Space-based detectors allow us to reliably distinguish between meteorites and nuclear explosions”€”a good thing to know. Because of these “€œnational technical means,”€ the US and Russia can probably avoid an accidental nuclear war, at least of this kind. Close allies of the US such as Britain and France, which have access to our data as well as some space assets of their own, should also be able to avoid accidental war. That might not be the case for other nuclear-armed countries that don’t have sophisticated space surveillance or close intelligence ties with those who do, such as India, Pakistan, or North Korea. North Korea has mostly been pretending to be crazy, but a meteorite striking Pyongyang might make the crazy real. Still, such a precise strike”€”hitting the capital city of the right country”€”is fantastically unlikely. The chance is something like one in a hundred million per year.

Anyhow, minor nuclear powers can only fight minor nuclear wars. We’d pull through. I’m not saying we wouldn’t get our hair mussed. 

There are other far greater risks associated with rocks from space. Consider a medium-size asteroid, say a mile across. If it hit anywhere, it would cause a worldwide disaster. Precise aim is no longer necessary. 

Certainly such an asteroid would destroy any city it hit, but that’s not the point. If enough dust is lofted into the atmosphere, it blocks sunlight. If this lasted for even one year, food production would collapse worldwide, and we would have to rely on reserves. Unfortunately, there aren’t any. Billions of people would starve to death. I’m not sure that they’d go quietly. More like the wreck of the Medusa rather than a Birkenhead drill. 

There have been events like this in recorded history, although they were far milder. Mount Tambora, an Indonesian volcano, erupted in 1815 and threw about 25 cubic miles of rock into the stratosphere. 1816 is known as the year without a summer: Connecticut had frosts in June. Snow fell in Albany on June 6th. Crops failed and prices skyrocketed. There were food riots in Ireland, England, France, and Switzerland. The more sensible New Englanders moved to the Midwest.

There are things that we could do to protect ourselves or at least soften the blow. We could try to develop methods of shifting the paths of dangerous asteroids and comets, although that’s far from easy. Humanity certainly couldn’t do it today. We could build up food reserves, which would be life-savers in this kind of crisis, and in others, such as supervolcano eruptions like Toba or Yellowstone, or massive crop blights like the Irish potato famine. We certainly know how to do that. 

But we won’t. We won’t do a damn thing. It’s hard to get Washington to worry about next year, let alone disasters that strike every hundred or thousand years. Nor would the public support such action: Preparing for a rainy day is terminally uncool. It’s as white-bread as being Swiss or joining the Boy Scouts.

Be prepared? Not on your life!