The average distance to the centre of the Earth is 6,371 km or 3,959 miles. In other words, if you could dig a hole 6,371 km, you'd reach the center of the Earth. At this point you'd be in the Earth's liquid metal core. I said that this number is an average. read more
Of course, digging down to the centre of the Earth was always out of reach. In order to be able to dig down to the center of the Earth, my friends and I would have needed to dig our way through 6,378 km of rock, mantle, and iron. read more
The distance to the center of the Earth is 6,371 kilometers (3,958 mi), the crust is 35 kilometers (21 mi) thick, the mantle is 2855km (1774 mi) thick — and get this: the deepest we have ever drilled is the Kola Superdeep Borehole, which is just 12km deep. read more