I’ve been reading a lot about Los Alamos, the Manhattan Project and the Trinity Test, the 70th anniversary of which was July 16. Here’s my story from last week; please take a few minutes to read it. I wrote the story after seeing Los Alamos for the first time while on a reporting assignment for a different article. Los Alamos is in a spectacular, remote location, on a finger mesa extending from the Jemez Mountains, which form the rim of a giant caldera. (Speaking of things that explode.)

After my story ran, I got an e-mail from Jim Hershberg, a professor at George Washington University who is the author of a biography of James Conant, the Harvard president who was a leader of the Manhattan Project. Hershberg writes:

I thought you might be amused to check out my book [James B. Conant: Harvard to Hiroshima and the Making of the Nuclear Age (Knopf, 1993; Stanford UP, 1995)], and in particular its account of Conant’s experience at Trinity. As he recounted in his personal notes (which I obtained through a FOIA request for my undergrad history thesis), at the very first instant of the nuclear age, Conant, momentarily blinded by the flash (staring opposite ground zero, he had not thought it necessary to look through the dark glass provided), thought something had gone horribly wrong and that the thermal transformation of the atmosphere (secretly debated as a possibility at a 1942 conference at Berkeley, and the subject of Fermi’s dark humor earlier in the long night) was actually happening.
When you think about it, how many people in human history who were 1) awake 2) sober [and otherwise unmedicated] 3) had an intellectual justification for their belief and 4) were (at least partly) responsible for the event literally believed they were witnessing the end of the world? I doubt it was more than one: Conant.
Watch the first atomic bomb explosion from 70 years ago. (Gillian Brockell/The Washington Post)

I ran this by Jennet Conant, James Conant’s granddaughter and the author of the terrific book “109 East Palace,” about the creation of the secret laboratory at Los Alamos. She confirms it.

The professor is absolutely right. Not only did my Grandfather have no confidence the bomb would work, but when it did he believed they had botched it with disastrous consequences, and that he was witnessing, as he put it, “the end of the world.”
Conant was basically a very cautious, calibrated scientist and the whole full-throttle, do-or-die push leading up to the Trinity test alarmed him more than he could admit to anyone, including himself.
Not that there was any alternative.
As I wrote in 109 East Palace, quoting from his personal notes at the time, his first reaction to the enlarging mushroom cloud was one of awe — then fear:
“Staring at the horizon through the dark green welder’s glass, he waited for what would be the largest man-made explosion in history:
‘Then came a burst of white light that seemed to fill the sky and seemed to last for seconds. I had expected a relatively quick and bright flash. The enormity of the light and its length quite stunned me. My instantaneous reaction was that something had gone wrong and that the thermal nuclear transformation of the atmosphere, once discussed as a possibility and only jokingly referred to a few minutes earlier, had actually occurred.’”

And it wasn’t just Conant who had this scary thought. In the classic book on the Bomb by Richard Rhodes, we hear the recollection of physicist Emilio Segre:

“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.” [“The Making of the Atomic Bomb," Simon & Schuster, 1986 (trade paper),p. 673]

They knew it was not possible because they’d done the math, the calculations and understood the basic physics. This notion that the atmosphere might catch on fire had first cropped up in 1942, according to the Rhodes book. Edward Teller had raised the possibility and J. Robert Oppenheimer had dutifully relayed the concern to Arthur Compton, another important Manhattan Project physicist. “Better to accept the slavery of the Nazis than to run a chance of drawing the final curtain on mankind!” Compton later wrote. But Hans Bethe, another physicist, later said, “I very soon found some unjustified assumptions in Teller’s calculations which made such a result extremely unlikely, to say the least.”

Still. In science there are no absolutes. That’s a lot of faith to put into your equations. The belief that they could understand the workings of the atom was essential to the whole process of building the bomb. Leo Szilard conceived of a chain reaction of neutrons while crossing a London street in 1933; only a dozen years later these scientists and generals were out in the middle of the New Mexico desert to test ideas and hardware thrown together under wartime pressure. They had a decent understanding of what would probably happen — but this had never been done before. This was a new thing on the planet. And — as Oppenheimer said — the world would never be the same.