RALEIGH -- Sixty-five years ago today, high in the mountains of northern New Mexico, the public address system at a secret facility called Site Y - now known as Los Alamos National Laboratory - crackled to life.
Worth Seagondollar paused, along with hundreds of other scientists, engineers and technicians who had been working for years to figure out how to create the first nuclear bombs.
"Attention, please. Attention, please," the announcer said. "One of our units has just been successfully dropped on Japan."
That was it. No details about the destruction or even the name of the city that had been struck, Hiroshima.
But Seagondollar, 89, who now lives at Springmoor retirement center in North Raleigh, was one of only a handful of people who had seen an atomic bomb blast firsthand, and he knew that the world was suddenly much different.
Thousands of people had probably died in an instant, and a new weapon had been unleashed that allowed humans to kill each other in vast numbers. But it also surely meant the end of the most horrific war in world history and of the global march of fascism.
"I didn't have any feelings of regret at all," he said in an interview this week. "My feeling was that it was the beginning of the end of the Japanese war, and it was."
Later that day at another Manhattan Project site, Oak Ridge in the Tennessee mountains, Raymond Murray came home to his hastily-built government house where his wife had learned a secret he had been keeping. She had heard about the bomb on the radio.
"I finally know what you've been doing all this time," she said.
Seagondollar and Murray both later came to teach at N.C. State University's physics department and became department heads. By coincidence, Murray, now 90, also lives at Springmoor, making that retirement center an unusual repository of the memories of how the atomic age was born.
Murray and Seagondollar have given many talks on the bomb program, and Murray still makes annual presentations to groups of high school students who come to NCSU each summer and to a group at MIT.
Many of those who were in the heart of the Manhattan Project - the formal name of the U.S. effort to beat Germany in the race to building nuclear weapons - are gone now. Murray and Seagondollar were unusually young when they were recruited into the project, both in their early 20s.
Youngsters in new field
Nuclear science was young, too. Fission had been discovered just three years earlier, in 1939, and there were only a handful of scientists that physicist J. Robert Oppenheimer and his senior staff could call on to help develop a nuclear weapon.
At Los Alamos, Seagondollar was part of a team doing research on "critical mass," the minimum amount of fissionable material it takes to start a nuclear chain reaction and create a blast.
Murray, meanwhile, was assigned to run one of four massive production buildings at Oak Ridge that used electromagnetic radiation to extract Uranium-235, the isotope used in the bomb that was dropped on Hiroshima.
Murray's building was able to separate out only about 25 pounds of it in a year and a half of production, he said.
They remember the mistakes and setbacks and the growing pains for the two isolated communities as thousands of people flooded in.
Murray remembers the red clay mud that dominated the instant town of Oak Ridge, built by the government for the project. It had been planned for about 13,000 residents but grew to 75,000 in three years. One uranium separation facility covered 44 acres and was the largest building in the world, though Oak Ridge was kept secret by the government and didn't appear on maps for years.
Los Alamos, meanwhile, was so far up in the mountains that people bought their food at the military PX on the facility and made their own entertainment. There was a lively group of square dancers, though when Worth and Winifred Seagondollar first arrived, they found that they weren't ready for so much exercise at 7,200 feet.
Worth Seagondollar was among a handful of people to get a preview of the terrible force that would be unleashed on Hiroshima and Nagasaki when he was sent to a remote bombing range south of Los Alamos to help with the first test explosion of a nuclear bomb, on July 16, 1945.
He had fashioned eye protection from the darkest lenses he could find, dark blue glass used by welders in their hoods.
Seagondollar and other observers were put nine miles from the bomb and told to look in the opposite direction from the blast itself, but even with their backs turned they were still startled.
"It was like looking into a photographer's flashbulb, except that's concentrated in one place and this was just everywhere, the brightest light I've ever seen," he said.
He counted to 15 and turned to face the blast.
"My first reaction was, 'You darned fool, you forgot the blue glass,'" he said. "I was looking through the blue glass, but it was just pure white light coming through.
"When I saw it, the ball of fire was about its own diameter above the valley floor, and I watched it go on up and the clouds above it; a huge hole opened up, and the ball of fire went up through that, and it went through the proverbial mushroom cloud about 70,000 feet. ... It was not particularly loud, but it was heavy rolling thunder."
Germany had surrendered months before the Hiroshima blast, ending any threat that the United States would be beaten to a bomb, and the debate continues about whether it was proper to continue the program and use the bomb, given that Japan didn't have a serious program to build one.
An estimated 70,000 people in Hiroshima and 40,000 in Nagasaki were killed instantly, and tens of thousands more continued to succumb to burns and the effects of radiation, including cancer. Estimates of total deaths range to 240,000 or more.
Lives lost, lives saved
Both Murray and Seagondollar say that the suffering and loss of life in Japan was a terrible thing. Their lives, though, were built around clinically analyzing data, and they can't help but look at the deaths the same way.
By ending the war before a planned invasion of Japan, on balance the bombs helped save lives, they say. By some estimates, an invasion of Japan would have killed 250,000 U.S. troops or more, and an even greater number of Japanese troops and civilians.
"I have had many, many people come up to me over the years and thank me because they were going to be part of the invasion force," Murray said.
Once, Seagondollar said, he had just finished a speech at NCSU on the Manhattan Project and said, as he always did, that the use of the bombs had been effective and positive, when he noticed a member of the audience walking stiffly toward him with a cane.
His heart sank. It was a professor visiting from Japan.
The man looked at him, then took the cane and whacked one of his own legs, which made a hollow sound.
"He told me that he had lost his leg at Hiroshima, and that he agreed that what happened was beneficial to both the Americans and the Japanese," Seagondollar said.
Still, Murray and Seagondollar both worry about the threats posed by terrorism and unpredictable regimes like that in North Korea.
"The use of nuclear weapons so far has been to the advantage of the civilized world," Seagondollar said. "I'm not so sure it will be in the future."
Correspondent Don McKinney and news researcher Brooke Cain contributed to this story.
