guess this is a dead topic but I feel like commenting with this: THE NORTH POLE IS ICE, even if there was a hole in it it'd just be a hole into water, very very salty water, and if there was a hole through THAT to the center of the earth then there'd just be a big whirlpool, but I'd also like to say that there is so much in this world that we do not know, that we can't know, maybe the earth is hollow but the gravity and such is the way it is BECAUSE it's hollow and it's just us humans with the flawed logic heck just look at how just a few hundred years ago everybody thought the earth was flat, and a few hundred years before that people believed that the earth was the center of the universe (you know that statment there pretty much sums up the human mind. . .)
I personally believe in only one thing We Do Not Know.
Heck for all we know South Park's right and this is all some cosmic reality TV show. . .