I know this won't work, I'm having trouble explaining why to someone who thinks it will. Make a ring around a planet. Give it low walls. Fire countless pellets at hypersonic speeds around the inside of the ring. The pellets are moving at super-orbital speed, pushing the ring outward, making it rigid. Supposedly, this will also keep it stable over the planet, since essentially, you've got forces pushing outward on the ring in all directions. I know that this does not work. I know it's because a] the pellets are not in "orbit", since they are restrained by the ring and therefore cannot move freely in an elliptical orbit, trading altitude for velocity and back again, and b] the net gravitational force on such an object is zero. So it has no reason to stay stable. I know this arrangement is slightly different from Larry's Niven's Ringworld, but it's a difference that makes no difference. (A fact that is lost on my adversary). How can I describe the problem in a way that will disabuse him of the notion that the supposed super-orbital push of the pellets will cancel out?