space craft change speed as they swing by Earth

[DonAVP]

Here is something to talk about. Apparently sceintists have noticed small anomalies as various space craft swung Earth to launch them to other planets or outside the solar system. First noticed on Pioneer 10 and later called "Pioneer Anomaly". Here is the LINK
http://www.space.com/scienceastronomy/080229-spacecraft-anomaly.html

Anyway everyone is scratching there heads and trying to figure out what is causing it. This could through a wrench into the standard model and Celestia as well. Just kidding about Celestia.

So, I will throw out my theory. Even though these craft a small relative to mass because of their high rate of speed they are being effected by dark matter or energy or both in ways yet unknown. Do I hear any other ideas. The scientific world is waiting!

Don

PS Here is some eye candy if you don't know about this site.
http://antwrp.gsfc.nasa.gov/apod/astropix.html

[revent]

I've kinda suspected for a long time that the 'Pioneer Anomaly' was due to disregarding the effects of the (admittedly minute) change in rotational inertia (and rotational kinetic energy) of the solar system as the probes move outward. The same effect would occur during a close approach, but would generally be opposite in sign as the probe approaches and recedes, so it would tend to cancel itself out except for the residual of the asymmetry between the two paths.

Anyway, I don't think the effect is due to a shortcoming in GR, I think it's due to some simplifying assumptions made when modeling the system (ignoring the cumulative effect of frame dragging, essentially). My understanding is that any unknown effect large enough to cause the anomaly would have been noticed during GR experiments here on earth. I am NOT an expert on this or anything, though, so this is just me handwaving.

Just so you know, BTW, the term 'standard model' generally refers to particle physics, and isn't really related to issue of gravity and relativity. It was obvious what you meant, tho.

[selden]

There's no need for any non-standard physics.

Previously unmodelled thermal emissions seem to account for most, perhaps even all, of the observed acceleration.

http://www.planetary.org/blog/article/00001400/