The Pioneer Anomaly Options

[remcook]

http://www.planetary.org/news/2005/pioneer_anomaly_faq.html

The planetary society may be checking it out...

The Planetary Society has committed to raise the funds to preserve the priceless Pioneer data from destruction.


After years of analysis, but without a final conclusion, NASA, astonishingly, gave up trying to solve the "Pioneer Anomaly" and provided no funds to analyze the data. The Pioneer data exists on a few hundred ancient 7- and 9-track magnetic tapes, which can only be read on "antique" outdated computers. The agency is going to scrap, literally demolish, the only computers able to access and process that data in the next few months!

[lyford]

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:

The simple engineering explanation cannot yet be ruled out, but enough work has been done in trying all the different possibilities that even Occam's Razor allows us to cut a little way into the idea of a new physics.

[The Messenger]

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 -

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.

[lyford]

Pioneer 10 & 11 are not the only odd-ball observations.... (edit) ....There is a possibility that when all the dots are connected, something fundamental will jump out of the wood work.

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.

[ljk4-1]

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

[ljk4-1]

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

[tfisher]

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 :^)

[ljk4-1]

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)