Earth has an inertia of \(5.97 \times 10^{24} \mathrm{~kg}\) and a radius of \(6.37 \times 10^{6} \mathrm{~m}\).

(a) Calculate its rotational inertia about the rotation axis, assuming uniform density.

(b) The rotational inertia of Earth about its rotation axis has been measured to be \(8.01 \times 10^{37} \mathrm{~kg} \cdot \mathrm{m}^{2}\). What does the difference between this value and the value you calculated in part \(a\) tell you about the distribution of inertia throughout the planet?