Atom bombs over Nevada. The Frenchman Flat tests

In 1951 a couple of atom bomb tests in the Frenchman Flat of the Nevada desert caught the public's attention.

This amazing photograph shows for the first time (to the large public - my annotation) a detailed view of the explosion of what is probably a "small-size" atomic bomb. Recently released by the U.S. Atomic Energy Comission, it was taken during A-bomb tests the AEC held early this year (1951- my annotation) at Frenchman Flat in Nevada. Observers estimated the Nevada bombs were small in size, perhaps reduced in power for tactical use in artillery shells or fighter planes.

The AEC offered no information about the picture, but an estimate of what it shows can be made from the report on the effects of atomic weapons released last year by the comission (1950- my annotation). Because of its intense white heat the ball of fire probably was photographed less than a second ater the bomb's detonation. It has begun to rise and in a few seconds will be climbing at a speed of almost 200 mph. The reddish column beneath the fireball is formed by dust sucked up from the ground below. This dust, churning upward with the fireball, will later help form the familiar mushroom cloud of atomic explosions. Since only the fifth and final Nevada bomb appeared to produce such a cloud, this pocture may show an earlier stage of that explosion.

The bomb's fission products (fragments of plutonium or uranium atoms) are already so intensely radioactive they can cause air to glow. And since they were vaporized in the first instant of the explosion, they may have been carried even higher than the fireball itself to produce the mysterious violet haze at the top.