Wanted to jump in and ask, does anyone remember a site that went through the math of two magnetic rings being charged and discharged out of sync, utilizing the delay in the speed of light between the rings to create a net force? Imagine a craft shaped like a dumbbell, with the rings where the weights are:<p>|---|<p>1...2<p>The idea was that you'd create a strong magnetic field in ring 1, and then the wave would travel outward both directions (one away from the ship, and one along it) and interact with ring 2, which has the opposite polarity. Ring 2 would be attracted to the magnetism from ring 1, and pull the ship to the left. Then ring 1 would turn off, and by the time the wave from ring 2 reached it, there would be no interaction. So the craft would feel a net thrust to the left. The process would repeat over and over again at high frequency, propelling the craft faster and faster.<p>I believe the site said the process was 25% efficient, and didn’t violate any laws of physics. The difficulty lies with hysteresis because it takes a comparatively long time to charge a magnetic field, compared to the time it takes light to span the distance. So it went off on a tangent about using lasers to charge a superconducting ring.<p>But I’ve always wondered if resonance could somehow be used to take the coils out of sync automatically, a bit like a tesla coil but with an imbalance the puts one ring slightly behind the other in time with respect to their frames of reference. As they move more out of phase, the net force on the coils should get stronger and stronger. This sounds similar in some ways to the the way a magnetron works, so if it can be put out of phase in a similar way, then I’m not entirely surprised by NASA’s result. If it’s true that the time delay in the speed of light can be converted to a propulsive force, then it’s going to change, well, pretty much everything about space travel. I really wish I had the link to that site.