 Ida's rotation period is 4.63 hours, making it one of the fastest rotating asteroids yet discovered. The calculated maximum moment of inertia of a uniformly dense object the same shape as Ida coincides with the spin axis of the asteroid. This suggests that there are no major variations of density within the asteroid. Ida's axis of rotation precesses with a period of 77 thousand years, due to the gravity of the Sun acting upon the nonspherical shape of the asteroid.
