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One Cause Several
Effects
The Effects of a Nuclear Bomb
Jonathan Schell
Whereas most conventional bombs produce only one destructive effect – the shock wave – nuclear weapons produce many destructive effects. At the moment of the explosion, when the temperature of the weapon material, instantly gasified, is at the superstellar level, the pressure is millions of times the normal atmospheric pressure. Immediately, radiation, consisting mainly of gamma rays, which are a very high-energy form of electromagnetic radiation, begins to stream outward into the environment. This is called the "initial nuclear radiation," and is the first of the destructive effects of a nuclear explosion. In an air burst of a one-megaton bomb – a bomb with the explosive yield of a million tons of TNT, which is a medium-sized weapon in present-day nuclear arsenals – the initial nuclear radiation can kill unprotected human beings in an area of some six square miles. Virtually simultaneously with the initial nuclear radiation, in a second destructive effect of the explosion, an electromagnetic pulse is generated by the intense gamma radiation acting on the air. In a high-altitude detonation, the pulse can knock out electrical equipment over a wide area by inducing a powerful surge of voltage through various conductors, such as antennas, overhead power lines, pipes, and railroad tracks... . When the fusion and fission reactions have blown themselves out, a fireball takes shape. As it expands, energy is absorbed in the form of X rays by the surrounding air, and then the air re-radiates a portion of that energy into the environment in the form of the thermal pulse – a wave of blinding light and intense heat – which is the third of the destructive effects of a nuclear explosion.... The thermal pulse of a one-megaton bomb lasts for about ten seconds and can cause second-degree burns in exposed human beings at a distance of nine and a half miles, or in an area of more than two hundred and eighty square miles.... As the fireball expands, it also sends out a blast wave in all directions, and this is the fourth destructive effect of the explosion. The blast wave of an air-burst one- megaton bomb can flatten or severely damage all but the strongest buildings within a radius of four and a half miles.... As the fireball burns, it rises, condensing water from the surrounding atmosphere to form the characteristic mushroom cloud. This mixture will return to earth as radioactive fallout, most of it in the form of fine ash, in the fifth destructive effect of the explosion. Depending upon the composition of the surface, from 40 to 70 percent of this fallout – often called the "early" or "local" fallout – descends to earth within about a day of the explosion, in the vicinity of the blast and downwind from it, exposing human beings to radiation disease, an illness that is fatal when exposure is intense.
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© 1998 Ervin Nemeth. All rights reserved.
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