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Friday, February 13, 2004


For three years, we lived inside the atom.[*]

When you're a physicist, you stand in the cold shadow of gods. Not just Newton (distant from us now) and Einstein (who was sui generis), but men like Pauli, Fermi, Schrodinger, Heisenberg, and Bohr. From the late 19th century to the middle of the 20th, these men revolutionized physics, and the world. At the end of the 19th century, many believed that we were approaching the end of physics, that soon we'd know all there was to know about the way the universe worked, and there were only the details to be worked out. (Or, I should say, we knew most of what we could know---for example, how could we ever hope to discover the nature of the stars?) And then Max Planck looked into a little problem of the way in which hot things glowed...and the world was changed.

Much of the groundwork for modern physics was laid in the twenties and thirties in Europe, especially in Germany, by a group of brilliant men (mostly men) who collaborated closely with one another. That was a heroic time, when vast, previously-unknown layers of reality were exposed---a new wonder found under every rock.

And this Age of Legends culminated, in a way, with the creation of the atomic bomb. The mind of Man started with some mathematical equations and and primitive experiments and, in a few short years, was able to tap one of the fundamental forces of nature. This was an almost magical act, like a fairy-tale wizard summoning the lightning.

Physics students read these tales of old with awe, marvelling at the time of intellectual ferment and flowering, imagining themselves in the role of the gods and heroes in some future physics revolution.

Or maybe that's all horseshit. Maybe it's just me.

This is all leading up to the fact that Niles and I went to see the play Copenhagen at the Main Street Theater in Houston last night. Copenhagen, by Michael Frayn, centers around Werner Heisenberg's visit to Niels Bohr in Copenhagen in 1941. Bohr (a Dane) and Heisenberg (German) were two of the giants of modern physics; Heisenberg had worked for Bohr in Copenhagen, and the two had been working together on and off for nearly twenty years, and were good friends.

But in 1941, Denmark was under German occupation, and Heisenberg was head of Germany's nuclear weapons program (not that Bohr knew that). Their meeting would've been awkward in any case, given the political situation; Bohr didn't want to be seen to be "collaborating" with the Germans. But Heisenberg had something urgent to discuss with Bohr. Fearing that Bohr's house was bugged, they took a walk in the open, just the two of them, and had a discussion which is mysterious to this day.

It evidently involved the progress (or lack thereof) of Germany's weapons program. Bohr returned early from the walk, greatly agitated, and Heisenberg left soon afterward. What did Heisenberg want from Bohr? Did he want Bohr's help on a physics problem? Did he want to pass information to the Allies? Did he want to reassure them that he would ensure Germany would not get the bomb? Or did he want to suggest to Bohr that the two of them had the ability to slow down any research on the weapons, preventing anyone from having them?

The play begins with the ghosts of Heisenberg, Bohr, and Bohr's wife Margarethe, hashing over the visit once again. These are the only three characters in the play, and they're all on stage the entire time. Sometimes two of the characters discuss things, or one has a soliloquy, while the other[s] stand[s] aside silently. Margarethe is there to have an excuse for the men to tell their history again, and as a layman to explain the science to, since they'd hardly need to tell or explain to each other. The narrative wanders back and forth across time, from the ghosts' discussion in the present to the meeting itself in the past, and at either time the characters are liable to lapse into a flashback on some other event.

They talk about physics a lot, and use various phenomena as analogies for their own behavior. For example, the two-slit experiment, which shows that an electron goes through two slits simultaneously (because it's a wave), seems to be related to the choices people make in life. For example when skiing, it might be deadly to think about which way to turn when encountering an obstacle. You can swerve right, you can swerve left, or you can stop to think about it, and die. (This isn't a particularly good analogy with the two-slit experiment, by the way.)

Another theme is the drowning death of Bohr's oldest son Christian, at the age of 18. They were out sailing together when Christian went overboard, and his father couldn't save him. They live those moments over and over again, relating Bohr's failure to save Christian with his failure to "save" his other "son", Heisenberg.

In the end, they never conclude what it was that Heisenberg wanted. Bohr (in reality) ought to know, but in the play it's as if Heisenberg started to say something and Bohr fled in anger (or terror), and Heisenberg was never able to explain his mission. (Bohr is also painted as rather forgetful.) Now Heisenberg can't remember. He keeps offering explanations, but can't settle on one.

As a play, I enjoyed it, rather unexpectedly. Most reviews I've seen fasten on the explanation that Heisenberg wanted to keep Germany from having the bomb, and for that reason I was prepared to be displeased, but the play doesn't go that far. Towards the end, there seems to be an assumption that of course making the bomb was immoral. Bohr tries to minimize his part in it, and his wife tries to assure him that he had done nothing wrong. I don't think the historical Bohr believed he had, although after the war he, like many who worked on the bomb, promoted some very naive (translation: dumb) ideas for international control.

The play is certainly very talky, and often the characters argue---about history, philosophy, physics. Sometimes their arguments are pointless---as when they argue who it was that Bohr "shot" with a cap pistol---and then the play gets a bit tedious.

The Main Street Theater is a theater in the round (only it's a rectangle), and very small, so you're close to the action. Their set for the play was simply three ordinary wooden chairs, which the characters keep rearranging, sitting in, and bouncing out of, and a floor painted with very inaccurate copies of illustrations from physics textbooks, among other things. (Their two-slit experiment in particular was very mangled; they had one slit behind the other! Maybe it was some subtle dramatic license thing.) Even though I was in the back (third) row, I found the setting too intimate, and with no scenery or other characters to distract me, discovered I could not watch the play except by focussing on the lights, or the floor. I could barely stand to look at the actors, out of some vague sense of embarrassment.

I was surprised at the amount of physics in the play---which is accurate from what I can remember---and the emphasis on it. I would think a lot of people would be quite lost.

For me, it was like being a member of a small tribe who suddenly sees their richbut obscure mythology made into a movie. Or perhaps like someone whose father took part in a thrilling but little-known battle, which is then made into a movie. With every scene you find yourself nodding, "I remember that!"; remembering, of course, Dad's war stories, not the actual events. When a name is mentioned you know not only the name but the history, significance, and fate of the name. And no one else in the theater does.

(After a bit, though, it begins to sound a little bit like name-dropping: Schrodinger, Einstein, Fermi, Pauli, Ehrenfest, Goudsmit, Uhlenbeck, Dirac, Frisch, Peierls, Hahn, Meitner, Gerlach, Jordan, Chadwick, Kramers, Wheeler, Born, De Broglie, Casimir, Landau, Gamow, and Oppenheimer are all mentioned at one time or another.)

Niles, also a physicist, was bored. He is not as steeped in the lore as I am, and he wanted there to be a point to the play, an ending and a conclusion.

So what was the point of Heisenberg's visit? He told Robert Jungk, author of the book Brighter Than a Thousand Suns (and an anti-nuclear activist), that he had gone to try to convince Bohr that they could work together to slow down the research into atomic weapons. But apparently he told various people different stories at different times.

Because of the interest aroused in the matter by the play, the Bohr family authorized an early release of a draft of a letter Bohr wrote (but never sent) to Heisenberg after reading Heisenberg's quotes in Brighter Than a Thousand Suns (Bohr's papers are scheduled to be released in 2012). Bohr remembers that Heisenberg told him that Germany's victory was inevitable---possibly telling him about the nuclear weapons work as proof---so that Bohr and his institute had better start collaborating with the Germans. This wasn't so much a threat as an effort to forestall future threats from the German government.

Apparently the play has been made into a movie. If we'd known that, we probably wouldn't have gone to the play.

Epilogue: Bohr's mother was Jewish, and in 1943 he was slated to be arrested and probably deported. He and his family were smuggled to neutral Sweden (this is mentioned in the play). After Bohr reached Sweden, a disarmed Mosquito bomber was sent to take him to Britain. There was no room for passengers, so Bohr had to ride in the bomb bay. The oxygen mask they gave him was too small for his big ol' head, and he passed out from lack of oxygen. When the pilots couldn't raise him on the intercom, they hurriedly descended to a more congenial altitude, and had to fly on to Britain at that altitude, at an increased risk of being shot down. Bohr was delivered safely in the end. (This part isn't mentioned in the play, more's the pity.)

[*] A line from the play, one of the few that I thought was beautiful in its own right. Heisenberg is remembering his awe at H.A. Kramers, who was Bohr's assistant (a much grander position than it sounds) when Heisenberg was a grubby lecturer in Cophenhagen. The lecturers had crummy offices, while Kramers had an office adjacent to Bohr, "like a single electron with its nucleus". Then Kramers moved on and Heisenberg became the assistant, and "For three years, we lived inside the atom." (I can't find that this is exactly historically accurate.)