On the day of July 16, 1945, a gigantic plume of smoke soared to an incredible height of 30,000 feet (9,144 meters) above the remote Jornada Del Muerto Desert in New Mexico. This was preceded by a dazzling flash that illuminated the sky.
Sighted by military personnel and scientists about 20 miles (32 kilometers) away, this was a pivotal point in World War II and the dawn of a new era — the successful detonation of the atomic bomb.
The Trinity test marked the apex of the Manhattan Project, a US initiative dedicated to developing an atomic bomb. In this excerpt from “American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimer” (Knopf, 2005), authored by Kai Bird and Martin J. Sherwin, we hear from witnesses who experienced this momentous event firsthand.
RICHARD FEYNMAN, one of the scientists present, was 20 miles from the site when he was handed a pair of dark glasses. However, he decided to ditch them and hopped into a truck’s cab facing Alamogordo, thinking the windshield would better protect his eyes. Even so, he instinctively ducked at the sight of a blinding flash. When he looked up again, he saw a brilliant display of colors transitioning from white to yellow to orange: “A big ball of orange, the center that was so bright, becomes a ball of orange that starts to rise…” He only heard the deafening boom a minute and a half later, accompanied by the deep rumbles of what felt like a man-made thunderstorm.
James Conant was expecting a swift burst of light. Instead, the overwhelming brightness made him think “something huge went wrong” and that the world had caught fire.
“I could feel the heat on my face a full twenty miles away.”
— Bob Serber, American physicist
Bob Serber was also stationed 20 miles away, lying down with a piece of welder’s glass over his eyes. In a twist of fate, just as he lowered the glass because his arm was tired, the bomb detonated, blinding him completely from the flash. Once he regained his vision 30 seconds later, he was stunned to see a colorful violet column ascending høj620 as tall as 30,000 feet. “I could feel the heat on my face a full 20 miles away,” he astounded.
Joe Hirschfelder, tasked with measuring radioactive fallout, recounted the moment: “Suddenly, night vanished, replaced by blinding brightness. As the warmth enveloped me, the fireball shifted from white to yellow, then red, climbing into the sky. After a span of about five seconds, it was darkness again, now illuminated by a violet glow, as if we were encircled by an aurora borealis… I was left in awe as the shockwave lifted the desert’s dirt and rushed past us.”
Frank Oppenheimer was near his brother [Robert] when the detonation happened. Though he was down on the ground, the initial light penetrated through his closed eyelids. Once he opened his eyes, he was met with an unreal scene — a bright fireball instantly followed by an ethereal purple cloud. Concern crept in as Frank mused about whether it might drift toward them. He wasn’t prepared for the extreme heat generated by the flash. Moments later, the echo of the explosion rattled against the distant mountains. Looking back, Frank recalled, “But the most terrifying thing was that brilliant purple cloud, darkened with radioactive dust. You didn’t know if it would float away or head towards you.”
“Lots of boys not grown up yet will owe their life to it.”
— J. Robert Oppenheimer
What he was thinking at that crucial moment remains unknown. According to his brother, they perhaps merely stated in astonishment, “It worked.” Later in the morning, upon meeting with William L. Laurence, a New York Times reporter assigned to cover the event, Oppenheimer shared his mixed feelings: the blast was “terrifying” and “not entirely undepressing.” Then he mentioned, “Lots of boys not grown up yet will owe their life to it.”
This excerpt is from American Prometheus: The Triumph and Tragedy of J. Robert Oppenheimerby Kai Bird and Martin J. Sherwin, published by Atlantic Books in 2023.
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Check out the ultimate biography of J. Robert Oppenheimer, a prominent figure from the twentieth century, who led the design of the atomic bomb in wartime and later confronted the ethical implications of scientific progress.
