http://www.newtonphysics.on.ca/Anoma...eleration.html
This says it's due to dust in the Kuiper belt. Whaddaya think of that?
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http://www.newtonphysics.on.ca/Anoma...eleration.html
This says it's due to dust in the Kuiper belt. Whaddaya think of that?
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I say the next probe should bring some Pledge and a dusting rag along to clean up the belt.
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I found this near the end interesting.
So if in a million years Pioneer 11 passes near an alien civilization, they may not know it is artificial and think it is just another pile of rock and dust? So much for worrying about whether some alien will understand the plaque or not.Finally, considering that the Pioneer spacecrafts are submitted to such an acceleration of about –8. x 10-8 cm/s2 while moving through an enormous Kuiper and Oort cloud, the spacecrafts will absorb that dust due to the mechanism of accretion of dust. After millions of years of accretion, these spacecrafts will become larger and larger in time, while slowing down (unless reaccelerated later by other bodies). Pioneer spacecrafts will become the nucleus of asteroids flying away from the solar system with the interstellar dust.
Kizarvexis
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Uh oh -- how many small comets and asteroids in our solar system are really dust-caked space probes sent out from other star systems?
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YeahOriginally Posted by Kizarvexis
I found this near the end interesting.
So if in a million years Pioneer 11 passes near an alien civilization, they may not know it is artificial and think it is just another pile of rock and dust? So much for worrying about whether some alien will understand the plaque or not.Finally, considering that the Pioneer spacecrafts are submitted to such an acceleration of about –8. x 10-8 cm/s2 while moving through an enormous Kuiper and Oort cloud, the spacecrafts will absorb that dust due to the mechanism of accretion of dust. After millions of years of accretion, these spacecrafts will become larger and larger in time, while slowing down (unless reaccelerated later by other bodies). Pioneer spacecrafts will become the nucleus of asteroids flying away from the solar system with the interstellar dust.
KizarvexisIt seems that the authors haven't spotted their own little logic problem. If this dust is so adhesive, why is it still there? - we consider that there are possibly billions of bodies in the Kuiper belt, most of them much much larger than the Pioneers. They should all be sweeping up and accreting this magic dust, so there would be precious little left over by now for the probes to undergo this snowball process and turn themselves into interstellar asteroids.
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How was this acceleration detected? I thought Pioneer 10 was no longer functional...
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Heh. Can you imagine if that's what killed off the dinosaurs?I found this near the end interesting.
So if in a million years Pioneer 11 passes near an alien civilization, they may not know it is artificial and think it is just another pile of rock and dust? So much for worrying about whether some alien will understand the plaque or not.Finally, considering that the Pioneer spacecrafts are submitted to such an acceleration of about ?8. x 10-8 cm/s2 while moving through an enormous Kuiper and Oort cloud, the spacecrafts will absorb that dust due to the mechanism of accretion of dust. After millions of years of accretion, these spacecrafts will become larger and larger in time, while slowing down (unless reaccelerated later by other bodies). Pioneer spacecrafts will become the nucleus of asteroids flying away from the solar system with the interstellar dust.
Kizarvexis
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Nice nod down there at the bottom, John: "The author acknowledges the collaboration of John Kierein for bringing up the IRAS information"
But, I am concerned about the titles on the FAQ page. "Series #8 Why Quantum Mechanics is Non-sense? " for instance, or "Series #14 They burn heretics, don't they?".
I looked into the Series #10: Energy Required to Move a Mass from the Pole to the Equator. Although I didn't wade through the math, it looks like the conclusions were OK. I was concerned because of the blurb on the main page: " It requires external (Earth) energy to move from the equator to the pole..." That is wrong, as Paul's writeup goes to great lengths to show. The surface at the pole and the surface at the equator are in an equilibrium, as the main body of the article states. The entire surface (geoid, or "sealevel") of the Earth is an equipotential surface, in other words.
That's why the water is "flat".
It also neatly explains the relativity phenomenon.
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I pointed out the IRAS picture to Paul. It's interesting that the Pioneer drag data may be the only direct measurement of the dust density. I was a little surprised that it hadn't been considered before.
The IRAS picture has always been interesting to me because it dramatically shows that the projection of the plane of the ecliptic crosses the galactic plane right at the center of the galaxy. I've always wondered if there's a gravitational reason for this and if it is true for other planetary systems. Unfortunately, so far as I have been able to find out, there is not yet a way to determine the orbital planes of extrasolar planets.
We also studied the zodiacal light and gegenschein from Skylab. I collected the pictures for this chapter:
http://history.nasa.gov/SP-404/ch3.htm
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So does that mean instead of V-ger we will be revisited by P-neer?I found this near the end interesting.
So if in a million years Pioneer 11 passes near an alien civilization, they may not know it is artificial and think it is just another pile of rock and dust? So much for worrying about whether some alien will understand the plaque or not.Finally, considering that the Pioneer spacecrafts are submitted to such an acceleration of about –8. x 10-8 cm/s2 while moving through an enormous Kuiper and Oort cloud, the spacecrafts will absorb that dust due to the mechanism of accretion of dust. After millions of years of accretion, these spacecrafts will become larger and larger in time, while slowing down (unless reaccelerated later by other bodies). Pioneer spacecrafts will become the nucleus of asteroids flying away from the solar system with the interstellar dust.
Kizarvexis
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I'm not impressed. As far as I can tell, once you remove the "filler", they just assume a density and size of "sand" grains which then magically accounts for the acceleration and then they claim their assumptions as the result!
The "study" makes no reference to changes in acceleration over different time frames. If this idea was correct, there should be no anomalous acceleration except while traversing the Kuniper belt. This is not what has been observed.
The level of analysis here is pretty laughable when compared to the 2002 study (54 pages worth) by Anderson, et. al. And note that the authors still think there is a systematic reason for the acceleration, so they are not arguing for "farfetched hypotheses". http://xxx.lanl.gov/abs/gr-qc/0104064
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Here's another interesting article about the anomalous deceleration of the Pioneers.
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This article submitted to a journal for review finds the following:
In this work we study the gravitational influence of the material extending from Uranus orbit to the Kuiper belt and beyond on objects moving within these regions. We conclude that a density distribution given by rho(r) ~ 1/20r (for r > 20 AU) generates a constant acceleration towards the Sun on those objects, which accounts for the blue shift detected on the Pioneers space crafts. We also discuss the effect of this gravitational pull on Neptune, and comment on the possible origin of such
a matter distribution.
Vulcan Administrator
Use asteroids to investigate
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.
...
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.
Everything I need to know I learned through Googling.
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Nope. They will launch a HUGE copper ingot 'bullet' to smash it to bits to see what it is made of.
So if in a million years Pioneer 11 passes near an alien civilization, they may not know it is artificial and think it is just another pile of rock and dust? So much for worrying about whether some alien will understand the plaque or not.
Kizarvexis
Nick :wink:
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But we do have orbit planes for some binary stars (the Hipparcos catalogues have a doubles and multiples annex with orbital information); I just checked a bunch of them at random and a disproportionate number seem to intersect the plane of the galaxy within 20-30° of the galactic center - Sirius B in particular is almost right-on despite its orbit being tilted on its side with respect to the plane of the galaxy.
Not to hijack the thread or anything
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(I wasn't paying attention and didn't notice at first that you were the OP. #-o )
But having completed a survey of binary stars with known orbit planes, I did find something interesting. I measured the apparent declination of the galactic center (GC) as seen from each star, referenced to the plane of its companion's orbit. I also took into account the obliquity of the orbit to the galactic plane.
If my math is correct (and please do correct me if I've made any errors) then in a perfectly random distribution one would expect a mean obliquity of 90° / sqrt(2), and a mean declination equal to the mean obliquity / sqrt(2).
In fact, I found a mean obliquity of 57.46° which is a little over 90% of the expected figure. So there's a slight tendency for stellar orbits to want to lay flat against the galactic plane. The mean declination of the GC is only 71% of the expected figure, meaning the orbits have a considerably greater tendency to line up to the GC as you describe. Furthermore, when each individual star system's apparent GC declination is divided by its obliquity, the resulting mean is higher - closer to 74%.
The difference between the 71% and 74% figures can be explained if stars whose orbit planes lie closer to the plane of the galaxy have less tendency to line up with the GC than stars whose planes have a high obliquity.
Here is a complete MS Excel spreadsheet of the stars I surveyed and resulting figures.
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Bump.
Questions? Comments? Point out some major error on my part?Anyone?
That survey took me almost 3 weeks. :wink: (Satisfied my own curiosity, at the very least, so it was worth it.)
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Planetary Society coverage of the
2005 Pioneer Anomaly Conference
November 6-11, 2005
Greetings from Switzerland! My name is Merek Chertkow. The Planetary Society sent me to the 2005 Pioneer Anomaly Conference in Bern, Switzerland to participate in and report on the exciting analyses, conclusions, and new questions formed by scientists from around the world working to understand the Pioneer anomaly. The conference consists of some 15 scientists from France, Canada, Norway, Germany, and the United States.
Throughout the week, I'll try to introduce and remind you of the different complicated elements involved in understanding the Pioneers' position, environment, the way in which it communicates with Earth, and the current modeling techniques that are being used.
Everything I need to know I learned through Googling.
Order of Kilopi
That is a good link.
Not only can a space probe be covered with debris, but the metal itself forms these small fiber like burr/extrusions to bond with it.
It makes me wonder about Teton again.
Order of Kilopi
Applause!Bump.
Questions? Comments? Point out some major error on my part?
That survey took me almost 3 weeks. :wink: (Satisfied my own curiosity, at the very least, so it was worth it.)
There are a number of reasons to suspect an underlying symmetry that is not predicted by Newton - Bode's law, the correlation between planetary energy emission excess and rotational speed, the roundness of planetary orbits (assuming they are captured, rather than cloud synthesized). Many of these phenomena are written off as coincidental, but I don't see how the relationship you just describe could be. (I have an explanation, but now is not the time or the place, and it is probably wrong anyway.)
I'll file this somewhere between the Tiger Stripes of Enceladus, and the fact that the rotational period of Venus correlates quite well with the Earth/Venus orbital periodic. (The same face of Venus always points towards the Earth.)
Order of Kilopi
Vulcan Administrator
Update from the Pioneer Anomaly Team
The original investigation used about 11.5 years worth of data for Pioneer 10, and slightly less than 4 years of data for Pioneer 11. We can now report on the recovery of a much larger data set: essentially all Doppler data for the entire 30-year time span of the Pioneer 10/11 missions will soon be available for analysis. This is not an easy process: 30 years is a very long time! The challenges are formidable, including having to deal with numerous obsolete data formats, no longer supported software packages, and last but not least, the fact that people with the right expertise are no longer around. Nevertheless, the formats are now understood and the media has been collected. We now have up to 60,000 data points (about 20 gigabytes) of data for Pioneer 10, and 50,000 data points (about 15 gigabytes) for Pioneer 11. The data recovery process in nearly complete and the data will be available for the analysis in early this year.
Everything I need to know I learned through Googling.
Order of Kilopi
I don't buy it. How can a pair of spin stabilized probes be suffering this dust phenomenon, but not two probes that are relatively stable platforms? Yes, they are thruster stabilized, but it should have shown up somewhere that additional thrust was required to accomplish adjustments, or that adjustments weren't having the desired effect.
Something stinks here.
Vulcan Administrator
I vote for some sort of systemic effect based on unaccounted-for aspects of the spacecraft. As Ned Wright points out, the effect is so small that it's equivalent to shining a 60-watt light on (or from) the spacecraft. I find it easier to believe that something like that was missed than that we're talking about new physics.
Everything I need to know I learned through Googling.
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Pioneer 10 is just getting too tired. wouldnt you want to slow down a bit after a 15 billion km journey?
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The trouble with the Voyagers is that every attitude stabilisation manoeuvre also alters the velocity slightly because the thrusters are not exactly balanced. This effect, though small, is sufficient to completely swamp the Pioneer effect.
Order of Kilopi
Still, if something were accumulating on the probes, there would be some level of alteration to the probe's performance. It would be a different anomoly, but there would still be an anomoly of some kind.
Banned
What are the implications of the acceleration anomalies measured for Pioneer 10 and 11 http://www.setterfield.org/accelanom.htm ?
Although Setterfield's a creationist, variable c" models aren't that rare -- Hoyle and Narlikar proposed one where the value of c was a function of the local energy density, for example. Who knows what constitutes conclusive proof, since other constants of nature shift with c (e.g., the electrical permittivity and magnetic permeability of free space, not to mention other constants)?
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Many alternative theorists point to the Pioneer 10 and 11 anomalies, which show a slight increase in the force experienced toward the Sun as the spacecraft get further out into the Solar System. If you call everything in Physics into question, then any small number of things we hold as known physics might be wrong, which would require that radical explanations of the rest of the universe would be in order. This section of the forum isn't really the place to explore a catelog of these implications. Try the ATM section.
Forming opinions as we speak
Order of Kilopi
I think the Pioneer anomalies are an exception to the rule here: This is a well studied phenomenon where most of the suggestions as to cause on this thread have been ruled out by a team a very competent researchers. This is one of several observations that should be considered a gut-check for the mainstream, because it is mainstream: Two well-controlled experiments, the results of which have no known causality.
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