Well, just think about how silly it is to spend time worrying about something you cannot really affect. A meteorite large enough to destroy all life on the planet could hit us at any time and we would not necessarily have more than few days warning, and absolutely no means to do anything about it. Does it make sense to worry about such thing though? no it does not.
Death comes as it comes anyway and with absolute certainity, no use to worry about when and how.
To give some perspective about things too, think about this:
NY: USA 2001: 9/11 Plane Crashes: 2,752 dead
Gujarat, India, 2001: Earthquake: 20,000 dead
Natural disasters still get upper hand over what us humans manage to cause.