The fact that no limits exist to the destructiveness of this weapon [the 'Super', i.e. the hydrogen bomb] makes its very existence and the knowledge of its construction a danger to humanity as a whole. It is necessarily an evil thing considered in any light. For these reasons, we believe it important for the President of the United States to tell the American public and the world what we think is wrong on fundamental ethical principles to initiate the development of such a weapon.

Suddenly, there was an enormous flash of light, the brightest light I have ever seen or that I think anyone has ever seen. It blasted; it pounced; it bored its way into you. It was a vision which was seen with more than the eye. It was seen to last forever. You would wish it would stop; altogether it lasted about two seconds.[Witnessing the first atomic bomb test explosion.]

The most striking impression was that of an overwhelming bright light. I had seen under similar conditions the explosion of a large amount—100 tons—of normal explosives in the April test, and I was flabbergasted by the new spectacle. We saw the whole sky flash with unbelievable brightness in spite of the very dark glasses we wore. Our eyes were accommodated to darkness, and thus even if the sudden light had been only normal daylight it would have appeared to us much brighter than usual, but we know from measurements that the flash of the bomb was many times brighter than the sun. In a fraction of a second, at our distance, one received enough light to produce a sunburn. I was near Fermi at the time of the explosion, but I do not remember what we said, if anything. I believe that for a moment I thought the explosion might set fire to the atmosphere and thus finish the earth, even though I knew that this was not possible.

Should the research worker of the future discover some means of releasing this [atomic] energy in a form which could be employed, the human race will have at its command powers beyond the dream of scientific fiction, but the remotest possibility must always be considered that the energy once liberated will be completely uncontrollable and by its intense violence detonate all neighbouring substances. In this event, the whole of the hydrogen on earth might be transformed at once and the success of the experiment published at large to the universe as a new star.

I looked for it [heavy hydrogen, deuterium] because I thought it should exist. I didn't know it would have industrial applications or be the basic for the most powerful weapon ever known [the nuclear bomb] ... I thought maybe my discovery might have the practical value of, say, neon in neon s

I am an atheist, but as far as blowing up the world in a nuclear war goes, I tell them not to worry.

I am an atheist.

The scientist is not responsible for the laws of nature. It is his job to find out how these laws operate. It is the scientist’s job to find the ways in which these laws can serve the human will. However, it is not the scientist’s job to determine whether a hydrogen bomb should be constructed, whether it should be used, or how it should be used. This responsibility rests with the American people and with their chosen representatives.