Trying to recall the purpose of the clock from memory, it’s supposed to be an estimate of how far away are we from thermonuclear annihilation. Specifically, how tense international politics are, how physically far apart the world’s militaries are from conflict, how long it would take for chain-of-command to actually launch nukes. Are we one bad phone call from launching? 00:00:00 would mean the rockets are armed and in the air, no turning back.