Bomb (9 page)

*   *   *

A
MONG 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.”

*   *   *

O
PPENHEIMER 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.

*   *   *

“T
HE CONTROLLED RELEASE
of atomic power has been demonstrated for the first time in history,” Fermi said of his experiment. The pile had generated only enough energy to power a small light bulb. But the chain reaction had been proved—humans now knew they could release the enormous power locked inside atoms.

“For some time, we had known that we were about to unlock a giant,” remembered Eugene Wigner. “Still, we could not escape an eerie feeling when we knew we had actually done it.”

Wigner pulled out a bottle of red wine and a stack of paper cups. He filled the cups, and the scientists and students silently passed them around.

No one offered a toast, Leona Woods recalled. “There was a greater drama in the silence than if words had been spoken.”

Woods couldn't be sure what the others were thinking. She had a feeling their thoughts were similar to her own. “Of course, the Germans have already made a chain reaction,” she said to herself. “We have, and they have been ahead until now.”

Then she thought,
When do we get as scared as we ought to?

OPERATION GUNNERSIDE

KNUT HAUKELID LAY
in his hospital bed in Britain, recovering from the accidental bullet wound in his foot. He was furious with himself for missing the chance to parachute into Norway. But he was about to get a second chance.

In spite of the glider disaster, the British and Americans were still determined to destroy the Vemork heavy water plant in Norway. Like the graphite Enrico Fermi used in his Chicago pile, heavy water can be used to slow down neutrons and create a chain reaction in uranium. In fact, heavy water is more efficient than graphite—Fermi would have used heavy water if he could have gotten his hands on enough. But Adolf Hitler held tight to the world's only supply. Breaking that grip was the key to stopping the German bomb. The Allies could try bombing Vemork from the air, but the cliffside target would be difficult for planes to hit. They'd be more likely to kill civilians living nearby than to seriously damage the plant.

As soon as Haukelid got out of the hospital, he was brought to London with five other Norwegian volunteers for a talk with Colonel John Wilson of the S.O.E. Wilson explained the new mission, code-named Gunnerside. The Norwegians would parachute onto the Hardanger Plateau and find Jens Poulsson and his team—they were still camped somewhere on the plateau. Together, they'd ski to Vemork, bust into the building, and blow up vital equipment in the plant basement.

Wilson told them about the glider operation. He told them the Nazis had executed every one of the British soldiers. “You must reckon,” he said, “that the Germans will in no circumstances take any prisoners.” It was not normal procedure to give commandos this kind of information, but Wilson wanted the men going in with no illusions.

“You have a fifty-fifty chance of doing the job,” Wilson said, “and only a fair chance of escaping.”

*   *   *

O
N THE NIGHT OF
F
EBRUARY 17,
1943, Knut Haukelid and the other Gunnerside men hunched inside a British plane, cruising 10,000 feet above the North Sea.

“It was a tight fit inside the aircraft,” remembered Haukelid. “With our heavy equipment, weapons, and thick clothes, we could hardly move.”

The team had spent weeks preparing for their mission. They studied photographs and technical drawings of the Vemork plant. They planned routes in and out of the factory and practiced wrapping explosives around the type of equipment they expected to find inside. They were given cross-country skis, with which they needed no training. And there was one final tool.

“We were all issued the death pill,” Haukelid recalled.

Rather than allow themselves to be taken prisoner and tortured for information, the men were instructed to bite this pill. “It was cyanide enclosed in a rubber cover,” said Haukelid. “It could be kept in the mouth. Once bitten through it would ensure death within three seconds.”

At one in the morning, the British pilot announced they were ten minutes from the jump site. The team leader, twenty-two-year-old Joachim Ronneberg, stood over the open hatch in the plane's floor, looking down. The drop target was a frozen lake deep in the wilderness—hopefully, far from any German patrols.

“No doubt the hearts of most of us beat a little faster at the thought that we were about to jump into the moonlight over heaven knew what,” Haukelid later said. “The warning lamp in the roof burned green. All clear!”

Ronneberg tumbled out first, then the others, and then crates of equipment.

“I felt the marvelous jerk, which told me that the parachute had opened,” said Haukelid. “Beneath me there was nothing but snow and ice. Here lay the Hardanger Plateau, the largest, loneliest, and wildest mountain area in northern Europe.”

Haukelid landed in the snow. The other men and the equipment glided down all around him. He got up and looked around at the low, snow-covered hills dotted with bare bushes. Clearly they were not on the frozen lake they'd been aiming for.

“Do you know where we are?” asked Ronneberg.

Haukelid shook his head. “We may be in China, for all I know.”

*   *   *

“I
T WAS OBVIOUS
that we had not landed on the lake,” Ronneberg recalled. “But we didn't have time to worry about that. We had to gather our equipment and stow it away before daylight.”