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Retired Physics Prof & A-bomb

Retired physics professor is only man alive who saw all three atomic explosions

By Sandra Lee
Reprinted with permission from the Lewiston Tribune

MOSCOW - Not all who serve their countries in wartime wear uniforms or carry guns.

Lawrence H. Johnston carried a slide rule.

Seven decades ago, most people had never heard of computers, including Johnston, now a retired University of Idaho physics professor. Electronics was essentially a new word.

And the Atomic Age had not yet dawned.

But when it did, Johnston, now 93, was in the front row.

He was on the observation airplane that watched Trinity, the code name for the first atomic bomb test, July 16, 1945, in New Mexico. And he was on the B-29 dubbed Great Artiste when Little Boy was dropped on Hiroshima Aug. 6, 1945, and three days later when Fat Man devastated Nagasaki and finally brought World War II to an end.

It's pretty much accepted, Johnston said during a recent conversation at his Moscow home, that he is the only person to have seen all three bombings. He was there because he developed the detonator that made them work, the result of two weeks of isolated, intense work in a desert location where, if he failed, he wouldn't blow up anyone else.

But he didn't fail, the bombs went off and more than 200,000 people died. And many more lived.

The invasion was expected to create 1 million casualties. A warehouse on Tinian Island had been prepared with 300,000 coffins.

That risk, 66 years ago, was less important than the result, Johnston says as he looks again into the face of death, although this time after a long life filled with adventure and science and love. The goal was simple: to end a devastating war that was the focus of virtually every person, every part of society at that time.

Morality wasn't an issue, Johnston says.

"Not 'til later when everyone criticized us," adds his wife of 69 years, Millie Johnston.

Scientists knew as they worked that the force of the bomb would be enormous, perhaps beyond anything they could envision. But they also had a purpose.

"It made the invasion of Japan unnecessary," Larry Johnston says. "That would have been a very bloody invasion."

At Trinity, they watched the blast from 50 miles away instead of overhead, a last-minute restriction by some suddenly cautious people, he says. He remembers still the brilliant flash, a huge cloud, but no noise and no physical impact, unlike three weeks later over Japan. In less than a minute, the infamous mushroom cloud that would become the symbol of the Atomic Age ballooned upward, passing them as they circled around it.

"At Hiroshima and Nagasaki we were a lot closer and we did feel something of an impact. It felt like somebody hit the side of the airplane with a footlong 2-by-4. Whack!"

Prior to the explosions, there was no discussion of protection from radiation exposure or health risks, he says. "I think there's too much concern about it now. The reason is whoever designed the human body built cells with wonderful repair mechanisms."


Johnston's journey to Moscow began in China in 1918, where he was born to missionary parents. He could have been a missionary instead of a physicist, Johnston says. He believes God steered him the direction he was intended to go.

He was 22 in 1940, with just a bachelor's degree in physics from the University of California at Berkeley. But the war effort was gathering in everyone, and one of his professors was Luis Alvarez, winner of the 1968 Nobel Prize in physics, "really a genius and the smartest man I have ever met."

Life changed for everyone the day the Japanese bombed Pearl Harbor, but that accelerated for Johnston when J. Robert Oppenheimer, who was in charge of the Manhattan Project that started in 1939, summoned Alvarez to help with a detonation problem. Alvarez asked Johnston to go along. In the ensuing whirlwind of activities, history and his life changed.

They went first to Boston, where he and Alvarez developed the Ground Control Approach Radar System that allowed a plane to land with zero visibility.

Alvarez was an enthusiastic amateur pilot, "so this whole laboratory at MIT (Massachusetts Institute of Technology) was built on the basis of suddenly having an electronic unit called a magnetron. And the interesting fact is that microwave ovens are now powered by magnetrons."

But seven decades ago, "it was a secret thing the British let us have and that was how it was invented."

No one then was thinking about how it might be used down the road, he said. "I was just thinking, can we contribute something to this war."

His bosses saw something else, however - Johnston was an unhappy man. Alvarez sent him back to California to see Millie. "He ordered me, 'bring her back with you,' " Johnston says. They were married in February 1942, then hurried back to Boston where his work waited.

From there, Alvarez and the Johnstons packed up and went to New Mexico to the government town of Los Alamos.

Increasingly as he is asked to speak about those years, Johnston says, people turn to Millie and ask her what it was like then as the world changed around them.

When the war ended, they headed east to visit family. Johnston found himself in demand as a speaker and for newspaper interviews. That long road trip also led him to appreciate modern marvels like tires without inner tubes that still seal well enough to hold air.

They then returned to Stanford where Wolfgang K.H. Panofsky, who had also worked on the Manhattan Project, asked Johnston to take charge of instrumentation on a new mega electron accelerator at the Stanford Linear Accelerator. It was to be 2 miles long with instrumentation every 20 feet.

"But I discovered that Panofsky was a very ambitious guy and he had promised the Atomic Energy Commission he would build the accelerator on time and on budget, which was unheard of for big projects like this."

He finished that project and began working on things that interested him, like a hydrogen cyanide laser that produced radiation in the far infrared of the spectrum, "way below the visible. ... All sorts of new physics could be done with this laser."

He still holds numerous patents, but he found teaching was fun.

It was more than that, Millie says. "He is a born teacher. He taught our kids so much." When the oldest of their four children was a freshman at Berkeley, she was tutoring her boyfriend in physics just from what she learned listening to her father, "because he couldn't help explaining things to everybody."

He chuckles remembering an early class in conservation of momentum. To demonstrate it to his students, he took a fire extinguisher from the hallway, sat on a chair with wheels and pulled the trigger. It pushed him clear across the room. "They thought that was quite interesting except this fire extinguisher also had some other powdered chemicals in it so everybody started choking."

The room had to be evacuated and cleaned thoroughly before the next class.

After retiring in 1988, "I decided to get into more interesting things so I went to the head of the biology department and said can you teach me something about evolution. He said, I don't know very much about evolution. Can you imagine that from the head of the biology department?"

So he called a friend in the field, an agnostic, and asked her how she thought life got started on Earth. "She said, nobody knows, but it's almost a miracle."

That makes him laugh again.

What started as a campus seminar has dwindled to a weekly gathering at his home where old friends debate the greatest mystery of mankind - how the universe began.

"I think some creative personality, very powerful, went ahead and did it," he says of his own belief.

He expects to know with certainty in the not too distant future. He has lung cancer and he's short of breath at times, but not so much that the scientist in him is quenched.

He has a plan for when death does come.

"Well, I hope I get to see Jesus and I have a bunch of questions I want to ask him," Johnston says. "But probably at that time they won't be as interesting."