So, I just finished Ringworld's Children and I was wondering how feasible the proposal of a ringworld would be if it had a Dyson sphere on the inside of it. The sphere would be open or transparent in places in order to allow light to reach the ringworld surface of course. However, would the sphere be able to maintain a stable spin so that the openings stayed lined up with the ringworld? I imagine that some kind of magnetic force could be used to keep the sphere in line with the ringworld, but it just seems odd. Also, what would you all think up as an alternate form of meteor defense for the ringworld? I know the sun cannon would be inoperative by having a sphere around the sun so I'm interested to hear what you guys think up.