Well let’s say you’re not quite at the center but maybe a few hundred or a thousand miles out and the metals there are all liquified. In that case you would expect great pressures, wouldn’t you?
Yeah, I guess we can go tell coal miners that when they dig out a big room of coal 400 feet deep that they don’t need to put up any roof supports or leave pillars of coal, because there’s no pressure in a cave.
I'm not really sure. I'm not at all sure that the metals there are all liquid. I don't see why they would be liquefied. But if you are 1000 miles from the center of the earth, you are surrounded by a more or less uniform mass field 3000 miles in diameter which cancels itself out gravitationally, and another shell of mass about half of the mass of the entire earth which would act gravitationally upon you from its center of mass which is about 4400 miles away from you. (which reduces the gravitational attraction by another 20% or so because surface gravitation acts from only 4000 miles away)
ML/NJ