We were lying there, very tense, in the early dawn, and there were just a few streaks of gold in the east; you could see your neighbor very dimly. Those ten seconds were the longest ten seconds that I ever experienced. 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 right through 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. Finally it was over, diminishing, and we looked toward the place where the bomb had been; there was an enormous ball of fire which grew and grew and it rolled as it grew; it went up into the air, in yellow flashes and into scarlet and green. It looked menacing. It seemed to come toward one.
A new thing had just been born; a new control; a new understanding of man, which man had acquired over nature.
To Teller at Compafiia Hill the burst “was like opening the heavy curtains of a darkened room to a flood of sunlight.” Had astronomers been watching they could have seen it reflected from the moon, literal moonshine.
Joseph McKibben made a comparison at S-10000: “We had a lot of flood lights on for taking movies of the control panel. When the bomb went off, the lights were drowned out by the big light coming in through the open door in the back.”
It caught Ernest Lawrence at Compania Hill in the act of stepping from his car: “Just as I put my foot on the ground I was enveloped with a warm brilliant yellow white light — from darkness to brilliant sunshine in an instant and as I remember I momentarily was stunned by the surprise.”
To Hans Bethe at Compania Hill “it looked like a giant magnesium flare which kept on for what seemed a whole minute but was actually one or two seconds.”
Serber at Compania Hill risked blindness but glimpsed an earlier stage of the fireball:
At the instant of the explosion I was looking directly at it, with no eye protection of any kind. I saw first a yellow glow, which grew almost instantly to an overwhelming white flash, so intense that I was completely blinded… By twenty or thirty seconds after the explosion I was regaining normal vision… The grandeur and magnitude of the phenomenon were completely breathtaking.
Segre at Base Camp imagined apocalypse:
The most striking impression was that of an overwhelmingly bright light… 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… 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.
Not light but heat disturbed Morrison at Base Camp:
From ten miles away, we saw the unbelievably brilliant flash. That was not the most impressive thing. We knew it was going to be blinding. We wore welder's glasses. The thing that got me was not the flash but the blinding heat of a bright day on your face in the cold desert morning. It was like opening a hot oven with the sun coming out like a sunrise.
It unfolded in silence, a ballistics expert watching from Compania Hill realized with awe:
The flash of light was so bright at first as to seem to have no definite shape, but after perhaps half a second it looked bright yellow and hemispherical with the flat side down, like a half-risen sun but about twice as large. Almost immediately a turgid rising of this luminous mass began, great swirls of flame seeming to ascend within a rather rectangular outline which expanded rapidly in height… Suddenly out of the center of it there seemed to rise a narrower column to a considerably greater height. Then as a climax, which was exceedingly impressive in spite of the fact that the blinding brightness had subsided, the top of the slenderer column seemed to mushroom out into a thick parasol of a rather bright but spectral blue… All this seemed very fast… and was followed by a feeling of letdown that it was all over so soon. Then came the awe-inspiring realization that it was twenty miles away, that what had flared up and died so brilliantly and quickly was really a couple of miles high. The feeling of the remoteness of this thing which had seemed so near was emphasized by the long silence while we watched the grey smoke grow into a taller and taller twisting column, a silence broken after a minute or so that seemed much longer by a quite impressive bang, about like the crack of a five-inch anti-aircraft gun at a hundred yards.
“Most experiences in life can be comprehended by prior experiences,” Norris Bradbury comments, “but the atom bomb did not fit into any preconceptions possessed by anybody.”
As the fireball rose into the air, Joseph W. Kennedy reports, “the overcast of strato-cumulus clouds directly overhead [became] pink on the underside and well illuminated, as at a sunrise.” Weisskopf noticed that “the path of the shock wave through the clouds was plainly visible as an expanding circle all over the sky where it was covered by clouds.” “When the red glow faded out,” writes Edwin McMillan, “a most remarkable effect made its appearance. The whole surface of the ball was covered with a purple luminescence, like that produced by the electrical excitation of the air, and caused undoubtedly by the radioactivity of the material in the ball.”
Fermi had prepared an order-of-magnitude experiment to determine roughly the bomb's yield:
About 40 seconds after the explosion the air blast reached me. I tried to estimate its strength by dropping from about six feet small pieces of paper before, during and after the passage of the blast wave. Since, at the time, there was no wind, I could observe very distinctly and actually measure the displacement of the pieces of paper that were in the process of falling while the blast was passing. The shift was about 21/2 meters, which, at the time, I estimated to correspond to the blast that would be produced by ten thousand tons of T.N.T.
“From the distance of the source and from the displacement of the air due to the shock wave,” Segre explains, “he could calculate the energy of the explosion. This Fermi had done in advance having prepared himself a table of numbers, so that he could tell immediately the energy liberated from this crude but simple measurement.” “He was so profoundly and totally absorbed in his bits of paper,” adds Laura Fermi, “that he was not aware of the tremendous noise.”
Frank Oppenheimer found his brother watching beside him outside the control bunker at S-10000:
And so there was this sense of this ominous cloud hanging over us. It was so brilliant purple, with all the radioactive glowing. And it just seemed to hang there forever. Of course it didn't. It must have been just a very short time until it went up. It was very terrifying.
And the thunder from the blast. It bounced on the rocks, and then it went — I don't know where else it bounced. But it never seemed to stop. Not like an ordinary echo with thunder. It just kept echoing back and forth in that Jornada del Muerto. It was a very scary time when it went off.
And I wish I would remember what my brother said, but I can't — but I think we just said, “It worked.” I think that's what we said, both of us. “It worked.”
Trinity director Bainbridge appropriately pronounced its benediction: “No one who saw it could forget it, a foul and awesome display.”
At Base Camp Groves “personally thought of Blondin crossing Niagara Falls on his tightrope, only to me the tightrope had lasted for almost three years, and of my repeated, confident-appearing assurances that such a thing was possible and that we would do it.” Sitting up in their trenches before the blast wave arrived, he and Conant and Bush ceremoniously shook hands.
The blast had knocked Kistiakowsky down at S-10000. He scrambled up to watch the fireball rise and darken and mushroom purple auras, then moved to claim his bet. “I slapped Oppenheimer on the back and said, ‘Oppie,
