Hair Brained Theory
Believed to be so in the forums of Bungie.net, an individual discovered a "good thought," they said that the Moon or (luna) was the main part of the mechanism that fires the installations. He goes on to say that they (the gigantic "doors" opening on the halo 3 teaser) are not the ark, but wrather the earth itself is, and that the "doors" are really an impulse being sent out. Like a wireless rc car, the "doors" would release a MASSIVE ammount of energy from within, which in turn the moon recieved and distributed it throughout the universe at sub-luminos speeds. Though that is all theory, it is a pleasent one.