By the fall of 1942, this was making KGB officials in Moscow very angry. “The organizational pace is entirely unsatisfactory,” Moscow scolded its American spies. “The project is taking a very long time to get going.”
In New York, Semyon Semyonov got the message. As part of his search for a way into the America bomb project, he turned to his best courier, Harry Gold.
“One evening in New York City,” Gold remembered, “about October-November 1942, Semyonov asked me if I had heard anything of a military weapon.” It was a bomb, Semyonov said, a weapon of almost unimaginable power.
“I was puzzled,” Gold said. “I had no idea that anything was going on in regard to atomic energy in the United States.”
Semyonov knew it was a long shot, but he was desperate. He asked Gold to keep his eyes and ears open.
*
MEANWHILE, Moscow officials reminded their West Coast agents that they’d been sent a list of scientists to cultivate. Moscow was particularly annoyed that no contact had been made with Robert Oppenheimer. The Soviets had no way of knowing that Oppenheimer had just been named the scientific director of the American atomic bomb project, but they knew he was a top American physicist. They knew it was probable he was involved.
Peter Ivanov, a KGB agent in San Francisco, thought about how he could get close to Oppenheimer. As a Soviet agent, watched closely by the FBI, it would be too risky for him to make a direct approach.
Ivanov went to see George Eltenton, a chemical engineer known to be sympathetic to the Soviet Union. Ivanov pointed out to Eltenton that the Americans and Soviets were allies in World War II, but the Soviets were the ones doing the fighting against Hitler. Why, Ivanov asked, was America keeping secrets from its ally?
Eltenton agreed; the Soviets deserved better.
Ivanov then asked Eltenton what he knew about atomic bomb research being done at the University of California, Berkeley.
“I, personally,” said Eltenton, “know very little of what’s going on.”
“Do you know any of the guys?” asked Ivanov. “Any others connected with it?”
“Not very well,” Eltenton said.
Ivanov tossed out names of well-known Berkeley physicists: “Ernest Lawrence? Luis Alvarez? Robert Oppenheimer?”
Eltenton said he knew Oppenheimer casually. They’d been at a few political meetings together over the years.
Ivanov asked Eltenton to talk with Oppenheimer, to subtly feel out his interest in sharing information with the Soviets. Eltenton said he didn’t know Oppenheimer well enough to do it. Ivanov wouldn’t give up—wasn’t there anyone Eltenton knew who could be trusted to approach Oppenheimer?
“On thinking the matter over,” Eltenton remembered, “I said that the only mutual acquaintance whom I could think of was Haakon Chevalier.”
Chevalier was a professor of French literature at Berkeley and the host of the Communist discussion group at which Oppenheimer had been spotted by the FBI about two years earlier. Chevalier and Oppenheimer were good friends. Eltenton asked Chevalier to approach his friend on behalf of the Soviets. Chevalier agreed.
*
THE PERFECT OPPORTUNITY arose a few weeks later, when Robert and his wife, Kitty, invited Haakon and his wife, Barbara, over for dinner.
“Haakon was one hundred percent in favor of finding out what Oppie was doing and reporting it back to Eltenton,” Barbara remembered. “Haakon also believed that Oppie would be in favor of cooperating with the Russians.” Barbara strongly disagreed. They fought about it in the car on the way to dinner.
As soon as the guests arrived, Oppenheimer announced it was time to mix a batch of his famous martinis. He walked toward the kitchen. Chevalier followed.
As Oppenheimer began carefully pouring the liquor, a nervous-seeming Chevalier announced, “I saw George Eltenton recently.”
Oppenheimer looked up from his work.
Chevalier continued, saying that Eltenton had a contact with Soviet intelligence. If Oppenheimer ever wanted to share any scientific information with the Soviets, he could use this connection.
Oppenheimer was visibly disturbed by the suggestion. “That would be a frightful thing to do,” he said. “That would be treason.”
Chevalier said nothing more.
Oppenheimer went back to his martinis. “That was the end of it,” he later said. “It was a very brief conversation.”
Chevalier reported the results to Eltenton. A disappointed Eltenton told Peter Ivanov, the KGB agent, that there was “no chance whatsoever of obtaining any data—Dr. Oppenheimer does not approve.” Ivanov relayed the news to Moscow.
Oppenheimer chose not tell General Groves that he’d been approached by the Soviets. It was a decision that would haunt him for the rest of his life.
DISAPPEARING SCIENTISTS
ON THE AFTERNOON OF NOVEMBER 16, 1942, Robert Oppenheimer and Leslie Groves stood together in a deep canyon in northern New Mexico. Steep red-rock cliffs rose on both sides of the canyon. A clear mountain stream trickled down the center. It was a gorgeous spot.
“This will never do,” Groves grunted.
The two men walked back toward their car.
“If you go on up the canyon,” Oppenheimer suggested, pointing east, “you come out on top of the mesa, and there’s a boys’ school there which might be a usable site.”
The men climbed into the car and continued their search for the perfect place to build an atomic bomb lab. The site had to be remote, so work could be kept secret. But it also had to be fairly close to railroad lines, so people and equipment could quickly move in and out. And, ideally, it would have some buildings already in place, so scientists could move right in and get to work.
A light snow began falling as the car wound its way up a narrow dirt road carved into the side of a mesa. The car reached the top and pulled up to a gate with a sign reading Los Alamos Ranch School.
From their car seats, Groves and Oppenheimer peered through the gate. “We didn’t want to get out,” Groves remembered, “as we should have had to give some reason why we were inspecting the place.”
Inside the gate, boys ran around playing sports in the snow—in shorts. “It was bitterly cold,” recalled Groves. “I thought they must be freezing.”
Beyond the playing fields were a few school buildings, a dining lodge, log dormitories, and several small houses for teachers. Oppenheimer loved the mountain and desert views. Groves loved the isolation.
“This is the place,” Groves said.
A few weeks later, the school director opened an official-looking letter and saw that it was signed by Secretary of War Henry Stimson. “You are advised,” declared Stimson, “that it has been determined necessary to the interests of the United States in the prosecution of the war that the property of Los Alamos Ranch School be acquired for military purposes.”
The school was closed, the students sent home.
While construction crews began expanding roads and nailing together new buildings at Los Alamos, Oppenheimer turned to his next task: “a policy of absolutely unscrupulous recruiting of anyone we can lay hands on.”
*
A SHORT WHILE LATER, a Harvard University chemistry student named Donald Hornig was doing research in an explosives lab when the lab director walked in. Hornig’s boss took him to the attic and locked the door.
“How would you like another job?” asked the lab director.
“What have I done wrong?” Hornig asked.
“Nothing,” said his boss.
“What kind of job?” Hornig wanted to know.
“Can’t say.”
“Well, where is it?”
“Can’t say.”
“East or west?”
“Sorry, my lips are sealed,” said the director. “Think it over and let me know in the morning.”
Hornig decided to turn the offer down. It just sounded too strange. Then he started getting phone calls from former professors, and the president of Harvard. They all wanted to know what his
problem was—didn’t he realize his country needed him?
He took the job.
*
SIMILAR SCENES were taking place at top universities all over the country.
“People I knew well began to vanish, one after the other,” Stanislaw Ulam, a mathematician at the University of Wisconsin, recalled. Then Ulam got a letter inviting him to join a project doing important war work in New Mexico. Suddenly he knew where everyone had gone.
“I accepted immediately with excitement and eagerness,” he said.
When the physicist Robert Marshank got a similar letter, he announced to his wife that they were leaving immediately.
“What’s it all about?” she asked.
“I can tell you nothing about it,” he replied. “We’re going away, that’s all.”
“At least tell me why we are going away,” she demanded.
He refused. Only when they were halfway across the country did she find out they were headed for the Southwest.
Oppenheimer did a lot of the recruiting personally. “I traveled all over the country,” he said, “talking with people who had been working on one or another aspect of the atomic energy enterprise.” It wasn’t always easy to get them to sign up. “The notion of disappearing into the New Mexico desert for an indeterminate period,” he recalled, “disturbed a good many scientists.”
And yet Oppenheimer’s offer did have appeal. “Almost everyone knew that if it were completed successfully and rapidly enough, it might determine the outcome of the war,” he said. “Almost everyone knew that this job would be part of history. This sense of excitement, of devotion and of patriotism prevailed. Most of those with whom I talked came to Los Alamos.”
*
AMONG THOSE WON over was a twenty-four-year-old physics grad student named Richard Feynman. He was working in his room at Princeton University when in burst a young physics teacher named Bob Wilson.
Wilson announced that he’d just been given a top-secret job. “He wasn’t supposed to tell anybody,” Feynman remembered, “but he was going to tell me because he knew that as soon as I knew what he was going to do, I’d see that I had to go along with it.”
The work, Wilson explained, had to do with uranium and fission and a whole new kind of bomb. “There’s a meeting at—”
“I don’t want to do it,” Feynman cut in.
“All right,” said Wilson. “There’s a meeting at three o’clock. I’ll see you there.”
Wilson turned and left.
“I went back to work,” Feynman said, “for about three minutes.”
Then he got up and started pacing, thinking about what little he knew about fission and the possibility of building atomic bombs. “This would be a very, very powerful weapon,” he said, “which in the hands of Hitler and his crew would let them completely control the rest of the world.”
He decided to go to the meeting. Soon after, Richard Feynman disappeared from the Princeton campus.
CHICAGO PILE
EARLY ON THE MORNING OF DECEMBER 2, 1942, two figures crunched over the frozen snow covering the campus of the University of Chicago.
“It was terribly cold—below zero,” remembered Leona Woods, a twenty-three-year-old physics grad student. Walking alongside Woods, hunched against the cold, was the world-famous Italian physicist Enrico Fermi.
Woods and Fermi ducked through a gate leading into the football stadium. They nodded to security guards and hurried down a dark hallway beneath the stands, their breath forming frost clouds in the air. It was just as cold inside as out.
Under the football stands were a series of unheated squash courts. They opened the door to one of the courts and stepped inside.
“The scene of this test at the University of Chicago would have been confusing to an outsider,” Fermi later said. “He would have seen only what appeared to be a crude pile of black bricks.” Shaped like an oval, the black pile was about twenty-five feet wide in the middle and twenty feet high.
Woods and Fermi climbed up to a balcony high above the court. “The balcony was originally meant for people to watch squash players,” said Woods, “but now it was filled with control equipment and read-out circuits glowing and winking.”
A young physicist named Herb Anderson walked in, yawning, and helped do a few last-minute checks. Everything was set for one of the most important experiments in the history of science.
But first, breakfast.
“Herb, Fermi and I went over to the apartment I shared with my sister,” Woods said. “I made pancakes, mixing the batter so fast that there were bubbles of dry flour in it. When fried, these were somewhat crunchy between the teeth, and Herb thought I had put nuts in the batter.”
After the quick meal, the three set out across campus to the football stadium. “Back we mushed,” said Woods, “through the cold, creaking snow.”
*
OPPENHEIMER WAS BUSY recruiting scientists for Los Alamos—but that didn’t mean he knew for sure an atomic bomb was technically possible. He and other physicists had spent a few years studying fission. They knew they could bombard a uranium atom with neutrons and cause its nucleus to split. They knew the splitting nucleus would release energy. But what happened next?
Theoretically, as the uranium nucleus split in two, more neutrons would break free and fly off on their own. The speeding neutrons would collide with other uranium atoms, causing them to fission also. As these uranium atoms split, they would release more neutrons, which would hit more uranium atoms. These atoms would also split, releasing still more neutrons, which would hit more uranium atoms, causing more fission, more free-flying neutrons, more fission, more neutrons, and so on. Though they didn’t know if it would actually happen, physicists had a name ready for this process: chain reaction.
Each splitting atom would release a small amount of energy. So scientists knew that if they could cause a fast enough chain reaction, they might be able to build atomic bombs. But first they had to prove a chain reaction was even possible.
That’s what Enrico Fermi and his team were trying to do in the squash court under the football stands in Chicago. The black blocks were graphite, the mineral used to make pencil leads. Slid into holes in some of the blocks were small pieces of uranium. Fermi used graphite to slow down the speeding neutrons—he knew that neutrons would bounce off the carbon atoms that make up graphite and lose speed. Traveling a bit more slowly, they’d be more likely to hit the uranium atoms and cause fission.
Stuck through the pile at various points were long wooden poles wrapped with a bluish-white metal called cadmium. Cadmium was chosen for its ability to absorb huge numbers of neutrons. As long as the cadmium poles were in place, they would absorb the neutrons shooting out of the uranium. This, Fermi told Leslie Groves, would prevent a chain reaction from starting.
Still, the idea of attempting to release nuclear energy in the middle of a city of three million made Groves very nervous. “If the pile should explode, no one knew just how far the danger would extend,” Groves fretted. “Because of this I had serious misgivings about the wisdom of doing the experiment there.”
Fermi assured Groves he knew exactly what he was doing.
*
A LITTLE BEFORE 10:00 A.M., Fermi and his team of about fifteen students and scientists assembled in the freezing squash court. Most climbed to the balcony, but three stood on an elevated platform near the ceiling, holding buckets full of cadmium. If the reaction got out of control, they were to dump the cadmium on the pile—then get out fast.
Fermi sat in a chair on the balcony. He looked over his blinking monitors, then ordered the first cadmium rod to be lifted out of the pile.
As the rod went up, specially built machines measured the flying neutrons, clicking loudly as more and more neutrons were released inside the pile. Fermi did some quick calculations in his notebook. Then he ordered another rod up. The clicking sounds increased again. Fermi did a new set of calculations and called for another rod to be lifted.
; As the experiment continued, more and more curious scientists crammed onto the balcony. Leo Szilard and Eugene Wigner—the ones who’d triggered the Manhattan Project by convincing Albert Einstein to warn President Roosevelt of the danger of atomic bombs—came to watch. Everyone was shivering and covered with black graphite dust. No one spoke but Fermi.
Only one cadmium rod remained in the pile; Fermi’s team called it the “zip” rod. A physicist named George Weil stood on the floor, holding the rope that lifted it.
Fermi called, “Go ahead, George!”
The rod went up a foot. The clicking increased.
“Another foot, George.”
Weil pulled the rod a bit higher.
“You could hear the sound of the neutron counter, clickety-clack, clickety-clack,” said Herb Anderson. Leona Woods kept her eyes on the monitors, calling out measurements to Fermi.
“Another foot, George.”
The rod went up again. The tension in the room rose with the clicking. Only Fermi seemed to be enjoying himself. “This will do it,” he announced, a confident grin spreading across his face. “Now the pile will chain-react.”
Weil pulled the rod completely out of the pile. “Then the clicks came more and more rapidly,” said Anderson, “and after a while they began to merge into a roar.”
Fermi’s smile got bigger. “The pile has gone critical,” he said. The chain reaction was going and would continue doubling in power every two minutes until he shut it down.
Two minutes passed. Fermi watched the monitors, but said nothing.
“Everyone began to wonder why he didn’t shut the pile off,” Anderson said.
The machines continued to roar. Fermi calmly took a few notes.
“He waited another minute, then another,” said Anderson. “The anxiety was too much to bear.”
Finally Fermi said, “Zip in!”
The cadmium rod dropped back into the pile, followed by the other rods. The clicking machines went quiet. There was a long silence in the squash court. Then, unsure what else to do, everyone began to clap.
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