The encounter between the fighter plane and the bomber may well take place in our own country over populated areas. This possibility would fill most people with alarm lest the population underneath the explosion should be hurt. Fortunately, in a recent nuclear test in Nevada, five well-informed and courageous Air Force officers demonstrated that there is complete safety to people on the ground. They did this by standing directly beneath the explosion at ground zero. This important test took place only a few months ago—on July 19, 1957. An F-89 jet fighter plane flying at 19,000 feet above sea level delivered an air-to-air atomic rocket to a preassigned point in the sky. The ground zero men were 15,000 feet immediately below. They wore no helmets, no sun-glasses, and no protective clothing. At the instant of the explosion the men looked up, saw the fireball and felt the heat. There was no discomfort, only a gentle warmth. Then they waited for the shock wave to arrive—approximately ten seconds. When the shock came, it was actually just a loud noise. However, one of the men ducked his head instinctively. (See pictures 9 and 10.) The blast and the thermal pulse were over. But the Air Force men stood their ground. One question still remained: Would there be any fallout? They checked their radiation instruments and waited while the cloud drifted slowly away. There was no significant rise in the radiation level. The test had been a complete success. The effects of the explosion were utterly insignificant on the ground. But high in the air an enemy plane could have been demolished even if the nuclear explosion had missed it by a considerable distance. In order that nuclear weapons should be effective against armed invaders, it is clear that great numbers of these weapons are needed. Such great numbers of weapons, some of which must be ground-burst, will produce a considerable amount of radioactive contamination, and this contamination will endanger friend and foe alike. In particular, the radioactivity is likely to kill people in the very country whose liberty we are trying to defend. For this reason it is most important that we should be able to use nuclear weapons which cause the least possible contamination. In recent nuclear tests more and more attention has been paid to the development of such clean weapons, and most fortunately these efforts are well on the way toward success. The radioactive fallout from nuclear testing gives rise to a possible danger which is quite limited in size. The danger from the fallout in a nuclear war, however, would be real and great. If we stop testing now, and if we should fail to develop to the fullest possible extent these clean weapons, we should unnecessarily kill a great number of noncombatants. Not to develop the explosives with the smallest radioactive fallout would, indeed, be completely inexcusable.