Strange Resistance on Pioneer 10/11

[Pangloss]

http://education.guardian.co.uk/higher/sciences/story/0,12243,1302857,00.html

 

The story says, in a nutshell, that both of the probes are experiencing identical change in trajectory not consistent with projections.

[5614]

there have been many articles about this, maybe it was with other probes or something, its not the first time i've read about stuff like this... the key thing is that it is unknown, no one knows what it is or why.... only more theories!

[Martin]

http://education.guardian.co.uk/higher/sciences/story/0' date='12243,1302857,00.html

 

The story says, in a nutshell, that both of the probes are experiencing identical change in trajectory not consistent with projections.[/quote']

 

5614 is right

there have been many article on this

it is important to keep being reminded of this

it is a real unsolved problem

 

it involves both probes: Pioneer 10 and Pioneer 11

each probe is behaving as if it feels the pull of the sun to be slightly stronger than would be predicted by the Newton formula for gravity.

 

people have been tracking them for years and also have been trying very hard to come up with reasonable mundane explanation like a gas leak acting as a tiny retro-jet and slowing the probes (but why would the same leak develope at the same distance from the sun in both probes in just the same way?)

 

as time goes on and the tracking goes on and it remains unexplained, more scientists appear to be accepting that this is evidence that the Newton gravity formula has to be reconsidered, and this would probably lead to a correction in Gen Rel too.

 

I will get some links later, if no one else provides some. have to go now

[HAL]

Well that's interesting. Another little window of opportunity to find out what is really going on.

[Martin]

Well that's interesting. Another little window of opportunity to find out what is really going on.

 

a bit of good luck. couldnt agree more

see if you can get anything out of this

http://arxiv.org/gr-qc/0307042

Laurent Nottale

The Pioneer anomalous acceleration: a measurement of the cosmological constant at the scale of the solar system

[Dave]

I find it amazing that these probes we launched in the 1980's (?) are still serving uses now. Has anyone got any ideas as to what's going on there?

[RICHARDBATTY]

I find it amazing that these probes we launched in the 1980's (?) are still serving uses now. Has anyone got any ideas as to what's going on there?

If you mean power it the rtg supplies used in these probes. Radioisotope thermal generator. A plutonium 238 slug provides heat to a plate, on the plate is a post of n type material and a post of p type material then on those are cold plates attached to a radiator to keep them cool. The heat plate is solid and the cold plates are like the battery terminals. The n/p materials are semi conductor types like electronic components.

[Martin]

I find it amazing that these probes we launched in the 1980's (?) are still serving uses now. Has anyone got any ideas as to what's going on there?

 

Here is a fairly recent (2003) paper

http://arxiv.org/abs/gr-qc/0308017

Finding the Origin of the Pioneer Anomaly

Michael Martin Nieto, Slava G. Turyshev

 

 

the conclusion is not atypical: the authors feel that after all the searching for a conventional-physics explanation, nothing satisfactory has surfaced.

So, they say, there should be a further mission. Another probe sent.

there seems to be a gradually crystalizing consensus that they really dont know what's going on (gas leak or sunlight pressure dont explain it, its real)

 

Another paper along those lines came out just this week

http://arxiv.org/abs/astro-ph/0409373

In this case the author proposes adding something to a possible mission to Pluto so that the mission can have a secondary goal of

investigating the Pioneer anomaly

-----------------------------------

 

I think when you say "I find it amazing that these probes we launched in the 1980's (?) are still serving uses now."

then you are commenting on the serendipity

or that it is a sign of good science that an experiment accidentally reveals something you weren't investigating-----a kind of grace.

 

However as richard batty says, one reason the probes are still providing information is because of the radioisotope generators----thermocouples I guess. so there is a practical angle to it too