"greywolf42" wrote in message ...
Jonathan Silverlight wrote
in message ...


There's an article in the current issue of Nature that seems relevant to
the Pioneer anomalous acceleration question ("A test of general
relativity using radio links with the Cassini spacecraft" B Bertotti, L
Iess and P Tortora, Nature vol 425. No. 6956 p. 374,
doi:10.1038/nature01997)
AFAICS they have accurately modelled emission from the RTGs and they
don't see any unexplained acceleration.

They haven't looked for anomalous acceleration with this experiment. The
referenced experiment measures the time-delay of the signal in a
gravitational field. Nothing more.

Does that mean the question is settled, or isn't their measurement
sufficiently sensitive?

The question was settled years ago. There *is* definitive anomalous
acceleration in pioneer and the voyagers. No theoretical explanation has
yet been settled on.

Finally gathered the courage to tentatively suggest that when photons
are emmitted, they give a 'recoil' against the source. If radiation
from within the craft is directed in a particular direction, a thrust
might occur. (I thought that this would be so insignificant as to be
immesurable and undetectable, but maybe not)
What would happen to a high-power laser carefully suspended- any
chance of detecting an observable thrust counter to beam direction???

Jim G