"Do you get seizure from the stroboscopic effect of the Sun lightning you up once every 24 hours???Look at the size of those cylinders! And lookup in wikipedia if you can't remember your physics lessons!The centrifugal force is F=m.w^2.R so w^2=(F/m)/Rw=sqrt((F/m)/R)F/m is the acceleration. If you want to get an accelleration similar to Earth gravity (but actually I guess most people would want a smallest gravity, perhaps down to half Earth gravity), you take F/m=9.81;With a radius R=500 m (that's only 3.14 km around, if you have six sectors, only 523 m wide!), you get w = sqrt(9.81/500) = 0.14 rd/s or 0.000371 rotations per minute. The inverse is 2691 minute per rotation, or 44 HOURS per rotation!Is it still too fast a strobe for you???The problem is actually to get a day cycle of 24 hours. would either have to reduce the radius for example, 145 m for 9.81 m/s^2, but this gives a very small cylinder. Alternatively, you could have smaller windows, and use mirrors to project light during smaller periods. But you would want to do that synchronously for all the sections, because it would be no night if you had two lighted sections overhead."