Thanks for the info, edstrick. The lumpy ring you speak about is the innermost of the three rings, the one which is coplanar with the star.





Yes there are some models predicting a nuclear explosion of the star, without gravitationnal collapse. In this case all the mass is blasted away and nothing remains in the centre. But this is for peculiar cases of binary stars, I do not think it fits for SN1987A, which is believed to be basically a gravitationnal collapse of a massive star which exhausted all its nuclear power. But the process leading from a star to a neutron star or black hole is not yet understood. The only thing sure is that there was a blast of neutrinos detected, indicating very high temperatures reached in the core. But we do not know if a black hole or a neutron star was created. By the way this star was not very massive, it could have given only a white dwarf (an idea of mine, without any waranty). I remember that the detection of a blinking light was expected 10 years after. Now 18 years passed by...

News to me - can you provide a source? Middleditch based his models on fast rotating binary systems, and the resulting Gamma Rays, so I don't think prior rings cause a conundrum (prior rings being a product of the orbital dog-and-cat fight (?)).

This set of three non-coplanar rings was photographied just after the blast was extinct, some months after the supernova, when astronomers began to examine the place. I remember well that it was in all the science reviews (Here in France "Science et Avenir", "Science et Vie", "Pour la science" , and also in amateur astronomy reviews. At that time the fireball from the explosion was just an unresolved point at the centre of the well resolved three rings. Previous photos of the same place showed the parent star, but were not large enough to show the rings. These rings much puzzled the astronomers, and they played a role in the planetary nebula theory (since it was found one or several planetary nebula looking like hour glasses, ressembling the rings of 1987A). They are now expected to form from binary systems. But I never heard of a companion star of SN1987A, with my opinion if it exists it must be a very weak star, white dwarf, neutron star or black hole. Anyway it puzzles me that today some people (and even scientists) seem to think that the three rings resulted from the explosion. Today the fireball of the explosion is just catching the innermost ring.


Another curious thing is that, while the fireball was still very bright, days of weeks after the explosion,I heard mentioned that just nearby there was a huge transcient infrared source, most powerfull than the entire Magellanic cloud. But I never heard of this again, perhaps it was just an observation error. Often unexplained facts are considered as mistakes and forgotten. But there may be some new thing about. Today people may think that it was the effect of a focused gamma ray beam like those predicted by some supernova theories.

Sorry, I have no other sources than my memories of the scientific press at this epoch. If you want more precise sources, I think you should look in the archives of science and astronomy reviews (like the "scientific American" in the months following the supernova, I think you cannot miss the images of the three rings.

Thanks -

Nisenson argues the 'spots' are indeed likely supernova remnants, but I am not sure if he is arguing the rings are actual remnants or "spotlighted" illuminations of existing nebula.

http://arxiv.org/abs/astro-ph/9904109

You are correct in stating a companion star for 1987A has never been discovered. The column of energy released was so enormous, Middleditch speculates a high volume of the star may have undergone 'unidirectional weak interactions'. A relativistic laser(?)

I was looking for a mechanism to explain the relativistic accelerations Nisenson is trying to interpret, when I stumbled across the possibly 'non-Newtonian' trend in the solar system I outlined above. FWIW, I haven't convinced anyone in the field this could be a real aspect of gravity, but I haven't found anyone who's eyes don't glaze over the second they realize the implications, either.

Such a companion is deemed necessary to explain the existence of the rings (some planetary nebulae geometries are suposed to appear in binary systems). Alas we don not have precise spectra of 1987A before the explosion (it was just a blue spot among thousands of others). To explain the "disappearance" of the companion, we can suppose:
-it is very weak (white dwarf, neutron star, black hole. But I think we cannot expect the presence of a white dwarf as a companion to a large star)
-it was blasted away during the explosion
-it was absorbed some thousands years ago when 1987A was a red giant, just after involving in the rings. Eventually such three-ring geometry would be the signature of this kind of event.

Remember also that a blue star exploding as a supernova was a surprise; astronomers were thinking of SN1987A as being an ordinary blue star on its main sequence, not the likely candidate for a supernova. (It was the first time the star forming the supernova was known). The generaly retained explanation is that 1987A had undergone a red giant stage earlier, but since some thousand years it had subsided into a smaller blue star. Such variations in near-death stars are expected by theories and supported by observations.

Perhaps it was an industrial accident.

From the article "Detectability of Extraterrestrial Technological Activities"
by Guillermo A. Lemarchand:

http://www.coseti.org/lemarch1.htm


FIGURE 2: Concept of an "artificial" blue straggler star according to Reeves (1985). In this figure, a series of hydrogen bombs or powerful laser beams are aimed at the surface of a star, creating a "hot point" and rejuvenating the unused hydrogen, thus keeping the star on the Main Sequence for a longer period of time than would be natural.

http://www.coseti.org/images/lefig_2.gif

Reeves (1985) speculated on the origin of mysterious stars called blue stragglers. This class of star was first identified by Sandage (1952). Since that time, no clear consensus upon their origins has emerged. This is not, however, due to a paucity of theoretical models being devised. Indeed, a wealth of explanations have been presented to explain the origins of this star class. The essential characteristic of the blue stragglers is that they lie on, or near, the Main Sequence, but at surface temperatures and luminosities higher than those stars which define the cluster turnoff. A review of current thinking about these stars in the light of recent visible and ultraviolet Hubble Space Telescope observations assigns an explanation to stellar mergers occurring in the dense stellar environment of globular clusters (Bailyn, 1994).

Reeves (1985) suggested the intervention of the inhabitants that depend on these stars for light and heat. According to Reeves, these inhabitants could have found a way of keeping the stellar cores well-mixed with hydrogen, thus delaying the Main Sequence turn-off and the ultimately destructive, red giant phase.

Beech (1990) made a more detailed analysis of Reeves' hypothesis and suggested an interesting list of mechanisms for mixing envelope material into the core of the star. Some of them are as follows:

* Creating a "hot spot" between the stellar core and surface through the detonation of a series of hydrogen bombs. This process may alternately be achieved by aiming "a powerful, extremely concentrated laser beam" at the stellar surface.

* Enhanced stellar rotation and/or enhanced magnetic fields. Abt (1985) suggested from his studies of blue stragglers that meridional mixing in rapidly rotating stars may enhance their Main Sequence lifetime.

If some of these processes can be achieved, the Main Sequence lifetime may be greatly extended by factors of ten or more. It is far too early to establish, however, whether all the blue stragglers are the result of astroengineering activities.

Suggestions, by anyone, of engineering on this scale, is not productive and not scientifically motivated.

I mostly agree with you, but...


Imagine a million years old civilization, with technologies such as self-reproducing machines, fusion energy, etc... and plenty of time. Soon within reach of us.

Unless such a civilisation turns more ethical/spiritual than technological, there is no limit with such a technology, and it is not impossible we discover stars and even galaxies which were engineered over millions (or billions) of years. Simply we have not yet evidences (and even not suspicion) of it. There is alway this temptation when we discover something we do not understand: and if it was artificial? Remember the first pulsars: their extreme accuracy was not yet understood, and many scientists seriously considered they could be some interstellar beacons...

Coalescence of stars are a sufficient explanation for blue stragglers. A catastrophe which could happpen in some years, projecting all their planets (inhabited?) into blaze or into the darkness of space. Living into a dense star cluster may offer aver beautiful night sky, but it is also a ver dangerous place where most plants are ejected from their orbit by star encounters. so it is not the most likely place to find evolved life.

Returning to the Pioneer Anomally:

You may or may not be aware of the curious brightening phenomenon being studied by Ann Verbiscer, per the Planetary Weblog:



There is an explanation that is consistent, actually a necessary constraint, upon the permeability hypothesis I entered above:

The rings of Saturn, the highly reflective surfaces of some of the moons, are more like mirrors than nominal planetary surfaces. The sunlight reflected by the rings, therefore, more closely resembles a mirrored reflection of the sun, and will return a loosely coherant image of the sun.

When the Earth passes exactly between the Sun and Saturn, the rings and more reflective moons brighten. Why would the reflection be brighter at the very center?

If and ony if there is curvature of space. The image of the sun is focused only at the center, at anyother position of the Earth relative to the sun and Saturn, the image is deconvoluted.

When the Earth is exactly positioned in front of the sun, a perfectly curved lens would return a much brighter reflection of the sun. That is exactly what is happening.

And why would there be curvature? If and only if the permeability of space varies, increasing the speed of light with increasing distance from the center of the solar system, and this would be true if and only if the permeability of space is a function of MASS.

OK, There may be other solutions: Fressnel lensing, for example, but the solution is a lensing solution because the amount of brightening is also a function of wavelength, as would be expected with any single density lensing element.

The curvature has to be very slight...almost undetectable, but not quite, because it produces this brilliant mirror effect exactly in the center - just as a gravitational lens should. But the Earth is too far from the sun to experience this kind of curvature, with GR, as formulated by Einstein, to be the cause. (Also the mass of the Earth is not great enough to cause a GR bending of the light.)

This also explains why there are so many 'Gravitational' lenses, and 'micro quasar' lenses in the galaxy: There is a not-so-new physical principle being manifest: The permeability of space is a function of mass, the speed of light is only a constant in an ideal vacuum that includes the absence of any matter.

Returning to the Pioneer Accelerations, they are an artifact: We use the two-way time and speed of light to determine the distance to the probes. As the speed of light increases at a rate of ~1X10^-9m/s^2, the time it takes light to reach the probes and return is less than if the speed of light were constant. We interpret this as an acceleration of the probes towards the sun, when it is actually a slight acceleration of light away from the sun. (Of course both the speed of light, and the acceleration of the probes are not independently constrained at this time, so the true acceleration of the probes is unknown.)

Messenger, yes the Earth does have a "gravitationnal lens" effect, but it can significantly concentrates light only at a distance of several thousand light-years. This was put at work in the search of "machos" (massive objects such as blue dwarf stars, planets, brown dwarfs, black holes... explaining the dark matter around the galaxy). But the "machos" detected were very far, for instance in the Magellanic cloud, and the most common mass was around half what of the Sun, much larger than Earth. So I think the effect of gravitationnal lens is undetectable from Saturn. The opposition effect is well explained in terms of shadow hiding and back reflection from ice crystals, an effect we can also see on earth clouds (from above). The best evidence is that it was also photographied by Cassini (see somewhere on Cassini site or on this site) and from here it appears as a bright spot on the rings.

http://www.issi.unibe.ch/teams/Pioneer/

The Pioneer Explorer Collaboration
Investigation of the Pioneer Anomaly at ISSI

First Team Meeting at ISSI in Bern, Switzerland
November 7-11, 2005

Focus: the Pioneer anomaly

To date, the Pioneer 10 and 11 spacecraft are the most precisely navigated deep-space vehicles. However, as indicated by their radio-metric data, the Pioneers’ orbit reconstructions were limited by a small, anomalous, constant, blue-shifted, Doppler frequency drift of approximately 6 x 10^-9 Hz/s. The drift can be interpreted as due to a constant sunward acceleration of a_P = (8.74 ± 1.33) 10^-10 m/s^2. This interpretation has become known as the Pioneer anomaly.

Although the most obvious explanation would be that there is a systematic origin to the effect, the limited set of the analyzed data does not support any of the suggested mechanisms. We assert that analysis of the entire existing Pioneer data is vital to understanding the anomaly and, hopefully, to finding its origin. Indeed, analysis of the entire existing Pioneer data record is critical in attacking the anomaly on two fronts: (i) an analysis of the early, not rigorously analyzed, data could yield a more accurate direction of the anomaly and hence might help to determine its origin; (ii) by using the entire data set, from 1972 to 2002, one could study the temporal evolution of the anomaly and determine if it is due to on-board nuclear fuel inventory and related heat radiation or other mechanism.

Goal: analysis of the entire Pioneer 10/11 data record

The limited data analyzed previously allowed the detection of the anomaly in the Pioneer data, but not a determination of its origin. With new knowledge of all on-board processes and a diverse team, we propose a two-step process in understanding the origin of the anomaly, namely: (i) analysis of the entire set of existing Pioneer 10 and 11 data, obtained from first launch to the last telemetry received from Pioneer 10, on 27 April 2002, when it was at a heliocentric distance of 80 AU. This data could yield critical new information about the anomaly. If the signal is confirmed and is not due to an on-board systematic, (ii) we will use our new knowledge to develop an instrumental package that will be capable to provide an independent confirmation of the anomaly. We will also study a design for a dedicated mission to explore the anomalous behavior of the Pioneer spacecraft.

Significance: finding the origin of the Pioneer anomaly

This ISSI investigation could lead to a determination of the origin of the anomaly and to a characterization of its physical properties. The proposed investigation is scientifically important, it is timely, and is well situated in Europe. The investigation would be an excellent example to demonstrate the value of interdisciplinary teams in addressing complex problems in fundamental physics and in application of new technologies in spacecraft and mission designs. The results of this study could find their way into many other areas of space-exploration applications in the near future. The most important outcome of this study will be the understanding of the Pioneer anomaly.

http://www.issi.unibe.ch/teams/Pioneer/

ljk4-1: "...The Pioneer Explorer Collaboration -- Investigation of the Pioneer Anomaly at ISSI.."

I totally concur with the proposed analysis. We have an "anomaly". Not an "Anomaly" or an "ANOMALY" (if you get what I mean...).

We have an APPARENT force acting on the spacecraft. The best modelling has been unable to explain this anomaly in terms of systematic internally generated forces on the spacecraft, or known, modelable external forces acting on the spacecraft. We now need to extract the most information possible from the mission's data to see how the force varies with 1.) mission phase, 2.) radial location in solar system, and 3.) azimuth/inclination in solar system.

For example, if a reanalysis shows no anomalous acceleration before Jupiter flyby and identical accelerations afterwards... that would suggest an effect arising in an unknown effect on the spacecraft of the Jovian system environment..... particularly the extreme radiation environment.

For another example...Pioneer 11 flew "across" the solar system in a significantly inclined orbit between the Jupiter encounter and it's Saturn encounter, getting a foretaste of out-of-ecliptic science before Ulysses. If a reanalysis shows a force varying with inclination or angle around the sun in the ecliptic and then a relatively constant force after Saturn flyby puts Pioneer 11 on an escape trajectory...... Hmmmmmm.....!

Thanks ljk4-1 for your interesting contribution. And edstrick too

To analyse the existing set of data is obviously the first thing to do before building a space probe to investigate a gaz leak on Pioneer.
-Is the effect real?
-Is it constant, or depending on distance, attitude, fuel aging, direction, planet neighbouring, distance from the ecliptic?
All this would give us clues about its nature: gravitation, electromagnetic, solar wind, local reaction...

By the way it is said that the computers able to read the Pioneer data are to be scraped by the NASA. The first thing to do is obviously to save the data on modern supports. New domain for archaeology: rumaging in old computers magnetic bands.

edstrick, I never heard that the word "anomaly" bears a capital letter, in any of its uses. The Pioneer anomaly may have a very extraordinary explanation, for instance that the probe was followed by a spaceship from another civilization, or that it was used by yogis to demonstrate their supernatural powers. Simply such kind of explanations can be envisioned only after all the other explanations failed. More likely the Pioneer anomaly bears the possibility of some fundamental discovery in physics or in astronomy, so it is worth the study. But there are many chances that we simply find a gaz leak, thruster malfunction or something trite in this style.

But of course I did not missed your point about ANOMALIES! I am no more interested than you by people who spread false informations and false theories: they only muddle things. If there is somewhere something really unexplained, they may rather spoil the discovery than encourage its study.

sooooo did the planetary soc. get the data or what...? They haven't updated on us the status of thier original $250K begathon since like March.

<grin> by "anomaly" I mean an ordinary scientific/engineering unexplained datum due to inadequate modeling, systematic error in measurements, etc.... like the false indications that there was a 10'th planet making Neptune "wander", triggering the search that found Pluto.

An "Anomaly" (tone of voice emphasis implied) would be something that really starts to look like it suggests new astronomy, new physics.... something that is well defined enough and stubborn enough after sustained efforts to make it go away, that people (not just the arm-waving fringe) start to work hard on resolving it. The solar neutrion flux anomaly was one... solved by the confirmation that solar neutrinos change type en-route from the sun, so we only detect 1/3 of them with the original detectors.

And of course ANOMALY (capslock, funny font, guy with tin hat handing out mimeographed treatises to anybody he can buttonhole at a scientific meeting) is what the Hoaxland crowd assume it's most likely to be. (eyeballs rolled expression).

Thank you for the nuances. The Pioneer anomaly if likely of the first kind (anomaly) but there is enough chance it is of the seconc kind (Anomaly) so that it is worth studying it (and re-examining the whole data set is definitively the best to start with).

By the way, the custom of wearing tin-hats comes from the idea that naughty aliens influence us by telepathy. But if telepathy exists, it is likely not an electromagnetic phenomenon, so the tin hat is of no use.

Aliens?... I thought it was the CIA and FBI.... or maybe they are space aliens here to control us!

NATIONAL OUTQUIRER
(Picture of Michael Jackson, Elizabeth Taylor, and H. Ross Perot)
Headline: CELEBRITY SPACE ALIENS LIVING AMONG US.

(HRP is obviously a disguised Ferengi... the ears.. the nose.. the money...)

They do not need telepathy for this, they have tele...vision.

There are rumors too of electromagnetic weapons able of having effects of the brain, such as make us hear voices. Far-fetched, but not completelly impossible I think. But if ever there is one day a government pervert enough to use such weapons against its citizens, it will be that the society would have gone very very wrong far before...

You know what the problem is with make-believe paranoia?

(looking around suspiciously...)

YOU'RE PROBABLY RIGHT!

AAAAAARRRGGHH

Astrophysics, abstract
astro-ph/0504367
From: Gary Page [view email]
Date (v1): Sun, 17 Apr 2005 17:04:48 GMT (32kb)
Date (revised v2): Sat, 1 Oct 2005 13:46:27 GMT (43kb)

Utilizing Minor Planets to Assess the Gravitational Field in the Outer Solar System

Authors: Gary L. Page, David S. Dixon, John F. Wallin

Categories: astro-ph

Comments: Added substantial new material dealing with ability to observed effects addressed in paper

The twin Pioneer spacecraft have been tracked for over thirty years as they headed out of the solar system. After passing a heliocentric distance of 20 AU, both exhibited a systematic error in their trajectories that can be interpreted as a constant acceleration towards the sun and that has come to be known as the Pioneer Effect.

Spacecraft systematics are its most likely explanation, but there have been no convincing arguments that that is the case. The alternative, that the Pioneer Effect represents a real phenomenon, is very appealing for many reasons. What is lacking is a means of measuring the effect, its variation, its potential anisotropies, and its region of influence.

We show that minor planets provide an observational vehicle for investigating the gravitational field in the outer solar system, and thus provide a means of measuring the Pioneer Effect and potentially to either support or refute its existence as a real phenomenon. Minor planets can be used for this purpose because they have a large mass and are large and bright enough to be observed for useful intervals.

Thus, even if the Pioneer Effect does not represent a new physical phenomenon, minor planets can be used to probe the gravitational field in the outer solar system. Since there are very few intermediate range tests of gravity at the multiple AU distance scale, this is a worthwhile endeavor in its own right. It might even be possible to differentiate between the predictions of alternative explanations for the Pioneer Effect.

http://arxiv.org/abs/astro-ph/0504367

Paper: astro-ph/0506281

replaced with revised version Mon, 24 Oct 2005 20:43:50 GMT (41kb)

Title: Analytic Gravitational-Force Calculations for Models of the Kuiper Belt,
with Application to the Pioneer Anomaly

Authors: Michael Martin Nieto

Comments: 11 pages, 8 figures, final corrections for publication

Report-no: LA-UR-05-4414

Journal-ref: Phys. Rev D 72 (2005) 083004

We use analytic techniques to study the gravitational force that would be produced by different Kuiper-Belt mass distributions. In particular, we study the 3-dimensional rings (and wedge) whose densities vary as the inverse of the distance, as a constant, as the inverse-squared of the distance, as well as that which varies according to the Boss-Peale model. These analytic calculations yield physical insight into the physics of the problem. They also verify that physically viable models of this type can produce neither the magnitude nor the constancy of the Pioneer anomaly.

\\ ( http://arXiv.org/abs/astro-ph/0506281 , 41kb)

Paper (*cross-listing*): gr-qc/0511026

Date: Sun, 6 Nov 2005 02:40:04 GMT (162kb)

Title: Gravitational solution to the Pioneer 10/11 anomaly

Authors: J. R. Brownstein and J. W. Moffat

Comments: 11 pages, 4 figures, 1 table
\\
A fully relativistic modified gravitational theory including a fifth force
skew symmetric field is fitted to the Pioneer 10/11 anomalous acceleration. The
theory allows for a variation with distance scales of the gravitational
constant G, the fifth force skew symmetric field coupling strength omega and
the mass of the skew symmetric field mu=1/lambda. A fit to the available
anomalous acceleration data for the Pioneer 10/11 spacecraft is obtained for a
phenomenological representation of the "running" constants and values of the
associated parameters are shown to exist that are consistent with fifth force
experimental bounds. The fit to the acceleration data is consistent with all
current satellite, laser ranging and observations for the inner planets.

\\ ( http://arXiv.org/abs/gr-qc/0511026 , 162kb)

Calculations using the 'MOND' theory (Modified Newtonian dynamics) also have been applied and did fit well with the Pioneer data. No fifth force needed in that case.

Some more on MOND here:
http://www.astro.umd.edu/~ssm/mond/

I wonder if we could do any theory of any kind, adjust parametres and obtain a fit with anything.

But if the fit goes for not only Pioneer data, but all similar data, it is more intersting. Not an evidence of any given theory, but a last of a common mechanism.

That's what a theory is.

We've been a little preoccupied!

There are updates on our website here, including reports from a staff member who we sent to the conference in Switzerland:
http://www.planetary.org/programs/projects...ly/updates.html
And "begathon"...I like it...captures the tone of those four-page letters nicely...

--Emily

Yes, why I was somewhat vary of the idea of a "fifth force" suggested here.
I like things bare bones simple, and so a strong supporter that Occam sharpen his blade.
So when MOND theory originally for explaining the rotation of galaxies also turned out to fit for the much closer Pioneer I happily accepted the notion that there might be something more that makes this idea deserves attention.
(Note: I originally read about the theory in Scientific American, and got interested in it.)

Call me old fashioned, but I am a bit wary of jettisoning the "old physics" when the effects are at what I understand to be the threshold of detection, and we really don't know what the environment the little guys are swimming in right now is like - we may need to look for a new theory of interstellar wind before altering the laws of motion.

Still it is fun to think about - and it IS possible I suppose -

This page from the Planetary Society puts it well:

Dear Emily,

Speaking of TPS-funded projects, what has happened with Project BETA? Was the Harvard dish ever repaired? If not, is there an alternate plan to keep BETA running? Or is everything focused on Optical SETI now? And what has happened with that project lately?

Thank you.

Pioneer 10 & 11 are not the only odd-ball observations, and I am not talking about rocks that look like a pock-marked Elvis.

Pioneer 6 charted heavy Doppler residuals, and a linear component (similar to the term used in this paper) had to be added to the solar wind to plot both Galileo and Ulysses during interplanetary transitions. There is a possibility that when all the dots are connected, something fundamental will jump out of the wood work.

That's a good question, and I don't know the answer, and the SETI areas of our website have suffered a bit through the redesign process. We should have answers for you there and we don't. I'll try to follow up. Amir Alexander here at the Society is the one who does SETI, I'll see if he can answer your question.

--Emily

True, but we have too few dots right now, and this is another great reason to have more outer solar system missions!

Though, infuriatingly, we will have to wait quite a long time for a return on investment, even for the New Horizons data.

I don't mean to imply that only odd balls that make odd ball observations, and I realize an anomaly to be explained can be a doorway to new understanding - Black Body Radiation anyone?

I find it fascinating nonetheless that the universe is understandable at all, and if you think about it, Science has only had a few centuries to explore the entire span of space time from our little home here. I am sure there are plenty of surprises in store.

Astrophysics, abstract
astro-ph/0505310

From: Michael A. Ivanov [view email]

Date (v1): Sat, 14 May 2005 19:34:27 GMT (122kb)
Date (revised v2): Mon, 19 Dec 2005 16:23:51 GMT (124kb)

Low-energy quantum gravity leads to another picture of the universe

Authors: Michael A. Ivanov

Comments: 13 pages, 4 figures, LaTeX. Contribution to the 1st Crisis in
Cosmology Conference (CCC-1), Moncao, Portugal, 23-25 June 2005. A computational error amd some misprints are corrected in this version

If gravitons are super-strong interacting particles and the low-temperature graviton background exists, the basic cosmological conjecture about the Dopplerian nature of redshifts may be false: a full magnitude of cosmological redshift would be caused by interactions of photons with gravitons. Non-forehead collisions with gravitons will lead to a very specific additional relaxation of any photonic flux that gives a possibility of another interpretation of supernovae 1a data - without any kinematics. These facts may implicate a necessity to change the standard cosmological paradigm. Some features of a new paradigm are discussed. In a frame of this model, every observer has two different cosmological horizons. One of them is defined by maximum existing temperatures of remote sources - by big enough distances, all of them will be masked with the CMB radiation. Another, and much smaller, one depends on their maximum luminosity - the luminosity distance increases with a redshift much quickly than the geometrical one.

If the considered quantum mechanism of classical gravity is realized in the nature, then an existence of black holes contradicts to the equivalence principle. In this approach, the two fundamental constants - Hubble's and Newton's ones - should be connected between themselves. The theoretical value of the Hubble constant is computed. Also, every massive body would be decelerated due to collisions with gravitons that may be connected with the Pioneer 10 anomaly.

http://arXiv.org/abs/astro-ph/0505310

General Relativity and Quantum Cosmology, abstract
gr-qc/0512121

From: Slava G. Turyshev [view email]

Date: Wed, 21 Dec 2005 21:49:36 GMT (882kb)

The Study of the Pioneer Anomaly: New Data and Objectives for New Investigation

Authors: Slava G. Turyshev, Viktor T. Toth, Larry R. Kellogg, Eunice. L. Lau, Kyong J. Lee

Comments: 42 pages, 40 figures, 3 tables

Radiometric tracking data from Pioneer 10 and 11 spacecraft has consistently indicated the presence of a small, anomalous, Doppler frequency drift, uniformly changing with a rate of ~6 x 10^{-9} Hz/s; the drift can be interpreted as a constant sunward acceleration of each particular spacecraft of a_P = (8.74 \pm 1.33) x 10^{-10} m/s^2. This signal is known as the Pioneer anomaly; the nature of this anomaly remains unexplained. We discuss the efforts to retrieve the entire data sets of the Pioneer 10/11 radiometric Doppler data. We also report on the recently recovered telemetry files that may be used to reconstruct the engineering history of both spacecraft using original project documentation and newly developed software tools. We discuss possible ways to further investigate the discovered effect using these telemetry files in conjunction with the analysis of the much extended Doppler data. We present the main objectives of new upcoming study of the Pioneer anomaly, namely i) analysis of the early data that could yield the direction of the anomaly, ii) analysis of planetary encounters, that should tell more about the onset of the anomaly, iii) analysis of the entire dataset, to better determine the anomaly's temporal behavior, iv) comparative analysis of individual anomalous accelerations for the two Pioneers, v) the detailed study of on-board systematics, and vi) development of a thermal-electric-dynamical model using on-board telemetry. The outlined strategy may allow for a higher accuracy solution for a_P and, possibly, will lead to an unambiguous determination of the origin of the Pioneer anomaly.

http://arxiv.org/abs/gr-qc/0512121

I just read through the last paper linked. They've done quite well at recovering a complete data set, including telemetry data like temperature and voltage readouts useful for reconstructing thermal contributions to the Pioneers' accelerations. Another cool tidbit: there is one last opportunity to attempt to contact Pioneer 10, coming up in this February/March. (They think that, just barely maybe there is enough power still now in the old RTGs...) The round-trip light-time is 25 hours, so the contact would proceed by sending out a signal from Goldstone, waiting a day while the earth spins around once and the radio waves make their merry way, and listening for a response again at Goldstone. Somehow that image amuses me :^)

Paper: astro-ph/0504367

Date (v1): Sun, 17 Apr 2005 17:04:48 GMT (32kb)
Date (revised v2): Sat, 1 Oct 2005 13:46:27 GMT (43kb)
Date (revised v3): Mon, 2 Jan 2006 16:12:03 GMT (36kb)

replaced with revised version Mon, 2 Jan 2006 16:12:03 GMT (36kb)

Title: Can Minor Planets be Used to Assess Gravity in the Outer Solar System?

Authors: Gary L. Page, David S. Dixon, John F. Wallin

Comments: Accepted for publication in The Astrophysical Journal

The twin Pioneer spacecraft have been tracked for over thirty years as they headed out of the solar system. After passing 20 AU from the Sun, both exhibited a systematic error in their trajectories that can be interpreted as a constant acceleration towards the Sun. This Pioneer Effect is most likely explained by spacecraft systematics, but there have been no convincing arguments that that is the case.

The alternative is that the Pioneer Effect represents a real phenomenon and perhaps new physics. What is lacking is a means of measuring the effect, its variation, its potential anisotropies, and its region of influence.

We show that minor planets provide an observational vehicle for investigating the gravitational field in the outer solar system, and that a sustained observation campaign against properly chosen minor planets could confirm or refute the existence of the Pioneer Effect.

Additionally, even if the Pioneer Effect does not represent a new physical phenomenon, minor planets can be used to probe the gravitational field in the outer Solar System and since there are very few intermediate range tests of gravity at the multiple AU distance scale, this is a worthwhile endeavor in its own right.

\\ ( http://arXiv.org/abs/astro-ph/0504367 , 36kb)

I bet it is not as simple as this, but I will post an idea and watch it be shredded . . .



Any possibility either Voyager craft could be spun at a few revs per hour, with the thrusters turned off, and keep the dish pointed at earth for maybe a year or two?

My thought is if we could get a confirmation of the Pioneer anomaly with a Voyager craft it might help JPL design a more capable or sophisticated 'Pioneer Anomally Probe' someday.

With the 'nodding' motion compensation used at Triton, I am cautiously optimistic that there might still be a new trick for our favorite 'old dog' to learn.

Having a spin stabilised period of flight for a Voyager might yield enough high quality tracking data at what would have to be an attractive price compared to launching another probe designed for the task.

Besides, I'm getting old and would like this mystery cleared up while I am still around . . .

One problem is that something that was not designed to be spin stabilized (like Voyager) would very likely not spin very well. E.g. the spin axis would move around. In the case of Voyager, a stable spin axis (is such exists) may not align with the axis if the high gain antenna.

Wasn't the spacecraft-solid rocket stack spin stabilized for the duration of the rocket's burn during Jupiter injection or was it also in 3-axis stabilization mode? I would have figured delivery errors would be minimized by spinning up first.

Another possible problem with spin-stabilizing is the star sensor, would it be able to cope with starfield smearing during rotation?

If all that's required is a beacon, then setting up a slow spin where the aim point of the antenna nutates around the position of the Earth might be better than a precisely-aimed but data-free arangement. The CG and dynamic behaviour of the Voyagers must be *very* well known by now (unless something has dropped off with the cold). If data is required, that's perhaps another story. Perhaps the lesson here is that future interstellar-precursor probes should be designed with graceful aging in mind, so that as their output of data reduces it still remains - just - there.

Oh, and isn't it good to hear that there's going to be another attempt to reach Pioneer!

Bob Shaw

Can New Horizons participate in this experiment? Or was that another item left off the menu?

That's an unfair and unjustified jab at the mission.

From http://www.planetary.org/programs/projects...e_20050720.html


Doug

If an objection to putting a Voyager into a slow spin is the likelihood that it would not be possible to stop the spin, do we care?

{well, of course we care, but you catch my drift}

IIRC, some of the fields and particle experiments on Voyager work better when the craft is spinning, and the craft has spun for short periods for that very reason during planetary encounters.

Maybe this isn't so unlikely?

Yes, but unlike the Voyagers, NH also has a spin mode which will be used during the long interplanetary cruise. So we might get long intervals when the s/c will be spin-stabilized and use it to get periods of precise tracking data. This will of course not be possible during the Jupiter encounter as well as the Pluto encounter phase, but at all other times (assuming thrusters will be off) it should be possible.
Seven years or so between Jupiter flyby and start of Pluto approach phase is a pretty good sample, IMHO.

Damn good point actually UG - hadnt thought of that.

Then again, they're planning a yearly checkout iirc though - and that may involved pitching/rolling/yawing the spacecraft to look at astronomical calibration targets, which would trash the effect wouldnt it?



Doug

I don't think it would trash the effect. At least much. They'll still have periods of inertial coast in between and still see if the modelled-out Doppler plots fit with the observed segments. A residual should still be detectable, though it won't take time do reach a big, nice and well-detectable magnitude before another "trashing" period. Then again, the s/c will probably have more stable RF oscillators so the balance could still hold.
On the other side, I vaguely *seem* to remember reading somewhere that NH actually won't be a good tool to measure the acceleration, I forget why.
Might have been something with the ultrastable oscillators thing.
Might have been a pigment of my imagination...

Alan addressed this back in Feb 05 in the "New Horizons, Pluto and the Kuiper belt" page. It seems like he plans to take full advantage of this opportunity.

Below is an excerpt from The Planetary Society's website of Merek Chertkow's report on the 2005 Pioneer Anomaly Conference:

Just what colour is your imagination?

tty