial mass" per the Equivalence Principle, if G is "accelerating" in terms of kilograms with distance from the Sun: the end result is a commensurate "acceleration" in terms of distance (towards the Sun), if this is true. For this reason, ESA's search for gravitational anomalies in the outer solar system, which may reveal a G anomaly, may be more important than we suspect. And if it is found that G is variable in a continuous way, i.e., ~1G per 1AU, then there may be a match between rate of change of inertial mass and rate of change of distance traveled. However, this would then call for a new physics, if so.-- Ivan Alexander, 23 February 2006.

---

I think we need to back up a little bit. Acceleration is defined as "the rate of change of velocity of an object with respect to time". Velocity is "the rate and direction of motion". It is from these definitions that the units are derived. Units are not just chosen arbitrarily. Nothing you've written above changes the fact that you are ultimately trying to calculate an acceleration which is measured in m/s², but the result of your method is not acceleration. Put another way, you're just performing various mathematical operations and then changing the units to whatever you like when you're done.

There's nothing magical about what you are trying to do. You're just trying to determine the difference between two accelerations. This is very straightforward.

Any model of gravity needs to be able to calculate the rate of acceleration of an object due to the effects of gravity on that object. The trick in this case is figuring out how to calculate the acceleration on Pioneer under a variable G model. If you're determined to model the Pioneer Anomaly as the result of a variable gravitational constant this is where you need to start. Once this is accomplished you need only calculate the acceleration predicted by Newtonian physics and compare it to the acceleration predicted by the variable G model. The difference between these two results will have the correct units, and is the value you are looking for.

If none of this is getting through, consider this: How was the value you are trying to duplicate, (8.74 ± 1.33) × 10⁻¹⁰ m/s², arrived at in the first place? It was calculated by subtracting the observed acceleration of Pioneer from the acceleration predicted by Newtonian physics. If this variable G model is correct, you should arrive at the same number, using the same method, merely by replacing the observed acceleration with the acceleration predicted by the variable G model.

So why not approach the problem correctly and try to calculate the acceleration on Pioneer using the variable G model? --Fringec 19:18, 24 February 2006 (UTC)

---

Per Equivalence, where change in G is reflected in comparably-equivalent inertial mass, taking the square root of this delta -a, it becomes:

$-a=~8.165E-7.5cm/s^{2}$

This is largely irrelevant because of your first mistake, but you should be aware that when taking the square root you need to consider the units as well. The square root of $cm/s^{2}$ is not $cm/s^{2},$. Additionally, it's unclear why you decided to take the square root of your previous result in the first place, but that's another story.

Also note that the square root of $6.67E-14$ is $2.58E-7$, so the magnitude of your result is incorrect as well as the units.--Fringec 00:22, 24 January 2006 (UTC)

My mistake. Looking at it again, $8.165E-7.5$ equals $2.58E-7$, so the square root is in fact correct, it's just an odd way of expressing it. Of course, the magnitude still doesn't match the anomalous acceleration and, more importantly, the comments about the units being incorrect still stand.--Fringec 19:30, 30 January 2006 (UTC)

This is a result within one half order of magnitude of the measured Pioneers Anomaly, $-a=~8E-8cm/s^{2}$

One should remain very much aware that such a constant rate of change for Newton's G in the outer solar system had never been demonstrated, and other explanations for the Pioneers Anomaly, searching for systemic reasons, have not as yet yielded verifiable results. Therefore, neither should this hypothetical 'phantom G' explanation be taken as a definitive reason for the Anomaly. It is shown here merely as a representation of how this anomalous acceleration may be numerically explained using a constant rate of change for Newton's G, where this 'phantom' G grows at a comparable rate of 1G per 1AU - shown here for illustration purposes only.

As pointed out, the value you have calculated is not an acceleration. Units are critically important. You have a lot more work to do to model the Pioneer Anomaly using a varying gravitational constant..--Fringec 00:22, 24 January 2006 (UTC)

References:

(1)"Study of the anomalous acceleration of Pioneer 10 and 11" by Anderson et al. http://arxiv.org/abs/gr-qc/0104064

(2) Fig. 1: Comparisons between atmospheres of Titan and Earth. http://www.nature.com/nature/journal/v438/n7069/fig_tab/438756a_F1.html

(3) "The Pioneer Anomaly: The Data, its Meaning, and a Future Test", by Nieto, Turyshev, and Anderson http://arxiv.org/pdf/gr-qc/0411077v2

(This alternate idea cannot be included in Wiki, so list it here merely as a curiosity on the Discussion page. Any comments welcome.)

Original research

This WP talk page is not really the right place to have a conversation on the type of original research being conducted above. Please find another forum for having this conversation. linas 17:31, 26 February 2006 (UTC)

The Planetary Society Project

The Planetary Society is currently (2006) sponsoring a project to analyze thirty years of Pioneer data in an attempt to shed light on the anomaly.

Joe Macke 16Jan2006

ERRATUM?

RE text in the Pioneer Anomaly text, it says: "The effect is seen in radio Doppler and ranging data, yielding information on the velocity and distance of the spacecraft. When all known forces acting on the spacecraft are taken into consideration, a very small but unexplained force remains. It causes a constant sunwards acceleration of The effect is seen in radio Doppler and ranging data, yielding information on the velocity and distance of the spacecraft. When all known forces acting on the spacecraft are taken into consideration, a very small but unexplained force remains. It causes a constant sunwards acceleration of (8.74 ± 1.33) × 10−10 m/s2 for both spacecraftfor both spacecraft."

Just a note, but shouldn't $-a=8.74x10-8cm/s2$ read as $-a=8.74x10-6m/s2$ when converted from centimeters to meters? The text in the article on Pioneer Anomaly reads as "It causes a constant sunwards acceleration of (8.74 ± 1.33) × 10−10 m/s2 for both spacecraft," which looks wrong. After all, if the acceleration is taken over a greater distance, shouldn't it be greater? The way the article now reads, it appears the conversion from centimeters to meters makes it smaller.

Ivan D. Alexander

Hi, -- the short answer is "no", that is not how one converts units. An acceleration of 1 m/sec^2 is equal to an accelearation of 100 cm/sec^2. linas 01:02, 18 January 2006 (UTC)

---

Hi linas, sorry for my very slow response, as my neurons fire as fast as those of a jellyfish, at times.

I could plainly see how velocity in meters is smaller, per second, than centimeters. The source of my confusion was that acceleration, as a rate of change per second per second, was larger over the distance of a meter than a centimeter, and still larger over the distance of a kilometer, which is why I had it reversed from the obvious answer. This ends my end of this discussion, Thanks. Ivan Alexander, 15 April, 2006

Coronal mass ejection

In a paper accepted for publication in Astronomy & Astrophysics by Øystein Olsen, he shows that the anomaly is consistent with the delay the *radio signals* experience working through the ejected plasma on their way back to Earth. That's how I understand his press release (in Norwegian), anyway. Kjetilho 01:03, 29 December 2006 (UTC)

No, he says that

The Doppler data itself can not be used to distinguish between a constant acceleration model and acceleration proportional to the remaining plutonium in the radioisotope thermoelectric generators. There are significant short term variations in the anomalous acceleration. These are shown to be consistent with radio plasma delay from coronal mass ejections.

He made no attempt to explain the anomaly, or otherwise accepted it as an RTG effect. The CMEs were correlated with the variations in the anomaly. When a wave is delayed/refracted by passing through something, it isn't shifted in the long term but rather "bounces back" when the obstacle is removed. Potatoswatter (talk) 13:15, 8 December 2008 (UTC)

Why it is called "anomaly"?

The Pioneer "anomaly" is the same as "cosmological redshift" and that latter is explained by Einsteinian physics. So why it is still called "anomaly"? It is only anomaly in Newtonian physics since it does not have any explanation there but it confirms Einstein's physics. It's theoretical value is $c^{2}/R$, where R is "Einstein's Radius", 4.3 Gpc. So its theoretical value according to Einstein's gravitation should be $7\times 10^{-10}m/s^{2}$. Am I doing something wrong here? Jim 20:01, 28 March 2007 (UTC)

The only Einstein radius I'm familiar with is the formula for calculating the size of a gravitationally lensed ring given mass M. What are you referring to?Maury 21:28, 18 April 2007 (UTC)

the anomaly is a blueshift. Potatoswatter (talk) 13:17, 8 December 2008 (UTC)

Possible explainations

The wrong sign? Please explain

"The pressure of sunlight is too small at this distance, and the wrong sign, as are the spacecraft's radio emissions"

You mean, "and is on the wrong side"?? --129.139.18.18 18:54, 9 April 2007 (UTC)

Not really, see the very first post above. The "sign" of the force created by the radio emissions, for instance, would be the wrong one, it would accelerate the craft ourward, not inward. Maury 21:18, 18 April 2007 (UTC)

Zoran Ozimec ?

I removed today (April, 18, 2007) the likely self-promoting external link to [1], compilation of JPEG files of non-peer-reviewed scanned manuscripted work (see the historic to see when and how it had been added, November 2006). Nevertheless, I have no clue in physics, so it would be useful that anyone a bit more aware than I am have a look at his page and see if the link needs be added once more.

People have been doing Eotvos experiments with non-similar masses for a very long time now, pretty much right from the start, in order to test this concept. They've even done it with anti-matter because some supersymmety threories suggested antimatter would fall slower. In every peer-reviewed case I have heard of, the equivalence principle remained perfect to measurable capabilities. That page has a link to several such experiments, with modern ones that are to parts in the trillions. The P10 effect is parts per ten billion. These experiments directly contradict this guy's claim, over 30 years ago. Maury 21:16, 18 April 2007 (UTC)

The Many Directions of Time

Someone took issue with my addition of a link to Alexander Mayer's The Many Directions of Time, so I thought I'd expand on it a little here. First, I have absolutely no connection with Mayer other than having read his work. Yes, it is a self-published ebook. However, the transverse gravitational redshift theory is firmly grounded in general relativity and makes many empirically testable predictions. This is the hallmark of a good scientific hypothesis. If this was obvious quackery such as Time Cube removing it would be justified, but that's not the case here. Whether Mayer is right or wrong, removing a reference to a possible explanation because you don't like the web page is, in my opinion, a disservice to Wikipedia readers.

I took a look at this, and don't think it belongs in an encyclopedia article. As far as I can see it has at least 6 strikes against it. (1) On the very first page, it says "This book is going to change the course of scientific history. Many old ideas (and inflated reputations) will pass away." This is a VERY BAD SIGN. If your theory is really that good, you don't need to assert it, and the reputations will take care of themselves.(2) The document claims not only to solve the Pioneer anomaly, but reverse many other long-standing physics ideas. For example, all conventional redshift interpretations are wrong. "The 1929 [conventional] interpretation of cosmological redshift is certainly incorrect and therefore all the WMAP team's confident conclusions outlined below actually have no bearing on empirical reality". Also general relativity - "The common obsequious drivel about the "beauty" of Einstein's equations is ironic to say the least. In fact, his theory incorporated a momentous error that created an artificially convoluted monstrous tangle of tensor equations that do not accurately reflect physical reality", Einstein's equivalence principle is not correct, and so on. (3) Explaining away inconvenient experimental results: His theory predicts the atomic clocks in Paris will see the American clock go more slowly, *and* vice versa (the Americans will see that the French clocks are going slow. ). But this is not observed, so he claims that for political reasons (his italics) everyone ignores this and just sets their clocks to the global average to avoid controversy. (As a personal note, has he ever met any of these folks?? These are folks to whom an unexplained variation in the 16th decimal place is cause for panic. These are the *last* people in the world to simply ignore an error and calmly set their clock to a politically acceptable value.) (4) The document quotes great swaths of other publications, and goes to great pains to say why this is needed for an accurate discussion of other's ideas. But his document itself is locked against any selection of text. I had to type in the above quotes above.

And this is not just me - (5) It has never been published in any scientific literature I could find, including arXiv. And arXiv standards are pretty loose, at most you need one endorsement from some existing author. And this is plenty to get people to take your ideas seriously. Craig Markwardt's "Independent Confirmation of the Pioneer 10 Anomalous Acceleration" has never been published anywhere else, but has 26 cites. (6) It is never referred to anywhere I can find in any scientific literature (google scholar, arxiv, citeseer), either as "the many directions of time" or "traverse gravitational redshift".

So I think this should go. Any other votes??

I'll try to address each of your points.

1. Yes, Mayer has a habit of making bold and/or arrogant statements. This may be unfortunate, but it has little bearing on the science.
2. Yes, the theories are radical. So were relativity, quantum theory and the big bang. You seem to have one error here though - Mayer does not claim that the equivalence principle is wrong. In fact it's part of the basis of the TGR hypothesis and Mayer states "Einstein's Equivalence Principle is one of the most powerful ideas in the history of science and one of the simplest."
3. I do not understand your comments on the atomic clocks at all. Mayer makes the claim as you say, and then proceeds to produce data and graphs that support the claim - he's not explaining away anything. In one paragraph he mentions that this experiment should be fairly easy to do, given the falling cost of highly accurate clocks. I believe that he hopes that someone will do the experiment.
4. Yes, the PDF is digitally signed and protected against selection. I believe this is simply an attempt to maintain control over hardcopy publishing of the book, since he is selling the printed version.
5. I'm afraid I can't say much about Mayer's choice of publishing method.
6. This material is quite new - it didn't emerge in any form until late last year and the book is only a few months old. I don't find it surprising that it hasn't been cited anywhere.

In summary, I have no idea if Mayer is right. He may well be wrong. But I find his claims and supporting data compelling enough to warrant some investigation. Given the plethora of empirically testable predictions made in the book, some enterprising experimentalists ought to be able to discover whether or not Mayer is on to something - but for that to happen, they have to at least be aware of the theories, hence my motivation for making the information available. The list we are editing is called "Possible explanations", not "Ironclad explanations" and all of the new physics portion involves controversial modifications to current theories. I don't see why Mayer is any different in that regard. I'll say one thing - he seems to be doing a heck of a lot better than the superstring theorists at making testable predictions.

I think his theories fail some common sense tests. For example, we both agree that he thinks that the clocks in the USA and Paris should each perceive each other as running more slowly. Let's see what this implies.

• First set up fiber optic lines between the clocks. They will transmit ticks to each other, each at a rate determined by their own clock. They merely observe the other's clock, and do not control it. Pick the tick rate such that at most one tick is in transit between the clocks at any time, as seen by either clock.
• Now have the USA clock count the ticks until it has ticked 3 more times than Paris. This will eventually happen since the USA perceives the Paris clock to be slower. Call the USA clock count at this point N. At this time the Paris clock has ticked at most N-2 times, since at most 1 tick can be in transit. Now switch to the Paris clock, and consider when it has ticked N-2 times. At this time it has seen N-5 ticks from the American clock. (since it perceives the American clock as going slower, and the effect is symmetrical). So the American clock has emitted at most N-4 ticks, since only one can be in transit.
• So the theory predicts than when the USA clock has ticked N times, we can also show it has ticked at most N-4 times. This is a contradiction.

This is a very specific example of a much more general case. Two clocks, ticking at rate R, separated by a bounded time T, cannot each see the other ticking at rate uniformly lower than themselves. Eventually the difference will exceed T *in both directions*, and a contradiction is assured. You might as well seek two functions, each smaller than the other by a uniform multiplier. LouScheffer 05:34, 28 June 2007 (UTC)

The case you are talking about (two clocks each perceived as running more slowly than the other) is extremely common within Einsteinian special relativity - that's how relativistic time dilation works. If one observer is moving at high speed relative to another and each are transmitting clock data, they will perceive each other's clocks as being slower than theirs. Do you also assert that special relativity is wrong? I think the problem with your scenario is that you are making the assumption that there really is a consistent universal time axis that you can measure against, which is just not the case for Mayer's geometric time or for relativistic time dilation. It defies common sense, but each observer really will have different tick counts because the perceived frequencies of each clock is not the same. In fact, if you read Mayer's work you find that the whole concept of geometric time is rooted within special relativity, much as TGR is rooted in general relativity. Pheran 15:39, 28 June 2007 (UTC)

No, the reason these cases work in special relativity is that they only happen when there is relative motion, and the limit of the speed of light. The number of ticks in transit varies, and always adds/subtracts to the clock differences, at least so that all events that happen in the same place happen in the same order to all observers, independent of their frame of reference.

This is not true in the proposed theory. Take a satellite equally spaced between the US and Paris atomic clocks. It emits a flash of light and each group starts their clock when they see it. After 1 year (each as measured by their own clocks) each group emits a flash of light. Which does the satellite see first? The USA group will say the USA flash will be seen first, since they see the Paris clock as running slower. The Paris group will expect the Paris flash first. But only one of these two results is possible. Any theory that makes two different predictions of the order of events *at the same place* is inconsistent. (And if the result is a tie, then each group must conclude the other clock is running at the same rate.)

At some larger level, you don't need me to be a skeptic - there are plenty of skeptics. What you need are people (preferably people with a track record in physics) who believe in this theory, or at least that it *might* be right.

Finally, this theory is much larger than the Pioneer anomaly. Putting a reference here is like putting a reference to atomic energy on a page on night-lights. It's certainly true that atomic energy might make a longer lasting night-light, but that's not its main importance. Likewise, if the cosmological interpretation of redshift is wrong, or general relativity is wrong, that's a much bigger deal than explaining the Pioneer anomaly. If anywhere it should go on these pages.

update tag.

I put the update tag in the article as the June 2007 date has passed, have we concluded anything?

Also during a bit of research, I found a scheduled meeting for next year: [2] . Can we put this into the article somewherE? Capuchin 08:20, 19 July 2007 (UTC)

Update tag removed. The article isn't outdated, it simply might be lacking the latest speculation. Potatoswatter (talk) 12:50, 8 December 2008 (UTC)

1. Effect, 1.1 Possible explanations: effects in the gravitational field

Dear editors, the data provided below was added earlier into the article, in the related section, but then removed with the comment "ESA ref does not mention pioneer, second ref is another self-published TOE by a non-scientist". Well, although the ESA link, 2006, does not mention the pioneer anomaly it does demonstrate the possible deviations from Einstein-Newtonian law of gravitation that Kunst's paper already in 1999 refers as being measured in laboratory and at astronomical scale; the second ref as you may very well deduce, and as it is known by several "relativity" editors around, it is a 2002 paper from a scientist with a highly reputable background, yet a taboo among the academic physics community (ask yourselves why!):

« The research into the apparent deviations from the Einstein-Newtonian law of gravitation, both on laboratory and astronomical scale,(1) suggest that the phenomena (the Pioneer 10/11 gravitation anomaly) is due to the gravitational effects of the mass of the gravitational field, the mass of the field-vacuum (2); a similar conclusion was also reached by an elderly aether theorist, suggesting that the phenomena is due to an effect attributable to retarded energy deployment in the gravitational field.(3)

References

(1) ESA News, Towards a new test of general relativity, March 2006

(2) Kunst, Ernst Karl. Do Gravitational Fields Have Mass? (arXiv:physics/9911007v1 [physics.gen-ph])

(3) Aspden, Harold (MInstP). A New Insight into the Pioneer 10/11 Gravitation anomaly »

Obviously, from my past editing experiences here at Wikipedia there seems to be many individuals around not interested that the lay public becomes acquainted with these other perspectives within the scientific community. Friendly. —The preceding unsigned comment was added by 213.58.99.92 (talk • contribs) 23:17, 23 July 2007 (UTC).

Yes, choosing to interpret the removal "unsupported self-published" material as unfriendly is certainly easy. Unfortunately it doesn't change the fact that it's unsupported self-published material, which is clearly against wikipedia guidelines. You're perfectly free to make your own site and publish as you see fit, which is what I assume is what the site in question is. Further, the ESA report has nothing to do with the topic at hand, and we have only your word that it is in any way related. The only useful link was the arxiv one, and its link to the ESA is likewise unmentioned. There have been many other theories of gravity, scalar-tensor for instance, but their existence, by itself, is meaningless. Maury 00:39, 24 July 2007 (UTC)

Pruning external links

In line with WP:BOLD, I am removing a pile of external links that I think are better not in the article. If someone, after double checking relevant wikipedia guidelines, feels that some of these should be restored, do please feel free to revert individual links as you see fit. If this occurs, I will not revert back. I may tag the link, and engage discussion here.

Here are links I have removed.

• A New Insight into the Pioneer 10/11 Gravitation anomaly, an effect attributable to retarded energy deployment in the gravitational field (August, 2002) I have removed this one because it appears to be a private web site of dubious credibility.

Re: No current PhD, or any other scholastic grade, is able to offer you even the shadow of the knowledge that this elderly author (see the backgound) has uncovered in a whole life devoted to pursuit Truth, not the instituted dogma nor its proud and vain honorific titles and prizes. And you label it as "dubious credibility"!? You should at least consider to do what the rest of the his peers appear to have been doing already for a while: to be silent and learn (read a book) about how the future paradigm of Science, not the current materialist-reducionist science, will look like. Hope it helps; A layman.

• (preprint) Self-creation cosmology predicts the Pioneer anomaly as a time drift between ephemeris and atomic clocks. This preprint is not actually published; and uploading to arxiv should be treated with special caution. I think this should be omitted, as self-published.
• C-news (in Russian) Foreign language sources are only necessay if exceptionally significant. This one isn't.
• Newfound Data Could Solve NASA's Great Gravity Mystery Removed as broken link.
• Article contemplating explanations for the Pioneer Anomaly Private website of very dubious reliabilty.

These are the links that remain.

• "Pioneering Gas Leak? The strange motions of two space probes have mundane explanations--probably" Scientific American (December 1998)
• "A Force to Reckon With: What applied the brakes on Pioneer 10 and 11?" Scientific American (October 2005)
• "Gravity theory dispenses with dark matter" - STVG (Scalar-tensor-vector gravity) theory claims to predict Pioneer anomaly
• Planetary Society data recovery effort enables study
• Pioneer anomaly on arxiv.org The .ru site which has annoying "pop-up" ads
• Space.com: The Problem with Gravity: New Mission Would Probe Strange Puzzle

—Duae Quartunciae (talk · cont) 22:17, 29 July 2007 (UTC)

Consider this (a non-broken version of the Yahoo link) for re-inclusion, although I think much of it is already covered. Maury 21:31, 30 July 2007 (UTC)

Is this really significant?

Maybe I did the math wrong, but a force of (8.74 ± 1.33) × 10^−10 m/s2 across 35 years (1.10449241 × 10^9 seconds) works out to just a few meters. We don't even know the exact location of GPS satellites orbiting Earth within a few meters. So I would imagine that it's well within the range of measuring error for the Pioneer spacecraft. —Preceding unsigned comment added by 69.244.30.43 (talk) 18:37, 14 October 2007 (UTC)

Sorry, but your math *is* wrong. The change in *speed* = a*t is about 1 m/sec, relatively easy to measure with doppler shift, which is orders of magnitude more sensitive. The change in distance is quite big: s = 1/2 a t^2. Assuming for simplicity 10^-9 m/s^2 and t=10^9, the distance differs by 5x10^8 meters, or about 500,000 km. So the measurement is quite secure. —Preceding unsigned comment added by LouScheffer (talk • contribs) 18:50, 14 October 2007 (UTC)

New Paper from 2-28-08 - American Institute of Physics

http://www.aip.org/pnu/2008/split/857-2.html

A new look at the trajectories for various spacecraft as they fly past the Earth finds in each case a tiny amount of surplus velocity. For craft that pursue a path mostly symmetrical with respect to the equator, the effect is minimal. For craft that pursue a more unsymmetrical path, the effect is larger. In the case of the NEAR asteroid rendevous craft (<http://near.jhuapl.edu/>), for instance, the velocity anomaly amounts to 13 mm/sec. Although this is only one-millionth of the total velocity, the precision of the velocity measurements, carried out by looking at the Doppler shift in radio waves bounced off the craft, is 0.1 mm/sec, and this suggests that the anomaly represents a real effect, one needing an explanation.

Some ten years ago another anomaly was identified for the Pioneer 10 spacecraft (see http://www.aip.org/pnu/1998/split/pnu391-1.htm) and a certain amount of controversy has clung to the subject since then. One of the researchers on that earlier measurement is part of the new study, conducted by Jet Propulsion Lab scientists. John D. Anderson (jdandy@earthlink.net, 626-449-0102) says that the JPL scientists are now working with German colleagues to search for possible velocity anomalies in the recent flyby of the Rosetta spacecraft. (Anderson et al., Physical Review Letters, upcoming article; designated as an editor’s suggested articlePhysical Review Letters)

sunward acceleration?

Er, please forgive me for not being a scientist, but the article doesn't explain what is meant by a "constant sunward acceleration". Since the Pioneers are, I assume, traveling away from the sun, then how can they be accelerating towards it? Maybe something could be added to the article to clear this up? 70.20.149.174 (talk) 02:57, 3 March 2008 (UTC)

They are moving away from the Sun, but at slower and slower speeds due to the Sun's gravity. The anomoly is that they are being slowed slightly more than they should, as if there is a small additional force/acceleration towards the Sun. Someone could explain that more concisely in the article. Bubba73 (talk), 03:10, 3 March 2008 (UTC)

I admit that when I first heard "Pioneer accelerating towards the sun", the first thing I imagined is what you'd think when you read that. It took me a minute to realize it was a relative acceleration, and I only took that minute to think about it because I know which direction Pioneer is actually travelling. Its important that Wikipedia not be written for people who already know this information, or its use degrades to nil. It must be an encyclopedia and although detailed scientific explanation is appreciated within the body of the article, the topic statement must be clearly defined and understandable, even for someone who knows very little about the subject. Just my opinion. 207.154.101.37 (talk) 07:10, 5 March 2008 (UTC)

OK, I changed the initial paragraph to make this more clear (I hope). LouScheffer (talk) 18:20, 5 March 2008 (UTC)

Don't all orbital satellites spend their time about split between moving toward and away from the sun? JD Lambert^(T|C) 16:06, 6 March 2008 (UTC)

Not all. Once they reach escape velocity, as these have, they just keep going out. The sun's gravity slows them down, but will never add up to enough to make them reverse directions. LouScheffer (talk) 17:25, 6 March 2008 (UTC)

Coverage in The Economist

None other than The Economist covered a part of this topic recently : [3]. Perhaps it should be added in the refs or such. --Childhood's End (talk) 21:23, 7 March 2008 (UTC)

Weyl geometry explanation has been corrected

The author of the Weyl geometry based explanation has posted on arxiv a correction of his previous explanation, stating that it cannot hold, see http://arxiv.org/abs/astro-ph/0701132

The solar system is a binary system

Could are solar system being a two star binary system explain the pioneer effect? i.e. the nemesis hypothesis put forth by doctor Richard A. Muller and others?--Nbritton (talk) 11:08, 14 April 2008 (UTC)

That would not explain why the effect is seemingly similar on both crafts. Plus, it's kind of unrealistic to presume that an entire sun has been overlooked in the local vicinity. Jefffire (talk) 12:54, 14 April 2008 (UTC)

Unless you would consider the 'local vicinity' our entire galaxy the star wouldn't be. It is possible we can't see it... read nemesis hypothesis for more. - Anon —Preceding unsigned comment added by 74.237.55.196 (talk) 13:13, 15 April 2008 (UTC)

That's even more silly. If it's having an effect on the craft it would need to be near given that gravity weakens at an inverse square. Jefffire (talk) 14:36, 15 April 2008 (UTC)

Jiffire - The nemesis wiki says we might not see a brown dwarf and if it exists it will be easily found in "the upcoming WISE mission (scheduled for June 2009)". interesting idea

Anon - at least read an article before you refer to it :P Way too human (talk) —Preceding comment was added at 21:30, 17 April 2008 (UTC)

This isn't a general debate on the nemesis hypothesis. A user asked if it was a plausible explanation for the pioneer anomaly. Jefffire (talk) 21:40, 17 April 2008 (UTC)

"Plus, it's kind of unrealistic to presume that an entire sun has been overlooked in the local vicinity." looks like i'm not the only one who needs to remember that. now i'm just bitter, forgive me, enough's been wasted here. Way too human (talk)

On the idea of a binary star system.

1) It has been discovered that approximately half the the observable stars in the sky are binary star systems so it's not such a far out idea that our own sun is in a binary star system. It is at least plausible.

2) It has been observed that the sun is missing a significant amount of angular momentum. That is to say, the sun is not spinning fast enough to account for the total angular momentum of the solar system or it's own mass. There are two kinds of angular momentum: spin momentum and rotational momentum. If spin momentum is missing from the sun, then it must have rotational momentum. The sun must be curving through space in order to account for the sun's missing angular momentum.

3) When two masses are attracted and rotate about a center of mass, each mass observes a centripetal force directed to the center of mass of the system proportional to 1/r (not 1/r^2 per the mutual gravitational pull of the two masses). Again, the centripetal force(1/r) is directed toward the center of mass of the system. The gravitational force(1/r^2) is directed toward a mass. There are two cases. One example is when the center of mass is inside the much larger mass in which case the smaller mass is observed to simply rotate about the much larger mass as is the case of the earth and the sun. The other case is when the two masses are of similar scale and the center of mass is not found inside either mass but is found somewhere in space between the two masses. In this case, the two masses are in elliptical orbits about the center of mass of the system and the center of mass would be closer to the sun than the other mass and the centripetal force would fall off as 1/r (instead of 1/r^2) making it possible to account for the anomalous force. — Preceding unsigned comment added by Mabell108 (talk • contribs)

Anomaly and Comets

If Pioneer really is following a different trajectory, and it's not due to mechanical failure or reading the data incorrectly, then wouldn't that also imply that the calculated trajectory of comets we know about also be slightly incorrect? Infonation101 (talk) 21:10, 14 April 2008 (UTC)

Yes, but comets distances cannot be measured nearly as precisely, because they do not carry transponders or precise oscillators for use as time standards. Wwheaton (talk) 16:33, 14 October 2008 (UTC)

Quantum Gravity Waves

If you accept both Einstein's theory that gravity around massive objects is actually a curvature of space and time accelerating matter toward the massive object, and you accept the presence of vacuum energy (dark energy), then is easy to imagine very dense vacuum energy generating the same curvature of space and time accelerating matter toward the dense energy (accelerating matter outwardly in all directions at once, which can be felt as inertial forces, resistance to change in motion). We can then 'feel' vacuum energy gravity when we accelerate in the weightlessness of space, and when we resist the force of Earth's gravity we are experiencing both curvatures (matter gravity accelerating matter downward toward Earth and vacuum energy gravity resisting acceleration forces). Some work being done at open source project http://www.BigCrash.org, including speculation that vacuum energy might flow into black holes. --Jtankers (talk) 14:32, 16 April 2008 (UTC)

Speculation, if dark energy is dense enough to cause its own powerful gravity, (if it is the force that gives matter inertia by resisting change in motion), and if large objects like the sun create waves of density in the dark energy (similar to a wake left by a speeding boat on a pond, but in 3d), then perhapses the energy density waves caused by the sun moving through the dark energy field might subtlety affect motion of space craft. --Jtankers (talk) 14:32, 16 April 2008 (UTC)

Is this anomaly force really stable (8.74 ± 1.33) × 10^−10 m/s2) ?

• Or is this an average based on several measurements?
• When will NASA release the exact data: dd/mm/yy for measurements and the exact measured deviance of velocity? —Preceding unsigned comment added by Bjarne Lorenzen (talk • contribs) 12:34, 22 July 2008 (UTC)

The anomaly is not measured per se. It is inferred. What is being measured is the frequency of the radio signal received from the spacecraft; tens of thousands of data points over the span of several years. This same frequency is then calculated using an orbital model that takes into account the laws of celestial mechanics, nongravitational effects, effects on signal propagation, the location of receiving stations, you name it. The finding is that the computed and observed frequencies cannot be reconciled unless one supplements the force model with something. When that something is assumed to be a constant sunward acceleration of 8.74 × 10^−10 m/s^2, good agreement with the data is achieved. The one-sigma error of 1.33 × 10^−10 m/s^2 is a combined error budget that includes statistical fitting errors, rounding errors, physical uncertainties, etc. --Vttoth (talk) 02:16, 31 August 2008 (UTC)

5,000 km/yr

The specification of the deviation per year has been added here. The value is apparently taken from this blog article, the author of which apparently took it from here (see first two responses). However, the calculation

Δx = 1/2 a t² = 0.5 × 8.74 × 10⁻¹⁰ m/s² × (365.25 × 24 × 60 × 60 s)² ≈ 435.2 km

shows clearly a much smaller result. Can someone explain this? --80.129.78.14 (talk) 15:12, 18 September 2008 (UTC)

I stumbled upon this discrepancy independently, so you are likely to be right. I will change the article. I also find the sentence "This results in the spacecraft being about 5,000 km closer to the sun than they should be, every year." hard to understand. I'll try to improve it. --Art Carlson (talk) 08:36, 12 November 2008 (UTC)

Vacuum Modified Gravity and other not-yet-discussed theories

There are many (>100) different theoretical proposals for the Pioneer anomaly on arXiv alone. Wikipedia's point is to present a summary to the reader, and so cannot include them all. So which ones to include?

This is a problem for almost all articles, and not just the Pioneer anomaly alone. The normal Wikipedia standard is that someone, not the author, comments on the proposed inclusion in a reasonably reputable and verifiable place.

This has nothing to do with whether an idea is correct or not, or a valuable contribution, just a more-or-less objective way of deciding what should go in an encyclopedia. LouScheffer (talk) 11:31, 25 September 2008 (UTC)

I think that Masreliez, C. Johan (2001), http://www.estfound.org/ doesn't belong to here. He selectively "solves" a lot of old anomalies, many of them already solved in other ways, such as the too-old globular clusters, the spiral forms of galaxies, and introduces much-much worse ones, such as that earth must have been at distance of 2 AU from sun in the early solar system 4.5 Ga ago, such as the stars fall in spiral into the center of the galaxy in a time span of undefined (maybe 400 Ma, since the stars are assumed to follow the spiral form), such that when correlating with the stars orbit vectors around the center it is very hard to not conclude that sun was born very far outside Milky Way. Unless there are very serious objections, I'll remove that ref soon. Said: Rursus (☻) 13:12, 12 October 2008 (UTC)

While you're at it, could you please review this addition? From what I can tell, it also doesn't meet the requirements for inclusion, but the contributor emailed me requesting a review. Thanks. --Ckatz^chat_spy 19:23, 12 October 2008 (UTC)

Well, the latter is a clear violation of WP:WEIGHT: including a huge discussion sourced to the ICR (that is, the Institute for Creation Research, a Creationist think-tank) rather than a physics journal or otherwise reliable third-party source. siℓℓy rabbit (talk) 19:43, 12 October 2008 (UTC)

I also looked at this, can could find no references in arXiv, or citebase, or google scholar (which are fairly inclusive) where anyone discusses the plusses and minuses of this theory. Without this third party discussion, it's not received enough discussion to appear in an encyclopedia article. LouScheffer (talk) 03:35, 13 October 2008 (UTC)

Someone was faster than me! Thank you guys: Well done! Said: Rursus (☻) 14:02, 14 October 2008 (UTC)

Forgot to say: creationism? Not in this article. There are dedicated articles for religion, this is science. Said: Rursus (☻) 14:05, 14 October 2008 (UTC)

Aethereal Gravitation Theory

The reference to "Aethereal Gravitation Theory" seems to hold as much water as the timecube theory. I can not find any credible sources other than the linked website: "Site created to explain a completely new theory of gravity". Yeah, sure. Perhaps someone should add the FSM to this page. —Preceding unsigned comment added by 86.211.43.70 (talk) 19:57, 11 November 2008 (UTC)

Cosmological constant

The observed cosmological constant also cannot explain the Pioneer anomaly because it is many orders of magnitude too small and has the wrong sign (repulsive instead of attractive).

I agree that the cosmological constant, or, more precisely, dark energy, which may not actually take the form of a cosmological constant, is much too small to account for the anomaly. I have my doubts about the sign, though. Dark energy has negative pressure, which results in an acceleration of the universe, but it has positive energy density, so it is not clear what sign the acceleration should have, or whether it should be zero because of the uniform distribution of dark energy in space. Unless we can cite a RS, it is safer not to speculate on this. --Art Carlson (talk) 09:01, 12 November 2008 (UTC)

I wrote that because in the Newtonian approximation you can model a cosmological constant as a repulsive acceleration proportional to distance, and I figured the Newtonian approximation would be good enough here. In fact, the exact geodesics through the origin (x = t = 0) in de Sitter space (ds² = dt² − e^2kt dx²) are χ(t) = (v_o / k) sinh(kt), where χ = e^kt x is the metric distance from the origin at the time t. This is not only always accelerating away from the starting point, it's exactly what you get in the Newtonian approximation.

But now I think I was wrong, because when I calculate the redshift of an object moving along one of those geodesics as seen by someone at rest at the origin, I get (exactly)

$1+z(t)={\frac {1}{1-v_{o}\ {\text{sinh}}(kt)}}{\sqrt {\frac {1+v_{o}e^{-kt}}{1-v_{o}e^{-kt}}}}$

where t is the coordinate time of emission. z'(t) can be positive or negative, so the apparent acceleration (if it's calculated as c dz/dt) can be either towards or away from the origin, even though χ''(t) is always directed away. The crossover from apparent deceleration to apparent acceleration happens at t ~ v_o²/k, and weirdly enough t ~ v_o²/k for the Pioneer anomaly (1/k ~ 10¹⁰ years, t ~ 10¹ years, v_o ≈ 10^−4.5), so I can't get a reliable sign from this toy model. But the magnitude is k² v_o t < 10⁻²² m/s², so it hardly matters.

I know all this is OR (I'm just posting it here because I thought it was interesting), but can we put back just a claim that the CC is far too small (if the dark energy is a CC), leaving out the bit about the sign? -- BenRG (talk) 00:52, 13 November 2008 (UTC)

If nobody else has written about the (lack of) connection between the Pioneer anomaly and the cosmological constant, then what we are doing here is indisputably OR. Still, I've done similar things in other articles and believe it can be a service to the reader, but it must be done with a light touch. All we really know about CC/DE is (1) that there is a big chunk of mass density in the universe that we can otherwise identify (mostly from CMB), and (2) that the expansion is accelerating (SNe). The mass density doesn't play any direct role here, but the acceleration is a direct measurement. I'd be good with mentioning the measured acceleration of the universe and juxtaposing that number with the acceleration of the Pioneer anomaly. That should be enough to convince speculating readers that this is not fruitful terrain, regardless of the proper way to do the theory.

You may have noticed that I am running on the ragged edge of my knowledge of both theoretical and experimental cosmology. I leave the final choice up to you. --Art Carlson (talk) 08:59, 13 November 2008 (UTC)

OK, hopefully no one hates me for this

I converted many inline links and many bare refs into cite webs. I dug down and cited underlying refs in a couple of cases. I worked on copy throughout. I removed content obsoleted by time (some not updated since 2005, it appears).

There is still much that can be done.

I am CONFIDENT that I damaged something, somewhere, and I apologize for that. I found a few and fixed them where I saw them.

I think overall the article is better now.

Best regards. :) sinneed (talk) 04:38, 11 January 2009 (UTC)

Conjecture?

"The magnitude of the Pioneer effect is numerically quite close to the product of the speed of light and the Hubble constant, but the significance of this, if any, is unknown." This part seems a reasonable part to drop, or at least flag and then drop it eventually if no one sources why it should even conceivably be significant... there are so many constants and measurements that almost any number will be numerically similar to a product/sum/whatever of some of them. :) I was going to restore the sourced bit about the expansion of the universe thing. I wondered if it might be better in the "possible explanations" area.

I read the edit summary, and I think that is what the IP was saying... 1 sentence conjecture, 2nd sentence nice but belonged somewhere else. I don't think the 2nd bit should have been cut...maybe moved and reworked a bit. Either way, you beat me to the restore. :)sinneed (talk) 16:59, 16 January 2009 (UTC)

What about gravity waves?

Redshifting gravity waves could make a craft like that deacelerate. But we know so little about that.

I wonder too if you could make the same experiment with blueshifting gravity waves trowing something to the sun at high speeds. —Preceding unsigned comment added by 190.140.33.63 (talk) 04:05, 5 October 2009 (UTC)

Predicted by Paul LaViolette

According to this interview (time ca. 01:42:00) this phenomenon was first predicted by Paul LaViolette. __meco (talk) 14:21, 9 October 2009 (UTC)

Thanks for pointing this out. A quick goggling found this online excerpt from LaViolette's 1985 paper, and this press release. I have my doubts about his claim, but I'll have to read up on this before I can form an opinion about including it in the article. Paradoctor (talk) 20:45, 9 October 2009 (UTC)

I don't think that claim is credible. -- BenRG (talk) 20:37, 9 October 2009 (UTC)

Great. Why? Paradoctor (talk) 20:45, 9 October 2009 (UTC)

Question about page history

THIS PAGE WAS LAST MODIFIED ON 10th MARCH 2010 AT 19 HOURS, THEN WHAT WAS THE MODIFICATION, WHO REMOVED IT; WITH WHAT INTENTION? Hasmukh Tank 123.201.176.199 (talk) 15:01, 13 March 2010 (UTC)

Please familiarize yourself with Wikipedia:talk page guidelines. ALL CAPS TEXT is considered the equivalent of shouting, and usually seen as WP:UNCIVIL here.

I think you mean this edit by me and this one.

To answer your question of why, please note that the text added by you is not in accordance with our policy of Wikipedia:No original research. It also violates Wikipedia:talk page guidelines. If you want to discuss your paper, this is not the place. If you'd like assistance in finding a more appropriate discussion forum, feel free to notify me on my talkpage. Finally, I'd like to suggest that you register a user account for yourself. It is free, easy, quick, and has a few bells and whistles not available to anonymous IP editors. Happy editing, Paradoctor (talk) 18:02, 13 March 2010 (UTC)

The Pioneer anomaly has been completely solved

Archved self-published work.
The following discussion has been closed. Please do not modify it.
Mechanism-Revealed Physics (27/40) What is the famous Pioneer anomaly? The famous Pioneer anomaly (or Pioneer effect) refers to a very small, constant sunwards acceleration of (8.74 ± 1.33) x 10 -10 m/s2 experienced by Pioneer spacecraft at the distance from 20 to 70 AU from the Sun (note, 1AU = 1.496 x 1011 m), being unable to be explained with the laws of Newton and Einstein (Ref., the encyclopedia of physics). Two acronyms: MRSRT = Mechanism-Revealed Scales Relativity Theory (P. 133 ~ 147, Ch.1C, reference #1), MRGT = Mechanism-Revealed Gravitational Theory (P. 445 ~ 514, Ch.4B, reference #1). Completely solving the Pioneer anomaly: the Pioneer anomaly has been completely solved with the newly developed Pioneer anomaly equation based on the newly established MRSRT and MRGT (Ch.5A, P. 517 ~ 530, reference #1). The Pioneer anomaly equation (on P. 524, reference #1) includes five factors, they are: the effect of Pioneer spacecraft motion, the effect of the gravitational field of Earth, the effect of Earth orbiting, the effect of the gravitational field of Sun on the orbit of Earth, and the effect of the gravitational field of Sun on the location of Pioneer spacecraft. The calculated values of the Pioneer anomaly with the Pioneer anomaly equation exactly agree with the known results: the calculated values at the velocities of 11,542, 12,535 and 13,869 m/s of the Pioneer spacecraft are sequentially the lower bound, average and upper bound of the known result of the Pioneer anomaly, which is (8.74 ± 1.33) x10 -10 m/s2. After solving the Pioneer anomaly: the newly established Pioneer anomaly equation reveals the mechanism behind the Pioneer anomaly phenomenon is that: comparing to the time scale on the surface of Earth, the time scale on Pioneer spacecraft is reduced because of the motion of the spacecraft. As a result, since being measured with the larger time scale on the surface of Earth, the magnitude of the deceleration acting upon Pioneer spacecraft by the gravitational force of Sun is correspondingly amplified (because the magnitude of deceleration is inversely proportional to time scale, i.e., the decrease in time scale results in correspondingly proportional increase in deceleration) — the amplified deceleration, whose direction is from the Pioneer spacecraft towards the Sun (i.e., sunwards acceleration), is the Pioneer anomaly. Therefore, the essence of the Pioneer anomaly is the amplification of the deceleration acting upon Pioneer spacecraft by the gravitational force from the Sun, being caused by the time scale reduction resulting from the motion of the Pioneer spacecraft themselves. The definition of the Pioneer anomaly is thereby as that: the Pioneer anomaly, being caused by the time scale reduction on the Pioneer spacecraft resulting from the motion of the spacecraft themselves, is the increased amount of deceleration acting upon Pioneer spacecraft by the action of the gravitational force of Sun (P. 527, reference #1). The fundamentally profound implications after solving the Pioneer anomaly: (i) the key to solving the Pioneer anomaly is the newly established and verified MRSRT and MRGT. (ii) Neither Einstein’s general relativity nor Newton’s classical gravitational theory is able to solve the Pioneer anomaly. The key to understanding of the solving of the Pioneer anomaly: (i) in order to solve the Pioneer anomaly, we must have the theory that reveals and quantifies why time and space are variable thus relative. Please notice that: the newly established and verified MRSRT and MRGT reveal and quantify why time and space are variable thus relative; either Einstein’s special relativity or general relativity is unable to know why time and space are variable thus relative, being a well-known and undeniable fact. (iii) As long as you have known the greatest equation in the history of science, which is Einstein’s famous mass-energy equation (E = mc2 or E0 = mc2), you will easily understand the solving of the Pioneer anomaly, because the law of object’s mass doing work (P. 93 ~ 109, Ch.1A, reference #1), which lays the foundation of MRSRT and MRGT, also reveals the mechanism behind the greatest equation (P. 114 ~ 118, Ch.1B, reference #1). Reference #1: 2009, Bingcheng Zhao, From Postulate-Based Modern Physics to Mechanism-Revealed Physics [Vol. 1(1/2)], ISBN: 978-1-4357-4913-9. Reference #2: 2009, Bingcheng Zhao, From Postulate-Based Modern Physics to Mechanism-Revealed Physics [Vol. 2(2/2)], ISBN: 978-1-4357-5033-3. Ph.D., Bingcheng Zhao, The author of “From Postulate-Based Modern Physics to Mechanism-Revealed Physics” 1401 NE Merman Dr. Apt. 703, Pullman, WA 99163 USA. Email: bczhao12@gmail.com or bzhao34@yahoo.com or bingcheng.zhao@gmail.com —Preceding unsigned comment added by 204.52.246.120 (talk) 18:18, 18 March 2010 (UTC)

Wikipedia is not the place to try to publish or popularize your own ideas. See WP:OR and WP:RS. --Christopher Thomas (talk) 18:58, 18 March 2010 (UTC)

Russel Humphreys

This addition with the edit summary "adding pseudoscientific creationist theory - I think it's worth a mention" was reverted with the edit summary "I disagree. It's non-notable fringe work.".

First, let's note that WP:N is about entire articles. For deciding whether to mention Humphreys, we need to know about the reception of this theory. Is it considered a substantial contribution to creationist thought? Have mainstream physicists actually commented on Humphreys explanation of the Pioneer effect? I. e. has it had impact beyond Humphreys himself? If yes, it is encyclopedic and needs to be mentioned. If not, it needs to go, because then it would nothing more than another uninteresting internet rant. Paradoctor (talk) 19:14, 30 March 2010 (UTC)

WP:UNDUE discusses the incorporation of minority views into articles. This article is about a scientific topic; whether this explanation is notable among creationists is irrelevant. Whether it's notable among scientists is, and I think the onus is on you and Tonicthebrown to demonstrate that it is, rather than on me to demonstrate that it isn't, given that it's being billed as a religion-based proposal. --Christopher Thomas (talk) 19:28, 30 March 2010 (UTC)