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In July 1943, at a holiday home in Michigan, American scientist Arthur Compton was enjoying his family by a lake with his wife and children. Suddenly, he received a call from his colleague, hoping to discuss an urgent matter with Compton face to face. On the other end of the phone was a middle-aged man who was preparing to take a train all the way from Los Alamos, New Mexico to Michigan. This man is the leader of the Manhattan Project, Julius Robert Oppenheimer (Julius Robert Oppenheimer).

Oppenheimer's colleague, Compton, is a famous physicist. Compton won the Nobel Prize in Physics for his study of the interaction between light and matter. At the same time, Compton is also one of the core scientists of the Manhattan Project. The Manhattan Project was a covert operation conducted by the United States at Los Alamos during World War II to build an atomic bomb ahead of the Nazis. The Manhattan Project was led by Oppenheimer. Robert Oppenheimer is a mysterious American theoretical physicist who has made important contributions in the fields of quantum mechanics, nuclear and molecular physics, astronomy and general relativity.

The advent of nuclear energy has made electricity more available. Image source Pexels

A big bet on screen when Oppenheimer arrived at his vacation house in Michigan, Compton drove him to the lake where they could have a secret conversation. In Compton's later account, Oppenheimer and him say that scientists at Los Alamos have found that in addition to releasing atomic energy through nuclear fission, very light atoms such as hydrogen can also release energy by aggregating to form heavier nuclei. This process starts only at extremely high temperatures-but this is exactly what nuclear fission can provide. If the Manhattan Project succeeds, will the nuclear bomb trigger an uncontrollable chain fusion reaction of hydrogen in sea water or nitrogen atoms in the atmosphere? If so, will the nuclear bomb turn the earth itself into an expanding fireball?

Compton later told Pearl Buck, a writer and Nobel laureate in literature, that in the face of the possibility of what Oppenheimer described as the "ultimate disaster", "it is better to accept the defeat of the war than to risk a devastating disaster for mankind."

Fearing that German scientists working for Hitler would give priority to developing a nuclear bomb, Compton and Oppenheimer decided to work on the first atomic bomb. At the same time, they also assess the possibility of uncontrollable fusion of light nuclei in the environment caused by atomic bombs.

It was too late: in 1965, Oppenheimer was asked whether the United States should negotiate a nuclear weapons non-proliferation treaty with the Soviet Union. In Prometheus, the original book on which Oppenheimer is based, writers Cabold and Martin J. Sherwin recorded the scene: "Oppenheimer puffed hard on his pipe and said,'it's 20 years late... it should have been done the day after the Trinity Nuclear Test (Trinity) in New Mexico.'" . Source: HauptmannSchlaf / Wiki sharing according to Pearl Buck's article "Nuclear bomb-the end of the World?" published in us Weekly in 1959. At that time, Compton decided that the project should continue only if it was calculated that the probability of the atomic bomb destroying the world was less than 3/1000000. It is said that scientists' theoretical calculations met this threshold, but these discussions did not settle until July 1945, when the first nuclear bomb was detonated at the Trinity nuclear test site in the New Mexico Desert. The life-and-death gamble was finally put on the big screen.

Reality is not as dramatic as in movies and TV dramas. Oppenheimer seems to have quickly shaken off his fear of the end of the world. In the end, Oppenheimer's concern is not that the nuclear bomb developed by his team in Los Alamos will accidentally trigger fusion-the first live combat in Hiroshima and Nagasaki three years later-but that the fusion process will also be used to create more terrifying weapons of destruction.

Writer Pearl Buck's article "Nuclear bomb-the end of the World?" published in US Weekly in 1959. "in fact, World War II only accelerated the emergence of nuclear bombs. Since the end of the 19th century, some heavy elements, especially uranium, have been known to fission and release energy. In his 1914 book The World Set Free, Herbert George Wells speculated that the enormous energy contained in the nucleus was being used to make what he called an "atomic bomb", a weapon that could destroy cities. But it was not until shortly before the outbreak of the second World War that scientists figured out how to achieve the atomic bomb. In 1938, German scientists Otto Hahn and Fritz Strassmann, working in Berlin, discovered that uranium nuclei could fission and split into two light nuclei, releasing huge amounts of energy. Hahn and Strasman were initially baffled by their findings, and their former colleague Lise Meitner, a Jewish exile from Nazi Germany in Sweden, explained the process as a fission process.

Scientists who study nuclear physics immediately realized that if the process were carried out in a sufficiently large ("critical") mass of fission isotope uranium-235, it could trigger a runaway continuous chain reaction and release all the energy in an instant. After learning this, the then US President Franklin D. Roosevelt was persuaded to carry out the Manhattan Project in Los Alamos. The project is hosted by Oppenheimer.

Compton's story of meeting Oppenheimer by the lake is actually a little strange. Because Compton initially thought their discussion was out of concern about the nuclear fusion process discovered by the Los Alamos team. What he seems to mean is that light nuclear fusion can be used to achieve nuclear bombs, because the scientific community discovered decades ago that light nuclei can be fused to release energy.

"I didn't believe it at first." in the 1920s, British astrophysicist Arthur Arthur Eddington proposed that hydrogen fusion might be the energy source of stars such as the sun. In 1932, Mark Oliphant, a researcher in the Ernest Rutherford (Ernest Rutherford) group in Cambridge, England, demonstrated the nuclear fusion process in a particle accelerator. In 1939, physicist Hans Bethe, Nobel laureate and leader of the Los Alamos theory group, explained the mechanism of the major fusion reactions taking place in the sun, and Russian-American physicist George Gamo and Hungarian immigrant Edward Teller perfected this view and promoted it in Gamo's 1940 book the birth and death of the Sun.

Another member of the Los Alamos team, Edward Taylor (Edward Teller), first proposed the possibility of a "superbomb" by thermonuclear fusion of hydrogen nuclei (more specifically, the heavy hydrogen isotope deuterium). The fusion process that triggers hydrogen requires huge amounts of heat, which can be provided by nuclear fission reactions-raising concerns about whether the bomb will ignite the atmosphere. Taylor proposed that the two nuclei of the isotope nitrogen-14 (nitrogen is the main component of air) may have nuclear fusion under huge energy and form a variety of other elements, releasing large amounts of heat.

But how likely is it that this process will happen? "I didn't believe it from the beginning." Physicist Hans Bette said in an interview in 1982. He admitted that if he had been the project manager instead of Oppenheimer, he would not have gone to Michigan to discuss the matter with Compton. Bette said he found some unreasonable assumptions in Taylor's calculations that led to the wrong conclusions.

Taylor worked with physicists Emile Emil Konopinski and Cloyd Marvin to further calculate the possibility of nuclear fission igniting the atmosphere. They concluded that even if the maximum temperature produced by the atomic bomb was fully estimated, there was no danger of igniting the atmosphere. They published their report in Los Alamos, codenamed "LA-602", which was not declassified until 1973.

Before Pearl Buck's 1959 article was published, the public knew nothing about the scientists' discussion about the nuclear bomb igniting the earth. Bette felt that Ms. Pearl S. S., who had no scientific background, completely misunderstood what Compton said. In 1975, radiation physicist H. C. Dudley retold the story in an alarmist article in the Bulletin of Atomic scientists. Bette later published another article refuting: "this statement is pure nonsense." . Frankly, you have to doubt the authenticity of Pearl Buck's interview, because much of the article basically repeats what Compton wrote about the Manhattan Project in his 1956 autobiography, Atomic Exploration.

Bette said that although Ms. Pearl Buck's article claimed that the danger threshold for Compton to ignite the atmosphere was 3/1000000, this was not the case. "Nuclear fission igniting the earth is not a matter of probability; it is impossible." As David David Hawkins, a philosopher of science and official historian of the Manhattan Project, recorded in a 1947 history of technology, calculations show that "no matter how high the temperature is, the energy loss of nuclear fusion will exceed the energy generated by fusion by reasonable projections." The process will soon lose power, so "science and common sense ensure that it is impossible for a nuclear bomb to ignite the atmosphere." This is true not only for the air, but also for hydrogen nuclei in the ocean, Bette added.

Doomsday weapons became the man's nightmare scientists' attention to the nuclear bomb igniting the atmosphere-though it was once again discovered that it was impossible-was actually focused on another thing, the more powerful nuclear bomb proposed by Taylor. Taylor strongly promoted the concept of a hydrogen bomb, although it seemed "a terrible thing" for Bette. However, because Bette thought German scientists would come to the same conclusion, he decided to develop a hydrogen bomb while developing an atomic bomb. The project continued until the end of the war and the beginning of the Cold War. In 1952, the first hydrogen bomb, codenamed "Mike", blew up Erugrab Island on the Pacific Ocean's Enervetak Atoll, creating a mushroom cloud three miles in diameter.

The mushroom cloud created when the hydrogen bomb code-named "Mike" exploded. Photo: Wikipedia in 1942, after German physicists led by Werner Karl Heisenberg raised the possibility of building a uranium bomb to the German Supreme Command, German Armament and War production Minister Albert Speer and Adolf Hitler also raised concerns about atomic bombs igniting the earth, but they knew almost nothing about science. Speer asked Heisenberg if he was convinced that the fission chain reaction would not continue indefinitely, but did not get a clear answer. Speer wrote in the Interior of the third Reich, published in 1970: "Hitler was clearly uneasy about the possibility that the earth under his rule might become a glowing star." . However, it is not for this reason that Germany did not concentrate its resources on developing an atomic bomb, but because of German scientists' uncertainty about whether it would be able to develop a nuclear bomb on time that would affect the course of the world war. As a result, Germany has invested a lot of energy and money in the research and development of the Vmuri 2 rocket.

The structure schematic diagram of VMur2 missile. Source: Wikipedia is familiar to anyone who has read Kurt Kurt Vonnegut's 1963 novel Cradle of Cats, the storyline that physicists inadvertently destroy the world. The protagonist of the novel is writing a book called "the end of the World" based on first-hand information about what Americans did on the day they dropped the first atomic bomb on Hiroshima. " He went to see a Manhattan Project scientist, the fictional Felix Hoenikker, who is now working on how to make a new type of ice called Ice-9 that freezes at room temperature. The book ends with a piece of ice-9 falling into the sea, causing the ocean to freeze. The world doesn't end in fire, it ends in ice.

Vonnegut's Holnick is based on Irving Langmuir, an American chemist and Nobel laureate, who came up with the idea of stable ice at room temperature during a visit to Wells at General Electric Research's Langmuir lab in the 1930s. Langmuir, Vonnegut said, "is indifferent to who will apply the scientific laws he has discovered for what purpose. Although the scientific laws he has discovered shine in the right use, he doesn't care who will do what with them."

The end of the world described in the Cradle of the Cat is caused not so much by immorality as by pure negligence. At the very least, the scientists of the Manhattan Project seem to have calculated the possibility of danger more carefully. If their nuclear bombs eventually destroy us all, it is not because they mistakenly ignited the atmosphere, but because we humans deliberately brought the destruction of the world to ourselves.

This is Oppenheimer's real fear. Although he initially supported the hydrogen bomb project (codenamed "Super"), by 1949, he had begun to oppose the promotion of the project. He believes that if the United States continues to press ahead with the project, it will only trigger an arms race with the Soviet Union. At the 1954 hearing of the United States Atomic Energy Commission, the hearing members cited Oppenheimer's negative attitude as adverse evidence against Oppenheimer, which was suspected of sympathizing with the left-wing movement. Oppenheimer's security concession was revoked. When asked when he began to boycott the hydrogen bomb development program out of moral conviction, Oppenheimer replied: "when I knew clearly that we would use any weapons we had."

Author: Philip Ball

Translation: * 0

Revision: depth

Original link: The Day Oppenheimer Feared He Might Blow Up the World

This article comes from the official account of Wechat: Institute of Physics, Chinese Academy of Sciences (ID:cas-iop), author: William Harris

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