On 5/06/2018 12:30 AM, John Berry wrote: John, there might be the odd exception.
I can give you an example that seems to break the CoM and CoE, it isn't practical. Now there might be an explanation, MAYBE it produces a photos that explains the propulsive effects... But I doubt it. Now, the easiest way to explain (though there is a way this can work without switching and just use DC electromagnets or even permanent magnets to affect Inertial mass positively or negatively) this is if you have an electromagnet establish a field, a large field And then you have a second electromagnet turn on suddenly, and it is attracted or repelled. Then, before the magnetic field from the second electromagnet can affect the first electromagnet, you turn off the first electromagnet. Standard physics says that the momentary field from the second electromagnet will propagate outwards from it at light speed so that it passes completely through the first electromagnet and affects it to just the extent that it would have affected it if the field propagation was instantaneous. So after a very short time, CoM is restored. I am confident that if you were to include the momentum of the field in the calculation, then CoM would be continuously satisfied over all space. (That is after all how physicists would work out the momentum of the field - by *assuming* that the total must always be conserved!) So now you have gained thrust from one electromagnet, but the other has experienced no forces. As I say, a version without switching can be envisioned where one magnet, or both are suddenly accelerated in the same direction so that one moves deeper into the field of the other, and the other moves out of the field, so one finds the attraction or repulsion between then increased, the other finds it decreased as neither sees the "new" or current position for the other magnet. By doing this you can create without and doubt thrust, break the CoM and therefore the CoE... And the only way it could fail is if you prove that magnetic fields, near-fields transfer forces and information INSTANTLY which Einstein would consider a blow. This is not wrong, Unless as I said that a bit fat photon carries all that momentum in the opposite direction. I personally cannot see where there would be a cost of energy though for the photon to be coming from. There is something usually called "radiation damping" which is the mechanical effect on moving charge that is the *reaction force* of suddenly accelerating or decelerating the charge. After this sudden acceleration, its effect then radiates outward at light speed and can finally cause acceleration of remote charges - which finally balance the CoM equations for solid matter (which were unbalanced while the radiation was in transit).