The Science of a Bottomless Pit

StartsWithABang writes It's the ultimate dream of many children with time on their hands and their first leisurely attempt at digging: to go clear through the Earth to the other side, creating a bottomless pit. Most of us don't get very far in practice, but in theory, it should be possible to construct one, and consider what would happen to a very clever test subject who took all the proper precautions, and jumped right in. Here's what you would have to do to travel clear through the Earth, come out the other side, and make the return trip to right back where you started.