Latest / Sleepless History: Sleep Documentaries / The Manhattan Project: Oppenheimer, Trinity & Hiroshima | Sleepy History with Rain Sounds

Transcript

The Manhattan Project: Oppenheimer, Trinity & Hiroshima | Sleepy History with Rain Sounds · Sleepless History: Sleep Documentaries

0:00
[SPEAKER_00]: Good evening, and welcome back to Sleepless History.
0:03
[SPEAKER_00]: I want to start with a letter.
0:05
[SPEAKER_00]: In the summer of 1939, a Hungarian physicist named Leo Zilard drove out to a cottage on the eastern end of Long Island, where Albert Einstein was spending the summer sailing.
0:20
[SPEAKER_00]: Zilard did not drive.
0:22
[SPEAKER_00]: So another Hungarian physicist, Eugene Vigner, took the wheel and they got lost looking for the house.
0:31
[SPEAKER_00]: What Silhard wanted was a signature.
0:34
[SPEAKER_00]: He had written a letter to the president of the United States, and he knew perfectly well that a letter from Leo Silhard would go into a draw.
0:45
[SPEAKER_00]: and a letter from Albert Einstein would not.
0:48
[SPEAKER_00]: The letter said that recent work in physics suggested that uranium might be made into an extremely powerful bomb that Germany had stopped the sale of uranium from the mines it had just seized in Czechoslovakia and that the United States might want to look into the matter.
1:05
[SPEAKER_00]: Einstein read it and signed it.
1:08
[SPEAKER_00]: He said later that it was the one great mistake of his life.
1:12
[SPEAKER_00]: That letter is where most tellings of this story begin, and it is a good place to begin, but I want to be careful with it because the letter did not do what people think it did.
1:24
[SPEAKER_00]: It reached the president in October of 1939.
1:27
[SPEAKER_00]: It produced a small committee and a grant of $6,000.
1:34
[SPEAKER_00]: For nearly two years after that, almost nothing happened.
1:38
[SPEAKER_00]: The thing that actually started the Manhattan Project came from Britain in 1941 and we will get to it.
1:46
[SPEAKER_00]: So here is what we are doing tonight.
1:49
[SPEAKER_00]: We are going to follow a line that runs from a laboratory bench in Berlin in December of 1938 to a city in Western Japan on a clear morning in August of 1945.
2:03
[SPEAKER_00]: Along the way, we will build three secret cities that did not appear on any map, employ roughly 130,000 people.
2:13
[SPEAKER_00]: almost none of whom knew what they were making, spent two billion dollars of public money with no congressional debate about what it was for, and solve several problems that the best physicists alive had considered unsolvable, and then we will arrive at the hardest part, and I am going to handle it the way I would want it handled.
2:33
[SPEAKER_00]: I am not going to dwell in the suffering at Hiroshima and I am not going to give you images at this hour that you did not ask for.
2:46
[SPEAKER_00]: But I am also not going to tidy it away because the people it happened to were real and the sum of this entire story is what happened to them.
2:57
[SPEAKER_00]: I will also tell you, honestly, that the question of whether the bombs should have been used is one that serious historians have argued about for 80 years and have not settled.
3:10
[SPEAKER_00]: There is a case on each side.
3:12
[SPEAKER_00]: both of them made by people who have read the documents.
3:16
[SPEAKER_00]: I am going to give you both, and I am not going to tell you which one to hold, because that is not my job, and because you are trying to go to sleep.
3:26
[SPEAKER_00]: One last thing before we start.
3:29
[SPEAKER_00]: Everything in this story happened faster than seems possible.
3:33
[SPEAKER_00]: The discovery that made the bomb conceivable was published in 1939.
3:38
[SPEAKER_00]: The first one was used in 1945.
3:43
[SPEAKER_00]: six and a half years from a scientific curiosity understood by a few dozen people to a weapon that reorganized the politics of the entire planet.
3:55
[SPEAKER_00]: Almost nobody involved thought it could be done in the time.
3:59
[SPEAKER_00]: Many of them were hoping it could not.
4:01
[SPEAKER_00]: Before we begin, one short thing.
4:05
[SPEAKER_00]: If this show has become part of how you get to sleep,
4:08
[SPEAKER_00]: The most useful thing you can do takes about 4 seconds.
4:13
[SPEAKER_00]: Follow or subscribe wherever you are listening right now, so that new episodes arrive on their own without you having to go looking.
4:22
[SPEAKER_00]: And if your app lets you leave a rating or a review, that is the single thing that puts a small, independent show in front of new listeners.
4:32
[SPEAKER_00]: It matters more than anything else available to me.
4:35
[SPEAKER_00]: If you would like to go further than that,
4:37
[SPEAKER_00]: There is a Patreon for sleepless history, and the link is in the episode description.
4:43
[SPEAKER_00]: We still have a few founding member slots available, which is $3 per month, for as long as you have the subscription.
4:50
[SPEAKER_00]: Members get episodes early, and they get them with no advertisements at all, and the price will never increase.
4:59
[SPEAKER_00]: It is also the reason this show can keep being made by one person.
5:04
[SPEAKER_00]: Either way, thank you for being here tonight.
5:09
[SPEAKER_00]: chapter 1, a discovery nobody wanted.
5:15
[SPEAKER_00]: In December of 1938, in a laboratory in Berlin, two chemists named Otto Hahn and Fritz Strassmann were bombarding uranium with neutrons and finding something that made no sense.
5:30
[SPEAKER_00]: They had been at this for years.
5:32
[SPEAKER_00]: The idea was that if you fired neutrons at the heaviest element known, you might build something heavier still, a new element beyond uranium, teams in Rome, in Paris and in Berlin had been racing each other at it.
5:49
[SPEAKER_00]: what Han and Strasman found in their samples was barium.
5:54
[SPEAKER_00]: Barium sits roughly in the middle of the periodic table.
5:58
[SPEAKER_00]: It is not a little heavier than uranium.
6:01
[SPEAKER_00]: It is about half of it.
6:03
[SPEAKER_00]: Han was a superb chemist, and he did not believe his own result.
6:09
[SPEAKER_00]: He wrote about it to the person he had worked with for 30 years, a physicist named Lee's mightner,
6:20
[SPEAKER_00]: Mikener was Austrian and Jewish.
6:23
[SPEAKER_00]: She had kept her position in Berlin after 1933, only because her Austrian citizenship protected her.
6:31
[SPEAKER_00]: And when Germany annexed Austria in March of 1938, that protection vanished overnight.
6:39
[SPEAKER_00]: colleagues smuggled her across the Dutch border in July with a diamond ring that Han had given her in case she needed to bribe somebody.
6:47
[SPEAKER_00]: She was in Sweden, in exile, with no laboratory of her own.
6:51
[SPEAKER_00]: She received Han's letter at Christmas, in the village of Kangel, where she was staying with friends.
6:58
[SPEAKER_00]: her nephew Otto Frisch, also a physicist, and also a refugee, was visiting, and the two of them worked it out, walking in the snow.
7:08
[SPEAKER_00]: The nucleus, they reasoned, was not a solid thing.
7:12
[SPEAKER_00]: It behaved more like a drop of liquid held together by surface tension, and a very large drop could be made to wobble, elongate, pinch in the middle, and split into.
7:25
[SPEAKER_00]: They did the
7:28
[SPEAKER_00]: The two halves together weighed slightly less than the original.
7:32
[SPEAKER_00]: The missing mass had become energy.
7:36
[SPEAKER_00]: And when they put it through the equation that Einstein had published 33 years earlier, the number that came out was about 200 million electron volts per atom.
7:50
[SPEAKER_00]: That is an almost incomprehensible amount of energy from a single atom.
7:55
[SPEAKER_00]: Frisch went back to Copenhagen, confirmed it experimentally within weeks, and asked a biologist what the word was for a cell dividing in two.
8:04
[SPEAKER_00]: The biologist said, Fission, the news crossed the Atlantic in January of 1939 with Niels Bohr.
8:13
[SPEAKER_00]: and it went through the world's physics departments, like a current.
8:18
[SPEAKER_00]: Within weeks, laboratories everywhere had reproduced it.
8:22
[SPEAKER_00]: And almost immediately, a few people saw the thing that nobody had asked for.
8:29
[SPEAKER_00]: If splitting the uranium nucleus released neutrons as well as energy, and if those neutrons went on to split other nuclei, each of which released more neutrons, then you would have a chain reaction.
8:42
[SPEAKER_00]: Each generation doubling over and over in a fraction of a second, not a power source, a bomb.
8:52
[SPEAKER_00]: Leo Silhard had thought of chain reactions years earlier in 1933, waiting at a traffic light on Southampton Row in London before anyone knew a vision at all.
9:04
[SPEAKER_00]: He had actually patented the concept and assigned the patent to the British Admiralty to keep it secret.
9:11
[SPEAKER_00]: So when Fission was announced, Sillaard did not need to be persuaded of anything.
9:16
[SPEAKER_00]: He needed to find out whether Uranium Fission released spare neutrons, and in March of 1939, working at Columbia University, he and Walter Zinn found that it did.
9:29
[SPEAKER_00]: Sillaard wrote afterward
9:31
[SPEAKER_00]: that he switched off the equipment and went home, and that there was very little doubt in his mind that the world was headed for grief.
9:39
[SPEAKER_00]: Now understand the fear that drove everything that follows.
9:44
[SPEAKER_00]: Fishen had been discovered in Germany by Germans in a German laboratory.
9:50
[SPEAKER_00]: Germany had the best physics tradition in the world, had the uranium of the checkmines, had heavy water production in occupied Norway, and had Werner Heisenberg, one of the greatest theorists alive.
10:05
[SPEAKER_00]: Every refugee physicist in Britain and America had been taught by or alongside the people now working for that
10:13
[SPEAKER_00]: They did not have to imagine a German bomb.
10:16
[SPEAKER_00]: They could name the men who would build it.
10:19
[SPEAKER_00]: That fear is the engine of this story.
10:23
[SPEAKER_00]: And it is important to say now at the start that it turned out to be wrong.
10:29
[SPEAKER_00]: The German program,
10:31
[SPEAKER_00]: never came close.
10:32
[SPEAKER_00]: It stayed small, it stayed divided between competing groups, it made a critical error measuring the properties of graphite that pushed it down a dead end, and it never got the resources.
10:45
[SPEAKER_00]: By 1942, the German leadership had been told a bomb could not be ready in time to matter, and the effort was scaled back to reactor research.
10:56
[SPEAKER_00]: But nobody in America or Britain knew that,
11:00
[SPEAKER_00]: until 1944, and by then the machine was running and could not be stopped.
11:06
[SPEAKER_00]: So back to the letter.
11:08
[SPEAKER_00]: Einstein signed it on the 2nd of August 1939.
11:13
[SPEAKER_00]: The Second World War began four weeks later.
11:16
[SPEAKER_00]: The letter reached President Roosevelt in October and Roosevelt did the reasonable thing which was to appoint a committee which did very little.
11:25
[SPEAKER_00]: Through 1940, American uranium research was a few university groups on small grounds and the general view among American physicists.
11:35
[SPEAKER_00]: was that a bomb was theoretically possible and practically out of reach, probably requiring tons of uranium.
11:43
[SPEAKER_00]: The thing that changed it happened in Birmingham, in England.
11:49
[SPEAKER_00]: Two refugee physicists at the University of Birmingham, Otto Frisch.
11:55
[SPEAKER_00]: the same man from the snow in Sweden and Rudolf Piles sat down in March of 1940 to calculate something that oddly nobody had carefully done.
12:07
[SPEAKER_00]: They asked how much pure uranium 235 you would need for a fast chain reaction.
12:15
[SPEAKER_00]: Uranium as it comes out of the ground is more than 99% Uranium 238, which does not sustain a fast chain reaction.
12:25
[SPEAKER_00]: The useful part, Uranium 235, is about 7 atoms in every thousand.
12:31
[SPEAKER_00]: Everyone had assumed that separating enough of it was impossible.
12:36
[SPEAKER_00]: Frisch and piles calculated that you would need something on the order of a few kilograms.
12:45
[SPEAKER_00]: a quantity you could hold in two hands, that changed everything.
12:51
[SPEAKER_00]: because a few kilograms, while brutally difficult, was not impossible.
12:56
[SPEAKER_00]: They wrote it up in a three-page memorandum that is one of the most consequential documents of the 20th century, and they added something else to it.
13:06
[SPEAKER_00]: They worked out that such a weapon would produce radioactive material that would make it dangerous long after the explosion, and they wrote plainly that it was probably not usable as a weapon
13:21
[SPEAKER_00]: without killing enormous numbers of them.
13:24
[SPEAKER_00]: The British took it seriously, a committee, given the deliberately meaningless name of the Maude Committee, spent 15 months studying it, and reported in July of 1941, that a uranium bomb was practical, could be ready in roughly two years, and should be pursued urgently.
13:45
[SPEAKER_00]: The Maude report went to Washington,
13:49
[SPEAKER_00]: It landed on Vanavar Bush's desk, and it was the thing that actually moved the American government.
13:57
[SPEAKER_00]: Roosevelt authorized a full effort in October of 1941, two months before Pearl Harbour.
14:04
[SPEAKER_00]: In December of 1942, in a converted squash court under the stands of the Football Stadium at the University of Chicago.
14:14
[SPEAKER_00]: Enrico Fermi's team assembled a pile of graphite blocks and uranium and withdrew the control rods one at a time until the neutron count stopped climbing and held steady.
14:28
[SPEAKER_00]: The first self-sustaining nuclear chain reaction running at about half a
14:34
[SPEAKER_00]: which is less than a nightlight.
14:36
[SPEAKER_00]: There was no celebration to speak of.
14:39
[SPEAKER_00]: Someone produced a bottle of kianty and they drank it out of paper cups.
14:44
[SPEAKER_00]: Eugene Wigner had bought the bottle and kept it in a closet for the occasion.
14:49
[SPEAKER_00]: The coded message that went to Washington said that the Italian navigator had landed in the new world and that the natives were friendly and with that the physics
15:02
[SPEAKER_00]: everything from this point on was engineering and the engineering was of a scale nobody had attempted in the history of the world.
15:12
[SPEAKER_00]: Chapter two, three cities that were not on the map.
15:18
[SPEAKER_00]: In September of 1942 the project was handed to the United States Army Corps of Engineers and because the first offices were in Manhattan the cover name on the paperwork
15:30
[SPEAKER_00]: was the Manhattan Engineer District.
15:33
[SPEAKER_00]: The name stuck to the whole enterprise, and the army put in charge of it a Colonel named Leslie Groves, who did not want the job.
15:42
[SPEAKER_00]: Groves had just finished building the Pentagon.
15:45
[SPEAKER_00]: He wanted a combat command overseas, and he was told that if he did this instead, he would win the war.
15:52
[SPEAKER_00]: He was promoted to Brigadier General on the spot.
15:55
[SPEAKER_00]: because the scientists he would be managing would not take orders from a colonel and he set to work the same week.
16:03
[SPEAKER_00]: Groves is not a sympathetic figure in most tellings.
16:07
[SPEAKER_00]: He was abrasive, suspicious, physically imposing, and almost entirely without charm.
16:14
[SPEAKER_00]: He ate chocolate constantly from a safe in his office.
16:18
[SPEAKER_00]: He had an absolute conviction that scientists talked too much to each other
16:25
[SPEAKER_00]: compartmentalization, under which a person was told what they needed for their own work and nothing beyond it.
16:34
[SPEAKER_00]: The physicists hated it and argued it slowed the science and they were probably right, but Groves was a formidable builder.
16:43
[SPEAKER_00]: And within weeks of taking the job, he had done three things that mattered more than anything the committees had managed in three years.
16:51
[SPEAKER_00]: He secured the highest procurement priority in the country.
16:55
[SPEAKER_00]: He bought the entire available supply of high-grade uranium ore, which was sitting in drums on Staten Island, having been shipped out of the Belgian Congo by a mining executive who had moved it for safekeeping, and he chose a director for the weapons laboratory.
17:12
[SPEAKER_00]: His choice was Julius Robert Oppenheimer, and on paper, it was indefensible.
17:18
[SPEAKER_00]: Oppenheimer was a theoretical physicist at Berkeley, brilliant and widely read who spoke eight languages and could quote Sanskrit poetry.
17:29
[SPEAKER_00]: He had never managed anything larger than a research group.
17:33
[SPEAKER_00]: He had no Nobel Prize at a time when the project was full of men who had won.
17:38
[SPEAKER_00]: And his security file was alarming.
17:41
[SPEAKER_00]: His wife had been a communist party member, his brother had been a member, his former fiancé was a member, and he had himself given money to Republican causes in the Spanish Civil War.
17:52
[SPEAKER_00]: through party channels.
17:54
[SPEAKER_00]: The security services objected, groves overruled them and signed the clearance himself, saying that Oppenheimer was absolutely essential to the project.
18:07
[SPEAKER_00]: It remains one of the better pieces of judgment in American administrative history, and it would be used against both of them afterward.
18:15
[SPEAKER_00]: Now, the engineering problem, because this is where the money went.
18:20
[SPEAKER_00]: To build a bomb, you need fissile material.
18:23
[SPEAKER_00]: And in 1942, there was essentially none in the world.
18:28
[SPEAKER_00]: There were two possible routes, and nobody knew which would work.
18:33
[SPEAKER_00]: So the United States did both at once at enormous expense.
18:38
[SPEAKER_00]: The first route was uranium-235, separated out of natural uranium.
18:45
[SPEAKER_00]: The difficulty here is that uranium 235 and uranium 238 are chemically identical.
18:53
[SPEAKER_00]: They are the same element.
18:55
[SPEAKER_00]: No chemical process can tell them apart.
18:58
[SPEAKER_00]: The only difference is that one is about one and a quarter percent heavier than the other.
19:04
[SPEAKER_00]: And every separation method has to work on that difference alone.
19:09
[SPEAKER_00]: Three atoms in a thousand at a time.
19:15
[SPEAKER_00]: an element that did not exist in nature in any useful quantity and had been discovered at Berkeley only in 1941.
19:25
[SPEAKER_00]: Plutonium 239 is made by putting uranium in a reactor and letting it absorb neutrons.
19:33
[SPEAKER_00]: It is a different element from uranium, which means it can be separated chemically, which is far easier.
19:40
[SPEAKER_00]: The catch is that you have to build the reactors.
19:44
[SPEAKER_00]: and then handle intensely radioactive material by remote control behind concrete walls.
19:51
[SPEAKER_00]: Groves built both, that meant three sites.
19:55
[SPEAKER_00]: Oak Ridge, Tennessee, in the Klinch River Valley, about 20 miles west of Knoxville.
20:02
[SPEAKER_00]: The Army took roughly 60,000 acres by eminent domain, gave around a thousand families a few weeks to leave farms, some had held for generations.
20:13
[SPEAKER_00]: and built a city that reached 75,000 people and appeared on no map of the state.
20:20
[SPEAKER_00]: At Oak Ridge, they pursued the uranium separation by two completely different methods simultaneously because nobody was confident in either.
20:34
[SPEAKER_00]: One was electromagnetic separation in enormous machines called
20:40
[SPEAKER_00]: which accelerated ironised uranium through a magnetic field, so that the lighter atoms curved on a slightly tighter arc, and landed a fraction of an inch away from the heavier ones.
20:53
[SPEAKER_00]: The magnets required thousands of tons of conductor and copper was rationed for the war.
21:00
[SPEAKER_00]: So the Treasury lent the project close to 15,000 tons of silver bullion out of the vaults at West Point.
21:08
[SPEAKER_00]: which was melted and drawn into bus bars and wound into coils.
21:13
[SPEAKER_00]: The treasury officials insisted on measuring it in Troy ounces.
21:19
[SPEAKER_00]: Almost all of it was returned after the war.
21:22
[SPEAKER_00]: The calutrons were operated in the main by young women recruited out of local high schools.
21:29
[SPEAKER_00]: who were trained to watch a dial and keep a needle in a particular position by adjusting a knob and who had told nothing whatever about what the machine did.
21:40
[SPEAKER_00]: They were later known as the Calutron Girls.
21:43
[SPEAKER_00]: The physicists were irritated to discover that the operators got better output than the scientists did.
21:52
[SPEAKER_00]: because the scientists kept stopping to investigate anomalies and the operators simply held the needle steady.
22:00
[SPEAKER_00]: The other method was Gaseous diffusion in a building called K25, which was at the time the largest building in the world under one roof, a mile long, with 44 acres of floor.
22:14
[SPEAKER_00]: Uranium was combined into a gas and pushed through thousands of successive barriers with holes measured in millions of an inch, through which the lighter molecules passed very slightly more often.
22:27
[SPEAKER_00]: Each stage enriched the material by a hair.
22:31
[SPEAKER_00]: There were thousands of stages.
22:33
[SPEAKER_00]: The third site was Hanford, in the high desert of eastern Washington state, on a bend of the Columbia River.
22:41
[SPEAKER_00]: Chosen because the reactors needed enormous quantities of cold water and because groves wanted them a long way from anybody.
22:50
[SPEAKER_00]: Another town was removed.
22:53
[SPEAKER_00]: 50,000 workers built three reactors and the chemical plants to process what came out of them.
23:01
[SPEAKER_00]: building so long and so heavily shielded that they were called the Queen Mary's.
23:07
[SPEAKER_00]: There was one serious scare there.
23:10
[SPEAKER_00]: The first Hanford reactor started up in September of 1944, ran beautifully for several hours and then died.
23:19
[SPEAKER_00]: It came back on its own and then died again.
23:23
[SPEAKER_00]: A young physicist
23:28
[SPEAKER_00]: Zenon 135 was absorbing neutrons and poisoning the reaction.
23:34
[SPEAKER_00]: By pure good fortune, the DuPont engineers had ignored the physicists and built the reactor with far more fuel channels than the design called for, as an engineer's margin.
23:46
[SPEAKER_00]: loading the extra channels overcame the poisoning.
23:50
[SPEAKER_00]: The industrial habit of overbuilding saved several months, and the third place was Los Alamos, New Mexico, on a Mesa 7000 feet up, reached by a bad dirt road where there had been a boy's ranch school.
24:07
[SPEAKER_00]: Oppenheimer had camped in that country as a young man and loved it and he proposed it himself.
24:16
[SPEAKER_00]: where the material from the other two sites would be turned into a weapon.
24:20
[SPEAKER_00]: And at its peak, it held several thousand people, including a remarkable number of the finest physicists alive.
24:28
[SPEAKER_00]: Taken together, the project at its height, employed around 130,000 people, and consumed somewhere near $2 billion.
24:39
[SPEAKER_00]: Which in the money of the time was roughly a percent
24:45
[SPEAKER_00]: almost none of those people knew what they were building, the overwhelming majority were told only what their own task required and found out what they had been part of from the radio in August of 1945.
25:03
[SPEAKER_00]: It is one of the strangest facts about the whole enterprise.
25:08
[SPEAKER_00]: The largest secret industrial undertaking in history scattered across three states and the secret essentially held with the public.
25:20
[SPEAKER_00]: it did not hold against the Soviet Union.
25:23
[SPEAKER_00]: There were at least three significant sources inside the project passing material to Soviet intelligence, including a German refugee physicist at Los Alamos, named Klaus Fuchs, who was in the theoretical division
25:40
[SPEAKER_00]: had access to the bomb design itself, and who was not caught until 1950.
25:48
[SPEAKER_00]: But that is a different episode.
25:53
[SPEAKER_00]: Chapter 3 The Mesa and the Thing in the Desert
25:59
[SPEAKER_00]: Los Alamos was an odd place to live.
26:03
[SPEAKER_00]: It was a town of several thousand people.
26:07
[SPEAKER_00]: A great many of them under 30.
26:09
[SPEAKER_00]: A great many of them extraordinarily clever.
26:13
[SPEAKER_00]: Sealed behind a fence on a mason in New Mexico with bad plumbing, mud, water shortages, and almost no privacy.
26:24
[SPEAKER_00]: every letter was censored.
26:26
[SPEAKER_00]: Nobody had a street address.
26:28
[SPEAKER_00]: Every resident had the same post office box in Santa Fe.
26:33
[SPEAKER_00]: Drivers licenses were issued with numbers instead of names.
26:38
[SPEAKER_00]: Children born there had the box number listed as their place of birth and the social texture of it was strange.
26:47
[SPEAKER_00]: There were weekly dances.
26:49
[SPEAKER_00]: There were hiking parties on the weekends.
26:52
[SPEAKER_00]: Richard Feynman then in his 20s, amused himself by cracking the safes containing the bomb secrets and leaving notes inside them to demonstrate that the security was theatre.
27:04
[SPEAKER_00]: Neil's ball turned up under the Covenant Nicholas Baker and was universally called Uncle Nick.
27:12
[SPEAKER_00]: Enrico Fermi, Hans Bethe, Edward Teller, Stanislaw Ulam, Emilio Segre, John von Neumann, and most of the rest of the greatest generation in the history of physics were living in prefabricated housing.
27:28
[SPEAKER_00]: and arguing in a converted school building.
27:32
[SPEAKER_00]: The design they had started with was simple in concept and is called the gun method.
27:38
[SPEAKER_00]: If a lump of missile material is below a certain size, neutrons escape through the surface faster than they multiply and nothing happens.
27:49
[SPEAKER_00]: Above that size, called critical mass, the reaction runs away.
27:58
[SPEAKER_00]: take two sub-critical pieces of uranium, put them at either end of an artillery barrel, and fire one into the other.
28:06
[SPEAKER_00]: They combine, exceed critical mass, and the chain reaction takes over.
28:12
[SPEAKER_00]: For uranium, this works.
28:15
[SPEAKER_00]: It is crude, and it wastes most of the material, but it works.
28:20
[SPEAKER_00]: And the physicists were confident enough in it that the uranium weapon
28:28
[SPEAKER_00]: The plan had been to use the same method for plutonium and in the summer of 1944, that plan collapsed.
28:35
[SPEAKER_00]: Emilio Segre's group was measuring plutonium from the first Hanford material, and they found that it contained a meaningful fraction of a second isotope, plutonium 240, which is produced when plutonium in a reactor absorbs another neutron.
28:54
[SPEAKER_00]: Plutonium 240 undergo spontaneous fission.
29:05
[SPEAKER_00]: which meant that, in a gun assembly, the strain neutrons would start the chain reaction while the two pieces were still coming together.
29:14
[SPEAKER_00]: The reaction would blow the assembly apart before most of the material had reacted.
29:20
[SPEAKER_00]: The result would be a fizzle, an explosion large enough to destroy the aircraft carrying it and small enough to be a humiliation.
29:30
[SPEAKER_00]: This was a genuine crisis.
29:32
[SPEAKER_00]: The country had built an entire industrial complex at Hanford to make plutonium, and the plutonium was not usable in the only bomb design anyone trusted.
29:42
[SPEAKER_00]: The alternative had been proposed early by a physicist named Seth Nedermire and had been treated as a curiosity.
29:51
[SPEAKER_00]: It was called implosion.
29:53
[SPEAKER_00]: Instead of firing two pieces together, you take a single subcritical sphere of plutonium and crush it.
30:01
[SPEAKER_00]: Compressed to high-adensity, the same amount of material becomes supercritical, and you
30:13
[SPEAKER_00]: outrunning the stray neutrons.
30:15
[SPEAKER_00]: The difficulty is that it requires the sphere to be crushed perfectly evenly from every direction at once.
30:22
[SPEAKER_00]: An ordinary explosive charge around a sphere does not compress it.
30:26
[SPEAKER_00]: It squirted the way a hand closing unevenly on wet clay sends it between the fingers.
30:33
[SPEAKER_00]: The shockwave has to arrive everywhere simultaneously within a fraction of a microsecond and converge inward as a perfect contracting sphere.
30:44
[SPEAKER_00]: Nobody had ever done anything like this.
30:48
[SPEAKER_00]: Through late 1944,
30:50
[SPEAKER_00]: Los Alamos reorganized itself almost entirely around the problem.
30:56
[SPEAKER_00]: The solution came from a Ukrainian-born chemist named George Kisterkowski, an explosive expert.
31:04
[SPEAKER_00]: and the idea is beautiful.
31:07
[SPEAKER_00]: You build a shell out of carefully machined blocks of two different explosives with different detonation speeds.
31:15
[SPEAKER_00]: Shaped so that the fast and slow materials bend the shock front, the way a glass lens bends light.
31:22
[SPEAKER_00]: They were called explosive lenses.
31:25
[SPEAKER_00]: 32 of them in a soccer ball arrangement around the core, each fired by a detonator that had to go off within a fraction of a millionth of a second of all the others, which required an entirely new kind of electrical firing circuit.
31:40
[SPEAKER_00]: John Von Neumann did much of the mathematics of the converging shock, and the calculations involved were so heavy that Los Alamos filled a room with
31:54
[SPEAKER_00]: Many of them, the wives of scientists on the Mesa, who ran the numbers by hand and by machine for months.
32:03
[SPEAKER_00]: By the spring of 1945, they thought they had it, and nobody was willing to better weapon on a design that complicated without trying it.
32:13
[SPEAKER_00]: So they decided to test one, in a stretch of desert on the Alamagordo bombing range.
32:19
[SPEAKER_00]: that the Spanish had called the Jornada del Muerto, the journey of the dead man.
32:24
[SPEAKER_00]: Oppenheimer named the test Trinity, and when Groves asked him years later why, he said it had come from a poem by John Dunn, which may or may not be the whole truth.
32:37
[SPEAKER_00]: They built a steel tower, a hundred feet high, and put the device on top of it.
32:43
[SPEAKER_00]: The mood in the days beforehand was not confident.
32:47
[SPEAKER_00]: Predictions of the yield were collected in a betting pool, and they ranged from zero to 45,000 tons of equivalent conventional explosive.
32:58
[SPEAKER_00]: Edward Teller, guest high.
33:00
[SPEAKER_00]: Oppenheimer guessed 300 tons, which is to say he mostly expected disappointment.
33:07
[SPEAKER_00]: Enrico Fermi offered a side bet on whether the atmosphere would catch fire, and whether it would merely destroy new Mexico or the entire world, which the soldiers present did not find funny.
33:21
[SPEAKER_00]: and which firmly apparently intended as a joke about the limits of theory.
33:26
[SPEAKER_00]: The question had in fact been investigated and ruled out on paper, the weather was bad.
33:34
[SPEAKER_00]: A thunderstorm ran over the site in the small hours of the 16th of July, 1945, and the test was delayed until it cleared.
33:45
[SPEAKER_00]: At half past five in the morning, local time, in the last darkness before dawn, they fired it.
33:52
[SPEAKER_00]: The yield was about 21,000 tons of equivalent conventional explosive, several times most of the predictions.
34:01
[SPEAKER_00]: The light was seen in three states.
34:04
[SPEAKER_00]: A blind woman in Albuquerque over a hundred miles away is said to have asked what the flash was.
34:12
[SPEAKER_00]: The steel tower was vaporized and the desert sand under it was fused into a layer of pale green glass that was later named Trinitite.
34:22
[SPEAKER_00]: The official cover story issued immediately was that an ammunition magazine at the airbase had exploded and local newspapers printed it.
34:32
[SPEAKER_00]: The reactions of the men who watched are the part that stays with people.
34:36
[SPEAKER_00]: Kistiakowski, who had bet his months pay against Oppenheimer that it would work, said, he knew the end of the world would look like that.
34:45
[SPEAKER_00]: Kenneth Bainbridge, the test director, turned to Oppenheimer and said that now they were all sons of bitches.
34:54
[SPEAKER_00]: Oppenheimer himself, decades later and on camera, said that the line that had come to him
35:00
[SPEAKER_00]: was from the Bhagavad Gita about becoming death, the destroyer of worlds.
35:06
[SPEAKER_00]: His brother Frank, who was standing nearby at the time, remembered him saying only that it worked, and there is a part of Trinity that went unmentioned for 60 years.
35:19
[SPEAKER_00]: The fallout from the test drifted across ranching country a new Mexico.
35:23
[SPEAKER_00]: where families lived off their own livestock, their own gardens, and rainwater collected in systems from their own roofs.
35:32
[SPEAKER_00]: Nobody was warned, nobody was evacuated, and nobody was monitored.
35:37
[SPEAKER_00]: The communities downwind of Trinity have spent decades seeking acknowledgment, and the question of what that fallout did is still a live one.
35:48
[SPEAKER_00]: 21 days after the test, a weapon of a different
35:55
[SPEAKER_00]: chapter 4, the 6th of August.
36:00
[SPEAKER_00]: By the spring of 1945, the reason the project had been started no longer existed, Germany surrendered on the 8th of May, a special intelligence unit that had followed the advancing armies into Europe, specifically to find the German bomb program, had already concluded that there had never been one worth the name.
36:23
[SPEAKER_00]: A number of the scientists stopped at that point and asked the obvious question, Joseph Rockblatt, a Polish physicist at Los Alamos, resigned and went home, the only senior scientist to leave on grounds of conscience.
36:40
[SPEAKER_00]: He later won the Nobel Peace Prize, nobody else left and the project accelerated.
36:47
[SPEAKER_00]: In June of 1945, a committee of scientists at the Chicago Laboratory chaired by James Frank produced a report arguing that a demonstration should be staged before neutral observers on an uninhabited area.
37:06
[SPEAKER_00]: with a warning to Japan and that a surprise attack on a city would make international control of the weapon impossible afterward and would start an arms race.
37:16
[SPEAKER_00]: The United States could not win permanently.
37:19
[SPEAKER_00]: The arguments against a demonstration were practical and were taken seriously.
37:25
[SPEAKER_00]: There were only two weapons with a third some weeks away and using one for a
37:34
[SPEAKER_00]: a demonstration that fizzled would be worse than none.
37:38
[SPEAKER_00]: A warned target could have its air defense is concentrated, or allied prisoners moved into it, and there was real doubt.
37:46
[SPEAKER_00]: that a flash over an empty island would move a government that had already absorbed the fire bombing of its cities without surrendering.
37:56
[SPEAKER_00]: Leo Zilard, the man who had started the whole thing with a letter, circulated a petition signed by 70 scientists, asking the president not to use the weapon on cities without warning and without terms.
38:12
[SPEAKER_00]: It was rooted through groves and never reached President Truman before the decision, and this is a point worth making plainly.
38:22
[SPEAKER_00]: There was never a single meeting at which the question of whether to use the bomb was put and decided.
38:29
[SPEAKER_00]: The documentary record does not contain one.
38:32
[SPEAKER_00]: The use of the weapon had been the working assumption since 1942 through two presidencies and it was woven into the planning, Truman, who had become president in April, and had been told about the project only after Roosevelt's death, inherited a machine that was already pointed
38:53
[SPEAKER_00]: The decision he actually faced was whether to stop it and he did not.
38:59
[SPEAKER_00]: The target committee met in the spring and chose its criteria.
39:04
[SPEAKER_00]: Cities of military or industrial significance largely undamaged by conventional bombing so that the effect could be assessed.
39:13
[SPEAKER_00]: and of a size that the blast would not be wasted.
39:17
[SPEAKER_00]: Their first choice was Kyoto.
39:20
[SPEAKER_00]: Kyoto was removed by Henry Stimpson, the Secretary of War personally, overgroves objections.
39:26
[SPEAKER_00]: and he went to the president twice to make sure it stayed off.
39:31
[SPEAKER_00]: Stimson had visited Kyoto, knew what it was, and argued that destroying the cultural capital of Japan would poison relations for a century.
39:41
[SPEAKER_00]: Groves kept trying to put it back.
39:44
[SPEAKER_00]: Stimson kept taking it off.
39:46
[SPEAKER_00]: The final list was Hiroshima, Kokura, Niyagata, and Nagasaki.
39:52
[SPEAKER_00]: Hiroshima was first for specific reasons.
39:55
[SPEAKER_00]: It was the headquarters of the second-general army, with a garrison in the city, a port and industry, and it had been almost untouched by the fire raids that had burned 60 odd Japanese cities over the preceding five months.
40:12
[SPEAKER_00]: The flat ground around it would let the blast spread evenly.
40:16
[SPEAKER_00]: The weapons went to Tinian in the Mariana Islands, where especially trained units
40:23
[SPEAKER_00]: the 509th composite group under Colonel Paul Tibbids had been practicing for months with modified B-29 bombers dropping single large conventional bombs and turning away in a sharp diving turn.
40:41
[SPEAKER_00]: The crews had not been told what they were training for.
40:45
[SPEAKER_00]: The uranium corps came out by sea, aboard the cruiser Indianapolis, which delivered it on the 26th of July and was sunk by a Japanese submarine four days later with heavy loss of life.
40:59
[SPEAKER_00]: in one of the worst maritime disasters in American naval history.
41:04
[SPEAKER_00]: And that is its own episode as well.
41:06
[SPEAKER_00]: On the 26th of July, the Allies issued the Pot-Stam Declaration, demanding unconditional surrender and warning of prompt and utter destruction.
41:19
[SPEAKER_00]: It did not mention the weapon.
41:21
[SPEAKER_00]: The Japanese government's response used a word muckusatsu that can mean no comment or can mean treat with silent contempt and it was translated abroad in the harshest sense.
41:34
[SPEAKER_00]: Historians still argue over how much that mattered.
41:37
[SPEAKER_00]: At a quarter to three in the morning on the 6th of August, 1945, a B-29 that Tibbets had named the Anola Gay after his mother took off from Tinian with a uranium gun type weapon aboard.
41:54
[SPEAKER_00]: The weapon was armed in flight, by a naval officer named Deak Parsons, who had decided to do the final assembly in the air, rather than risk a crash on takeoff with a live weapon.
42:06
[SPEAKER_00]: They flew for six hours, a weather aircraft ahead of them.
42:11
[SPEAKER_00]: reported clear skies over the primary target.
42:15
[SPEAKER_00]: The air-radalurte in Hiroshima had sounded earlier for that weather plane and had been lifted.
42:22
[SPEAKER_00]: And when a small number of aircraft appeared afterward, many people did not take shelter.
42:28
[SPEAKER_00]: At a quarter past eight in the morning,
42:31
[SPEAKER_00]: local time.
42:32
[SPEAKER_00]: The weapon was released from about 31,000 feet, and it detonated 43 seconds later, roughly 1900 feet above the city.
42:43
[SPEAKER_00]: I am going to tell you what happened plainly, and then I am going to stop.
42:48
[SPEAKER_00]: The yield was around 15,000 tons of equivalent conventional explosive.
42:54
[SPEAKER_00]: Everything within about a mile of the point beneath the detonation was destroyed by a blast wave and by a fire that followed and merged into a single conflagration across the flat center of the city.
43:09
[SPEAKER_00]: Somewhere between 70 and 80,000 people died that day.
43:14
[SPEAKER_00]: By the end of 1945, with injuries and radiation
43:23
[SPEAKER_00]: something close to 90% of the city's doctors and nurses were killed or injured in the first moments, because the medical district was near the center, which meant the survivors were cared for by almost nobody.
43:38
[SPEAKER_00]: That is the shape of it, and I am not going to take you any further into it tonight.
43:43
[SPEAKER_00]: If you want the human account, the thing to read is John Hersey's reporting,
43:48
[SPEAKER_00]: which we will come to in the last chapter, and which is the reason the world eventually understood what had happened.
43:54
[SPEAKER_00]: The crew of the Anola Gay saw the cloud for a long time on the way home.
43:59
[SPEAKER_00]: Tibbits said the taste of lead filled his mouth.
44:03
[SPEAKER_00]: The copilot, Robert Lewis,
44:06
[SPEAKER_00]: wrote a line in his log asking what they had done.
44:09
[SPEAKER_00]: In Washington, 16 hours later, a statement went out in Truman's name announcing that an atomic bomb had been dropped on Hiroshima.
44:19
[SPEAKER_00]: that it harnessed the basic power of the universe, and that if Japan did not accept the terms, it could expect a reign of ruin from the air, the like of which had never been seen on this earth.
44:33
[SPEAKER_00]: It was the first time that most of the 130,000 people who had built the thing, learned what they had been working on.
44:42
[SPEAKER_00]: Chapter five, after.
44:47
[SPEAKER_00]: three days later, on the night of August, a second weapon was used.
44:52
[SPEAKER_00]: This one was the implosion design, the plutonium device, the same kind that had been tested at Trinity.
44:59
[SPEAKER_00]: The primary target was Kokura, and the aircraft spent roughly 50 minutes over it, unable to see the aiming point through haze and smoke, under orders to drop visually.
45:10
[SPEAKER_00]: Running low on fuel, with a transfer pump already failed, the crew turned for the secondary target.
45:18
[SPEAKER_00]: Nagasaki was also covered, and they were preparing to turn away when a gap opened in the clouds.
45:25
[SPEAKER_00]: The weapon was released over a valley north of the city centre, somewhat off the aiming point, and the ridges around that valley contain the blast.
45:35
[SPEAKER_00]: It was a more powerful weapon than the one used Hiroshima, and it killed fewer people because of the terrain, with estimates of around 40,000 on the day, and perhaps 70,000 by the end of the year, the people of Kokura have a phrase for this.
45:53
[SPEAKER_00]: They call it Kukura's luck, on the same day between the two events, the Soviet Union declared war on Japan and invaded Manchuria with over a million troops, destroying the quantum army in a matter of days.
46:09
[SPEAKER_00]: Japan had been attempting to use Moscow as a mediator for better terms.
46:14
[SPEAKER_00]: That option vanished overnight.
46:17
[SPEAKER_00]: On the 15th of August, the Emperor's recorded statement was broadcast.
46:22
[SPEAKER_00]: Most of his subjects had never heard his voice, and he spoke in a formal, classical Japanese that many listeners struggle to follow.
46:30
[SPEAKER_00]: The line that is always quoted says that the war situation had developed not necessarily to Japan's advantage, and now the argument which I promised you I would give both sides of.
46:44
[SPEAKER_00]: The traditional case runs like this.
46:47
[SPEAKER_00]: Japan had not surrendered after five months of fire raids that killed more people in Tokyo in a single March night than either atomic bomb killed on its day.
47:00
[SPEAKER_00]: The military faction in the Japanese cabinet was committed to a final defensive battle on the homilons, intended to inflict casualties severe enough to win better terms.
47:10
[SPEAKER_00]: American planners estimated the invasion scheduled for November.
47:16
[SPEAKER_00]: In hundreds of thousands of allied casualties.
47:19
[SPEAKER_00]: and a far larger number of Japanese ones, military and civilian.
47:24
[SPEAKER_00]: Okinawa, where a third of the civilian population died, was taken as the model.
47:30
[SPEAKER_00]: On this reading, the bombs, horrifying as they were, ended the war sooner than any alternative, and at a lower total cost in lives, including Japanese lives.
47:43
[SPEAKER_00]: The revisionist case runs like this.
47:48
[SPEAKER_00]: its navy gone, its cities burning, its oil exhausted, and American intelligence intercepts showed its government seeking terms through Moscow.
47:58
[SPEAKER_00]: The sticking point was the status of the emperor, and the United States could have signalled that he would be retained, which it did in the end anyway.
48:07
[SPEAKER_00]: The Soviet Declaration of War on the 9th of August may have been the decisive shock to the Japanese leadership rather than the bombs.
48:17
[SPEAKER_00]: And some scholars who have worked in the Japanese archives argue exactly that, and the use of the weapons served a second purpose aimed at Moscow rather than Tokyo, demonstrating American power at the opening of the post-war settlement.
48:34
[SPEAKER_00]: Both of these are argued by serious historians with the documents in front of them.
48:40
[SPEAKER_00]: The casualty estimates for an invasion in particular are genuinely contested because the contemporary figures varied enormously and the very large numbers cited afterward were not all in the planning papers.
48:55
[SPEAKER_00]: I am not going to resolve it for you, what I would say is that anyone who tells you the question is obvious in either direction has not read much about it.
49:08
[SPEAKER_00]: Now the telling for about a year Americans did not know what had happened on the ground.
49:16
[SPEAKER_00]: The coverage was of the weapon,
49:22
[SPEAKER_00]: occupational authorities restricted reporting from the cities.
49:27
[SPEAKER_00]: The word that circulated most was atomic and it was mostly a word about power.
49:34
[SPEAKER_00]: Then in August of 1946 the New Yorker gave its entire issue to a single article by John Hersey.
49:45
[SPEAKER_00]: It carried no other features.
49:48
[SPEAKER_00]: Hersey had gone to Hiroshima and found six survivors, including a clerk, a Taylor's widow with three children, a German priest and two doctors, and he wrote what happened to those six people from the morning of the 6th of August onward, in flat, plain, unemotional prose, with no editorial comment whatsoever.
50:13
[SPEAKER_00]: It sold out in hours.
50:16
[SPEAKER_00]: It was read aloud on the radio over four nights.
50:20
[SPEAKER_00]: It was reprinted everywhere, and it changed what the word meant, because for the first time the American public was reading about a pharmacist's assistant and a widow and a man's leg, rather than about kilotons.
50:35
[SPEAKER_00]: The survivors have a name in Japanese.
50:37
[SPEAKER_00]: Hibakucia, which means the people affected by the explosion.
50:42
[SPEAKER_00]: For decades, many of them concealed it because there was social stigma attached in marriage prospects and in employment, from fears about illness and inheritance that were not well-founded.
50:55
[SPEAKER_00]: The long-term medical study of that population, run jointly by Japan and the United States over 70 years, is the single most important source of data on radiation and human health that exists.
51:10
[SPEAKER_00]: and almost everything we know about doslimits comes from it.
51:14
[SPEAKER_00]: It is a bleak origin for a body of knowledge.
51:18
[SPEAKER_00]: As for the men who built it, Oppenheimer became the most famous scientist in America and spent the rest of his life uneasy about it.
51:27
[SPEAKER_00]: He told Truman at a meeting in October of 1945 that he felt he had blood on his hands and Truman who found the remark intolerable
51:38
[SPEAKER_00]: Afterwards referred to him as a crybaby and said he did not want him in the office again.
51:44
[SPEAKER_00]: Oppenheimer opposed the development of the hydrogen bomb, made enemies, and in 1954 had his security clearance revoked in a hearing that used the communist associations of the 1930s that Groves had waved aside.
52:00
[SPEAKER_00]: in 1942.
52:02
[SPEAKER_00]: It ended his government career.
52:05
[SPEAKER_00]: The decision was formally vacated in 2022, 55 years after his death.
52:12
[SPEAKER_00]: Sillaard left physics for biology and spent his remaining years on arms control.
52:18
[SPEAKER_00]: Rockblatt spent 50 years campaigning against the weapon he had walked away from.
52:23
[SPEAKER_00]: Groves retired and wrote a memoir in which he regretted very little.
52:28
[SPEAKER_00]: Fineman described sitting in a bar in Manhattan after the war, looking at people building a bridge and thinking that there was no point because it was all going to be destroyed.
52:40
[SPEAKER_00]: And the last thing to say is the strangest and the most hopeful.
52:45
[SPEAKER_00]: No nuclear weapon has been used in war since the 9th of August 1945, not in Korea, where it was discussed, not in Cuba.
52:56
[SPEAKER_00]: not in any of the dozens of confrontations since, including several in which the people involved believed it was close.
53:05
[SPEAKER_00]: 81 years, a figure that would have astonished almost everyone who stood in that desert in July of 1945, most of whom expected the weapons to be used again within a decade.
53:18
[SPEAKER_00]: Whether that is deterrence, or wisdom, or luck, is an argument I will leave in the room with the other one.
53:26
[SPEAKER_00]: So that is the story.
53:28
[SPEAKER_00]: Six and a half years, three secret cities, 130,000 people and two mornings in August.
53:36
[SPEAKER_00]: If you are still awake, here is the thing I keep returning to.
53:41
[SPEAKER_00]: At Oak Ridge there were young women who spent two years of their lives watching a needle on a dial and keeping it steady with a knob, eight hours a day, in a building they were not allowed to describe, for a purpose nobody would tell them.
53:56
[SPEAKER_00]: They were good at it, they were better at it than the physicists were.
54:01
[SPEAKER_00]: And they found out what the needle had been doing at the same moment as everybody else, standing in a kitchen in Tennessee, listening to the radio in August of 1945.
54:12
[SPEAKER_00]: I think about that often because it is the ordinary condition of most people in most of history, almost everyone who built this was doing a small task carefully, inside something far too large to see from where they stood.
54:28
[SPEAKER_00]: The handful of people who could see the whole of it, the ones on the Mesa who understood exactly what they were making.
54:35
[SPEAKER_00]: were by most accounts the least at peace with it afterwards.
54:39
[SPEAKER_00]: There is no tidy lesson in that, and I am not going to invent one at this hour.
54:45
[SPEAKER_00]: It is simply true that the great machinery of the 20th century was built almost entirely by people who were given one piece of it and asked to do that piece well.
54:59
[SPEAKER_00]: Thank you for spending this one with me.
55:01
[SPEAKER_00]: Sleep well.
55:02
[SPEAKER_00]: There will be another one of these along soon.