Monday, March 25, 2013

Los Alamos reminiscences of Richard Feynman

Probably very well known but I noticed it only today
Los Alamos From Below: Reminiscences 1943-1945, by Richard Feynman
Some excepts. First about cracking safes "Once, however, I did open a safe purely by accident, and that helped to reinforce my reputation. It was a sensation, but it was pure luck...... For 20 minutes I turned pi upside down. Nothing happened.
            So I started walking out of the office, and I remembered in the book about the psychology, and I said, “You know, it's true. Psychologically, DeHoffman is just the kind of a guy to use a mathematical constant for his safe combination. And the other important mathematical constant is e.” So I walk back to the safe. 27-18-28 - click, clock, it opens."

About meeting Niels Bohr "Then the son told me what happened. The last time he was there, he said to his son, “Remember the name of that little fellow in the back over there? He's the only guy who's not afraid of me, and will say when I've got a crazy idea. So next time when we want to discuss ideas, we're not going to be able to do it with these guys who say everything is yes, yes, Dr. Bohr. Get that guy and we'll talk with him first.""

About watching the first atomic bomb explosion:
"The next thing that happened, of course, was the ' I 'test, after we'd made the calculations. I was actually at home on a short vacation at that time, after my wife died, and so I got a message that said, “The baby is expected on such and such a day."
            I flew back, and I just arrived when the buses were leaving, so I went straight out to the site and we waited out there, 20 miles away. We had a radio, and they were supposed to tell us when the thing was going to go off and so forth, but the radio wouldn't work, so we never knew what was happening. But just a few minutes before it was supposed to go off the radio started to work, and they told us there was 20 seconds or something to go, for people who were far away like we were. Others were closer, 6 miles away.
            They gave out dark glasses that you could watch it with. Dark glasses! Twenty miles away, you couldn't see a damn thing through dark glasses. So I figured the only thing that could really hurt your eyes - bright light can never hurt your eyes - is ultraviolet light. I got behind a truck windshield, because the ultraviolet can't go through glass, so that would be safe, and so I could see the damn thing. OK.
            Time comes, and this tremendous flash out there is so bright that I duck, and I see this purple splotch on the floor of the truck. I said, “That ain't it. That's an after-image.” So I look back up, and I see this white light changing into yellow and then into orange. The clouds form and then they disappear again; the compression and the expansion forms and makes clouds disappear. Then finally a big ball of orange, the center that was so bright, becomes a ball of orange that starts to rise and billow a little bit and get a little black around the edges, and then you see it's a big ball of smoke with flashes on the inside of the fire going out, the heat.
            All this took about one minute. It was a series from bright to dark, and I had seen it. I am about the only guy who actually looked at the damn thing the first Trinity test. Everybody else had dark glasses, and the people at six miles couldn't see it because they were all told to lie on the floor. I'm probably the only guy who saw it with the human eye.
            Finally, after about a minute and a half, there's suddenly a tremendous noise - BANG, and then a rumble, like thunder -- and that's what convinced me. Nobody had said a word during this whole thing. We were all just watching quietly. But this sound released everybody- - released me particularly because the solidity of the sound at that distance meant that it had really worked.
The man standing next to me said, “What's that?"
I said, “That was the bomb.""

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