Why is there an absolute universal reference frame with respect to rotation/spinning? I understand that rotation is a form of acceleration, but it still only seems to make sense in the context of a universe filled with other stuff. If you were the only entity in the universe, could you rotate in space? If you did, would you feel it? If every particle in the universe were artificially accelerated around you, such that it would look to you exactly like you were spinning around, would your arms be pulled outward as if it were you spinning?