Is time really slower the closer you get to the core of the earth, or is it simply that mechanical instruments are affected more by the forces of gravitational pull on objects closer to the the core of the earth? I think time is constant, and it’s just devices run at different speeds as they move further from the core of the earth and the effects of gravitational pull upon objects.
The effect is real, not an artifact of our instruments. And it’s not really correct to say time slows down more and more as you get closer to the earth’s core. Instead it slows down as you move to regions where the gravitational field is greatest or strongest. At the core itself, the strength of the field is zero: you’d float at the core if you hadn’t been burned up and crushed by the conditions down there, and your clock would run as fast as it can anywhere in the vicinity of the earth. I’ve seen some really great quotes about this that makes this clear. I’ll try to find some of them and put them up here for you.
t is not just the clocks that slow down: lower down, all processes are slower. Two friends separate, with one of them living in the plains and the other going to live in the mountains. They meet up again years later: the one who has stayed down has lived less, aged less, the mechanism of his cuckoo clock has oscillated fewer times. He has had less time to do things, his plants have grown less, his thoughts have had less time to unfold ... Lower down, there is simply less time than at altitude.
Photons are the carriers of present, the present of their creation. Since a black hole prevents photons from receding from such a deep gravity well, is time stopped inside a black hole?