Centrifugal Force -- continue spinning indefinately in space? I believe it is correct that if you spin up an object in space, like a space ship, it will continue spinning indefinately unless/until another force is applied to stop it from spinning. Then centrifugal force would push the objects in the ship outward and the outer walls of the ship would hold the objects in, simulating gravity. What I don't get is how this system can continue spinning indefinately when the objects inside are putting a force on the walls. Wouldn't that force have the effect of slowing it down over time? It seems odd that this force can exist in perpetuity without any energy source to continue driving it once it is set in motion.