- American scientists tested an atomic bomb in the New Mexico desert exactly 75 years ago.
- The launch, part of the Manhattan Project, marked the development of the deadliest and most powerful weapon in history.
- In an excerpt published by the Bulletin of Atomic Scientists, physicist Robert Wilson suggested that scientists did not deal with the moral consequences of their work until after the explosion.
- Visit the Business Insider home page for more stories.
Seventy-five years ago, a group of scientists and soldiers camped on a previously abandoned ranch in New Mexico, waiting for history to be made. Their mission, to produce the world’s first nuclear bomb, was so secret that many of their wives and children did not know what they were working on. Even his emails and phone calls were monitored.
The world would later know his work as the Manhattan Project. The code name for his first nuclear test, conducted on July 16, 1945, was “Trinidad”. It marked the development of the deadliest and most powerful weapon in history, and the beginning of the end of World War II.
But its success was never guaranteed.
Before the test passed, scientists debated whether the explosion could ignite the atmosphere and destroy life on Earth. The project went ahead after Nobel Prize winner Arthur Compton determined that the odds for that end-of-the-world scenario were “a little less” than one in 3 million.
In 1943, the team assembled a secret laboratory in the middle of the sweltering desert near Los Alamos, New Mexico, surrounded by scorpions and poisonous lizards. The location had to be remote to limit the premises to exposure to dangerous radioactive consequences. Scientists and soldiers slept on cots in humble barracks about 10 miles from the test site.
Housing for workers involved in the secret Manhattan project in Los Alamos, New Mexico.
Los Alamos National Laboratory / The LIFE Picture Collection / Getty Images
About a year after the Los Alamos project, researchers gathered in a small place known as “Building X” to discuss again how the bomb, nicknamed “The Gadget,” could affect civilization.
“At the time, perhaps we were too obsessed with what we consider to be the evil of military security,” recalled Robert Wilson, Los Alamos’ youngest research leader, in an excerpt published by the Bulletin of Atomic Scientists. (Wilson died in 2000). “We were afraid that the military would keep nuclear power secret if the bomb was not revealed by a real explosion.”
Scientists had become even more enthusiastic on their mission by then, Wilson added.
“It is significant that no one at that meeting in Building X even raised the possibility that what we were doing could be morally wrong,” he said. “No one suggested that we should pack up and leave.”
A rush to complete the test
In the days leading up to launch, scientists remembered burying their heads in their work.
“Perhaps the events were moving too fast,” said Wilson. “We were at the climax of the project, just about to explode the test bomb in the desert. Every faculty, every thought, every effort went to make that a success.”
He added that “there was an absolutely fantastic fascination as to whether the pump would really work.”
This July 16, 1945 file photo shows the mushroom cloud from the first atomic explosion at the Trinity test site near Alamagordo, NM
AP Photo / File
George Kistiakowsky, a Harvard physical chemist who led the explosives division at Los Alamos, recalled that scientists made bets on how big the explosion would be.
Kistiakowsky, who died in 1982, predicted that he could produce 100 tons of TNT (a measure of weapon strength), according to the Bulletin. But the real-life explosion was 200 times more powerful than his estimate.
“We didn’t know how big the explosion would be or what its effects would be,” Lt. Gen. Leslie Richard Groves said, according to the Bulletin. (Groves died in 1970). “Like many things in the Manhattan Project, we were dealing with unknowns outside of the realm of man’s experience, and we just had to try to imagine everything that could happen.”
‘The terrible magnitude of what we had done overwhelmed me’
Scientists were forced to make even more difficult guesses when a storm broke out the morning of the launch. By then, the bomb had already been loaded atop a 100-foot steel tower.
The test was originally scheduled for 2 a.m. on July 16. But bad weather delayed the launch at 5:30 a.m. Before his death in 1996, Kenneth Bainbridge, a Harvard physicist who supervised the test, reported that the weather was not yet ideal at the time, but scientists were not willing to wait another half day.
“To my distress, I found an air of excitement at base camp rather than the essential calm for making good decisions,” Groves said of the pre-test moments.
Officials of the Manhattan Project, including Dr. Robert J. Oppenheimer (white hat) and with him General Leslie Groves, inspect the remains of the Trinity Test Tower on September 9, 1945.
Los Alamos National Laboratory / The LIFE Picture Collection / Getty Images
Around 5:20 am, people stationed in the barracks crouched on the ground, wearing dark glasses to protect their eyes. Ten minutes later, the explosion produced a burst of light, followed by a gigantic orange fireball and a mushroom cloud.
Residents around Los Alamos noticed a bright flash in the sky. Some glass windows were smashed in Silver City, New Mexico, about 180 miles away. But for the most part, details of the test remained secret until shortly after the Hiroshima bombing in August 1945.
In the years that followed, scientists at the Manhattan Project grappled with the consequences of their work.
“What had been an intellectual reality for me for about three years had suddenly become a factual, existential reality,” said Wilson. “I finished my technical work, I ran the race and the full magnitude of what we had done invaded me.”
