Just before dawn on an August morning in 1945 an intense light called flashed across the New Mexican desert from a site called Trinity. It was bright in the pre-dawn darkness but had it been high noon on a clear day the flash of light would momentarily have eclipsed the sun. With that flash, atomic explosion moved from theory to reality. And like the burst of energy at creation called the big bang, in that flash, the nuclear age was born. This was a fission explosion, the splitting of the heavy atoms of Plutonium (p-239) into smaller atoms.
The weapon produced the explosive power of twenty kilotons or forty million pounds of TNT. A flight of a thousand B-17's could carry only about one tenth of that explosive power. The bomb that exploded at Trinity was the second generation of nuclear weapons, an implosion bomb. Many explosive charges around a spherical core of Plutonium imploded it to make a non-critical mass into a critical one which would explode.
The Uranium gun bomb that was detonated over Hiroshima was an untested but far simpler concept that used far more material. There was only enough Uranium for the two pieces of this bomb, a target and a bullet that was fired down a "gun barrel" to make a critical mass. There was enough plutonium for two of the more efficient bombs, the other was detonated over Nagasaki.
It would be a few years till we learned three more terms, thermonuclear weapon, megaton and hydrogen bomb. The latter was a bomb that fused two atoms of Deuterium or heavy hydrogen, an isotope of hydrogen that unlike regular hydrogen has a neutron in the nucleus to produce one helium atom and a very small parcel of energy but with many of these fusions the energy released was phenomenal. Instead of measuring yield in kilo tons or thousands of tons of TNT, with the hydrogen bomb it was measured in megatons or millions of tons of TNT. The explosive power of a bomb had increased by a factor of one thousand in less than ten years! It was in this environment that the Cold War was fought.
I realize I am in the minority, but I personally believe the World War II attacks on Hiroshima and Nagasaki were necessary. Sure they ended the war. But the destruction of those two cities brought on thinking that pervaded the minds of the decision makers in 50's and 60's, possibly into the 70's and 80's. If you have seen the short segments that show the civil defense "duck and cover" public service announcements of the 50's on TV Land showing children in schools ducking under their desks, you have probably laughed. I didn't when I saw it again for the first time in probably forty years. But you would not have laughed if you were there. I was.
To get a better perspective of the mood of the times look at the various pages of a document that was printed and circulated by our government. The one I have is the third edition published in July 1955. I have never seen other editions. It was to provide the family with information that would help them survive a nuclear attack. The front cover shows the civil defense logo, the black letters CD in a white triangle and that inside a black circle. It was a logo that was used to identify bomb shelters as well.
Some of the information is almost ludicrous, some is very practical for any family facing any disaster, man made or natural. It talks of planned evacuation which is only practical if there is sufficient time to carry it out. The material in the booklet, if applied may have saved lives if they had been dropped on New Orleans and their message of preparation had been heeded early in 2006. It includes a message on the inside cover from President Eisenhower. Take a tour of the document. It will give you a flavor of the thinking about this time.
The back of the cover contains several messages in addition to the one from President Eisenhower. The other two writers were not significant enough that I remember either of them. The theme is that the new H-bombs are much more powerful, we must be prepared for them to be used against us. The Hiroshima bomb had a yield of 20 Kilotons, the equivalent of exploding 20,000 tons of TNT. The bombs of the middle fifties were generally about 20 Megatons but some were as much as 100 Megatons or Million tons of TNT. A 20 MT bomb would be one thousand times as powerful as a 20 KT. In two decades the destructive power of a single bomber, carrying one bomb went from 2 tons (the biggest pre-World War conventional bomb to 20 KT, to 20 MT. This was mind boggling to say the least.
