Re: Pioneer anomaly

Gerard Westendorp <westy31@xxxxxxxxx> writes:

> If you look at plane wave solutions of the Maxwell equations in a space
> with charge density (c) and mass density (m), you get the dispersion
> relation:
>
> w^2 + k^2 + c/m = 0
>
> So if you had a sufficiently large charge density, you would get a
> big distortion of radio waves, especially low frequency ones, like you say.
> But if for example the the mass of the particles were large, than we
> would see a smaller effect.

Yes, but note it's not enough to know just the overall charge density;
positive and negative charges don't cancel out here. If you have fully
ionized hydrogen plasma (that is, free electrons and free protons), the
effect on radiation would be immense even if the net charge density is
zero.

> In the case of the earth's ionosphere, we do get quite an effect on
> low frequency radio, and a lot less on higher frequencies such as light.
> But these charge densities would be huge compared to the ones near
> Pioneer. So I am not so convinced.

I'm not convinced that we can get any deceleration on the Pioneer this
way. If the charge density is uniform al around the Pioneer, there's no
deceleration, so all of the charge would have to be in front of it and
none behind it. But that would only be possible if the charge was in a
long thin cloud along the Pioneer's trajectory, so that it picks up all
of it as it moves along. That's not very likely.

--
Esa Peuha
student of mathematics at the University of Helsinki
http://www.helsinki.fi/~peuha/

.