Here's a scary thought that unsettled me while driving my dump truck.

Apparently, the Russians have a "dead hand" retaliation system that is
activated by a nuclear explosion sensor, and launches a [counter]
attack against the US in case if it detects nuclear attack on Russia
and the missile base cannot communicate with Moscow.

http://en.wikipedia.org/wiki/Dead_Hand_(nuclear_war)

I was thinking that in case of a particularly unlucky asteroid impact
on Russia, if communications are lost with Moscow, and the impact is
recognized as a nuclear attack, then Russia could launch its missiles
and attack the USA. And that would trigger a global nuclear destruction.

An unsettling thought.

i