核武器

Reflections on the 70th Anniversary of the Manhattan Project: Questions and Answers

02.19.15 | 12 min read | 文字卡梅隆·里德

我通过获得物理学学位并从事教学和天文学研究的传统学术生涯开始了自己的职业生涯，但我一直对曼哈顿项目的物理学及其在结束第二次世界大战中的作用感到好奇。建立了赠款，出版物和任期，金博宝更改账户我开始将这种兴趣放在我工作的合法部分，大约20年前，以深入探索它。

As anybody that comes to this topic in more than a casual way will attest, it can grow into an obsession. I have now published two books on the Project, well over two dozen articles and book reviews in technical, historical, and semi-popular journals, and have made a number of presentations at professional conferences. Over this time I must have looked at thousands of archived documents and held hundreds of real and electronic conversations with other scientists, historians, and writers whose interest in this pivotal event parallels my own. While my knowledge of the Project is certainly not and never will be complete, I have learned much about it over the last 20 years.

令我惊讶的是（和荣幸），我经常问我有关该项目的问题，由学生，家庭成员，晚餐聚会上的客人，美国物理社会会议上的同事，甚至是我最喜欢的咖啡店的偶然熟人。典型的查询是：

“我们为什么放弃炸弹？他们有必要结束战争吗？”

“Did President Truman and his advisors really understand the power of the bombs and the destruction they could cause?”

“核武器是否有助于阻止随后的大规模战争，我们是否还需要威慑？”

“What about the ethical aspects?”

“在研究曼哈顿计划,大多数surprised you? Do you think it or something similar could be done now?”

At first I was awkward in trying to answer these questions but with passing years, increased knowledge, and much reflection I now feel more comfortable addressing them. With accumulating experience in a scientific career, you often learn that the questions you and others initially thought to be important may not be the ones that the facts address and that there may be much more interesting issues behind the obvious ones. In this spirit, I offer in this essay some very personal reflections on the Project and the legacies of Hiroshima and Nagasaki, framed as responses to questions like those above. In some cases a “yes” or “no” along with an explanation will do, but for many issues the nuances involved obviate a simple response.

I begin with the issue of the “decision” to use the bomb and the state of President Truman’s knowledge. In the spring of 1945, Secretary of War Henry Stimson assembled a committee to consider and advise upon immediate and long-term aspects of atomic energy. This “Interim Committee” comprised eight civilians, including three scientists intimately familiar with the Manhattan Project: Vannevar Bush, James Conant, and Karl Compton. In a meeting on May 31 which was attended by Army Chief of Staff General George C. Marshall, Stimson opened with a statement as to how he viewed the significance of the Project¹:

秘书表示，马歇尔将军分享的观点是，不应仅仅考虑军事武器，而应将其视为人与宇宙的新关系。这一发现可能与哥白尼理论的发现和重力定律的发现相提并论，但对人类生活的影响要重要得多。尽管战争需求促进了迄今为止的领域进步，但重要的是要意识到该项目的含义远远超出了当前战争的需求。如果可能的话，必须控制它是对未来和平的保证，而不是对文明的威胁。

For his part, President Truman had been thoroughly briefed on the project by Stimson and General Leslie Groves, director of the Project, soon after he became President in late April. In late July, Truman recorded his reaction to the三位一体test in his diary²:

We have discovered the most terrible bomb in the history of the world. … Anyway we think we have found the way to cause a disintegration of the atom. An experiment in the New Mexico desert was startling – to put it mildly. Thirteen pounds of the explosive caused the complete disintegration of a steel tower 60 feet high, created a crater 6 feet deep and 1,200 feet in diameter, knocked over a steel tower 1/2 mile away and knocked men down 10,000 yards away. The explosion was visible for more than 200 miles and audible for 40 miles and more. … The target will be a purely military one and we will issue a warning statement asking the Japs to surrender and save lives. I’m sure they will not do that, but we will have given them the chance. It is certainly a good thing for the world that Hitler’s crowd or Stalin’s did not discover this atomic bomb. It seems to be the most terrible thing ever discovered, but it can be made the most useful…

I have no doubt that Stimson, Marshall and Truman were well aware of the revolutionary nature of the bomb and the possibility (indeed, likelihood) that a postwar nuclear arms race would ensue. Any notion that Truman was a disengaged observer carried along by the momentum of events is hard to believe in view of the above comments. These men were making decisions of grave responsibility and were fully briefed as to both the immediate situation of the war and possible long-term geopolitical consequences: the “mature consideration” that Franklin Roosevelt and Winston Churchill agreed in 1943 would have to be carried out before use of the bombs was authorized. Perhaps Truman did not so much make a positive decision to use the bombs so much as he opted not to halt operations that were already moving along when he became President, but I have no doubt that he realized that atomic bombs would be a profoundly new type of weapon. Further, let us not forget that it was Truman who personally intervened after Nagasaki to order a halt to further atomic bombings when the Japanese began to signal a willingness to consider surrender negotiations.

尽管我坚信杜鲁门以最大的责任感承担了他的职责，但我无法回答“是”或“否”的爆炸性：这个问题总是充满许多未说明的观点。如果不能说服日本人投降，那么杜鲁门，斯蒂姆森和马歇尔就会面临犯下数十万人的恐怖入侵的前景，然后在日本的祖岛上可能更恐怖。70年后，很容易忘记1945年夏天的战争背景。历史学家知道日本人正在寻求一条荣誉投降的途径，并可能在几周内放弃，但是地面上非常流血的事实是他们有notyet surrendered; thousands of Allied and Japanese servicemen were dying each week in the Pacific. Military historian Dennis Giangreco has studied Army and War Department manpower projections for the two-part invasion of Japan scheduled for late 1945 and the spring of 1946³。计划基于平均维持100,000人伤亡每月from November 1945 through the fall of 1946. The invasion of Kyushu was scheduled to begin on November 1, 1945. Had this occurred, the number of casualties might well have exceeded the number of deaths at Hiroshima and Nagasaki, let alone those which would have occurred in the meantime. From the perspective of preventing casualties, perhaps it was unfortunate that the bombs were not ready at the time of the battle for Iwo Jima, one of the bloodiest protracted battles from February 19 to March 26, 1945, during which more than 25,000 were killed on both sides.

即使他们相信苏联declaration of war on the night of August 8, 1945, against Japan was the most significant factor in the Japanese decision to surrender, most historians allow that the bombs had at least some effect on that decision. The Soviet invasion came between the two atomic bombings on August 6 (Hiroshima) and August 9 (Nagasaki). These two bombings would convince the Japanese that Hiroshima was not a one-shot deal: America could manufacture atomic bombs in quantity. The impact of the bombings was alluded to by Emperor Hirohito in his message to his people on August 15, 1945, in which he stated that “ … the enemy has begun to employ a new and most cruel bomb,” which was one of the motivations for his government’s decision to accept the terms of the Potsdam Declaration. But there are certainly political aspects that muddy this story, namely justifying the immense resources poured into the Project and sending a message to the Soviets that at least for a while America wasthe世界战后的上升力量。我对必要问题给出了合格的“是”。

必要的辩论通常会忽略我认为“核接种”的推论问题。有炸弹not在1945年被使用,世界领导人意识到their frightening power, what far more awful circumstances might have unfolded in a later war when there were more nuclear powers armed with more powerful weapons? I am absolutely convinced that the bombings have had a significant deterrent effect and that they may well have prevented the outbreak of further major wars since 1945. Indeed, we know that there were occasions such as the Cuban missile crisis when national leaders looked into the maw of a possible large-scale war and backed away.

The “inoculation” issue leads to the question of whether or not America continues to need a nuclear deterrent. To this I say: “Yes, but for not entirely rational reasons.” Even very conservative military planners estimate that a few hundred warheads would be enough for any conceivable nuclear-mission scenario and that the thousands still stockpiled are a waste of resources and budgets. But the deterrent issue seems to me to be more psychological than mission-driven. With potentially unstable or irrationally-led states pursuing weapons and possibly encouraging proliferation, what “established” nuclear power would consider unilaterally disarming itself? If America and Russia engage in further rounds of treaties and draw down their numbers of deployed and reserved weapons from thousands of warheads, a time may come when these numbers will get down to those held by powers such as Britain, France, China, India and Pakistan⁴。那么如何进行谈判？Even if rigorous inspection regimes are agreed to, it seems to me that it will take decades until we might get to a level of trust where we won’t feel compelled to rationalize: “They could be slipping a few weapons into their arsenal under the table; we had better keep some in reserve.” In the meantime, I encourage students and acquaintances to question their elected representatives regarding the Comprehensive Test Ban Treaty and a possible Fissile Materials Cutoff Treaty.

What about the ethics of the bombings? To my mind the answer is: “The war had rendered this issue irrelevant.” Even against the “standards” of present-day terrorist acts, the ferocity of World War II seems almost incomprehensible. Deliberate atrocities against civilians and prisoners by the Axis powers were beyond the ethical pale, but how does one classify the Allied fire-bombings of Coventry, Dresden, and Tokyo even if there were arguable military objectives? The vast majority of victims at Hiroshima and Nagasaki succumbed not to radiation poisoning but to blast and burn effects just like the victims of these other attacks. I do not see that the bombs crossed an ethical threshold that had not already been breached many times before.

我对曼哈顿项目的了解特别让我感到惊讶？好吧，实际上一切。我作为物理学家接触了该项目，这对我来说是一个启示，涉及的许多物理学都可以完全可以接受一个好的本科生。计算临界质量涉及分离球形坐标的微分方程并应用边界条件：高级演算。估计爆炸炸弹芯释放的能量是使用新生水平物理学的牛顿工作能量定理与某些压力/能量热力学结合使用的一个很好的例子。欣赏量子的同位素如何使用大二电磁级的洛伦兹力量定律是一个美丽的例子。由于自发的裂变引用了基本概率理论，估计炸弹可能过早引爆的机会过早引爆。这些是异国情调的情况，需要邪恶的工程才能实现，但是物理学确实是基本的。

每个人都知道曼哈顿项目是一项艰巨的任务，但我现在意识到truly vastit was. At first, one’s attention is drawn to the outstanding personalities and dramatic events and locales associated the Project: J. Robert Oppenheimer, Enrico Fermi, Groves, Los Alamos,三位一体, Tinian, Hiroshima and Nagasaki. Then the appreciation of the complexity of the production factories at Oak Ridge and Hanford, facilities designed by unappreciated and now largely-forgotten engineers of outstanding talent. Hundreds of contractors and university and government laboratories were involved, staffed by hundreds of thousands of dedicated employees. Also, bombs are not transported by magic to their targets; bombers had to be modified to carry them, and training of crews to fly the missions was initiated well before the final designs of the bombs and choice of targets were settled. The magnitude of the feed materials program to source and process uranium ores is rarely mentioned, but without this there would never have been any bombs (or any later Cold War).

While physics, chemistry, and engineering were front-and-center, I have also come to appreciate that the organization and administration of the Project was equally important. This is a hard thing for an academic scientist to admit! The Project was令人难以置信精心管理，这里有一个课程。是的，该项目拥有监督和咨询委员会的一部分，但它们是由科学家，工程师，政府官员和军事官员经营的，具有出色的能力以及对民族商品的无私奉献精神。这些人知道他们在做什么，并且知道如何通过所涉及的官僚渠道来完成事情。存在的威胁总是对将注意力集中在问题上总是有益，但是实际上有人必须做某物。当然，安全泄漏和一些效率低下，但是您在这么大而新颖的事业中还会期待什么？

Could a Manhattan-type project be done now? I do not doubt for a moment that American scientists, technicians, engineers, and workers still possess the education, brains, dedication, and creativity that characterized Manhattan. But I do not think that such success could be repeated. Rather, headlines and breathless breaking news reports would trumpet waste, inefficiency, disorganization, technically clueless managers, and publicity-seeking politicians. The result would likely be a flawed product which ran far over-budget and delivered late if at all, no matter how intense the motivation. Do the words “Yucca Mountain” require further elaboration?

格罗夫斯将军的正式历史，曼哈顿地区历史，可以从能源部网站下载，我鼓励读者看一下⁵。It is literally thousands of pages, and is simply overwhelming; I doubt that anybody has read it from end-to-end. Click on any page and you will find some gem of information. Beyond the MDH lie thousands of secondary sources: books, popular and technical articles, websites and videos. But I have not one iota of regret that I plunged in. The Project was vast: many aspects of it have yet to be mined, and there are lessons to be had for scientists, engineers, biographers, historians, administrators, sociologists, and policy experts alike.

我对该项目的研究使我更加意识到世界核状况。撇开威慑的信念，我惊讶地说，在过去的70年中，没有意外或故意的攻击性核爆炸。我们现在知道，在许多情况下，我们非常接近，而且我们确实非常幸运。虽然我认为故意核动力与核电交流的机会是遥不可及的，但恐怖分子赞助的核事件的前景确实引起了我的关注。

Nuclear energy is the quintessential double-edged sword, and those of us who have some understanding of the history, technicalities and current status of nuclear issues have a responsibility to share our knowledge with our fellow citizens in a thoughtful, responsible way. The stakes are no less existential now than they were seventy years ago.