It does… a little bit. A rotating object will have its outer parts under tension because of the centripetal acceleration, which wants to pull them outward. Unless the object flies apart, it is doing a tiny amount of work by staying intact while rotating, because its outer parts have to keep changing direction. Because of this, the object will also radiate gravitational waves, and will very gradually slow down, probably over thousands and millions of years.
Quartersharp t1_j0fnrfp wrote
Reply to comment by [deleted] in Does rotation break relativity? by starfyredragon
It does… a little bit. A rotating object will have its outer parts under tension because of the centripetal acceleration, which wants to pull them outward. Unless the object flies apart, it is doing a tiny amount of work by staying intact while rotating, because its outer parts have to keep changing direction. Because of this, the object will also radiate gravitational waves, and will very gradually slow down, probably over thousands and millions of years.