Jim, there is a mathematical proof that angular momentum must be conserved if the dynamical laws are invariant under spatial rotations. That is Noether's theorem that I spoke of. Actually, though, the angular momentum of the physical bodies need not be conserved if there are radiative fields that carry some of it away. The sun-earth system could decay and still conserve angular momentum, if gravitational radiation carried the angular momentum away. However, its not supposed to do this, unlike the case of electromagnetism, which would. As far as the moon orbiting the sun, it does, but its orbit is highly perturbed by the presence of the earth, if you want to look at this way. Once you have the equations of motion of the system, you can interpret them any number of way. Its just when you are trying to calculate the motion that its convenient to work through starting with the strongest forces first.
Now, back to the fascinating topic of time-advanced forces. I am so far out on a limb that I am going to cut it off myself before somebody else can't resist the temptation. Here's an example of an obvious consequence if it were as easy as I hypothesized to shine a laser beam into the past:
Every time a geosynchronous-orbit communication satellite relayed a message from one ground station to another, the relayed message would be transmitted into both the past and the future. This would result in two messages received at the recieving ground station, one simultaneous with transmission by the transmitting station and one delayed by the round-trip travel time to geo-synch and back. Everybody has probably experienced this latter delay in a satellite phone call, but the advanced one is conspicuously absent.
Price attempts to get around this by supposing that the time-advanced radiation has the opposite effect to time-retarded light. That is, instead of the laser beam heating a spot on the detector, the time-advanced light would cool it. This kind of effect is of course more difficult to detect, though I think not impossible. However, I don't think theory supports that time-advanced radiation would act this way. The modulation on a time-advanced wave changes with time just like on the time retarded wave. The only difference is that it arrives at the reciever before it left the transmitter. This is a trivial consequence of the form of the functional arguments. So why should the same signal at different instants cause cooling in one instance and heating in another? I don't see how it can.
Another way to look at is if we move the transmitter and receiver close together. If the retarded beam is heating (that is, doing positive work on the matter in the detector) while the advanced beam is cooling (which corresponds to doing negative work) then as we approach the laser (say) transmitter the beam actually must become undetectable as the net work done on the detector becomes zero. This also is not observed.
Yet still, it is completely proper to say, current electromagnetic theory predicts that time-advanced radiation exists. This seems to me equally important as Einstein's criticism that quantum theory is not complete, which also has never been adequately answered.
