But the same properties which make cobalt⁶⁰ useful also make it potentially dangerous. A nuclear explosion produces many neutrons and these could be absorbed in ordinary cobalt. The radioactivity produced in this way lives long enough to become widely distributed. Its ray can easily penetrate a foot of masonry and several hundred feet of air. A cobalt bomb would indeed be a most unpleasant object. (See [pictures 7 and 8].)
One widely discussed possibility is that future nuclear tests will be used to develop a cobalt bomb or other bombs for radiological warfare. Actually tests have little to do with the cobalt bomb. Once one has a powerful nuclear weapon, such as a hydrogen bomb, it is relatively easy to make a radiological bomb. Further tests are not necessarily required. To the extent that any testing need be carried out, it is only necessary to activate a moderate amount of substance to find out in what way a certain bomb would function as a tool of radiological warfare. Tests of this kind would add only a negligible amount of radioactivity to the atmosphere. Therefore, in connection with the test program we need not worry about the cobalt bomb or any related experiment. The question of the cobalt bomb or radiological warfare in general is not whether it is feasible—it is—but rather whether it serves a useful military purpose.
It is not impossible that situations might arise in which radiological warfare could be militarily advantageous. Instead of cobalt, other materials may be placed near the nuclear bombs. In this way other radioactive substances can be produced. By an appropriate choice of such a substance one can get a radioactive material which, when deposited near the point of explosion, will contaminate the site for a time which can be adjusted to the military requirements. The lifetime of the radioactive material may be long enough to give an opportunity to the people to escape from the contaminated area. At the same time, one may precipitate almost all the activity near the explosion so that distant localities would not be seriously affected. It is conceivable, therefore, that radiological warfare could be used in a humane manner. By exploding a weapon of this kind near an island one might be able to force evacuation without loss of human life. No instrument, not even a weapon, is evil in itself. Everything depends on the way in which it is used.
Public opinion has all but persuaded itself that nuclear weapons will be used not for a military objective but to terrorize and kill the greatest number of people. This is technically feasible. In fact, it does not even require the atomic bomb. For the last hundred years this possibility has been with us. Bacteriological warfare may cause widespread destruction. Yet no one has resorted to this horrible way of making war. We do not believe that anyone will expose his enemy and ultimately himself to indiscriminate bacteriological or radiological destruction. Our guarantee against this danger is not that it cannot be done. Our guarantee is the better and saner part of human nature: the will to survive and the feeling of common decency.
CHAPTER XV
What About Future Tests?
Many people feel that tests should be discontinued. This feeling is widespread and strong. The question of tests is obviously important. It may influence our security as individuals. It certainly will influence our security as a nation. If in a free, democratic country the majority believes that something should be done—it will be done. The sovereign power in a democracy is “the people.” It is of the greatest importance that the people should be honestly and completely informed about all relevant facts. In no other way can a sound decision be reached. The basic and relevant facts are simple. The story can be presented without unnecessary frills or undue emotion. When this has been done, the right decision will be reached by common sense rather than by exceptional cleverness.
Unfortunately much of the discussion about continued experimentation with nuclear explosives has been carried out in a most emotional and confused manner. One argument concerning tests is so fantastic that it deserves to be mentioned for that very reason: It has been claimed that nuclear explosions may change the axis of the earth.
Of course, nuclear explosions do produce such changes. Only the changes are so small that they are impossible to observe and even difficult to estimate. Searching for effects connected with past tests that may displace the axis of the earth, or the position of the North Pole, we could find no effect that would have caused a change of position even as great as the size of an atom. One could design tests with the specific purpose to produce such a change, but these man-made effects could not be compared even remotely with the forces of nature. The motion of the Gulf Stream has a small effect on the North Pole; but this effect is incomparably greater than what any nuclear explosion could accomplish. It is good to know that the old top on which we live does have some stability.
The argument about world-wide radioactive fallout is more serious. It is asserted that fallout is dangerous and that we are ignorant of the extent of the danger.
In a narrow, literal sense both these statements are correct. But in the preceding chapters we have seen that the danger is limited. We do not know precisely how great it is. We do know, however, that the danger is considerably smaller than the danger from other radiations to which we continue to expose ourselves without worry. The danger from the tests is quite small compared with the effects of X-rays used in medical practice. The fallout produces only a fraction of the increase in cosmic ray effect to which a person subjects himself when he moves from the seashore to a place of higher altitude like Colorado. People may or may not be damaged by the fallout. But it is quite certain that the damage is far below a level of which we usually take notice.