Your link doesn't even relate to time dilation and is also about a hollow sphere, not a uniformly dense solid sphere. Moreover in a hollow sphere, time dilation

Your link doesn't even relate to time dilation and is also about a hollow sphere, not a uniformly dense solid sphere. Moreover in a hollow sphere, time dilation still occurs because it depends on the absolute (or rather, relative to an outside distant observer) potential, not the gravitational field (which is the only thing that is necessarily zero as a result of the flat spacetime in the sphere). See for example this http://physics.stackexchange.com/questions/69821/a-hollow-black-hole http://physics.stackexchange.com/questions/69821/a-hollow-bl... It's like you didn't read your link