Mass moment of inertia is calculated by multiplying an object's center of mass by the square of the distance to its axis of rotation. If that sounds a lot like torque, that's because it is.

Figure 2 Rotary Motion where the torque applied to an object is equal to its moment of inertia about the rotation axis multiplied by its rotary acceleration. Source: John Dunn. In a rotary motor, the ...

The spin axis precesses at a rate of 44.58 ± 3.3 arcseconds per year, which gives a normalized moment of inertia of 0.337 ± 0.024 and yields a rough estimate of the size of the core.