Copenhagen (7 page)

Heisenberg
  But what I stress is the difficulty of separating 235.

Margrethe
  You tell them about plutonium.

Heisenberg
  I tell some of the minor officials. I have to keep people’s hopes alive!

Margrethe
  Otherwise they’ll send for the other one.

Heisenberg
  Diebner. Very possibly.

Margrethe
  There’s always a Diebner at hand ready to take over our crimes.

Heisenberg
  Diebner might manage to get a little further than me.

Bohr
  Diebner?

Heisenberg
  Might. Just possibly might.

Bohr
  He hasn’t a quarter of your ability!

Heisenberg
  Not a tenth of it. But he has ten times the eagerness to do it. It might be a very different story if it’s Diebner who puts the case at our meeting with Albert Speer, instead of me.

Margrethe
  The famous meeting with Speer.

Heisenberg
  But this is when it counts. This is the real moment of decision. It’s June 1942. Nine months after my trip to Copenhagen. All research cancelled by Hitler unless it produces immediate results—and Speer is the sole arbiter of what will qualify. Now, we’ve just got the first sign that our reactor’s going to work. Our first increase in neutrons. Not much—thirteen per cent—but it’s a start.

Bohr
  June 1942? You’re slightly ahead of Fermi in Chicago.

Heisenberg
  Only we don’t know that. But the RAF have begun terror-bombing. They’ve obliterated half of Lübeck, and the whole centre of Rostock and Cologne. We’re desperate for new weapons to strike back with. If ever there’s a moment to make our case, this is it.

Margrethe
  You don’t ask him for the funding to continue?

Heisenberg
  To continue with the reactor? Of course I do. But I ask for so little that he doesn’t take the programme seriously.

Margrethe
  Do you tell him the reactor will produce plutonium?

Heisenberg
  I don’t tell him the reactor will produce plutonium. Not Speer, no. I don’t tell him the reactor will produce plutonium.

Bohr
  A striking omission, I have to admit.

Heisenberg
  And what happens? It works! He gives us barely enough money to keep the reactor programme ticking over. And that is the end of the German atomic bomb. That is the end of it.

Margrethe
  You go on with the reactor, though.

Heisenberg
  We go on with the reactor. Of course. Because now there’s no risk of getting it running in time to produce enough plutonium for a bomb. No, we go on with the reactor all right. We work like madmen on the reactor. We have to drag it all the way across Germany, from east to west, from Berlin to Swabia, to get it away from the bombing, to keep it out of the hands of the Russians. Diebner tries to hijack it on the way. We get it away from him, and we set it up in a little village in the Swabian Jura.

Bohr
  This is Haigerloch?

Heisenberg
  There’s a natural shelter there—the village inn has a wine-cellar cut into the base of a cliff. We dig a hole in the floor for the reactor, and I keep that programme going, I keep it under my control, until the bitter end.

Bohr
  But, Heisenberg, with respect now, with the greatest respect, you couldn’t even keep the reactor under your control. That reactor was going to kill you.

Heisenberg
  It wasn’t put to the test. It never went critical.

Bohr
  Thank God. Hambro and Perrin examined it after the Allied troops took over. They said it had no cadmium control rods. There was nothing to absorb any excess of neutrons, to slow the reaction down when it overheated.

Heisenberg
  No rods, no.

Bohr
  You believed the reaction would be self-limiting.

Heisenberg
  That’s what I originally believed.

Bohr
  Heisenberg, the reaction would not have been self-limiting.

Heisenberg
  By 1945 I understood that.

Bohr
  So if you ever had got it to go critical, it would have melted down, and vanished into the centre of the earth!

Heisenberg
  Not at all. We had a lump of cadmium to hand.

Bohr
  A
lump
of cadmium? What were you proposing to do with a
lump
of cadmium?

Heisenberg
  Throw it into the water.

Bohr
  What water?

Heisenberg
  The heavy water. The moderator that the uranium was immersed in.

Bohr
  My dear good Heisenberg, not to criticise, but you’d all gone mad!

Heisenberg
  We were almost there! We had this fantastic neutron growth! We had 670 per cent growth!

Bohr
  You’d lost all contact with reality down in that hole!

Heisenberg
  Another week. Another fortnight. That’s all we needed!

Bohr
  It was only the arrival of the Allies that saved you!

Heisenberg
  We’d almost reached the critical mass! A tiny bit bigger and the chain would sustain itself indefinitely. All we need is a little more uranium. I set off with Weizsäcker to try and get our hands on Diebner’s. Another hair-raising journey all the way back across Germany. Constant air raids—no trains—we try bicycles—we never make it! We end up stuck in a little inn somewhere in the middle of nowhere, listening to the thump of bombs falling all round us. And on the radio someone playing the Beethoven G minor cello sonata …

Bohr
  And everything was still under your control?

Heisenberg
  Under my control—yes! That’s the point! Under my control!

Bohr
  Nothing was under anyone’s control by that time!

Heisenberg
  Yes, because at last we were free of all constraints! The nearer the end came the faster we could work!

Bohr
  You were no longer running that programme, Heisenberg. The programme was running you.

Heisenberg
  Two more weeks, two more blocks of uranium, and it would have been German physics that achieved the world’s first self-sustaining chain reaction.

Bohr
  Except that Fermi had already done it in Chicago, two years earlier.

Heisenberg
  We didn’t know that.

Bohr
  You didn’t know anything down in that cave. You were as blind as moles in a hole. Perrin said that there wasn’t even anything to protect you all from the radiation.

Heisenberg
  We didn’t have time to think about it.

Bohr
  So if it
had
gone critical …

Margrethe
  You’d all have died of radiation sickness.

Bohr
  My dear Heisenberg! My dear boy!

Heisenberg
  Yes, but by then the reactor would have been running.

Bohr
  I should have been there to look after you.

Heisenberg
  That’s all we could think of at the time. To get the reactor running, to get the reactor running.

Bohr
  You always needed me there to slow you down a little. Your own walking lump of cadmium.

Heisenberg
  If I had died then, what should I have missed? Thirty years of attempting to explain. Thirty years of reproach and hostility. Even you turned your back on me.

Margrethe
  You came to Copenhagen again. You came to Tisvilde.

Heisenberg
  It was never the same.

Bohr
  No. It was never the same.

Heisenberg
  I sometimes think that those final few weeks at Haigerloch were the last happy time in my life. In a strange way it was very peaceful. Suddenly we were out of all the politics of Berlin. Out of the bombing. The war was coming to an end. There was nothing to think about except the reactor. And we didn’t go mad, in fact. We didn’t work all the time. There was a monastery on top of the rock above our cave. I used to retire to the organ-loft in the church, and play Bach fugues.

Margrethe
  Look at him. He’s lost. He’s like a lost child. He’s been out in the woods all day, running here, running there. He’s shown off, he’s been brave, he’s been cowardly. He’s done wrong, he’s done right. And now the evening’s come, and all he wants is to go home, and he’s lost.

Heisenberg
  Silence.

Bohr
  Silence.

Margrethe
  Silence.

Heisenberg
  And once again the tiller slams over, and Christian is falling.

Bohr
  Once again he’s struggling towards the lifebuoy.

Margrethe
  Once again I look up from my work, and there’s Niels in the doorway, silently watching me …

Bohr
  So, Heisenberg, why did you come to Copenhagen in 1941? It was right that you told us about all the fears you had. But you didn’t really think I’d tell you whether the Americans were working on a bomb.

Heisenberg
  No.

Bohr
  You didn’t seriously hope that I’d stop them.

Heisenberg
  No.

Bohr
  You were going back to work on that reactor whatever I said.

Heisenberg
  Yes.

Bohr
  So, Heisenberg, why did you come?

Heisenberg
  Why did I come?

Bohr
  Tell us once again. Another draft of the paper. And this time we shall get it right. This time we shall understand.

Margrethe
  Maybe you’ll even understand yourself.

Bohr
  After all, the workings of the atom were difficult to explain. We made many attempts. Each time we tried they became more obscure. We got there in the end, however. So—another draft, another draft.

Heisenberg
  Why did I come? And once again I go through that evening in 1941. I crunch over the familiar gravel, and tug at the familiar bell-pull. What’s in my head? Fear, certainly, and the absurd and horrible importance of someone bearing bad news. But … yes … something else as well. Here it comes again. I can almost see its face. Something good. Something bright and eager
and hopeful.

Bohr
  I open the door …

Heisenberg
  And there he is. I see his eyes light up at the sight of me.

Bohr
  He’s smiling his wary schoolboy smile.

Heisenberg
  And I feel a moment of such consolation.

Bohr
  A flash of such pure gladness.

Heisenberg
  As if I’d come home after a long journey.

Bohr
  As if a long-lost child had appeared on the doorstep.

Heisenberg
  Suddenly I’m free of all the dark tangled currents in the water.

Bohr
  Christian is alive, Harald still unborn.

Heisenberg
  The world is at peace again.

Margrethe
  Look at them. Father and son still. Just for a moment. Even now we’re all dead.

Bohr
  For a moment, yes, it’s the twenties again.

Heisenberg
  And we shall speak to each other and understand each other in the way we did before.

Margrethe
  And from those two heads the future will emerge. Which cities will be destroyed, and which survive. Who will die, and who will live. Which world will go down to obliteration, and which will triumph.

Bohr
  My dear Heisenberg!

Heisenberg
  My dear Bohr!

Bohr
  Come in, come in …

Heisenberg
  It was the very beginning of spring. The first time I came to Copenhagen, in 1924. March: raw, blustery northern weather. But every now and then the sun would come out and leave that first marvellous warmth of the year on your skin. That first breath of returning life.

Bohr
  You were twenty-two. So I must have been … Thirty-eight.

Bohr
  Almost the same age as you were when you came in 1941.

Heisenberg
  So what do we do?

Bohr
  Put on our boots and rucksacks …

Heisenberg
  Take the tram to the end of the line …

Bohr
  And start walking!

Heisenberg
  Northwards to Elsinore.

Bohr
  If you walk you talk.

Heisenberg
  Then westwards to Tisvilde.

Bohr
  And back by way of Hillerød.

Heisenberg
  Walking, talking, for a hundred miles.

Bohr
  After which we talked more or less non-stop for the next three years.

Heisenberg
  We’d split a bottle of wine over dinner in your flat at the Institute.

Bohr
  Then I’d come up to your room …

Heisenberg
  That terrible little room in the servants’ quarters in the attic.

Bohr
  And we’d talk on into the small hours.

Heisenberg
  How, though?

Bohr
  How?