I thought of a question and its been causing some debate with my collegues. Its completely hypothetical and possibly ridiculous but i'm looking for somebody's more educated take on it. Here goes: Say you could theoritically drill a large hole between the poles of the Earth, large enough that contact friction wouldn't be an issue and lined with some super insulator as to rule out the heat element. What would happen if you jumped down this hole? presumably you wouldnt emerge at the other side, shooting out the ground! What follows when you reach the centre?