After the end of the Cold War, the political movement striving for nuclear disarmament lost most of its momentum. Supposedly, even though enough missiles remained armed that life as we know it could be destroyed in minutes, the threat of Armageddon had fallen away because there was no plausible reason why the two largest remaining nuclear powers, the United States and Russia, should risk mutual destruction.

Because of this nuclear complacency, the opportunity provided by the 1990s, when giant strides towards disarmament could have been made, was wasted.

As animosity between the United States and Russia is once again on the rise, it’s worth being reminded of exactly what would happen if, for instance, a single 800-kiloton intercontinental ballistic missile (of which Russia possesses 700 such warheads) were to be detonated over Manhattan.

The Bulletin of the Atomic Scientists describes the effects: The warhead would probably be detonated slightly more than a mile above the city, to maximize the damage created by its blast wave. Within a few tenths of millionths of a second after detonation, the center of the warhead would reach a temperature of roughly 200 million degrees Fahrenheit (about 100 million degrees Celsius), or about four to five times the temperature at the center of the sun.

A ball of superheated air would form, initially expanding outward at millions of miles per hour. It would act like a fast-moving piston on the surrounding air, compressing it at the edge of the fireball and creating a shockwave of vast size and power.

After one second, the fireball would be roughly a mile in diameter. It would have cooled from its initial temperature of many millions of degrees to about 16,000 degrees Fahrenheit, roughly 4,000 degrees hotter than the surface of the sun.

On a clear day with average weather conditions, the enormous heat and light from the fireball would almost instantly ignite fires over a total area of about 100 square miles. [Continue reading…]