Long-exposure photo of the first atomic bomb test, code-named Trinity, and taken at 5:29:45 a.m. on July 16, 1945.

At 5:29:45 a.m. on July 16, it will be exactly 70 years since the first explosion of an atomic bomb, which took place atop a 100-foot-tall metal tower constructed expressly for that purpose in a remote part of the New Mexican desert, at a test site code-named “Trinity.” Located at the north end of the “Jornada del Muerto” (loosely translated as “Journey of the Dead”), the spot was considered an ideal test site because it was far removed from major population centers. The detonation of what J. Robert Oppenheimer called “The Gadget” released the equivalent of 20 kilotons of TNT, causing a flash that could be seen for miles—and ushering in the nuclear age.

The way in which these tests—and atomic power—have been covered over the years by the Bulletin of the Atomic Scientists says something about their authors and their audience. And the changing emphases probably reflect our changing perceptions of the event, along with the emergence of newer media and means of expression, including a haiku about Trinity, a slideshow, a documentary, an opera, and graphic novels, among others.

But some of the most interesting stories are the earliest ones, written by human beings who were there first-hand to see, hear, and feel the test from a supposedly safe distance away. In part, their stories reflect the passage of time; the past is a different country, and they do things differently there.

In the very early years, there was surprisingly little about Trinity, probably because a good bit of material was classified. In 1958—more than 13 years after the atomic bomb test—no less a figure than prominent physicist Hans Bethe was complaining in the Bulletin about the quality of the first attempts to write a history of the atomic bomb, reserving praise only for a single book he was reviewing, “Brighter Than a Thousand Suns.”

After more time had passed, more first-hand reports from the scene evidently became available—although many of the resulting articles focused more on the intense heat of the desert, the strangeness and isolation of the surroundings, and on the technical problems, as can be seen in this 1970 Bulletin excerpt of an Enrico Fermi biography written by Emilio Segré (who himself was present at the test, and won the Nobel Prize in physics in 1959). And the obstacles were indeed huge in such a sprawling endeavor, involving so many people—130,000 Americans out of a population of 140 million were involved in the Manhattan Project. Something could easily have been overlooked: important circuits grounded because of rain; a careless connection made by tired engineers late at night in the rush to get things done; a bad soldering job at crucial points. (Decades later, this last item was to cause the multibillion dollar Large Hadron Collider to shut down for a year.) Consequently, much of his writing was about the nuts and bolts of the job.

But the story really comes alive in a later passage, in which Segré describes what it felt like to lie flat on the ground nine miles away from Point Zero, wearing dark welders’ goggles in the early morning, and facing away from the bomb when it detonated: “The most striking impression was that of an overwhelmingly bright light. … 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. The margin of safety against such a catastrophe was sufficient to dispel any rational fear among knowledgeable scientists; however, one can always make errors.”

(The idea of runaway nuclear energy was not new. In 1903, Ernest Rutherford had quipped: “Some fool in a laboratory might blow up the universe unawares.”)

A few paragraphs later, Segré expresses the exultation he and others who’d worked on the bomb felt that day: “The explosion of the bomb had been a success beyond expectation; the energy liberated was clearly near the upper limit, or in excess of our rather dubious predictions. Our satisfaction and pride were great.” But he does eventually deal in the text with some of the implications of what he had just seen.

More detailed revelations about what precisely had happened at the test, moment by moment, appeared a few years later. In a 1975 issue, Kenneth T. Bainbridge—by that time a professor of physics at Harvard University—gave his account of events as part of an extended Bulletin series on the reminiscences of 12 nuclear pioneers. Some information was astounding: “In the middle of May, on two separate nights in one week, the Air Force mistook the Trinity base for their illuminated [training] target. One bomb fell on the barracks building which housed the carpentry shop, another hit the stables, and a small fire started … I asked Robert Oppenheimer if we couldn’t convince the next batch of military planes or the occasional curious individual plane to stay away by firing smoke shells ahead of any intruders to demonstrate that forbidden area meant just that.”

Bainbridge also brings up another unexpected angle. “My personal nightmare,” he writes, “was knowing that if the bomb didn’t go off or hangfired, I, as head of the test, would have to go to the tower first and seek to find out what had gone wrong.” Consequently, Bainbridge says, his first emotion after the gadget had gone off was one of relief. He would not have to worry any longer.

His second emotion was more complicated. Bainbridge wrote: “After the blast wave had passed, I got up from the ground to congratulate Oppenheimer and others on the success of the implosion method. I finished by saying to Robert: ‘Now we are all sons of bitches.’ Years later he recalled my words and wrote me, ‘We do not have to explain them to anyone.’ I think that I will always respect his statement, although there have been some imaginative people who somehow can’t or won’t put the statement in context and get the whole interpretation. Oppenheimer told my younger daughter in 1966 that it was the best thing anyone said after the test.”

Editor’s note: The Bulletin’s archives from 1945 to 1998, complete with the original covers and artwork, can be found here. Anything after 1998 can be found via the search engine on the Bulletin’s home page.