It's very simple. The earth isn't a flat disc.
The equivalent of saying "Nuh-uh!"
Gecko, you continue to astound me by how much of a geek you are not. You might be an outcast, socially awkward, or even a loser in general, but you by no means possess the level of intelligence required to be, what most people consider, a "geek."
We can only postulate, based on the assumption of the Earth being a sphere, that it must be approximately 4000 miles to the center. There isn't really any established method to prove that however, so it remains hypothetical.
But, given the scientific method, how can you postulate a hypothetical based on a theory you are trying to disprove WITH the hypothetical? That would be admission (albeit small) to some correctness in the Round Earth theory, demonstrating petitio principii.
Oh I see now, you are interpreting my statement that the distance to center of a
flat earth would be 4000 miles... No not at all.
I'm saying that even modern science can't tell you, with any amount of certainty, how deep the Earth is. We can only assume it would be roughly the radius of the Earth. We can't drill deep enough to prove it.