Gravity from the Ground up -- Schutz

Mike Hewson
Mike Hewson
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RE: Yes, I believe the

Quote:

Yes, I believe the Pioneer Anomaly has been solved. It wasn't due to low-frequency gravitational waves, or any one of a number of other theories.

The final resolution came from the recent work by Portuguese scientist Federico Francisco and colleagues at the Instituto de Plasmas e Fusao Nuclear in Lisbon, claiming the original thermal calculations -- the ones that ruled out heat as a possible explanation for the anomaly -- were wrong!

Specifically, Francisco et al. reworked the calculations taking into account not just how heat is emitted, but also how it gets reflected off various parts of the spacecraft. As a result, the anomaly disappears.

Whew!


Thanks for that input! I couldn't recall whom to attribute that work to. :-)

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Gundolf Jahn
Gundolf Jahn
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RE: RE: Yes, I believe

Quote:
Quote:

Yes, I believe the Pioneer Anomaly has been solved. It wasn't due to low-frequency gravitational waves, or any one of a number of other theories.

The final resolution came from the recent work by Portuguese scientist Federico Francisco and colleagues at the Instituto de Plasmas e Fusao Nuclear in Lisbon, claiming the original thermal calculations -- the ones that ruled out heat as a possible explanation for the anomaly -- were wrong!

Specifically, Francisco et al. reworked the calculations taking into account not just how heat is emitted, but also how it gets reflected off various parts of the spacecraft. As a result, the anomaly disappears.

Whew!


Thanks for that input! I couldn't recall whom to attribute that work to. :-)

Cheers, Mike.


There's been made an analysis with similar results at Zentrum für angewandte Raumfahrttechnologie und Mikrogravitation (ZARM) in Bremen. Other than Frederico Francisco, they used the finite elements method to calculate the thermal repulsive forces. (Annalen der Physik, June 2011 / Spektrum der Wissenschaft, July 2011)

Gruß,
Gundolf

Computer sind nicht alles im Leben. (Kleiner Scherz)

Matt Giwer
Matt Giwer
Joined: 12 Dec 05
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Credit: 6,891,649
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RE: Yes, I believe the

Quote:

Yes, I believe the Pioneer Anomaly has been solved. It wasn't due to low-frequency gravitational waves, or any one of a number of other theories.

The final resolution came from the recent work by Portuguese scientist Federico Francisco and colleagues at the Instituto de Plasmas e Fusao Nuclear in Lisbon, claiming the original thermal calculations -- the ones that ruled out heat as a possible explanation for the anomaly -- were wrong!

Specifically, Francisco et al. reworked the calculations taking into account not just how heat is emitted, but also how it gets reflected off various parts of the spacecraft. As a result, the anomaly disappears.

Whew!

http://arxiv.org/abs/1103.5222

Modelling the reflective thermal contribution to the acceleration of the Pioneer spacecraft
Authors: F. Francisco, O. Bertolami, P. J. S. Gil, J. Páramos
(Submitted on 27 Mar 2011)

Abstract: We present an improved method to compute the radiative momentum transfer in the Pioneer 10 & 11 spacecraft that takes into account both diffusive and specular reflection. The method allows for more reliable results regarding the thermal acceleration of the deep-space probes, confirming previous findings. A parametric analysis is performed in order to set an upper and lower-bound for the thermal acceleration and its evolution with time.

Comments: 11 pages, 7 figures, 3 tables
Subjects: Space Physics (physics.space-ph); Instrumentation and Methods for Astrophysics (astro-ph.IM); General Relativity and Quantum Cosmology (gr-qc)
Cite as: arXiv:1103.5222v1 [physics.space-ph]
Submission history
From: Frederico Francisco [view email]
[v1] Sun, 27 Mar 2011 15:07:48 GMT (275kb)

Mike Hewson
Mike Hewson
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Thank you Matt. I will

Thank you Matt. I will closely read that one. I immediately see that the modeling depends not only upon the decay of the onboard power generator but also the thermodynamic geometry of the craft and degradation of what putatively remains of it's functioning systems. Even when barely/not operating to specification it still speaks lessons to us from such an enormous distance. They are remote human artifacts and we can but hope that they reach the scrutiny, maybe even with insight and benefit, of sentient beings!

I visited Tidbinbilla near Canberra about 5 years ago and I believe they still are following the Voyager craft too.

Cheers, Mike.

I have made this letter longer than usual because I lack the time to make it shorter. Blaise Pascal

Matt Giwer
Matt Giwer
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RE: Thank you Matt. You

Quote:
Thank you Matt.

You want to while away an afternoon just scan what is available at arvix.org and collect more papers than you will ever find time to read. It is a real exercise in learning to prioritize.

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