A common solution to the problem of artificial gravity in space is to have the space ship or station rotate, and the centrifugal force would "pull" objects toward the outside. What I haven't seen considered is that the station would have to have some kind of central motor attached to a central part of the station that would not rotate in the same way as the rest. Imagine two of these space stations orbiting Earth. They are exactly the same in all regards, except that in the first, the spinning section is significantly more massive than the center, and in the second the center is significantly more massive than the spinning section. In both stations, both outer sections rotate at the same rate relative to the center. This leads me to believe that both stations would have the same amount of artificial gravity. However, relative to the Earth, the outer section of the second station would be spinning significantly faster than in the first station, leading me to believe that the second station would have significantly greater artificial gravity than the first. My question is, which is correct? How does the relativity of the rotational velocity of the outer sections relate to the non-relativity of the actual acceleration felt by people aboard the station?