[gumby]

What is the force of gravity at any point in such a sphere? So what does GR have to say?

[lalaithion]

The force of gravity is 0. But the potential of gravity is higher than on the outside, so clocks run slower.

[pdonis]

> the potential of gravity is higher than on the outside, so clocks run slower

Correction: the potential of gravity is lower inside the sphere than outside, so clocks run slower.