Lyric discussion by knifetohisthroat 

gives a lot of images of the end of the world, but what is this "Dead black disc" that slides silently overhead?

The end of the world is caused by a nuclear war, 8.5 minutes is the between when the public is first notified of the impending nuclear doom, and the actual detonation of most of the warheads. The dead black disk refers to the worldwide cloud of dirt/ash that was sprung up into the air after the explosions.

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