View Full Version : Pioneer 10 & 11 Data Puts Limit on Dust

2005-Jan-31, 01:18 AM
Here's a paper by Michael Martin Nieto, Slava G. Turyshev, and John D. Anderson about how the data from the two Pioneer extra-solar probes are providing limits to mass density of interplanetary dust in the outer (~20-70AU) solar system.

Directly Measured Limit on the Interplanetary Matter Density from Pioneer 10 and 11 (http://www.arxiv.org/PS_cache/astro-ph/pdf/0501/0501626.pdf)

Note that these are the same people who first reported the anomaly, and that many alternative theories depend on their data. While this paper pretty much rules out dust as the sole cause of the anomaly, the main focus is on what else can be learned from the motion of these probes.

John L
2005-Jan-31, 07:42 PM
That was a good article. I think they addressed the gas and dust inward acceleration versus the solar radiation pressure outward acceleration well. I'm also glad they pointed that an as yet unconsidered cause is dark matter.

Interestingly, the ESA (http://physicsweb.org/articles/world/17/9/3/1), back in September 2004, began investigating missions to identify the cause of this anomaly.

Pioneering mission

Thanks to new technologies such as precise accelerometers, improved launch techniques and optical navigation methods, we have come up with a proposal for the most precisely tracked spacecraft ever to go into deep space. The craft is also designed to eliminate essentially all on-board effects that might mask the result, such as forces due to radiated heat. And its hyperbolic orbit, like that of the Pioneer probes, will allow it to distinguish between the different types of effect that might be causing the anomaly.