Mysterious forces tug at the Pioneer probes.

[Mustaphile]

I read this in the guardian recently and thought some of the more scientifically minded might like to see it.

http://education.guardian.co.uk/print/0,3858,5014011-110865,00.html

 

[Amalthea]

I'll bet you it's outgassing from the probes.

 

[Suffolk Sean]

I'll bet you it's outgassing from the probes.

Out gassing at this stage? I would think any outgassing would have long ago ceased.

 

[Aeschylus]

It's old news, but nobody's managed to explain it yet, but then again it may well just be a systematic error.

 

[FromTheAshes]

'It's hard to imagine such a leak happening on both probes at the same time in such a way as to produce an identical acceleration,' he said.

My bet would be on particle accumulation. If they're picking up particles in their travels then their mass would be higher then our equations say it ought to be (we don't have statistics on particle density in the outer planetary systems). It's possible our understanding of gravity is fundimentally flawed, and Einstein screwed up as badly as Newton. That would make Quantum Physicists very very happy.

 

[Amalthea]

I'll provide a link later when I find it, I forgot the authors name but there was an important paper on this last year by a guy who was a big proponent of an exotic explanation. He now rejects this and favours the outgassing if I remember correctly.

 

[FromTheAshes]

Meh, outgassing would make a lot of sense if it's one probe, but for two probes (and I'm pretty sure they're both six-sigma precision) to fail the same way? Nah. Not unless there was something major overlooked. On the other hand the space equivelent of air resistance - constant impact with "space dust" would perfectly explain why they're slowing down the same amount. It might be that we've misestimated the density of space dust. It's not much of an effect, but over 30 years? It could make quite a difference.

 

[Ataradrac]

It's Planet X!! It's Planet X!!! *dons tinfoil hat*

 

[Amalthea]

Here is an interesting paper http://arxiv.org/abs/gr-qc/0107092.

And as his usual ascerbic self a Ned Wright summary

http://www.astro.ucla.edu/~wright/PioneerAA.html

I've always thought that jumping the gun for exotic physics is not a good idea when using data from 2 probes not designed for this work and even more importantly the fact that planets do not show these accelerations towards the Sun.

 

[FromTheAshes]

So an asymmetry in waste heat is all it takes? And an asymmetry of 3% no less? I wonder how many good explainations we can come up with without suggesting the laws of physics are busted?

P.S. WHY do the theoreticals jump the gun? Sometimes things not working right is just that - they're not working right. Doesn't imply the laws of physics screwed up

 

[Amalthea]

Hey I'm a theorist and I always look hard, very hard, for existing physics. Otherwise you end up being a "cold fusion" nutcase.

Actually it isn't all that bad for people to look for the exotic as long as others search out the mundane. Plus of course, if you show it's heat loss then you don't get anything more than a published paper that is soon forgotten since it quickly loses relevance whereas new physics and Nobel here I come.

 

[FromTheAshes]

Hey I'm a theorist and I always look hard, very hard, for existing physics. Otherwise you end up being a "cold fusion" nutcase.

That's unfair. Their original letter simply said that they'd found an energy increase when running a certain current through water a certain way, which, to paraphrase them, means jack, cause it's an exothermic process anyway. If we want to blame the right idiots we have to look at capitol hill.

Actually it isn't all that bad for people to look for the exotic as long as others search out the mundane. Plus of course, if you show it's heat loss then you don't get anything more than a published paper that is soon forgotten since it quickly loses relevance whereas new physics and Nobel here I come.

You see this is where your world and an engineer's differs. If we find some flaw in our calculations of forces we have to reconceptualize our models completely, then redo every simulation that ran with those models. It's a class A migraine. For you it's "quickly forgotten."