Bomb (2 page)

H
E'D ALWAYS BEEN DIFFERENT.
A girl who knew Robert as a child in New York City described him as “very frail, very pink-cheeked, very shy, and very brilliant.”

Oppenheimer was a tougher critic. “A repulsively good little boy,” he said of himself. “My life as a child did not prepare me for the fact that the world is full of cruel and bitter things.”

He was constantly getting sick, so his nervous parents tried to protect him by keeping him inside. While other boys played in the street, Robert sat alone in his room studying languages, devouring books of literature and science, and filling notebooks with poetry. Around kids his age he was awkward and quiet, never knowing what to say unless he could bring the conversation around to books. Then he would let loose annoying bursts of learning.

“Ask me a question in Latin,” he'd say, “and I'll answer you in Greek.”

Hoping to toughen up their stick-skinny fourteen-year-old, Robert's parents sent him to a sports summer camp. But he was an awful athlete and simply refused to participate. Then the other campers found out he wrote home every day, and that he liked poetry and looking for minerals. That's when they started calling him “Cutie.”

Robert never fought back. He never even responded. That made his tormentors even angrier.

One night, after dinner, Robert went for a walk. A group of boys waited for him in the woods. They grabbed him, dragged him to the icehouse, and tossed him on the rough wood floor. They ripped off his shirt and pants, dipped a brush in green paint, and slapped the dripping bristles against his bony body.

Robert never said a word about the attack to camp counselors. “I don't know how Robert stuck out those remaining weeks,” his only friend at camp later said. “Not many boys would have—or could have—but Robert did. It must have been hell for him.”

Science saved him. Robert dove deep into chemistry and physics in high school, graduated from Harvard University in 1925, then earned advanced degrees at top universities in Britain and Germany. Even in classes with some of the brightest students in the world, “Oppie,” as friends called him, never lost his know-it-all style. He interrupted physics lectures with his own theories, sometimes charging to the chalkboard, grabbing the chalk and declaring. “This can be done much better in the following manner.” Classmates got so annoyed they actually signed a petition asking him to allow others to speak in class. After that, Oppenheimer calmed down. A little bit. “The trouble,” a friend said, “is that Oppie is so quick on the trigger intellectually, that he puts the other guy at a disadvantage.”

He'd lucked into a thrilling time in theoretical physics. Physicists were just beginning to figure out what atoms look like, and how the tiny particles inside them move and affect each other. Theoretical physicists were the explorers of their day, using imagination and mind-bending math to dig deeper and deeper into the surprising inner workings of atoms. Oppenheimer knew he'd found his calling.

When he returned to the States, schools all over the country tried to hire him. He picked the University of California, in Berkeley, where he quickly built the country's best theoretical physics program. Students who came to study with Oppenheimer quickly realized they were in for a wild ride. “When you took a question to him,” one student remembered, “he would spend hours—until midnight perhaps—exploring every angle with you.”

“He generally would answer patiently,” another student agreed, “unless the question was manifestly stupid, in which event his response was likely to be quite caustic.”

While sitting in on other professors' lectures, Oppenheimer was known to squirm impatiently. “Oh, come now!” he'd call out. “We all know that. Let's get on with it!”

Oppenheimer's own lectures, according to a student named Edward Gerjuoy, were lightning bursts of ideas, theories, and math on the blackboard. “He spoke quite rapidly, and puffed equally rapidly,” Gerjuoy said. “When one cigarette burned down to a fragment he no longer could hold, he lit another.” Oppenheimer paced as he lectured, his wiry black hair sticking straight up, his large blue eyes flashing, as he furiously wrote, erased, wrote more, talked, puffed, and bobbed in and out of a cloud of white smoke.

During one lecture, he told students to think about a formula he'd written. There were dozens scrawled all over the board, and a student cut in to ask which formula he was talking about.

“Not that one,” Oppenheimer said, pointing to the blackboard, “the one underneath.”

There was no formula below that one, the student pointed out.

“Not below,
underneath
,” snapped Oppenheimer. “I have written over it.”

As one of Oppenheimer's students put it: “Everyone sort of regarded him, very affectionately, as being sort of nuts.”

*   *   *

“I
NEED PHYSICS MORE THAN FRIENDS,
” Oppenheimer once told his younger brother. Lost in his studies, Oppenheimer paid little attention to the outside world. He didn't hear about the stock market crash that triggered the Great Depression until six months after it happened. He first voted in a presidential election in 1936, at the age of thirty-two.

“Beginning in late 1936, my interests began to change,” he later said. There were a few reasons.

For one thing, the country's ongoing economic troubles began to hit home. “I saw what the Depression was doing to my students. Often they could get no jobs,” he said. “And through them, I began to understand how deeply political and economic events could affect men's lives. I began to feel the need to participate more fully in the life of the community.” Oppenheimer started going to political meetings and discussion groups. He began giving money to support causes like labor unions and striking farm workers.

But it wasn't only events in the United States that caught Oppenheimer's attention—he was also alarmed by the violent rise of Adolf Hitler and his Nazi Party in Germany. Hitler took over as chancellor of Germany in 1933 and started arresting political opponents and tossing them into concentration camps. With complete control of the country in his hands, Hitler began persecuting German Jews, stripping them of their legal rights, kicking them out of universities and government jobs. Oppenheimer, who was Jewish, still had family in Germany, as well as Jewish friends from his student days. When he heard that Hitler was harassing Jewish physicists, Oppenheimer dedicated a portion of his salary to help them escape Nazi Germany.

At the same time, the German dictator built up a huge military and started hacking out what he called a “Greater Germany,” a massive European empire that Hitler insisted rightfully belonged to Germans. He annexed neighboring Austria in 1938, then demanded a huge region of Czechoslovakia. Britain and France were strong enough to stand in Hitler's way—but they caved in to his threats, hoping to preserve peace in Europe.

“This is my last territorial demand in Europe,” Hitler promised.

A few months later, he sent German troops into the rest of Czechoslovakia. Just twenty years after the end of World War I, it looked like a second world war was about to explode.

Oppenheimer followed these terrifying events from his home in California, burning with what he described as “a continuing, smoldering fury” toward Adolf Hitler.

But how was a theoretical physicist supposed to save the world?

THE U BUSINESS

ACTUALLY, THEORETICAL PHYSICISTS
were about to become more powerful than Oppenheimer had ever imagined.

In late December 1938, in the German capital of Berlin, a chemist named Otto Hahn set up a new experiment in his lab. By the late 1930s, scientists like Hahn understood that everything in the universe is made up of incredibly tiny particles called atoms. They knew that atoms themselves are composed of even smaller particles. Atoms have a central core, or nucleus, made up of protons and neutrons packed tightly together. Surrounding the nucleus are electrons.

Scientists also knew that some atoms are radioactive. That is, their nucleus is naturally unstable—particles break away from the nucleus and shoot out at high speeds. This was useful to experimenters like Hahn, because they could use radioactive elements as tiny cannons.

Hahn began his experiment with a piece of silver-colored metal called uranium. He placed the uranium beside a radioactive element. He knew that neutrons would speed out of the radioactive material. He knew that some of these tiny particles would hit uranium atoms. The big question was: What happens when a speeding neutron crashes into a uranium atom?

The answer was shocking. Hahn was sure he'd made a mistake.

As expected, some of the speeding neutrons hit uranium atoms. What staggered Hahn was that the force of the collision seemed to be causing the uranium atoms to split in two. According to everything scientists knew in 1938, this was impossible.

*   *   *

A
T ONCE EXCITED AND DISTURBED,
Hahn needed help. He turned to his former partner, Lise Meitner, a Jewish physicist who'd been forced out of Germany by Hitler. Hahn wrote to Meitner at her new office in Sweden, describing the strange results of his experiment.

“Perhaps you can suggest some fantastic explanation,” Hahn said of the splitting uranium. “We understand that it really
can't
break up.”

Meitner responded immediately, agreeing that the news was amazing, but adding: “We have experienced so many surprises in nuclear physics that one cannot say without hesitation about anything: ‘it's impossible.'”

A few days later Meitner's nephew Otto Frisch, also a physicist, came to Sweden for a visit. Over breakfast, she showed him Hahn's letter.

“I don't believe it,” he said. “There's some mistake.”

The two went outside to discuss the mystery. “We walked up and down in the snow, I on skis and she on foot,” Frisch recalled.

They talked over an idea proposed by the great Danish physicist Niels Bohr. Bohr had recently suggested that the nucleus of an atom might act like a “wobbly droplet” of liquid. If that were true, they asked each other, what would happen if a speeding neutron hit the nucleus of a uranium atom? Could the force of the collision cause the uranium nucleus to stretch and stretch—just like a liquid drop—until it split?

They brushed the snow off a fallen log and sat. Meitner pulled out a scrap of paper and pencil, and Frisch sketched a diagram of a circle stretching into a long oval shape, and finally breaking in two.

“Yes,” said Meitner. “That is what I mean.”

They agreed: this must be what happened to the uranium atoms in Hahn's lab. Meitner took the pencil and paper and began working out the math.

“If you really do form two such fragments,” she said, “they would be pushed apart with great energy.”

An atom splitting was incredible enough. But what made this a world-changing discovery was that if atoms really
could
be split, they would release energy as they broke in two. How much energy? Just enough, Meitner and Frisch calculated, to make a grain of sand jump. That doesn't sound like much—but keep in mind how tiny atoms are. With 238 protons and neutrons, uranium is the largest atom in nature. Still, each atom is incredibly small. A single ounce of uranium has about 100,000,000,000,000,000,000 atoms.

What if you had a twenty-pound lump of uranium? A fifty-pound lump? What if you were able to get all those atoms to split and release energy at the same moment? You'd have
by far
the most powerful bomb ever built.

“I feel as if I had caught an elephant by its tail, without meaning to,” Frisch wrote to his mother. “And now I don't know what to do with it.”

*   *   *

N
EWS OF THE DISCOVERY SPREAD QUICKLY
within the small world of theoretical physicists. Otto Frisch rushed to Copenhagen, Denmark, catching up with Niels Bohr just as Bohr was boarding a ship for America. Frisch began telling Bohr that uranium atoms could split in two and was halfway through his explanation when Bohr slapped himself on the forehead.

“Oh, what idiots we have all been!” shouted Bohr. “Oh, but it is wonderful. This is just as it must be!”

Bohr was so excited, he ran home to get a blackboard. He set it up in his cabin on the ship and spent most of the two-week Atlantic crossing exploring this new discovery. By the time he reached New York City in January 1939, he was convinced—uranium atoms really could split in two. He took the news to a physics conference in Washington, D.C., where it leaped from one physicist to another.

“Bohr has just come in,” one scientist announced. “He has gone crazy. He says a neutron can split uranium!”

A newspaper reporter attending the conference described the news in a short article, which was picked up by papers across the country. The next morning a young physicist named Luis Alvarez was sitting in a barber shop in Berkeley, California. While the barber snipped his hair, Alvarez grabbed the
San Francisco Chronicle
from a pile of papers beside the chair. “In the second section,” he remembered, “buried away some place, was an announcement that some German chemists had found that the uranium atom split into two pieces.”