I saw on Discovery Channel a few years back that an eon ago the South Pole was the dominant pole and when it switched North it caused the magnetasphere to weaken and allow the sun's rays to melt the caps. The show said that soon the North would swing dominance back to the south and we would have devastation again. Perhaps the hatches are protection against this, hence the magnetism, Sayid's compass being off, and the Polar bear. The Oersted Sattelite circles the earth every 108 minutes, maybe the computer is communicating with it somehow.