Re: Pioneer anomaly

John Baez wrote:
>
> I've added a new entry about the Pioneer anomaly to my
> "open questions in physics" webpage:
>
> http://math.ucr.edu/home/baez/open.questions.html
>
> I think it's ripened to a nice mystery.
>
> .........................................................................
>
> Cosmology and Astrophysics Open Question #13
>
> What is the explanation of the Pioneer anomaly?
>
> The Pioneer 10 and Pioneer 11 spacecraft are leaving the the Solar System.
> Pioneer 10 sent back radio information about its location until January
> 2003, when it was about 80 times farther from the Sun than the Earth is.
> Pioneer 11 sent back signals until September 1995, when its distance
> from the Sun was about 45 times the Earth's.
>
> The Pioneer missions have yielded the most precise information we have
> about navigation in deep space. However, analysis of their radio tracking
> data indicates a small unexplained acceleration away from the Sun! The
> magnitude of this acceleration is roughly 10^{-9} meters per second per
> second. This is known as the "Pioneer anomaly".
>
> Many physicists and astronomers have tried to explain the Pioneer using
> conventional physics, but so far nobody seems to have succeeded. There
> are now an increasing number of proposals that try to explain the anomaly
> using new physics - in particular, modified theories of gravity. But
> there is no consensus that any of these explanations are right, either.
>
> For more information, see:
>
> * The Pioneer Collaboration, A Mission to Explore the Pioneer Anomaly.
> http://arxiv.org/abs/gr-qc/0506139
>
> * Wikipedia, Pioneer Anomaly.
> http://en.wikipedia.org/wiki/Pioneer_anomaly

http://arxiv.org/abs/gr-qc/0205059
Pioneer anomaly
http://arXiv.org/abs/gr-qc/0307042
Rationalized Pioneer anomaly
http://arXiv.org/abs/gr-qc/9810085
Believable rationalized Pioneer anomaly
http://arXiv.org/abs/gr-qc/gr-qc/0310088
Believable Pioneer anomaly updated
http://arXiv.org/abs/physics/0502123
Commentary on Pioneer anomaly minutia

Assemble a redundant long duration vessel with a significant Pu-238
power supply, stick it atop a Saturn V, skim it hard behind Jupiter
for a massive gravitational boost, sit back and track it. Better
would be two vessels, one to be slingshot in the ecliptic plane and
one normal to it. Inner planet slingshots to get them to Jupiter are
merely paperwork.

NASA doesn't do space missions. NASA does publicity missions in
space. Numbers on the 04 July Deep Impact/Comet Tempel-1 stunt: 10.2
km/sec closing speed, 370 kg impactor, 19 gigajoules delivered - equal
to 4.8 tons of TNT. Four limiting outcomes:

1) Dirty snowball and gravity-dominated boom-boom. Deep, wide
crater with lots of ejecta.
2) Icy dirtball and strength-dominated ejecta. Crappy little
crater and ejecta. Rock doesn't vaporize well.
3) Unconsolidated foam of frozen gas and dirt with
compression-dominated impact. The thing goes in like an ice pick into
styrofoam. When the plasma ball detonates there is no easy exit. The
comet fragments.
4) NASA misses the broad side of Manhattan. We are then mildy
curious about whether the bullet can find its way back home.

--
Uncle Al
http://www.mazepath.com/uncleal/
(Toxic URL! Unsafe for children and most mammals)
http://www.mazepath.com/uncleal/qz.pdf
.

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